OpenCV, Python: How to stitch two images of different sizes and transparent backgrounds

Question

I\'ve been working on a project where I stitch together images from a drone flying in a lawn mower pattern. I am able to stitch together images from a single pass (thanks to

Answer 1

I think Flann is probably not what you want to use for matching here. First, indeed, since you're converting to grayscale, the black spots, the edges of the images, etc will likely be included in your feature set, which you do not want. Secondly, Flann uses methods to build specific descriptors for fast searching through an image database; it is used for CBIR, not for homography estimation.

Instead, just take a normal approach with SIFT or SURF or ORB or BRISK. Note that all of those allow to add a mask for their keypoint detection step, so that you can create a mask from the alpha channel to ignore keypoints in. See the OpenCV docs for SIFT and SURF and for ORB and BRISK for more.