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ANDREAS PLESCH
Image processing system
The image processing system comprises the hard- and software necessary
to control the camera and digitizer, and the microscope (if motorized)
with attachments like external excitation filter wheel. It further includes
the software to process the raw images and to enhance (for qualitative
interpretation) or to analyze (for measuring and quantitative interpretation) the image information. The image display finally provides the interface to the user. For optimum results the following requirements should be
met:
Image acquisition Focusing is a crucial step in image capture. The system should provide onscreen focussing of the digital live image. The exposure time used for
focussing is a compromise between displayed signal intensity and refresh
rate of the displayed image. Automatic or interactive contrast stretching of
the displayed image is helpful. Fast data transmission is of practical importance to obtain pseudo real-time display. An efficient software-supported focussing procedure will avoid unnecessary lengthy exposure of
the slide and excessive signal fading.
Long-term exposure is almost always necessary, except for a very
strong counterstain. The system must ensure correct exposure by controlling the integration time of the camera for all fluorochromes (color channels) of each individual image automatically. If done properly, automatic
integration time control will allow for making use of the full dynamic
range of FISH signals with an 8-bit digitizer. An algorithm that allows
the setting of the number of saturated points in the image, avoids underexposure of the image due to a few bright pixels that may be caused by
defective sensor elements of the CCD. The option of reducing the size of
the measuring window (similar to a "spot measurement" in photography)
is extremely helpful to exclude a bright artifact from the exposure control
which would otherwise result in too short an integration time and consequently underexposed signals.
Software-controlled filter change is convenient and further reduces total acquisition time. Automatic capture of a focus stack of images, which
can be used to calculate an extended focus image, requires automatic control of the microscope focus during the capture sequence. This function is
handy for conventional interpretation and documentation of interphase
nuclei or tissue sections; it is indispensable for automatic interphase FISH
scanning applications.
ANDREAS PLESCH
Image processing system
The image processing system comprises the hard- and software necessary
to control the camera and digitizer, and the microscope (if motorized)
with attachments like external excitation filter wheel. It further includes
the software to process the raw images and to enhance (for qualitative
interpretation) or to analyze (for measuring and quantitative interpretation) the image information. The image display finally provides the interface to the user. For optimum results the following requirements should be
met:
Image acquisition Focusing is a crucial step in image capture. The system should provide onscreen focussing of the digital live image. The exposure time used for
focussing is a compromise between displayed signal intensity and refresh
rate of the displayed image. Automatic or interactive contrast stretching of
the displayed image is helpful. Fast data transmission is of practical importance to obtain pseudo real-time display. An efficient software-supported focussing procedure will avoid unnecessary lengthy exposure of
the slide and excessive signal fading.
Long-term exposure is almost always necessary, except for a very
strong counterstain. The system must ensure correct exposure by controlling the integration time of the camera for all fluorochromes (color channels) of each individual image automatically. If done properly, automatic
integration time control will allow for making use of the full dynamic
range of FISH signals with an 8-bit digitizer. An algorithm that allows
the setting of the number of saturated points in the image, avoids underexposure of the image due to a few bright pixels that may be caused by
defective sensor elements of the CCD. The option of reducing the size of
the measuring window (similar to a "spot measurement" in photography)
is extremely helpful to exclude a bright artifact from the exposure control
which would otherwise result in too short an integration time and consequently underexposed signals.
Software-controlled filter change is convenient and further reduces total acquisition time. Automatic capture of a focus stack of images, which
can be used to calculate an extended focus image, requires automatic control of the microscope focus during the capture sequence. This function is
handy for conventional interpretation and documentation of interphase
nuclei or tissue sections; it is indispensable for automatic interphase FISH
scanning applications.