Hello, there is no error message regarding my code but the program is busy forever. what id the problem?

Question

Lama Awawdeh 2018-12-21

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/436801-hello-there-is-no-error-message-regarding-my-code-but-the-program-is-busy-forever-what-id-the-prob

回答： Image Analyst 2018-12-22

im = imread('retina.png');
im=rgb2gray(im);
S=size(im);
numR=S(1);
numC=S(2);  %now without  edges
 
%Voting
Accumulator = zeros(S); % initialize the accumulator
[yIndex ,xIndex] = find(im); % find x,y of edge pixels
r=30; r2 = r^2; % square of radius, to prevent its calculation in the loop
for cnt = 1:numel(xIndex)
    low=xIndex(cnt)-r;
    high=xIndex(cnt)+r;
    
    if (low<1) 
        low=1; 
    end
    
    if (high>numC)
        high=numC; 
    end
    
    for x0 = low:high
        yOffset = sqrt(r2-(xIndex(cnt)-x0)^2);
        y01 = round(yIndex(cnt)-yOffset);
        y02 = round(yIndex(cnt)+yOffset);
                
        if y01 < numR && y01 >= 1
            Accumulator(y01,x0) = Accumulator(y01,x0)+1;
        end
        
        if y02 < numR && y02 >= 1
            Accumulator(y02,x0) = Accumulator(y02,x0)+1;
%            rectangle('position',[x y 1 1],'EdgeColor','r');      
  
        end
    end
end
% Finding local maxima in Accumulator
thresh=4;
y0detect = []; x0detect = [];
AccumulatorbinaryMax = imregionalmax(Accumulator);
[Potential_y0 ,Potential_x0] = find(AccumulatorbinaryMax == 1);
Accumulatortemp = Accumulator - thresh;
for cnt = 1:numel(Potential_y0)
    if Accumulatortemp(Potential_y0(cnt),Potential_x0(cnt)) >= 0
        y0detect = [y0detect;Potential_y0(cnt)];
        x0detect = [x0detect;Potential_x0(cnt)];
        
    end
end
figure,imshow(im);
 
 for i=1:length(x0detect)
     x0=x0detect(i);
     y0=x0detect(i);
     
     for x=1:numC
         y=round(y0-sqrt(r2-(x-x0)^2));
         if y<=numR && y>=1
              rectangle('position',[x y 1 1],'EdgeColor','r');
         end
     end
 end 

1 个评论
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madhan ravi 2018-12-22

Try using logical indexing to avoid loops

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Answer 1

Cris LaPierre 2018-12-22

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/436801-hello-there-is-no-error-message-regarding-my-code-but-the-program-is-busy-forever-what-id-the-prob#answer_353554

You are looping through every pixel in the image. Your comment (% find x,y of edge pixels) makes me think this may be unintentional. That is going to take a while.

There are also several nested for loops, which add to the run time.

You may try seeing if you can take advantage of matrix math to eliminate some of them.