pythonopencvsiftkeypoint

Extract pixel values from an image for CV2.Keypoints objects

I have a tuple (Keypoints, Descriptors) extracted from img1 using the method:

(kp, des) = sift.detectAndCompute(img1,None)

kp is a list containing cv2.KeyPoint objects, and des is a numpy.array containing their 128 dimensional descriptors

I want to retrieve for each keypoint a pixel value taken from another image img2 of the same size and store them in the tuple (kp, des) to have in the end a tuple like (kp, des, pixel_values)

Thank you very much in advance.

Solution

  • You can access pixel coordinates from kp. Like below:

    kp[0].pt

    and i think following code does what you want:

    (kp[i], des[i], img2[kp[i].pt] for i in range(len(kp)))