MATLAB: How to scan binary image and stop if value image=0

image processingscanning

clear all; clc;
img = imread('asmfx.jpg');
[m,n,p] = size(img);
figure; imshow(img);
    [xreg yreg value] = ginput(1); 
    title(['Row',num2str(xreg),'Col',num2str(yreg)])
    if (length(xreg) < 1)
i want to snanning image with first set point with mouse like black rectangle. how can i scan up with row. and stop if value setpoint = 0. thanks before
      return%break
    end
    
   %% inisialisasi posisi awal 
   sisiKanan  = [xreg+10 yreg];
   sisiTengah = [xreg yreg];
   sisiKiri   = [xreg-10 yreg];
  %% scan tengah
  markedTengah = insertMarker(img,[xreg yreg],'star','color','r','size',5);
  
 for scanTengahY = xreg
  for scanTengahX = yreg : yreg-100
      %rr=[r(scanTengahX,scanTengahY),g(scanTengahX,scanTengahY),b(scanTengahX,scanTengahY)];
     if scanTengahX == sum(cumprod(a~=0))+1   
        break;
        markedTengah = insertMarker(img,[scanTengahX scanTengahY],'star','color','r','size',5);
        imshow(markedTengah); 
      end
   end
  end
      
%marked = insertMarker(img,[xreg yreg],'star','color','r','size',5);

Best Answer

Try this
[x,y] = ginput(1);
row = round(y);
column = round(x);
thisColumn = binaryImage(:, column); % Extract this one column from the binary image.
while row >= 1 && thisColumn(row)
    row = row - 1;
end
When it's done, row will equal the row of the first 0 above the clicked point (which may be the clicked pint itself if you clicked on a black place). If you want the last white pixel before we hit black, add 1 to row. If row = 0, then there were no black pixels in the column above the clicked point.
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