best approach for template matching of binary (edge) images

Question

To all skimage and opencv gurus, given:

1. Scene Image

1. Template Image

What is the best approach to find the cross in the scene image ? These are output from smoothing, and canny filters. Now, I tried all kinds of examples in skimage, and opencv template matching but the results are not satisfactory.

My ideal solution will be rotation, translation invariant (scale invariant will be a bonus) . Is there a way to just convert to contour points and them do a registration point cloud ? Will that be more accurate ? I thought about RANSAC but how do I give the inputs to RANSAC?

Thanks

Answer 1

My approach to solving a similar problem was to create a large set of rotated and scaled variations of the template image and use opencv's matchTemplate function.

I would also recommend the preprocessing step of filling all detected and closed contours (for both template and scene image) white since the largely black template image might create false positives in the black regions of the scene image.