Instrumentación & Señales 2014 - Jorge Márquez Flores UNAM 1
Imaging (ES: imagenología o imaginología (RAE), FR:
Imagerie) is the formation (physics), recording (technology),
representation or reproduction of an object's outward form;
especially a visual representation (i.e., the formation of an image).
It is extended to 3D and higher-dimensionality information, when
using the term "3D images", or "nD images", instead of volumes or
hyper-volumes, which refer rather to domain information
(coordinates). This list is still incomplete and highly biased to
medical imaging techniques.
Just a few imaging methodologies and technologies:
Basic imaging modalities (2D & 3D): Optical/Laser, Electromagnetism, X-
Ray/CT, MRI, Ultrasound, Radionuclides, Thermography.
Acoustic microscopy is microscopy that employs very high or ultra high
frequency ultrasound. Acoustic microscopes operate nondestructively and
penetrate most solid materials to make visible images of internal features,
including defects such as cracks, delaminations and voids.
Angiography or arteriography. A medical imaging technique used to visualize
the inside, or lumen, of blood vessels and organs of the body, with
particular interest in the arteries, veins and the heart chambers.
Angle-resolved low-coherence interferometry (a/LCI) is an emerging
biomedical imaging technology which uses the properties of scattered light
to measure the average size of cell structures, including cell nuclei. The
technology shows promise as a clinical tool for in situ detection of
dysplatic, or precancerous tissue.
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Annular dark-field imaging is a method of mapping samples in a scanning
transmission electron microscope (STEM). These images are formed by
collecting scattered electrons with an annular dark-field detector.
Aperture synthesis or synthesis imaging is a type of Interferometry that mixes
signals from a collection of telescopes to produce images having the same
angular resolution as an instrument the size of the entire collection. At each
separation and orientation, the lobe-pattern of the interferometer produces
an output which is one component of the Fourier transform of the spatial
distribution of the brightness of the observed object. The image (or "map")
of the source is produced from these measurements. Astronomical
interferometers are commonly used for high-resolution optical, infrared,
submillimetre and radio astronomy observations.
Arthrogram. A series of images, often X-rays, of a joint after injection of a
contrast medium.
Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very
high-resolution type of scanning probe microscopy, with demonstrated
resolution on the order of fractions of a nanometer, more than 1000 times
better than the optical diffraction limit.
Ballistic photons are the light photons that travel through a scattering (turbid)
medium in a straight line. Also known as ballistic light. If laser pulses are
sent through a turbid medium such as fog or body tissue, most of the
photons are either randomly scattered or absorbed. However, across short
distances, a few photons pass through the scattering medium in straight
lines. These coherent photons are referred to as ballistic photons. Photons
that are slightly scattered, retaining some degree of coherence, are referred
to as snake photons.
Biological imaging may refer to any imaging technique used in biology.
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Bioluminescence imaging (BLI) is a technology developed over the past decade
that allows for the noninvasive study of ongoing biological processes in
small laboratory animals. Recently, bioluminescence tomography (BLT)
has become possible and several systems have become commercially
available.
Bone densitometry or DEXA (Dual-Energy X-Ray Absorptiometry) - with short
scanning times and low X-ray doses, this sensitive equipment can help
identify risk of osteoporosis earlier than ever before.
Bright-field microscopy is the simplest of all the optical microscopy illumination
techniques. Sample illumination is transmitted (i.e., illuminated from below
and observed from above) white light and contrast in the sample is caused
by absorbance of some of the transmitted light in dense areas of the sample.
Bright-field microscopy is the simplest of a range of techniques used for
illumination of samples in light microscopes and its simplicity makes it a
popular technique. The typical appearance of a bright-field microscopy
image is a dark sample on a bright background, hence the name.
Cardiac Ventriculography. A medical imaging test used to determine a patient's
cardiac function in the right, or more typically, left ventricle. Cardiac
ventriculography involves injecting contrast media into the heart's
ventricle(s) to measure the volume of blood pumped. Cardiac
ventriculography can be performed with a radionuclide in radionuclide
ventriculography or with an iodine-based contrast in cardiac chamber
catheterization.
Chemical force microscopy (CFM) is a variation of atomic force microscopy
(AFM) which has become a versatile tool for characterization of materials
surfaces. With AFM, structural morphology is probed using simple tapping
or contact modes that utilize van der Waals interactions between tip and
sample to maintain a constant probe deflection amplitude (constant force
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mode) or maintain height while measuring tip deflection (constant height
mode).
Chemical imaging, is the analytical capability to create a visual image of
components distribution from simultaneous measurement of spectra and
spatial, time information (pictures and video).
Cinematography art or science of motion picture photography. It is the
technique of film photography, including both the shooting and
development of the film.
Computerized Tomography Imaging (CT). or Computed Axial Tomography
(CAT: A CT scan, also known as a CAT scan), is a helical tomography
(latest generation), which traditionally produces a 2D image of the
structures in a thin section of the body. It uses X-rays. It has a greater
ionizing radiation dose burden than projection radiography; repeated scans
must be limited to avoid health effects. CT is based on the same principles
as X-Ray projections but in this case, the patient is enclosed in a
surrounding ring of detectors assigned with 500-1000 scintillation detectors
(fourth-generation X-Ray CT scanner geometry).
Cone beam computed tomography (or CBCT, also referred to as C-arm CT,
cone beam volume CT, or flat panel CT) is a medical imaging technique
consisting of X-ray computed tomography where the X-rays are divergent,
forming a cone.
Confocal laser scanning microscopy (CLSM or LSCM) is a technique for
obtaining high-resolution optical images with depth selectivity. The key
feature of confocal microscopy is its ability to acquire in-focus images from
selected depths, a process known as optical sectioning. Images are acquired
point-by-point and reconstructed with a computer, allowing three-
dimensional reconstructions of topologically complex objects.
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Confocal microscopy is an optical imaging technique used to increase optical
resolution and contrast of a micrograph by adding a spatial pinhole placed
at the confocal plane of the lens to eliminate out-of-focus light It enables
the reconstruction of three-dimensional structures from the obtained
images.
Contrast-enhanced ultrasound (CEUS) is the application of ultrasound contrast
medium to traditional medical sonography. Ultrasound contrast agents rely
on the different ways in which sound waves are reflected from interfaces
between substances. This may be the surface of a small air bubble or a more
complex structure. Commercially available contrast media are gas-filled
microbubbles that are administered intravenously to the systemic
circulation. Microbubbles have a high degree of echogenicity, which is the
ability of an object to reflect the ultrasound waves. The echogenicity
difference between the gas in the microbubbles and the soft tissue
surroundings of the body is immense. Thus, ultrasonic imaging using
microbubble contrast agents enhances the ultrasound backscatter, or
reflection of the ultrasound waves, to produce a unique sonogram with
increased contrast due to the high echogenicity difference. Contrast-
enhanced ultrasound can be used to image blood perfusion in organs,
measure blood flow rate in the heart and other organs, and has other
applications as well.
Corneal topography. Also known as photokeratoscopy or videokeratography,
is a non-invasive medical imaging technique for mapping the surface
curvature of the cornea, the outer structure of the eye. Since the cornea is
normally responsible for some 70% of the eye's refractive power its
topography is of critical importance in determining the quality of vision and
corneal health.
Cryo-electron microscopy (cryo-EM), or electron cryomicroscopy, is a form of
transmission electron microscopy (EM) where the sample is studied at
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cryogenic temperatures (generally liquid nitrogen temperatures). Cryo-EM
is developing popularity in structural biology.
Cryo-electron tomography (cryo-ET or electron cryotomography) is a type of
electron cryomicroscopy where tomography is used to obtain a 3D
reconstruction of a sample from tilted 2D images at cryogenic temperatures.
A cryoelectron tomography can be used to obtain structural details of
complex cellular organizations at subnanometer resolutions.
Dark field microscopy (dark ground microscopy) describes microscopy
methods, in both light and electron microscopy, which exclude the
unscattered beam from the image. As a result, the field around the specimen
(i.e. where there is no specimen to scatter the beam) is generally dark.
Differential interference contrast (DIC) microscopy, also known as Nomarski
Interference Contrast (NIC) or Nomarski microscopy, is an optical
microscopy illumination technique used to enhance the contrast in
unstained, transparent samples. DIC works on the principle of
interferometry to gain information about the optical path length of the
sample, to see otherwise invisible features. A relatively complex lighting
scheme produces an image with the object appearing black to white on a
grey background. This image is similar to that obtained by phase contrast
microscopy but without the bright diffraction halo.
Diffraction topography (short: "topography") is an X-ray imaging technique
based on Bragg diffraction. Diffraction topographic images ("topographs")
record the intensity profile of a beam of X-rays (or, sometimes, neutrons)
diffracted by a crystal. A topograph thus represents a two-dimensional
spatial intensity mapping of reflected X-rays, i.e. the spatial fine structure of
a Bragg spot. This intensity mapping reflects the distribution of scattering
power inside the crystal; topographs therefore reveal the irregularities in a
non-ideal crystal lattice. X-ray diffraction topography is one variant of X-
ray imaging, making use of diffraction contrast rather than absorption
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contrast which is usually used in radiography and computed tomography
(CT).
Diffuse optical imaging (DOI) is a method of imaging using Near Infrared
Spectroscopic (NIRS) or Fluorescence based methods. When used to create
3D volumetric models of the imaged material DOI is referred to as diffuse
optical tomography, whereas 2D imaging methods are classified as diffuse
optical topography.
Diffuse optical tomography. Diffuse Optical Tomography (DOT) and Imaging
(DOI) are non-invasive techniques that utilize light in the near infrared
spectral region to measure the optical properties of physiological tissue. The
techniques rely on the object under study being at least partially light-
transmitting or translucent, so it works best on soft tissues such as breast
and brain tissue.
Diffuse optical topography is an alternative tool in functional near infrared
spectroscopy (fNIRS) since it avoids solving the forward and inverse
computational problems, which are encountered in diffuse optical
tomography. Topography is particularly useful when a sparse array of
optodes is used and depth specificity is not the primary interest.
Diffusion MRI (or dMRI, also Diffusion-weighted imaging) is a magnetic
resonance imaging (MRI) method which came into existence in the mid-
1980s. It allows the mapping of the diffusion process of molecules, mainly
water, in biological tissues, in vivo and non-invasively. Molecular diffusion
in tissues is not free, but reflects interactions with many obstacles, such as
macromolecules, fibers, membranes, etc. Water molecule diffusion patterns
can therefore reveal microscopic details about tissue architecture, either
normal or in a diseased state. Diffusion functional MRI (DfMRI) is a new
field, as it was suggested that with dMRI one could also get images of
neuronal activation in the brain.
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Digital holographic microscopy: DHM™ (DHM is a trademark belongings to
the Swiss company Lyncée Tec SA) is digital holography applied to
microscopy. Digital holographic microscopy distinguishes itself from other
microscopy methods by not recording the projected image of the object.
Instead, the light wave front information originating from the object is
digitally recorded as a hologram, from which a computer calculates the
object image by using a numerical reconstruction algorithm. The image
forming lens in traditional microscopy is thus replaced by a computer
algorithm.
Digital imaging, creating digital images, generally by scanning or through
digital photography.
Disk image, a file which contains the exact content of a data storage medium.
Document imaging, replicating documents commonly used in business.
Doppler echocardiography is a procedure that uses ultrasound technology to
examine the heart or blood vessels. An echocardiogram uses high frequency
sound waves to create an image of the heart while the use of Doppler
technology allows determination of the speed and direction of blood flow
by utilizing the Doppler effect.
Dual-energy X-ray absorptiometry (DXA, previously DEXA) is a means of
measuring bone mineral density (BMD). Two X-ray beams with different
energy levels are aimed at the patient's bones. When soft tissue absorption is
subtracted out, the BMD can be determined from the absorption of each beam
by bone. Dual-energy X-ray absorptiometry is the most widely used and
most thoroughly studied bone density measurement technology.
Dynamic Angiothermography. This technique utilizes thermal imaging but with
important differences with the tele-thermography and contact
thermography, that impact detection performance.
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Echocardiography. When ultrasound is used to image the heart it is referred to
as an echocardiogram. Echocardiography allows detailed structures of the
heart, including chamber size, heart function, the valves of the heart, as well
as the pericardium (the sac around the heart) to be seen.
Elastography. A new imaging modality that maps the elastic properties of soft
tissue. This modality can use ultrasound, magnetic resonance imaging and
tactile imaging.
Electrical Impedance Tomography (EIT) refers to a non-invasive medical
imaging technique in which an image of the conductivity or permittivity of
part of the body is inferred from surface electrode measurements.
Electron microscopy. An electron microscope is a microscope that uses
accelerated electrons as a source of illumination. Because the wavelength of
an electron can be up to 100,000 times shorter than that of visible light
photons, the electron microscope has a higher resolving power than a light
microscope and can reveal the structure of smaller objects. A transmission
electron microscope can achieve better than 50 pm resolution and
magnifications of up to about 10,000,000x whereas most light microscopes
are limited by diffraction to about 200 nm resolution and useful
magnifications below 2000x.
Endomicroscopy is a technique for obtaining histology-like images from inside
the human body in real-time, a process known as ‘optical biopsy’. It
generally refers to fluorescence confocal microscopy, although multi-
photon microscopy and optical coherence tomography have also been
adapted for endoscopic use.
Endoscopic ultrasonography or ultrasound (EUS) or echo-endoscopy is a
medical procedure in which endoscopy (insertion of a probe into a hollow
organ) is combined with ultrasound to obtain images of the internal organs
in the chest and abdomen. It can be used to visualize the walls of these
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organs, or to look at adjacent structures. Combined with Doppler imaging,
nearby blood vessels can also be evaluated.
Endoscopy means looking inside and typically refers to looking inside the body
for medical reasons using an endoscope, an instrument used to examine the
interior of a hollow organ or cavity of the body. Endoscope can also refer
to using a borescope in technical situations where direct line of-sight
observation is not feasible.
Epifluorescence_microscopy. A fluorescence microscope is an optical
microscope that uses fluorescence and phosphorescence instead of, or in
addition to, reflection and absorption to study properties of organic or
inorganic substances. The "fluorescence microscope" refers to any
microscope that uses fluorescence to generate an image, whether it is a
more simple set up like an epifluorescence microscope, or a more
complicated design such as a confocal microscope, which uses optical
sectioning to get better resolution of the fluorescent image.
Fluorescence microscopy. A fluorescence microscope is an optical microscope
that uses fluorescence and phosphorescence instead of, or in addition to,
reflection and absorption to study properties of organic or inorganic
substances. The "fluorescence microscope" refers to any microscope that
uses fluorescence to generate an image, whether it is a more simple set up
like an epifluorescence microscope, or a more complicated design such as a
confocal microscope, which uses optical sectioning to get better resolution
of the fluorescent image.
Fluoroscopy . This method of scanning reduces the patient’s radiation dose and
allows areas of the body to be examined in all directions. This is currently
used in conjunction with MRI for MR Arthrography.
Full spectral imaging is a form of Imaging spectroscopy and is the successor to
Hyperspectral imaging. Full Spectral Imaging was developed to improve
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the capabilities of Earth remote sensing (see also remote sensing).
Hyperspectral imaging acquires data as many contiguous spectral bands.
Full Spectral Imaging (FSI) acquires data as spectral curves. A significant
advantage of FSI over Hyperspectral is a significant reduction in data rate
and volume. FSI extracts and saves only the information that is in the raw
data. The information is contained in the shape of the spectral curves. The
rate at which data is produced by an FSI system is proportional to the
amount of information in the scene/image.
Functional magnetic resonance imaging or functional MRI (fMRI). is a
functional neuroimaging procedure using MRI technology that measures
brain activity by detecting associated changes in blood flow. This technique
relies on the fact that cerebral blood flow and neuronal activation are
coupled. When an area of the brain is in use, blood flow to that region also
increases.
Functional near-infrared spectroscopy. FNIR Is a relatively new non-invasive
imaging technique. NIRS (near infrared spectroscopy) is used for the
purpose of functional neuroimaging and has been widely accepted as a
brain imaging technique.
Gamma camera, also called a scintillation camera or Anger camera, is a device
used to image gamma radiation emitting radioisotopes, a technique known
as scintigraphy. The applications of scintigraphy include early drug
development and nuclear medical imaging to view and analyse images of
the human body or the distribution of medically injected, inhaled, or
ingested radionuclides emitting gamma rays.
Geophysical imaging (several techniques). Seismic-wave imaging is used for
deep soil and rock-bed composition, subterranean rivers, petroleum
reservoirs and ore mining.
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High-resolution computed tomography (HRCT) is computed tomography (CT)
with high resolution. It is used in the diagnosis of various health problems.
For example, HRCT of the lung is a medical diagnostic test used for
diagnosis and assessment of interstitial lung disease. It involves the use of
special computed tomography scanning techniques to assess the lung
parenchyma.
Hoffman modulation contrast (HMC) is a technique for enhancing the contrast
in unstained transparent biological specimens, invented by Dr Robert
Hoffman in 1975. This is achieved by using components in the light path
which convert phase gradients into variations in light intensity. Specimens
thus illuminated have a 3D appearance which renders them more easily
visible. In some specimens, the 3d appearance may be misleading, as a
feature which appears to cast a shadow may not necessarily have distinct
physical geometry.
Holographic interference microscopy (HIM) is holographic interferometry
applied for microscopy for visualization of phase micro-objects. Phase
micro-objects are invisible because they do not change intensity of light,
they insert only invisible phase shifts. The holographic interference
microscopy distinguishes itself from other microscopy methods by using a
hologram and the interference for converting invisible phase shifts into
intensity changes. Digital holographic interference microscopy (DHIM) is
a combination of the holographic interference microscopy with digital
methods of image processing for 3D imaging of phase micro-objects. The
holographic phase-contrast or interference-contrast images (interferograms)
are recorded by a digital camera from which a computer reconstructs 3D
images by using numerical algorithms.
Holography, recording and reproduction of a "light field", using arrays of
coherent light sources, projecting (on to or from) a recording media the
patterns of wave interferences; this allows to include all electromagnetic
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properties of light: magnitude and direction, wavelength spectra,
polarization, phase, etc. Digital holography allows synthesizing such "true"
3D images.
Hyperspectral imaging, like other spectral imaging, collects and processes
information from across the electromagnetic spectrum. The goal of
hyperspectral imaging is to obtain the spectrum for each pixel in the image
of a scene, with the purpose of finding objects, identifying materials, or
detecting processes.
Imaging cycler microscopy (ICM). This microscope is a fully automated
(epi)fluorescence microscope which overcomes the spectral resolution limit
resulting in parameter- and dimension-unlimited fluorescence imaging. The
principle and robotic device was described by Walter Schubert in 1997 and
eversince has been further developed with his co-workers within the human
toponome project. The ICM runs robotically controlled repetitive
incubation-imaging-bleaching cycles with dye-conjugated probe libraries
recognizing target structures in situ (biomolecules in fixed cells or tissue
sections). This results in the transmission of a randomly large number of
distinct biological informations by re-using the same fluorescence channel
after bleaching for the transmission of another biological information using
the same dye which is conjugated to another specific probe, a.s.o. Thereby
noise-reduced quasi-multi channel fluorescence images with reproducible
physical, geometrical, and biophyscial stabilities are generated. The
resulting power of combinatorial molecular discrimination (PCMD) per
data point is given by 65,536k, where 65,536 is the number of grey value
levels (output of a 16-bit CCD camera) and k is the number of co-mapped
biomolecules and/or subdomains per biomolecule(s). High PCMD has been
shown for k = 100, and in principle can be expanded for much higher
numbers of k. In contrast to traditional multi-channel-few parameter
fluorescence microscopy high PCMDs in an ICM lead to high functional
and spatial resolution
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Imaging spectroscopy (also hyperspectral or spectral imaging or chemical
imaging) is similar to color photography, but each pixel acquires many
bands of light intensity data from the spectrum, instead of just the three
bands of the RGB color model. More precisely, it is the simultaneous
acquisition of spatially coregistered images in many spectrally contiguous
bands.
Imaging technology is the application of materials and methods to create,
preserve, or duplicate images.
Infrared microscopy. The term infrared microscope covers two main types of
diffraction-limited microscopy. The first provides optical visualization plus
IR spectroscopic data collection. The second (more recent and more
advanced) technique employs focal plane array detection for infrared
chemical imaging, where the image contrast is determined by the response
of individual sample regions to particular IR wavelengths selected by the
user. IR versions of sub-diffraction microscopy (see above) also exist.
These include IR NSOM and photothermal microspectroscopy. Infrared
(IR) thermal microscopy is a tool for microelectronic temperature
measurement and failure analysis. It is a non-contact measurement
technique which utilises naturally emitted infrared radiation from a sample.
Commercial IR instruments are now available, offering spatial resolutions
down to around 2.5 µm and a range of options including real time
temperature mapping and transient detection.
Interference reflection microscopy or IRM is an optical microscopy technique
that utilizes polarized light to form an image of an object on a glass surface.
The intensity of the signal is a measure of proximity of the object to the
glass surface. This technique can be used to study events at the cell
membrane without the use of a (fluorescent) label in contrast to TIRF
microscopy.
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Interferometric microscopy or Imaging interferometric microscopy is the
concept of microscopy which is related to holography, synthetic-aperture
imaging, and off-axis-dark-field illumination techniques. Interferometric
microscopy allows enhancement of resolution of optical microscopy due to
interferometric (holographic) registration of several partial images
(amplitude and phase) and the numerical combining.
Interferometric synthetic aperture radar, abbreviated InSAR or IfSAR, is a
radar technique used in geodesy and remote sensing. This geodetic method
uses two or more synthetic aperture radar (SAR) images to generate maps
of surface deformation or digital elevation, using differences in the phase of
the waves returning to the satellite or aircraft. The technique can potentially
measure centimetre-scale changes in deformation over spans of days to
years. It has applications for geophysical monitoring of natural hazards, for
example earthquakes, volcanoes and landslides, and in structural
engineering, in particular monitoring of subsidence and structural stability.
Interferometry is a family of techniques in which waves, usually
electromagnetic, are superimposed in order to extract information about the
waves. Interferometry is an important investigative technique in the fields
of astronomy, fiber optics, engineering metrology, optical metrology,
oceanography, seismology, spectroscopy (and its applications to chemistry),
quantum mechanics, nuclear and particle physics, plasma physics, remote
sensing, biomolecular interactions, surface profiling, microfluidics,
mechanical stress/strain measurement, and velocimetry.
Laser microscopy is a rapidly growing field that uses laser illumination sources
in various forms of microscopy. For instance, laser microscopy focused on
biological applications uses ultrashort pulse lasers, in a number of
techniques labeled as nonlinear microscopy, saturation microscopy, and
multiphoton fluorescence microscopy
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Light sheet fluorescence microscopy (LSFM) is a fluorescence microscopy
technique with an intermediate optical resolution, but good sectioning
capabilities. In contrast to epifluorescence microscopy only a thin slice
(usually a few hundred nanometers to a few micrometers) of the sample is
illuminated perpendicularly to the direction of observation. For illumination
a laser lightsheet is used, i.e. a laserbeam which is focused only in one
direction (e.g. using a cylindrical lens). A second method uses a circular
beam scanned in one direction to create the lightsheet. As only the actually
observed section is illuminated, this method reduces the photodamage and
stress induced on a living sample. Also the good sectioning capability
reduces the background signal and thus creates images with higher contrast,
comparable to confocal microscopy.
Live-Cell Imaging Techniques. Live cell imaging is the study of living cells
using time-lapse microscopy. It is used by scientists to obtain a better
understanding of biological function through the study of cellular dynamics.
Live cell imaging was pioneered in first decade of the 20th century. One of
the first time-lapse microcinematographic films of cells ever made was
made by Julius Ries, showing the fertilization and development of the sea
urchin egg Since then, several microscopy methods have been developed
which allow researchers to study living cells in greater detail with less
effort. A newer type of imaging utilizing quantum dots have been used as
they are shown to be more stable.
Magnetic induction tomography. An imaging technique used to image
electromagnetic properties of an object by using the eddy current effect. It is
also called electromagnetic induction tomography, electromagnetic
tomography (EMT), eddy current tomography, and eddy current testing.
Magnetic resonance imaging (MRI) nuclear magnetic resonance imaging
(NMRI), or magnetic resonance tomography (MRT). A medical imaging
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technique used in radiology to investigate the anatomy and physiology of
the body in both health and disease. MRI scanners use strong magnetic
fields and radiowaves to form images of the body. The technique is widely
used in hospitals for medical diagnosis, staging of disease and for follow-up
without exposure to ionizing radiation. See also Functional MRI (fMRI).
Mammography is the process of using low-energy X-rays (usually around 30
Kvp) to examine the human breast and is used as a diagnostic and a
screening tool. Digital mammography is a specialized form of
mammography that uses digital receptors and computers instead of x-ray
film to help examine breast tissue for breast cancer. The electrical signals
can be read on computer screens, permitting more manipulation of images
to theoretically allow radiologists to more clearly view the results. Digital
mammography may be "spot view", for breast biopsy, or "full field"
(FFDM) for screening. Digital mammography is also utilized in stereotactic
biopsy. Breast biopsy may also be performed using a different modality,
such as ultrasound or magnetic resonance imaging (MRI)..
Medical imaging, creating images of the human body or parts of it, to diagnose
or examine disease..
Microdensitometry. A microdensitometer is an optical instrument used to
measure optical densities in the microscopic domain. A well-known
microdensitometer, used in the photographic industry, is a granularity
instrument or granularity machine. The granularity measurement involves
the use of an optical aperture, 10-50 micrometers in diameter, and in the
recording of thousands of optical density readings. The standard deviation
of this series of measurements is known as the granularity of the measured
transmission surface, optical film, or photographic film, in particular.
Micrography. A micrograph, or photomicrograph, is a photograph or digital
image taken through a microscope or similar device to show a magnified
image of an item. This is opposed to a macrographic image, which is at a
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scale that is visible to the naked eye. Micrography is also the art of using
microscopes to make photographs. 'Micrograph' is an image obtained by
means of a microscope and contains extensive details that form the features
of a microstructure. "Etching" is done to improve contrast between phases
by selective attack of some phases using reagents. Optical microscope and
electron microscope are extensively used in micrography or metallography
and are indispensable. A wealth of information can be obtained from a
simple micrograph like behavior of the material under different conditions,
the phases found in the system, failure analysis, grain size estimation,
elemental analysis and so on.
Microscopy is the technical field of using microscopes to view samples and
objects that cannot be seen with the unaided eye (objects that are not within
the resolution range of the normal eye). There are three well-known
branches of microscopy: optical, electron, and scanning probe microscopy.
For a summary of optical-microscopy techniques, see the Optical
Microscopy tutorial from Olympus. See also Specialized Microscopy
Techniques.
Molecular imaging. These techniques originated from the field of
radiopharmacology due to the need to better understand fundamental
molecular pathways inside organisms in a noninvasive manner. It enables
the visualisation of the cellular function and the follow-up of the molecular
process in living organisms without perturbing them.
Multiphoton fluorescence microscopy (MFM) uses a specialized optical
microscope. The MFM uses pulsed long-wavelength light to excite
fluorophores within the specimen being observed. The fluorophore absorbs
the energy from two long-wavelength photons which must arrive
simultaneously in order to excite an electron into a higher energy state,
from which it can decay, emitting a fluorescence signal. It differs from
traditional fluorescence microscopy in which the excitation wavelength is
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shorter than the emission wavelength, as the summed energies of two long-
wavelength exciting photons will produce an emission wavelength shorter
than the excitation wavelength.
Multispectral imaging. A multispectral image is one that captures image data at
specific frequencies across the electromagnetic spectrum. The wavelengths
may be separated by filters or by the use of instruments that are sensitive to
particular wavelengths, including light from frequencies beyond the visible
light range, such as infrared. Spectral imaging can allow extraction of
additional information the human eye fails to capture with its receptors for
red, green and blue. It was originally developed for space-based imaging.
Myelography is a type of radiographic examination that uses a contrast medium
to detect pathology of the spinal cord, including the location of a spinal
cord injury, cysts, and tumors. The procedure often involves injection of
contrast medium into the cervical or lumbar spine, followed by several X-
ray projections. A myelogram may help to find the cause of pain not found
by an MRI or CT. Myelography has been largely replaced by the use of CT
and MRI scans.
Near-field scanning optical microscopy (NSOM/SNOM) is a microscopy
technique for nanostructure investigation that breaks the far field resolution
limit by exploiting the properties of evanescent waves. This is done by
placing the detector very close (distance much smaller than wavelength λ)
to the specimen surface.
Neuroimaging or brain imaging, includes the use of various techniques to either
directly or indirectly image the structure, function/pharmacology of the
brain. It is a relatively new discipline within medicine and
neuroscience/psychology. Physicians who specialize in the performance and
interpretation of neuroimaging in the clinical setting are neuroradiologists.
Neuroimaging has also been used as non-diagnostic imaging technique, in
Instrumentación & Señales 2014 - Jorge Márquez Flores UNAM 20
experimental circumstances to allow people (especially disabled persons) to
control outside devices, acting as a brain computer interface (BCI).
Nuclear imaging. A medical specialty involving the application of radioactive
substances in the diagnosis and treatment of disease. In nuclear medicine
procedures, radionuclides are combined with other elements to form
chemical compounds, or else combined with existing pharmaceutical
compounds, to form radiopharmaceuticals. These radiopharmaceuticals,
once administered to the patient, can localize to specific organs or cellular
receptors. This property of radiopharmaceuticals allows nuclear medicine
the ability to image the extent of a disease process in the body, based on the
cellular function and physiology, rather than relying on physical changes in
the tissue anatomy. In some diseases, nuclear medicine studies can identify
medical problems at an earlier stage than other diagnostic tests. Nuclear
medicine, in a sense, is "radiology done inside out", or "endo-radiology",
because it records radiation emitting from within the body rather than
radiation that is generated by external sources like X-rays.
Optical coherence tomography (OCT) is an optical signal acquisition and
processing method. It captures micrometer-resolution, three-dimensional
images from within optical scattering media (e.g., biological tissue). Optical
coherence tomography is an interferometric technique, typically employing
near-infrared light. The use of relatively long wavelength light allows it to
penetrate into the scattering medium. Confocal microscopy, another optical
technique, typically penetrates less deeply into the sample but with higher
resolution.
Optical imaging; Optics usually describes the behavior of visible, ultraviolet,
and infrared light used in imaging. Because light is an electromagnetic
wave, similar phenomena occur in X-rays, microwaves, radio waves.
Optical imaging also comprises microscopy and other imaging techniques
using endoscopy, boroscopy, projected light and image patterns, etc.
Instrumentación & Señales 2014 - Jorge Márquez Flores UNAM 21
Optoacoustic imaging (Photoacoustic Imaging) is an imaging technology based
on the photoacoustic effect, and can be used for obtaining images of
structures in turbid environments. The optoacoustic technique combines the
accuracy of spectroscopy with the depth resolution of ultrasound.
PACS. A picture archiving and communication system is a medical imaging
technology which provides economical storage of and convenient access to,
images from multiple modalities (source machine types). Electronic images
and reports are transmitted digitally via PACS; this eliminates the need to
manually file, retrieve, or transport film jackets. The universal format for
PACS image storage and transfer is DICOM (Digital Imaging and
Communications in Medicine).
Personal imaging, real-time sharing of personal experience through images. By
2025 the POV (at least visual and auditive, but may include all senses) of
one person will be recorded, "played" and shared to others. It would be
edited, combined with other POVs, or even synthetized for Mixed Reality
experiences.
Photothermal microspectroscopy (PTMS), alternatively known as photothermal
temperature fluctuation (PTTF), is derived from two parent instrumental
techniques: infrared spectroscopy and atomic force microscopy (AFM). In
one particular type of AFM, known as scanning thermal microscopy
(SThM), the imaging probe is a sub-miniature temperature sensor, which
may be a thermocouple or a resistance thermometer. This same type of
detector is employed in a PTMS instrument, enabling it to provide
AFM/SThM images: However, the chief additional use of PTMS is to yield
infrared spectra from sample regions below a micrometer, as outlined
below.
Phase-contrast imaging is a method of imaging that has a range of different
applications. It exploits differences in the refractive index of different
materials to differentiate between structures under analysis. In conventional
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light microscopy, phase contrast can be employed to distinguish between
structures of similar transparency, and to examine crystals on the basis of
their double refraction. This has uses in biological, medical and geological
science. In X-ray tomography, the same physical principles can be used to
increase image contrast by highlighting small details of differing refractive
index within structures that are otherwise uniform. In transmission electron
microscopy (TEM), phase contrast enables very high resolution (HR)
imaging (at resolutions below one ångström), making it possible to
distinguish individual atoms from each other by their different refractive
indices.
Phase contrast microscopy is an optical microscopy technique that converts
phase shifts in light passing through a transparent specimen to brightness
changes in the image. Phase shifts themselves are invisible, but become
visible when shown as brightness variations.
Phase-contrast X-ray imaging (PCI) or phase-sensitive X-ray imaging is a
general term for different technical methods that use information
concerning changes in the phase of an X-ray beam that passes through an
object in order to create its images. Standard X-ray imaging techniques like
radiography or computed tomography (CT) rely on a decrease of the X-ray
beam's intensity (attenuation) when traversing the sample, which can be
measured directly with the assistance of an X-ray detector. In PCI however,
the beam's phase shift caused by the sample is not measured directly, but is
transformed into variations in intensity, which then can be recorded by the
detector.
Pneumoencephalography (sometimes abbreviated PEG; also referred to as an
"air study") was a common medical procedure in which most of the
cerebrospinal fluid (CSF) was drained from around the brain by means of a
lumbar puncture and replaced with air, oxygen, or helium to allow the
structure of the brain to show up more clearly on an X-ray image. It was
Instrumentación & Señales 2014 - Jorge Márquez Flores UNAM 23
derived from ventriculography, an earlier and more primitive method where
the air is injected through holes drilled in the skull.
Positron emission tomography (PET). A nuclear medicine, functional imaging
technique that produces a three-dimensional image of functional processes
in the body. The system detects pairs of gamma rays emitted indirectly by a
positron-emitting radionuclide (tracer), which is introduced into the body
on a biologically active molecule. Three-dimensional images of tracer
concentration within the body are then constructed by computer analysis. In
modern PET-CT scanners, three dimensional imaging is often accomplished
with the aid of a CT X-ray scan performed on the patient during the same
session, in the same machine.
Positron emission tomography–computed tomography (better known as PET-
CT or PET/CT) - is a medical imaging technique using a device which
combines in a single gantry system both a positron emission tomography
(PET) scanner and an x-ray computed tomography (CT) scanner, so that
images acquired from both devices can be taken sequentially, in the same
session, and combined into a single superposed (co-registered) image. Thus,
functional imaging obtained by PET, which depicts the spatial distribution
of metabolic or biochemical activity in the body can be more precisely
aligned or correlated with anatomic imaging obtained by CT scanning..
Photoacoustic imaging. A recently developed hybrid biomedical imaging
modality based on the photoacoustic effect. It combines the advantages of
optical absorption contrast with ultrasonic spatial resolution for deep
imaging in (optical) diffusive or quasi-diffusive regime.
Photoacustic imaging. A method of image reconstruction using photo-acustical
phenomena and sensors. As a hybrid biomedical imaging modality, is
developed based on the photoacoustic effect. In photoacoustic imaging,
non-ionizing laser pulses are delivered into biological tissues (when radio
Instrumentación & Señales 2014 - Jorge Márquez Flores UNAM 24
frequency pulses are used, the technology is referred to as thermoacoustic
imaging).
Photoacoustic microscopy (PAM) is a hybrid in vivo imaging technique that
acoustically detects optical contrast via the photoacoustic effect. Unlike
pure optical microscopic techniques, PAM takes advantage of the weak
acoustic scattering in tissue and thus breaks through the optical diffusion
limit (~1 mm in soft tissue). With its excellent scalability, PAM can provide
high-resolution images at desired maximum imaging depths up to a few
millimeters.
Photoacoustic tomography (PAT), or Photoacoustic computed tomography
(PACT) is a materials analysis technique based on the reconstruction of an
internal photoacoustic source distribution from measurements acquired by
scanning ultrasound detectors over a surface that encloses the source under
study.
Photoemission Electron Microscopy (PEEM, also called photoelectron
microscopy, PEM) is a widely used type of emission microscopy. PEEM
utilizes local variations in electron emission to generate image contrast
Polarized Light Microscopy. can mean any of a number of optical microscopy
techniques involving polarized light. Simple techniques include
illumination of the sample with polarized light. Directly transmitted light
can, optionally, be blocked with a polariser orientated at 90 degrees to the
illumination. More complex microscopy techniques which take advantage
of polarized light include differential interference contrast microscopy and
interference reflection microscopy. These illumination techniques are most
commonly used on birefringent samples where the polarized light interacts
strongly with the sample and so generating contrast with the background.
Instrumentación & Señales 2014 - Jorge Márquez Flores UNAM 25
Photography, the process of creating still images. Large negatives have been
used traditionally by clinicians, radiologists and physicians, using a back-lit
negatoscope.
Positron emission tomography. A nuclear medicine, functional imaging
technique that produces a three-dimensional image of functional processes
in the body. The system detects pairs of gamma rays emitted indirectly by a
positron-emitting radionuclide (tracer), which is introduced into the body
on a biologically active molecule. Three-dimensional images of tracer
concentration within the body are then constructed by computer analysis. In
modern PET-CT scanners, three dimensional imaging is often accomplished
with the aid of a CT X-ray scan performed on the patient during the same
session, in the same machine.
Quantitative phase contrast microscopy is the collective name for a group of
microscopy methods that quantify the phase shift that occurs when light
waves pass through a more optically dense object.
Radar imaging, or imaging radar, for obtaining an image of an object, not just
its location and speed.
Radiography is the use of ionizing electromagnetic radiation such as X-rays to
view objects. Although not technically radiographic techniques, imaging
modalities such as PET and MRI are sometimes grouped in radiography
because the radiology department of hospitals handle all forms of imaging.
Treatment using radiation is known as radiotherapy.
Radiology. All techniques that use photographic film to record X-ray or other
ionizing radiations to see thru low dense structures, to reveal irregulairties
in density. Medical Radiology is a medical specialty that employs the use of
imaging to both diagnose and treat disease visualized within the body.
Radiologists use an array of imaging technologies such as X-ray
radiography, ultrasound, computed tomography (CT), nuclear medicine,
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positron emission tomography (PET) and magnetic resonance imaging
(MRI) to diagnose or treat diseases. Interventional radiology is the
performance of (usually minimally invasive) medical procedures with the
guidance of imaging technologies.
Radionuclide ventriculography. A type of cardiac ventriculography, is a form of
nuclear imaging, where a gamma camera is used to create an image
following injection of radioactive material, usually Technetium-99m
(99m
Tc) labeled red blood cells. In radionuclide ventriculography, the
radionuclide has the property of circulating through the cardiac chambers,
availing for studies of the pumping function of the heart. In contrast, in
myocardial perfusion imaging, the radionuclide is taken up by the
myocardial cells, making its presence correlating with myocardial perfusion
or viability of the cells.
Range imaging, distance recording point-per-point from the sensor to the
(visible) surface of a 3D object.
Remote Sensing. Satellite multispectral images, mainly. Techniques such as
Synthetic Aperture Radar gives 3D geographical information.
Reprography, reproduction of graphics through electrical and mechanical means.
Scanning acoustic microscopy. A scanning acoustic microscope (SAM) is a
device which uses focused sound to investigate, measure, or image an
object (a process called scanning acoustic tomography). It is commonly
used in failure analysis and non-destructive evaluation. It also has
applications in biological and medical research. The semiconductor industry
has found the SAM useful in detecting voids, cracks, and delaminations
within microelectronic packages.
Scanning confocal electron microscopy (SCEM) is an electron microscopy
technique analogous to scanning confocal optical microscopy (SCOM). In
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this technique, the studied sample is illuminated by a focussed electron
beam, as in other scanning microscopy techniques, such as scanning
transmission electron microscopy or scanning electron microscopy.
However, in SCEM, the collection optics is arranged symmetrically to the
illumination optics to gather only the electrons that pass the beam focus.
Scanning electron microscope (SEM). This technique employs a type of
electron microscope that produces images of a sample by scanning it with a
focused beam of electrons. The electrons interact with atoms in the sample,
producing various signals that can be detected and that contain information
about the sample's surface topography and composition.
Scanning Joule Expansion Microscopy is a form of scanning probe microscopy
heavily based on atomic force microscopy that maps the temperature
distribution along a surface. Resolutions down to 10 nm have been achieved
and 1 nm resolution is theoretically possible. Thermal measurements at the
nanometer scale are of both academic and industrial interest, particularly in
regards to nanomaterials and modern integrated circuits.
Scanning laser ophthalmoscopy (SLO) is a method of examination of the eye. It
uses the technique of confocal laser scanning microscopy for diagnostic
imaging of retina or cornea of the human eye.
Scanning probe microscopy (SPM) is a branch of microscopy that forms images
of surfaces using a physical probe that scans the specimen. SPM was
founded with the invention of the scanning tunneling microscope in 1981.
Many scanning probe microscopes can image several interactions
simultaneously. The manner of using these interactions to obtain an image
is generally called a mode. A list of established types of Scanning probe
microscopy is found here.
Scanning thermal microscopy (SThM) is a type of scanning probe microscopy
that maps the local temperature and thermal conductivity of an interface.
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The probe in a scanning thermal microscope is sensitive to local
temperatures - providing a nanoscale thermometer. Thermal measurements
at the nanometer scale are of both scientific and industrial interest.
Scanning tunneling microscopy. A scanning tunneling microscope (STM) is
an instrument for imaging surfaces at the atomic level. Its development in
1981 earned its inventors, Gerd Binnig and Heinrich Rohrer (at IBM
Zürich), the Nobel Prize in Physics in 1986. For an STM, good resolution is
considered to be 0.1 nm lateral resolution and 0.01 nm depth resolution.
With this resolution, individual atoms within materials are routinely imaged
and manipulated. The STM can be used not only in ultra-high vacuum but
also in air, water, and various other liquid or gas ambients, and at
temperatures ranging from near zero kelvin to a few hundred degrees
Celsius.
Scintigraphy. a form of diagnostic test used in nuclear medicine, wherein
radioisotopes (here called radiopharmaceuticals) are taken internally, and
the emitted radiation is captured by external detectors (gamma cameras) to
form two-dimensional images.
Second-harmonic imaging microscopy (SHIM) is based on a nonlinear optical
effect known as second-harmonic generation (SHG). SHIM has been
established as a viable microscope imaging contrast mechanism for
visualization of cell and tissue structure and function. A second-harmonic
microscope obtains contrasts from variations in a specimen’s ability to
generate second-harmonic light from the incident light while a conventional
optical microscope obtains its contrast by detecting variations in optical
density, path length, or refractive index of the specimen.
Serial time-encoded amplified imaging/microscopy (STEAM) is a fast real-time
optical imaging method that provides MHz frame rate, ~100 ps shutter
speed, and ~30 dB (× 1000) optical image gain. An example of time-stretch
microscopy, STEAM holds world records for shutter speed and frame rate
Instrumentación & Señales 2014 - Jorge Márquez Flores UNAM 29
in continuous real-time imaging. STEAM employs the photonic time stretch
along with optical image amplification to circumvent the fundamental
trade-off between sensitivity and speed that affects virtually all optical
imaging and sensing systems. This method employs a single-pixel
photodetector, eliminating the need for the detector array and readout time
limitations. Avoiding this problem and featuring the optical image
amplification for dramatic improvement in sensitivity at high image
acquisition rates, STEAM's shutter speed is at least 1000 times faster than
the state-of-the-art CCD and CMOS cameras. Its frame rate is 1000 times
faster than fastest CCD cameras and 10-100 times faster than fastest CMOS
cameras.
Single photon emission computed tomography (SPECT, or less commonly,
SPET) is a nuclear medicine tomographic imaging technique using gamma
rays. It is very similar to conventional nuclear medicine planar imaging
using a gamma camera.
Spectral imaging is a branch of spectroscopy and of photography in which a
complete spectrum or some spectral information (such as the Doppler shift
or Zeeman splitting of a spectral line) is collected at every location in an
image plane. Applications include astronomy, solar physics, planetology,
and Earth remote sensing.
Speckle imaging, a method of shift-and-add for astronomical imaging. Othe
describes a range of high-resolution astronomical imaging techniques based
either on the shift-and-add ("image stacking") method or on speckle
interferometry methods.
Spiral computed tomography is a computed tomography technology involving
movement in a helical pattern for the purpose of increasing resolution. Most
modern hospitals currently use spiral CT scanners.
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Stereo imaging, is an aspect of sound recording and reproduction concerning
spatial locations of the performers. For three-dimensional visual imaging,
see stereoscopy.
Stereomicroscopy. The stereo or stereoscopic or dissecting microscope is an
optical microscope variant designed for low magnification observation of a
sample, typically using light reflected from the surface of an object rather
than transmitted through it. The instrument uses two separate optical paths
with two objectives and eyepieces to provide slightly different viewing
angles to the left and right eyes. This arrangement produces a three-
dimensional visualization of the sample being examined. Stereomicroscopy
overlaps macrophotography for recording and examining solid samples
with complex surface topography, where a three-dimensional view is
needed for analysing the detail.
Stereo Vision (or Stereopsis). perception of depth and 3-dimensional structure
obtained on the basis of visual information deriving from two eyes by
individuals with normally developed binocular vision. In stead of animal or
human eyes, two cameras may also give the information required for
Stereoscopy. a technique for creating or enhancing the illusion of depth in an
image by means of stereopsis for binocular vision. Any stereoscopic image
is called stereogram. Originally, stereogram referred to a pair of stereo
images which could be viewed using a stereoscope.
Stethoscope. The stethoscope is an acoustic medical device for auscultation, or
listening to the internal sounds of an animal or human body. It is often used
to listen to lung and heart sounds. It is also used to listen to intestines and
blood flow in arteries and veins. In combination with a
sphygmomanometer, it is commonly used for measurements of blood
pressure. Less commonly, "mechanic's stethoscopes" are used to listen to
internal sounds made by machines, such as diagnosing a malfunctioning
automobile engine by listening to the sounds of its internal parts.
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Stethoscopes can also be used to check scientific vacuum chambers for
leaks, and for various other small-scale acoustic monitoring tasks. A
stethoscope that intensifies auscultatory sounds is called phonendoscope.
Super-resolution microscopy is a form of light microscopy. Due to the
diffraction of light, the resolution of conventional light microscopy is
limited as stated by Ernst Abbe in 1873. A good approximation of the
resolution attainable is the FWHM (full width at half-maximum) of the
point spread function, and a precise widefield microscope with high
numerical aperture and visible light usually reaches a resolution of
~250 nm.
Synthetic aperture photography: By integrating an appropriate 4D subset of the
samples in a light field, one can approximate the view that would be
captured by a camera having a finite (i.e., non-pinhole) aperture. Such a
view has a finite depth of field. By shearing or warping the light field
before performing this integration, one can focus on different fronto-parallel
(Isaksen 2000) or oblique (Vaish 2005) planes in the scene. If the light field
is captured using a handheld camera (Ng 2005), this essentially constitutes
a digital camera whose photographs can be refocused after they are taken.
Synthetic-aperture imaging. See Aperture synthesis imaging above.
Synthetic-aperture radar (SAR) is a form of radar which is used to create
images of an object, such as a landscape. SAR uses the motion of the SAR
antenna over a target region to provide finer spatial resolution than is
possible with conventional beam-scanning radars. SAR is typically
mounted on a moving platform such as an aircraft or spacecraft, and it
originated as an advanced form of side-looking airborne radar (SLAR). The
distance the SAR device travels over a target creates a large "synthetic"
antenna aperture (the "size" of the antenna). As a rule of thumb one can
assume that the larger the aperture is, the higher the image resolution
becomes, regardless whether phys ical aperture or synthetic aperture – this
Instrumentación & Señales 2014 - Jorge Márquez Flores UNAM 32
allows SAR to create high resolution images with comparatively small
physical antennas.
Synthetic aperture sonar (SAS) is a form of sonar in which sophisticated post-
processing of sonar data are used in ways closely analogous to synthetic
aperture radar. Synthetic aperture sonars combine a number of acoustic
pings to form an image with much higher resolution than conventional
sonars, typically 10 times higher. The principle of synthetic aperture sonar
is to move a sonar along a line and illuminate the same spot on the sea floor
with several pings. This produces a synthetic array equal to the distance
traveled. By coherent reorganization of the data from all the pings, a
synthetic aperture image is produced with improved along-track resolution.
In contrast to conventional side-scan sonar, SAS processing provides range-
independent along-track resolution. At maximum range the resolution can
be magnitudes better than that of side-scan sonars.
Tactile imaging is a medical imaging modality that translates the sense of touch
into a digital image. The tactile image is a function of P(x,y,z), where P is
the pressure on soft tissue surface under applied deformation and x,y,z are
coordinates where pressure P was measured
Thermography, infrared thermography (IRT) and termal video are examples of
infrared imaging science. At present, it is used basically for the breast
imaging. A thermographic camera (also called an infrared camera or
thermal imaging camera) is a device that forms an image using infrared
radiation, similar to a common camera that forms an image using visible
light. Instead of the 450–750 nanometer range of the visible light camera,
infrared cameras operate in wavelengths as long as 14,000 nm (14 µm).
Thrombelastography (TEG) is a method of testing the efficiency of blood
coagulation. It is a test mainly utilized in surgery and anesthesiology,
although few centers are capable of performing it. More common tests of
blood coagulation include prothrombin time (PT,INR) and partial
Instrumentación & Señales 2014 - Jorge Márquez Flores UNAM 33
thromboplastin time (aPTT) which measure coagulation factor function, but
TEG also can assess platelet function, clot strength, and fibrinolysis which
these other tests cannot. Thromboelastometry (TEM), previously named
rotational thromboelastography (ROTEG) or rotational
thromboelastometry (ROTEM), is another version of TEG in which it is the
sensor shaft, rather than the cup, that rotates.
Thromboelastometry (TEM), previously named rotational
thromboelastography (ROTEG) or rotational thromboelastometry
(ROTEM), is an established viscoelastic method for hemostasis testing in
whole blood. It is modification of traditional thromboelastography (TEG).
TEM investigates the interaction of coagulation factors, their inhibitors,
anticoagulant drugs, blood cells, specifically platelets, during clotting and
subsequent fibrinolysis. The rheological conditions mimic the sluggish flow
of blood in veins. TEM is performed with the ROTEM whole blood
analyzer (Tem Innovations GmbH, Munich) and is an enhancement of
thrombelastography, originally described by H. Hartert in 1948.
Transmission electron microscopy (TEM) is a microscopy technique in which a
beam of electrons is transmitted through an ultra-thin specimen, interacting
with the specimen as it passes through.
Time-lapse microscopy is time-lapse photography applied to microscopy.
Microscope image sequences are recorded and then viewed at a greater
speed to give an accelerated view of the microscopic process. Before the
introduction of the video tape recorder in the 1960s, time-lapse microscopy
recordings where made on photographic film. During this period, time-lapse
microscopy was referred to as microcinematography. With the increasing
use of video recorders, the term time-lapse video microscopy was gradually
adopted. Today, the term video is increasingly dropped, reflecting that a
digital still camera is used to record the individual image frames, instead of
a video recorder.
Instrumentación & Señales 2014 - Jorge Márquez Flores UNAM 34
Tomography is the method of imaging a single plane, or slice, of an object
resulting in a tomogram. There are several forms of tomography: Linear
tomography, Poly tomography, Zonography, Orthopantomography,
Computed Tomography, Magnetic induction tomography and Positron
emission tomography.
Total internal reflection fluorescence microscopy (TIRF Microscopy). A total
internal reflection fluorescence microscope (TIRFM) is a type of
microscope with which a thin region of a specimen, usually less than
200 nm can be observed.
Two-photon excitation microscopy is a fluorescence imaging technique that
allows imaging of living tissue up to a very high depth, up to about one
millimeter. Being a special variant of the multiphoton fluorescence
microscope, it uses red-shifted excitation light which can also excite
fluorescent dyes. However, for each excitation, two photons of infrared
light are absorbed. Using infrared light minimizes scattering in the tissue.
Due to the multiphoton absorption, the background signal is strongly
suppressed. Both effects lead to an increased penetration depth for these
microscopes. Two-photon excitation can be a superior alternative to
confocal microscopy due to its deeper tissue penetration, efficient light
detection, and reduced phototoxicity.
Ultrasonic Force Microscopy (UFM) has been developed in order to improve
the details and image contrast on "flat" areas of interest where the atomic
force microscopy (AFM) images are limited in contrast. The combination of
AFM-UFM allows a near field acoustic microscopic image to be generated.
The AFM tip is used to detect the ultrasonic waves and overcomes the
limitation of wavelength that occurs in acoustic microscopy. By using the
elastic changes under the AFM tip, an image of much greater detail than the
AFM topography can be generated.
Instrumentación & Señales 2014 - Jorge Márquez Flores UNAM 35
(Medical) ultrasonography, an ultrasound-based diagnostic imaging technique.
With consistent technological improvements, this modality is now used
throughout the body for imaging almost every soft tissue area, in particular
interfaces and cavities.
Ultraviolet microscopy. Ultraviolet microscopes have two main purposes. The
first is to utilize the shorter wavelength of ultraviolet electromagnetic
energy to improve the image resolution beyond that of the diffraction limit
of standard optical microscopes. This technique is used for non-destructive
inspection of devices with very small features such as those found in
modern semiconductors. The second application for UV microscopes is
contrast enhancement where the response of individual samples is
enhanced, relative to their surrounding, due to the interaction of light with
the molecules within the sample itself. One example is in the growth of
protein crystals. Protein crystals are formed in salt solutions. As salt and
protein crystals are both formed in the growth process, and both are
commonly transparent to the human eye, they cannot be differentiated with
a standard optical microscope.
USB microscopy. A USB microscope is a low-powered digital microscope
which connects to a computer, normally via a USB port. They are widely
available at low cost commercially. In essence USB microscopes are a
webcam with a high-powered macro lens and generally do not use
transmitted light, but rely on incident light from in-built LEDs lights
situated next to the lens. The light reflected from the sample then enter the
camera lens.
Video. Motion image recording as an electronic raster signal (kind of "inverse
TV"). Video is also the electronic medium for the recording, copying and
broadcasting of moving visual images.
Virtual microscopy is a method of posting microscope images on, and
transmitting them over, computer networks. This allows independent
Instrumentación & Señales 2014 - Jorge Márquez Flores UNAM 36
viewing of images by large numbers of people in diverse locations. It
involves a synthesis of microscopy technologies and digital technologies.
The use of virtual microscopes can transform traditional teaching methods
by removing the reliance on physical space, equipment, and specimens to a
model that is solely dependent upon computer-internet access. This
increases the convenience of accessing the slide sets and making the slides
available to a broader audience. Digitized slides can have a high resolution
and are resistant to being damaged or broken over time.
Whole Body Imaging. (WBI) refers to the internal display of the entire body in a
single procedure. It also refersto Backscatter low-level X-ray devices
employed in airports and customs for inspecting and security purposes.
Other WB techniques are the Millimeter wave scanner, WBI Backscatter X-
ray and Infra-red thermal difference detection. In medical imaging, it may
also refer to full-body CT scan or magnetic resonance imaging.
X-ray computed tomography (X-ray CT) is a technology that uses computer-
processed x-rays to produce tomographic images (virtual 'slices') of specific
areas of the scanned object, allowing the user to see what is inside it
without cutting it open. Digital geometry processing is used to generate a
three-dimensional image of the inside of an object from a large series of
two-dimensional radiographic images taken around a single axis of rotation.
Medical imaging is the most common application of x-ray CT. Its cross-
sectional images are used for diagnostic and therapeutic purposes in various
medical disciplines. The rest of this article discusses medical-imaging x-ray
CT; industrial applications of x-ray CT are discussed at industrial computed
tomography scanning.
X-ray fluorescence (XRF) is the emission of characteristic "secondary" (or
fluorescent) X-rays from a material that has been excited by bombarding
with high-energy X-rays or gamma rays. The phenomenon is widely used
for elemental analysis and chemical analysis, particularly in the
Instrumentación & Señales 2014 - Jorge Márquez Flores UNAM 37
investigation of metals, glass, ceramics and building materials, and for
research in geochemistry, forensic science and archaeology.
X-ray microtomography, like tomography and x-ray computed tomography, uses
x-rays to create cross-sections of a physical object that can be used to
recreate a virtual model (3D model) without destroying the original object.
The prefix micro- (symbol: µ) is used to indicate that the pixel sizes of the
cross-sections are in the micrometre range. These pixel sizes have also
resulted in the terms high-resolution x-ray tomography, micro–
computed tomography (micro-CT or µCT), and similar terms. Sometimes
the terms high-resolution CT (HRCT) and micro-CT are differentiated, but
in other cases the term high-resolution micro-CT is used. Virtually all
tomography today is computed tomography.
Xerography, (or electrophotography) the method of photocopying.
Zonography. This is a variant of linear tomography, where a limited arc of
movement is used. It is still used in some centres for visualising the kidney
during an intravenous urogram (IVU).