Creating a variable length color lookup table

Question

I was wondering if anyone has any words of advice or could point me to any good resources regarding the creation of color lookup tables for image synthesis. In my application I have floating point values between -1.0 and 1.0 that need to be mapped onto RGB space. The problem is, I don't know beforehand what precision those floating point values will have, so I don't know how many entries to put in the lookup table or what they should be. Are there any commonly used techniques to deal with mapping data in this form to colors? It seems it would be too costly to create a new color table for each image based on the range of values in the domain of the image data.

I guess defining a range of values for the mapping would work, but give me your thoughts. Also if anyone knows of any existing tools (preferbly python based) for creating color lookup tables that would be helpful.

Answer 1

The term you are looking for is false color image.

How to pick the color bands depends on what you are trying to show. The simple way is to split the data into two halves, above and below the mid-range

For the low half you set red=0, then blue=(255 - your value), green=(your value). This will give you a color between most blue for the lowest value and green for the highest.

Then in the high range set blue=0, red=your value, green=255-(your value), this gives you a color which is red for the highest value and green for the lowest.

YOu can also change the shape of the curve to emphasize particular ranges