How to find first white pixel in an image?

I have done few process on my image and got stuck here. So far,this is the result that i got: http://s20.postimage.org/5dg34043h/Pra_processing.png. For now, all i need is to find the first white pixel in that image and do some mark on it. We'll start at the bottom right corner of the grid, scan each column of pixels from the bottom going upwards-starting from the rightmost column and proceeding to the left-until we encounter a first white pixel. We'll declare that pixel as our "start" pixel.

Answer 1

[Image Analyst]

[row, column] = find(yourImage, 1, 'last');

Answer 2

[Ainul]

Hello guys..

I've got the same problem here and already use [row, column] = find(yourImage, 1, 'last'); but the result isn't show how it suppose to be..

Here is my code (from top left):

[row, column] = find(edge_s, 1, 'first');
hold on;
plot(row,column,'r.', 'MarkerSize',5,'LineWidth',5);

Result: Its being marked with red dot but the position isn't right.

http://postimage.org/image/okchtrlb5/

Do you have any idea?

[Jeff E]

The plot function accepts coordinates in X and then Y. You have provided it with Row (Y) and then Column (X). Switch them, and the point will be plotted correctly.

[Ainul]

well thanks.. It actually works... =)

Answer 3

[Prabira Sethy]

How to find middle white pixel in each row??

[Image Analyst]

Define "middle". If the pixel half way between the first and last white pixel is not also white, then which column do you want to return?