MATLAB: How to change specific pixel from black to white

pixel

suppose if i have given a image of cameraman ..is there way to select only cameraman image and convert only that region to white and rest to black color. i had gone through matlab answers where image analyst had suggested ROI unfortunately i am not to able to find it in my matlab help.
any help would be appreciated.

Best Answer

Suppose you did something like
I = imread('cameraman.tif');
mask = I <= 64;
imshow(mask)
This particular approach turns a bit too much white, but it illustrates that you can turn part of an image white selectively with the rest turning black.
The rest of the task is in identifying your object (or person) of interest without selecting other things.