How to work on the white region of this binary mask?

I have a mammogram database and I want to apply some features on the white region.

[Afaf Saad]

Did you removed the pectoral part ? if yes then how ?

Answer 1

[Image Analyst]

One easy way is to just process the whole image and then erase the resulting image outside the mask

outputImage = some algorithm using the entire image....
maskedOutputImage = outputImage; % Initialize
maskedOutputImage(~mask) = 0; % Set to zero outside the mask.

Answer 2

[KALYAN ACHARJYA]

Yes You can do that easily, Considering binary_image.jpg as a binary image

BW1=binary_image;
binary_image(BW1==1)=your do operation statement or values here:

[Image Analyst]

I think you meant binary_image(BW1 == 1). But be aware that binary_image(BW1=1) is a 1-D vector, not a 2-D image so your algorithm would have to account for that.