I want to find white pixel, from fill the from bottom to top. Once the white pixels is found, I want to fill the next (same columns,row++) with all black. I have BW image using Sobel Edge Detection.

1. From the bottom left of the pixel(first column), I want to find the edge pixel (white pixel=0)

[rows, columns]=size[BW];
% Output image output = false(rows, columns); % Initialize

for col = 1 : columns 
lastRow = find(BW==0); 
new_value=(row+1,col)==1;

2. I got stuck here. Once I find the white pixel from (first column,last row), as a result, I want to fill the next (row++) as all black pixels. Then move to the (second column, last row) with the same situation.

[Image Analyst]

I'm not sure how this differs from the need you asked in your other question. As far as I can tell, my answer will the same as http://www.mathworks.com/matlabcentral/answers/195861#answer_173774. If that is different, then please do a better job of explaining why that code won't work here.

Answer 1

[Image Analyst]

Here's a full blown demo in your other question: http://www.mathworks.com/matlabcentral/answers/210272#answer_175817