Posted by
Kenneth Sloan-2 on
URL: http://imagej.273.s1.nabble.com/Code-review-tp5024381.html
Context: Java plugins
I want to take a completely arbitrary ImageProcessor and produce a ColorProcessor, with the twist that I want to enhance images for display.
For my images, most color images (including 8-bit images with color LUTs) are already sufficiently enhanced (or - the colors actually mean something and I don’t want to interfere with that). But, the grayscale images include everything from 8-bit images with and without LUTs to 32-bit Float images with very strange ranges of values.
The intent is to produce an image to LOOK AT. Measurements are done using parallel copies of the images, which are not modified (and not displayed).
I started with a very verbose set of cases, for testing and debugging. I had some difficulty with the 32-bit images and found it necessary to convert (with scaling) to 16-bit before enhancing. I don’t remember what the issue was. Today, I decided to collapse the cases at the cost of possibly doing some extra work. Speed and other efficiency is NOT an issue.
I would appreciate it if someone more expert than myself would take a look at the following piece of code and comment. It appears to work properly, but I have really only tested it in 32-bit Float and 8-bit images with color LUTs. I’m especially interested in comments on why the computation of min/max and the conversion to 16-bit is required for 32-bit images (and also whether it is “wrong” to do that for other image formats). It appears to work, but this is the result of trial and error (lots of errors!) and I may have lost perspective. Of course, this is a tiny part of (several) larger Java plugins. I *think* that the use of IJ.run(…) is required for the “Enhance Contrast” step; some of the other steps might use more direct methods, but as long as I have the ImagePlus available, I thought I might as well use it.
I am grateful for any comments.
// enhance an ImageProcessor for display purposes
// Input is an arbitrary ImageProcessor
// Output is a ColorProcessor, possibly enhanced for display
private ColorProcessor ip2cp(ImageProcessor ipIn)
{
if(ipIn.isGrayscale())
{
ImageProcessor ip = ipIn.duplicate();
ImagePlus ipl = new ImagePlus("temp", ip);
ImageStatistics imStat = ip.getStatistics();
double min = imStat.min;
double max = imStat.max;
ipl.setDisplayRange(min,max);
IJ.run(ipl,"16-bit","true");
IJ.run(ipl,"Enhance Contrast","saturated=0.35");
IJ.run(ipl,"Apply LUT","");
return ipl.getProcessor().convertToColorProcessor();
}
return ipIn.convertToColorProcessor();
}
—
Kenneth Sloan
[hidden email]
Vision is the art of seeing what is invisible to others.
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