HELP...How to detect corners using Harris corner detection Algorithm?
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Hi, I am having trouble with getting this corner detection code to work properly. It works fine but points are scattered all over the place, i want the corner points to be detected within the bounding box. is there anything i need to add or edit?
This is the code i have so far:-
faceDetector = vision.CascadeObjectDetector('FrontalFaceCART');
cornerDetector = vision.CornerDetector('Method','Harris corner detection (Harris & Stephens)');
Irgb2gray=rgb2gray(Iface);
bboxes = step(faceDetector, Irgb2gray);
corners = detectHarrisFeatures(Irgb2gray);
Irgb2gray = insertObjectAnnotation(Iface, 'rectangle', bboxes, 'Face');
figure, imshow(Irgb2gray), title('Detected faces'); hold on;
plot(points.selectStrongest(50));
Thank you in advance.
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Anand
2013-11-17
Try the syntax with the 'ROI' parameter, something like this:
corners = detectHarrisFeatures(Irgb2gray,'ROI',bboxes(1,:));
This will detect Harris corners within the first bounding box in bboxes.
9 个评论
Anand
2013-11-17
Anand
2013-11-18
There's probably something missing/incorrect in your code snippet.
Take a look at this code snippet below and see if it helps. First run this and make sure all the detected Harris corners are within the faces displayed. Then replace 'visionteam.jpg' with your image.
% Create a detector object
faceDetector = vision.CascadeObjectDetector;
% Read input image
I = imread('visionteam.jpg');
% Detect faces
faces = step(faceDetector,I);
% Annotate detected faces
Iannotated = insertObjectAnnotation(I,'rectangle',faces,'Face');
figure; imshow(Iannotated);
% Detect corners on faces
for i = 1 : size(faces,1)
corners = detectHarrisFeatures(rgb2gray(I),'ROI',faces(i,:));
hold on;
plot(corners.selectStrongest(20))
end
hold off;
Hope that helps!
Anand
2013-11-21
Anand
2013-11-21
Anand
2013-11-21
I can speak to the first question, but don't know much about the second.
You should be able to use the Harris detector as you are using it and select the left and right most corner points in the mouth ROI.
Is the image you showed me the result of running the code snippet? If so, it may mean there aren't strong enough corners detected. In this case, you should try adjusting parameters - maybe increase the MinQuality.
Anand
2013-11-21
Anand
2013-11-21
To increase the MinQuality parameter, do something like this.
corners = detectHarrisFeatures(rgb2gray(I),'ROI',faces(i,:),'MinQuality',0.05);
Once you get corner points, use the Location property of corner points to find the left-most and right-most corners.
Anand
2013-11-21
so this is the code for it:-
the points are not detected inside the bounding box and they are not covering the corners of the mouth. is there anything that is wrong?
this is the result
Anand
2013-11-21
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