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matlabplotpixel

find and plot locations of minimum pixel intensity in each column

i have a gray scale image. i would like to scan column by column to find the location of the darkest pixel in each column, obtain the (x,y) locations and plot a mark on it. the output of the prog should be an image with marks on each column's darkest pixel.

my attempt resulted in no output at all. please help me.

[row col] =size(i11);
for j=1:col
    for i=1:row
        darkestPixelValue = min(i11(i,j));    
        [i,j]=find(i11==darkestPixelValue);
        plot (i,j);
    end
end
Solution

  • Use the second output argument of min:

    >> [mn row] = min( i11, [], 1 );
>> figure; imshow( i11 ); hold on; scatter( 1:size(i11,2), row, 40, 'xr' );