How to map the lowest 15 grayscale levels to 15 and highest 15 grayscale values to 240 in a 256*256 image?

i am working on IWT and i am losing the extremes of data when i apply transforms. i went through some documentation and found a histogram mod is needed. can someone please help me with the code and documention? thanks in advance

Answer 1

[Image Analyst]

Try this:

grayImage(grayImage < 15) = 15; % Everything 14 and less becomes 15.
grayImage(grayImage > 240) = 240; % Everything 241 and higher becomes 240.