MATLAB CVIP Toolbox Functions
Histogram
The histogram category allows the user to perform standard histogram
modification techniques for image enhancement such has histogram
equalization, stretching, sliding, specification, linear mapping and
local equalization. The unsharp masking sharpening algorithm is also
included here since it is an enhancement method that uses both a
histogram shrink and stretch. For histogram equalization with color
images, the user can specify which of the red, green, or blue bands to
base the equalization on. To recreate the functionality in CVIPtools,
which allows the user to perform histogram equalization on the lightness,
or L band, of an HSL transformed image, the CVIP Toolbox functions can be
used. This is accomplished by this sequence: 1) perform the HSL color
transform, 2) extract the L, or third, band from the image, 3) perform
histogram equalization on the L band, 4) assemble the color image with
the H, S and the histogram equalized L, bands, 5) perform the inverse HSL
color transform on the result.