Computes the descriptors for a set of keypoints detected in an image or image set
[descriptors, keypoints] = obj.compute(img, keypoints)
[descriptors, keypoints] = obj.compute(imgs, keypoints)
Input
- img Image (first variant), 8-bit/16-bit grayscale image.
- imgs Image set (second variant), cell array of images.
- keypoints Input collection of keypoints. Keypoints for
which a descriptor cannot be computed are removed. Sometimes
new keypoints can be added, for example: cv.SIFT duplicates
keypoint with several dominant orientations (for each
orientation). In the first variant, this is a struct-array of
detected keypoints. In the second variant, it is a cell-array,
where
keypoints{i}
is a set of keypoints detected in
imgs{i}
(a struct-array like before).
Output
- descriptors Computed descriptors. In the second variant of
the method
descriptors{i}
are descriptors computed for a
keypoints{i}
. Row j
in descriptors
(or descriptors{i}
)
is the descriptor for j
-th keypoint.
- keypoints Optional output with possibly updated keypoints.