Image Input

Image acquisition or digitization. Sources include-

Cameras Video camera w/ framegrabber Digital CCD camera w/ interface card Color or Monochrome

Flatbed Scanners

Photomultiplier Tubes

Electron Microscopes

Image Quality

Image Quality is critical. A good image depends on a good specimen.

Optimize input conditions - Select suitable acquisition system and conditions to acquire the best possible image.

Good specimens and proper imaging conditions will make image analysis much easier.

Limitations of Our Eyes

5 Gray Levels 10 Gray Levels

20 Gray Levels 40 Gray Levels

Instrument Setup

• Microscope adjusted for Koehler illumination

• Match magnification to object size and camera resolution

• Calibration- White Balance Dark CurrentExposure Time

• Background Subtraction

Camera Adjustments

• Adjust camera for best dynamic range

• Gain and brightness

• Exposure time

• For intensity/density measurements turn off autoexposure

• For fluorescence turn off autoexposure

Saving Image Data

Images are normally saved as TIFF (.tif) files.

Do not save images as JPEG (.jpg) files!

OK for e-mailing/viewing only

Loses data integrity

Could be impossible to analyze

Does not save computer memory or processing time

TIFF v. JPEG

TIFF JPEG