Help needed in debugging the code for Identifying round objects ..
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This is a matlab function that i wrote for identifying tound objects.i'm kinda a newbie in image processing so i'm guessing my code is messed up some where.But i don't seem to understand my error.please do help..:)
The code is ::
function [ ] =imagetestfile( im )
%This is a fuction to identify round objects from the given input image
im1=rgb2gray(im);
thresh=graythresh(im1);
im1=im2bw(im1,thresh);
[a b]=bwboundaries(im1);
info=regionprops(b,'Area','Centroid','Perimeter');
i=1;
for k=1:length(a)
q=(4*pi*info(k).Area)/(info(k).Perimeter)^2;
if q>0.80
c{i}=a{k};
info1{i}.Centroid=info{k}.Centroid;
i=i+1 ;
end
end
imshow(im);
hold on
for k=1:i-1
x=info1(k).Centroid(1);
y=info1(k).Centroid(2);
boundary = c{k};
plot(boundary(:,2), boundary(:,1), 'w', 'LineWidth', 6);
line(x,y, 'Marker', '*', 'MarkerEdgeColor', 'r');
end
hold off
end
采纳的回答
Sven
2011-11-13
This is a pretty good attempt, and I think the code below does what you intended.
The one biggest change is that instead of trying to "copy" into a new variable "info1", I just build up a mask called "isCircle". It holds one element for every label, and just gets set to true if that element is circular.
The only other changes were to use "noholes" in the bwboundaries call (it's a little quicker and I think what you intended) and using "plot" instead of "line" (which is just a simplification).
function [ ] = imagetestfile( im ) %This is a fuction to identify round objects from the given input image
im1=rgb2gray(im);
thresh=graythresh(im1);
im1=im2bw(im1,thresh);
[a b]=bwboundaries(im1,'noholes');
info=regionprops(b,'Area','Centroid','Perimeter');
isCircle = false(1,length(a));
for k=1:length(a)
q=(4*pi*info(k).Area)/(info(k).Perimeter)^2;
if q>0.80
isCircle(k) = true;
end
end
imshow(im);
hold on
for k=find(isCircle)
x=info(k).Centroid(1);
y=info(k).Centroid(2);
boundary = a{k};
plot(boundary(:,2), boundary(:,1), 'w', 'LineWidth', 6);
plot(x,y, 'r*');
end
hold off
end
6 个评论
Abel Babu
2011-11-13
Sven
2011-11-13
No problems abel - congrats on asking a good question (clear, code to show what you'd done so far, etc)
Abel Babu
2011-11-16
Sven
2011-11-16
Take a look at what the edge function returns - a binary matrix of only the edges. Also note the different "flavours" of the edge function (sobel, prewitt, etc.). It is not guaranteed to fully "connect" an edge right around the objects that you were otherwise connecting using bwboundaries.
Furthermore, consider what the "Area" of each connected group of pixels would be if they were *only* the pixels returned by the edge() function. Can you see that any calculations such as:
q=(4*pi*info(k).Area)/(info(k).Perimeter)^2;
No longer make sense when the Area is not the area of the closed region?
Abel Babu
2011-11-17
Image Analyst
2011-11-17
You can clear all this up by just posting your image somewhere so we can perfect the code for you.
更多回答（1 个）
Image Analyst
2011-11-13
0 个投票
You should be able to get rid of your first loop by doing something like (untested):
isCircle =(4*pi*[info.Area] ./ [info.Perimeter]^2) > 0.8;
That should get the entire "isCircle" array all in one shot without using a loop.
3 个评论
Abel Babu
2011-11-14
Image Analyst
2011-11-17
That makes no sense. You must have done something wrong, like omitted a dot or something.
Abel Babu
2011-11-24
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