How to detect ellipses in image without using fitEllipse() in opencv?

As you already got, you don’t need ellipse fitting, but ellipse detection. You can find in my other answer two papers with C++ code available. I’ll report here for completeness: L. Libuda, I. Grothues, K.-F. Kraiss, Ellipse detection in digital image data using geometric features, in: J. Braz, A. Ranchordas, H. Arajo, J. Jorge (Eds.), … Read more

Superimpose heatmap on a base image OpenCV Python

Updated Answer — 29th April, 2022. After the repeated comments I have decided to update this post with a better visualization. Consider the following image: img = cv2.imread(‘image_path’) I obtained a binary image after performing binary threshold on the a-channel of the LAB converted image: lab = cv2.cvtColor(img, cv2.COLOR_BGR2LAB) a_component = lab[:,:,1] th = cv2.threshold(a_component,140,255,cv2.THRESH_BINARY)[1] … Read more

OpenCV with GigE Vision Cameras [closed]

Gig-E is a communication standard for a wide range of cameras. OpenCV now contains a wrapper for The Prosilica Gig-E based cameras (see CV_CAP_PVAPI) But in general it’s better to use the camera’s native API to get the data and then use openCV to convert the returned data into an image, openCv contains a number … Read more

Are there any fast alternatives to SURF and SIFT for scale-invariant feature extraction?

Although you already choose BRISK, you might find FREAK interesting. Author claims to have better results than BRISK and ORB. I should also add that ORB is scale-invariant but has some problems in that area. So I would still recommend it for someone to try it. The FREAK source code is compatible with OpenCV (how … Read more