Ccd Sensors
Transcript of Ccd Sensors
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Revelutioning the Digital Imaging ..
Presented by:- Aritra Roy.
E.C.E. , 3rdYear.
University Roll No:- 071430103007.
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WHAT IS CCD ??????
WHAT IS CCD ?????? Charge-coupled device (CCD) is a device for the
movement of electrical charge, usually from within the
device to an area where the charge can be manipulated.
This is achieved by "shifting"
the signals between stages
within the device one at a time.
Technically, CCDs are implemented as shift registers
that move charge between capacitive bins in the device.
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BASICS OF OPERATIONBASICS OF OPERATION
In a CCD for capturing images, there is a photoactive region
and a transmission region made out of a shift register.
Image is projected through a lens onto the
capacitor array causing each capacitor to
accumulate an electric charge proportional
to the light intensity at that location.
A control circuit causes each capacitor to
transfer its contents to its neighbor as shift
register.
The last capacitor in the array dumps its charge into a charge
amplifier, which converts the charge into a voltage.
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CCD SENSOR
In CCD, the electrical field at different parts of the surface iscontrolled by an array or matrix of electrodes; called the
gates.
When light or photons of high enough
energy strike the surface, electrons
are usually liberated from the surface.
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CCD SCCD SENSORENSORAARCHITECTURERCHITECTURE
Three types of Architecture :--
1. Full-Frame CCD
2. Interline Transfer CCD
3. Frame-Transfer CCD
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IINSIDENSIDE THETHE DDIGITALIGITAL CCAMERAAMERA
Inside the digital camera, at first an IR blocking filter is there,
followed by a color separation filter called Bayer Mask.
And finally it falls on the sensor which
turns it into electrical pulses by
electron to voltage conversion.
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IIMAGEMAGE SSENSINGENSING
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CCOMPARISONOMPARISON
1. Long history of high
quality performance.
2. High Dynamic range.
3. Low noise and best dMax.
4. High power consumption.
5. Small pixel size (small
sensors - best to develop
new cameras & lenses).
6. High Fill Factor.
1. Lower performance in past,
but now providing
comparable quality.
2. Moderate Dynamic range.
3. Noisier, but getting better
quickly.
4. Relatively low power
consumption.
5. Larger pixel size (larger
sensors - easier to use withincurrent camera technology).
6. Lower Fill Factor.
CCD Sensors CMOS Sensors
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AADVANCEDDVANCED CCDCCD 3 CCD3 CCD
Three-CCD cameras have three separate
charge-coupled devices (CCDs), each one taking
a separate measurement of red, green, and blue
light.
A trichroic prism assembly splits the incoming
light and directs the appropriate wavelength of
light to their respective CCDs.
Compared to one CCD cameras , three-CCD cameras generallyprovide superior image quality and resolution. By taking separatereadings of red, green, and blue values for each pixel, three-CCDcameras achieve much better precision than single-CCD cameras.
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FFURTHERURTHERAADVANCEMENTSDVANCEMENTS
Electron Multiplying CCD (EMCCD):-
In EMCCD a gain register is placed in
between shift CCD register and output
amplifier, to reduce readout noise.
Super CCD:- It uses octagonal pixels for higherhorizontal and vertical resolution at expense of
diagonal resolution than a traditional sensor.
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AAPPLICATIONPPLICATION
In Astronomy:-
In Digital Cameras:-
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