# Algorithm for contour bands in falsecolor program

Hi,

I was exploring falsecolor.csh to see how exactly contour bands are defined
in it. Since method it is mixture of shell command + cal files and various
functions inside them, I couldn't determine how is exactly defined "width"
of contour bands.

I understand that idea is to color areas in image with radiance in some
range above and below each radiance value in the scale.
For example if blue color is defined with 500lux, on final image in blue
will be colored areas with luminance ranging *from 500-x to 500+y *values.
Question is how *x and y* values are calculated? I suppose they depend on
maximal scale value and number of color, but cant determine exact equation
from falsecolor script.

Marija

Hi Marija,

It is a bit difficult to sort through. Search for the following line:

iscontb = if(btwn(0,v,1),btwn(.4,frac(ndivs*v),.6),-1);

Changing the 0.4 and 0.6 values will affect the width of the bands. These fractions are relative to the spacing of band values.

Hope this helps.
-Greg

···

From: Marija Velickovic <[email protected]>
Date: December 16, 2010 2:42:48 AM PST

Hi,

I was exploring falsecolor.csh to see how exactly contour bands are defined in it. Since method it is mixture of shell command + cal files and various functions inside them, I couldn't determine how is exactly defined "width" of contour bands.

I understand that idea is to color areas in image with radiance in some range above and below each radiance value in the scale.
For example if blue color is defined with 500lux, on final image in blue will be colored areas with luminance ranging from 500-x to 500+y values.
Question is how x and y values are calculated? I suppose they depend on maximal scale value and number of color, but cant determine exact equation from falsecolor script.