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image-processingcolorsdetection

Improving detection of the orange colour in MATLAB

One of my tasks is to detect some colours from ant colonies from the 16000 images. So, I've already done it very good with blue, pink and green, but now I need to improve detection of the orange colour. It's a bit tricky for me, since I am new one in a field of image processing. I put some examples what I have done and what was my problem.

Raw image:http://img705.imageshack.us/img705/2257/img4263u.jpg

Detection of the orange colour:http://img72.imageshack.us/img72/8197/orangedetection.jpg

Detection of the green colour:http://img585.imageshack.us/img585/1347/greendetection.jpg

I had used selectPixelsAndGetHSV.m to get the HSV value, and after it I used colorDetectHSV.m to detect pixels with the same HSV value. Could you give me any sugesstion how to improve detection of the orange colour and not to detect whole ants and broods around them?

Thank you in advance!

function [K]=colorDetectHSV(RGB, hsvVal, tol)

HSV = rgb2hsv(RGB);

% find the difference between required and real H value:
diffH = abs(HSV(:,:,1) - hsvVal(1));

[M,N,t] = size(RGB);
I1 = zeros(M,N); I2 = zeros(M,N); I3 = zeros(M,N);

T1 = tol(1);

I1( find(diffH < T1) ) = 1;

if (length(tol)>1)
% find the difference between required and real S value:
diffS = abs(HSV(:,:,2) - hsvVal(2));
T2 = tol(2);
I2( find(diffS < T2) ) = 1;
if (length(tol)>2)
% find the difference between required and real V value:
difV = HSV(:,:,3) - hsvVal(3);
T3 = tol(3);
I3( find(diffS < T3) ) = 1;
I = I1.*I2.*I3;
else
I = I1.*I2;
end
else
I = I1;
end
K=~I;
subplot(2,1,1),
figure,imshow(RGB); title('Original Image');
subplot(2,1,2),
figure,imshow(~I,[]); title('Detected Areas');
Solution

  • You don't show what you are using as target HSV values. These may be the problem.

    In the example you provided, a lot of areas are wrongly selected whose hue ranges from 30 to 40. These areas correspond to ants body parts. The orange parts you want to select actually have a hue ranging from approximately 7 to 15, and it shouldn't be difficult to differentiate them from ants.

    Try adjusting your target values (especially hue) and you should get better results. Actually you can also probably disregard brightness and saturation, hue seems to be sufficient in this case.