Hi,

I have a question regarding the processing of the RGB images comming out of
a ZEISS LSM510. The images can be saved as 3 channel RGB Tiff-images,
containing Red Green an Blue channel information or combinations.

When you read such an image into any image processing program, the image is
regarded as comming from a 3-channel RGB-device. When you convert such an
RGB image containing colorinformation to a greyscale image the standard
conversion function (CIE) for mapping the color information to a grey
intensity image are used:

GREY-image intensity = 0.3xRed + 0.59xGreen + 0.11xBlue

The same goes for converting the three channels separately to 3 separate
grey images.

This is a valid approach for RGB-images comming form an RGB-generating
device in which the three color channels are related and somewhat
interdependent as they are in the human eye (cfr. CIE). In the RGB image
generated by the confocal microscope, the channels are "not" interdependent
and the conversion gives a wrong result. For the images comming from the
confocal in my opinion the procedure must be:

GREY-image intensity = 1.0xRed + 1.0xGreen + 1.0xBlue

So the only valid way to handle the RGB-files coming from the confocal is
not to use the "standard" RGB to B/W conversion, but simply split the "RGB"
channels independent and process them separatedly.

A more reliable way to handle these images during export would be (in my
opinion) to handle them as separate channel images and only use the "RGB"
for displaying., but not for analysis.

Has anyone ever encountered this "artefact" and dealt with it ?

Sincerely yours,

Peter Van Osta, MD

Senior Scientist Medical Image Analysis
Biological Imaging Laboratory
Life Sciences Department I - 6065
Janssen Research Foundation
Turnhoutseweg 30
B-2340 Beerse
Belgium
Europe

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