MATLAB: I want to mark the highest point of any non-black pixel within the image to find the max point.

algorithmduplicate postimage analysisimage processingpoint location

here is my image. I had ask before at https://www.mathworks.com/matlabcentral/answers/213198-i-want-to-mark-only-the-highest-middle-point-of-binary-image-but-it-show-the-min-point-too but i might ask in not clear question.

the last of my output will be like this.

Best Answer

row=find(sum(BWImage,2)==0,1,'last')+1;
col=find(BWImage(row,:)~=0);
row=row*ones(size(col));
Points=[row(:) col(:)];

Points contains the row and column of the point or points at the top.

Related Solutions

MATLAB: How to mark the highest white pixel through bottom to the top? using grayscale image.

The white pixels are the ones where all three color components R, G, and B equal 255, so you can get a 2D logical matrix of either white or non-white pixels like this:

I = imread('test.png'); 
white = sum(I,3)==3*255;

The highest white pixel in the image corresponds to the first white pixel in each column, so you can loop through columns going from left to right to find the first white pixel in each column:

row = nan(1,size(white,2)); % preallocates the rows.  
for k = 1:length(row) 
    try
        row(k) = find(white(:,k),1,'first');  
    end
end
imshow(I)
hold on
plot(1:k,row,'b-')

MATLAB: How to show the coordinate automatically after plot the marker

Do you mean you want a label near the plotted point? You could use the text command, using your Points variable to place it:

text(Points(1,2),Points(1,1),['This is (',num2str(Points(1,2)),',',num2str(Points(1,1)),')'])

You would then need to loop over your points.

Best Answer

Related Solutions

MATLAB: How to mark the highest white pixel through bottom to the top? using grayscale image.

MATLAB: How to show the coordinate automatically after plot the marker

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