Object-counting in image processing.

I am doing a project on object-counting from images. For that, I have taken two images- one is the background containing no objects and the other containing some objects(toy-cars) over it.

Background Image:

------------------------------------------------------------

Image with objects over it:

The difference-image between the two images is taken and converted to black-and-white using a threshold value. The problem is that some of the pixels inside the objects match with the background and so these pixels are also getting subtracted completely and as a result, some black pixels are occurring inside the objects as you can see from the b/w image below and so the objects are getting divided into parts.

I need each object to occur as one object so that we get the exact no of objects. Can someone please help me regarding this.

The code I have used is below:

I = imread('Snap5.png');

J = imread('bg1.png');

K = imabsdiff(I,J);

th = graythresh(K);

L = im2bw(K,th);

[LabeledIm,ConnectedObj] = bwlabel(L,4);

coloredLabels = label2rgb (LabeledIm, 'hsv', 'k', 'shuffle');

ConnectedObj

figure,

subplot(221), imshow(K), title('Difference'),

subplot(222), imshow(L), title('Thresholded BW'),

subplot(223), imshow(coloredLabels), title('Color-labeled Objects');

[Shivam Garg]

Hello I am Also Trying to Calculate the Number Of Vehicle on Road.

I am using OPENCV for that.

I am not able to understant what all u have done. Can u please explain what is the basic aglorithm u have used.

I am trying with background subtraction But it says that u need to have continuous frame to do that.

I will be very thankful to u

Shivam Garg

[Image Analyst]

You should ask in an OpenCV forum instead of a MATLAB/Simulink forum.

[Project Traffic]

can you please upload the exact matlab code for counting the objects even if there is another object within the same object and give a count of one

[Image Analyst]

Call imfill() to combine internal blobs, then call regionprops().

[Saqib Ali]

use strel (structuring elements) method for helping MATLAB to guess the size of object.

[Image Analyst]

"Project Traffic", 3.5 years old so I realize you probably won't answer but re-reading the question, when you say "can you please upload the exact matlab code for counting the objects even if there is another object within the same object and give a count of one" it sounds ambiguous. I'm unsure if you have an object containing another object, like a bullseye target,

do you want that to count as one white object or two? Normally bwlabel() whould give a count of 2.

[labeledImage, numRegions] = bwlabel(binaryImage);

If you want it to count as 1, then you can either fill the outer objects and label

binaryImage = imfill(binaryImage, 'holes');
[labeledImage, numRegions] = bwlabel(binaryImage);

However this would change the measurements returned by regionprops since now the blob's area is different - it's just one giant disc instead of a thin ring. Or you could get rid of "interior" blobs using some morphological tricks so that there is just one thin white ring. Let me know if you need that.

[Jeje Ahmad]

hi

can try your code to counting the number of cars?

@KangKan

[Jeje Ahmad]

@KangKan

[Image Analyst]

Kangkan hasn't been here in 7 years, but you can sure give it try. Just copy, paste, and change image filename, and run.

Answer 1

[Image Analyst]

Replace these two lines:

L = im2bw(K,th);
[LabeledIm,ConnectedObj] = bwlabel(L,4);

with these

binaryImage = im2bw(K,th);
binaryImage  = imclose(binaryImage, true(5)); % Close gaps and connect nearby blobs.
binaryImage = bwconvhull(binaryImage); % Make shapes convex and fill holes.
[LabeledIm,ConnectedObj] = bwlabel(binaryImage,4);

[Image Analyst]

Also see my Image Segmentation tutorial in my File Exchange http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

Answer 2

[Fasih Chishti]

Hello! I'm doing project on Image counting... How could i count the objects from any picture? Thanks