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

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.

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the last of my output will be like this.

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Answer 1

[Mohammad Abouali]

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.

[Image Analyst]

Basically the same answer I gave him in his duplicate question, though I used 'first' on the white profile instead of 'last' on the black profile to get the top row instead of the last row.

% Find the vertical profile
verticalProfile = sum(binaryImage, 2);
% Find the top row
topRow = find(verticalProfile, 1, 'first');

Guillaume did the same thing using min(). Seems did not clariff any thing there, because you give essentially a similar answer. Maybe he wants the center column in case the spike has a flat top???? In that case he can use regionprops() to find the centroid of the row containing the top.

[Nurul Najmah]

   % Find the vertical profile
for verticalProfile = sum(maxImage, 2);
% Find the top row
topRow = find(verticalProfile, 1, 'first');
hold on;
plot(topRow(1,:),'rs');

end

the mark is not on the whitetoprow..where am i got it wrong?

[Mohammad Abouali]

Well, execute the code I gave you and you should get this:

BWImage=imread('BWImage.png');
>> row=find(sum(BWImage,2)==0,1,'last')+1;
col=find(BWImage(row,:)~=0);
row=row*ones(size(col));
Points=[row(:) col(:)];
imshow(BWImage)
hold on
plot(Points(:,2),Points(:,1),'rs','MarkerSize',10)

So that code is doing what you asked.

[Nurul Najmah]

thank you so much. It works well. Thanks a lot.

[Image Analyst]

As would have the code in your duplicate question. Anyway, please vote for his answer and mark it as Accepted so he can get "reputation points" for it.

Answer 2

[jimmy]

i want to ask how i can sect the column which have maximum number of black pixel