What would be the outcome of this line?

Hi

If I use this line code

for col = col1 : col2
    row2 = find(mask(:, col), 1, 'last'); % Get bottom row of mask
    heights(col) = row2 - topRow;
    end

The heights will be a number of pixel intensity (e.g. pixel intensity value of X - pixel intensity value of Y) OR will be a number of pixels (e.g. 320 - 310 pixels = 10 pixels)??

Can you please clarify?

Thank you

[Stelios Fanourakis]

Ok, now I know that the above line gives an arithmetic value, like 320-310 = 10 pixels.

But why when I use the line

heights(col) = rgbImage(320,col) - rgbImage(340,col);

I get the difference of pixel intensity values of those two pixels on the image? What's the difference between those two lines?

For instance if the pixel at position X: 320 Y: 454 has value of RGB: 88

And the pixel at position X: 340 Y: 454 has value RGB: 90

I will get result 2.

Why should I get result of 2 and NOT 20 which is the number of pixels between the two points?

Can someone explain clearly the difference?

[Rik]

You are subtracting positions to get a distance, you are subtracting values to get an intensity difference.

Since in this line

heights(col) = rgbImage(320,col) - rgbImage(340,col);

you're doing the second, it stands to reason you get an intensity difference, not a distance.