MATLAB: For similar feature points in two image, How can i find angular displacements between all similar points

image analysisimage processingMATLABvideo processing

I have located the similar feature points in two consecutive image frames by A-SIFT. Now i need to find the angular displacements between similar feature points in two images.

Similar work was done in the paper ''A Video-based Speed Estimation Technique for Localizing the Wireless Capsule Endoscope inside Gastrointestinal Tract''(screenshot attached)

Best Answer

If a=[a1;a2] and b=[b1;b2] are two 2D matching points, you can measure the angle theta between them by inverting the cosine formula:

theta= acos((a'*b)/(norm(a)*norm(b)));

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Assuming you're on R2017b or later:

polygon = polyshape(vertices);  %vertices is a Nx2 matrix of points
[centroidx, centroidy] = centroid(polygon);
rotated_polygon = rotate(polygon, angle, [centroidx centroidy]);
plot([polygon rotated_polygon])

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