Help with Colorize... menu option
Sat, 04/18/2020 - 12:42 pm
Where can I find information about the Colorize... menu option for images? I would like to understand better what is being changed by the two sliders on the right of the image panel after this menu is invoked. Are they changing the mid-point and range of the histogram selection? What is being set when both sliders are at the bottom or when both sliders are at the top versus when both sliders are at the center?
For reference, take a simple 0-255 grayscale image being mapped to a Color Table: Gray. When I can understand how the colorize option maps the source histogram to a new histogram in the display as I adjust either of the sliders, I will understand how this works for any color scale.
Thanks!
Colorize works by creating a sinusoidal color table look-up wave, whose values range from 0 to 1.
The left slider is adjusting the phase (initial value of the lookup wave, which applies to the lowest-value image pixels).
The right slider is adjusting the frequency (number of cycles in the lookup wave).
If you save the resulting lookup wave (MIP_colorLookup by default), you'll understand.
April 18, 2020 at 12:52 pm - Permalink
OK. The clue is in the statement "sinusoidal". I can follow the mapping directly with this help. Thanks for the prompt reply.
April 18, 2020 at 01:21 pm - Permalink