# \#feature-detection **URL:** https://forum.opencv.org/tag/feature-detection/177.md [Latest](https://forum.opencv.org/latest.md) · [Categories](https://forum.opencv.org/categories.md) · [Tags](https://forum.opencv.org/tags.md) --- ## [\[Help\] Struggling to detect pool pockets and place these pockets in live video](https://forum.opencv.org/t/help-struggling-to-detect-pool-pockets-and-place-these-pockets-in-live-video/24487)
**Author:** [@Acookook](https://forum.opencv.org/u/Acookook)\ **Replies:** 5\ **Last updated:** [May 5, 2026, 6:33pm UTC](https://forum.opencv.org/t/help-struggling-to-detect-pool-pockets-and-place-these-pockets-in-live-video/24487 "2026-05-05T18:33:13Z")
I am working on a master’s thesis project -an augmented-reality training system for eight-ball pool. The goal is to detect the real pool-table state from an overhead phone camera, map balls and pockets into table-plane c… --- ## [Why are images not warped before feature detection and matching in the stitching pipeline?](https://forum.opencv.org/t/why-are-images-not-warped-before-feature-detection-and-matching-in-the-stitching-pipeline/23861)
**Author:** [@mapf](https://forum.opencv.org/u/mapf)\ **Replies:** 4\ **Last updated:** [September 1, 2025, 10:31am UTC](https://forum.opencv.org/t/why-are-images-not-warped-before-feature-detection-and-matching-in-the-stitching-pipeline/23861 "2025-09-01T10:31:30Z")
Hi, so I am new to image stitching. Ultimately, I would like to implement a pipeline for CUDA (which I am also unfamiliar with), but for now, I am trying to implement a pipeline in Python to understand the processes conc… --- ## [Detecting Perspective Angle](https://forum.opencv.org/t/detecting-perspective-angle/6358)
**Author:** [@UmerQaisar](https://forum.opencv.org/u/UmerQaisar)\ **Replies:** 2\ **Last updated:** [November 25, 2024, 12:27pm UTC](https://forum.opencv.org/t/detecting-perspective-angle/6358 "2024-11-25T12:27:35Z")
Hi, I’m trying to replace texture of a floor, I’m successfully able to to detect the floor and replace it with new texture but I’m unable to match the perspective angle of new floor. currently I’m manually setting the … --- ## [Image order in draw\_matches](https://forum.opencv.org/t/image-order-in-draw-matches/19011)
**Author:** [@vds87xqq](https://forum.opencv.org/u/vds87xqq)\ **Replies:** 0\ **Last updated:** [October 19, 2024, 1:01am UTC](https://forum.opencv.org/t/image-order-in-draw-matches/19011 "2024-10-19T01:01:35Z")
I am trying to visualize my matches using the draw\_matches() function. However, I noticed, that this function is very picky with the order of the images and the keypoints. If the order is not the exact same one from the… --- ## [Why doesn't my mask correctly divide DetectAndCompute into quadrants?](https://forum.opencv.org/t/why-doesnt-my-mask-correctly-divide-detectandcompute-into-quadrants/17907)
**Author:** [@kra2008](https://forum.opencv.org/u/kra2008)\ **Replies:** 5\ **Last updated:** [July 2, 2024, 5:25pm UTC](https://forum.opencv.org/t/why-doesnt-my-mask-correctly-divide-detectandcompute-into-quadrants/17907 "2024-07-02T17:25:54Z")
Ultimately I’m trying to align two photos for stereo viewing by humans. I’m NOT trying to rectify them to help a computer see in 3D. I have several decent methods of getting this done already but I’m trying to explore a … --- ## [Number of keypoints does not match number of descriptors](https://forum.opencv.org/t/number-of-keypoints-does-not-match-number-of-descriptors/17866)
**Author:** [@farhadbat](https://forum.opencv.org/u/farhadbat)\ **Replies:** 1\ **Last updated:** [June 7, 2024, 5:16am UTC](https://forum.opencv.org/t/number-of-keypoints-does-not-match-number-of-descriptors/17866 "2024-06-07T05:16:03Z")
Hi everyone, I have a set of keypoints extracted with an aribirary keypoint detector (orb, random pixel, GFTT, etc). Now, I want to extract ORB descriptor to each keypoint. I used the following code for it; however, nu… --- ## [Help Detecting Dark Patch Among Other Dark Features](https://forum.opencv.org/t/help-detecting-dark-patch-among-other-dark-features/11500)
**Author:** [@somethingvague](https://forum.opencv.org/u/somethingvague)\ **Replies:** 0\ **Last updated:** [January 5, 2023, 3:43am UTC](https://forum.opencv.org/t/help-detecting-dark-patch-among-other-dark-features/11500 "2023-01-05T03:43:16Z")
I’m looking for some help detecting a round, dark patch in the lower left of the attached image, and similar features in other images that will be in different locations. If the image was more uniform, it seems like thre… --- ## [Asynchronous feature detection not running asynchronously](https://forum.opencv.org/t/asynchronous-feature-detection-not-running-asynchronously/10889)
**Author:** [@ChrisN](https://forum.opencv.org/u/ChrisN)\ **Replies:** 3\ **Last updated:** [November 10, 2022, 8:57pm UTC](https://forum.opencv.org/t/asynchronous-feature-detection-not-running-asynchronously/10889 "2022-11-10T20:57:24Z")
I have been experimenting with the asynchronous feature detection calls, but when I time them it seems they still block the CPU for a significant amount of time. I tried to detect ORB features similar to the below: voi… --- ## [Not all Feature Points are displayed (with ORB)](https://forum.opencv.org/t/not-all-feature-points-are-displayed-with-orb/9026)
**Author:** [@skrippsta](https://forum.opencv.org/u/skrippsta)\ **Replies:** 0\ **Last updated:** [June 3, 2022, 8:53am UTC](https://forum.opencv.org/t/not-all-feature-points-are-displayed-with-orb/9026 "2022-06-03T08:53:39Z")
I have the problem that not all feature points are displayed in one image. I use the ORB algorithm with OpenCV-JS for the FeaturePoint “detection”. The figure shows my problem: The feature points that are on the edge ar… --- ## [goodFeaturesToTrack : only detecting bright features](https://forum.opencv.org/t/goodfeaturestotrack-only-detecting-bright-features/8901)
**Author:** [@felixn](https://forum.opencv.org/u/felixn)\ **Replies:** 2\ **Last updated:** [May 25, 2022, 11:33am UTC](https://forum.opencv.org/t/goodfeaturestotrack-only-detecting-bright-features/8901 "2022-05-25T11:33:32Z")
Hi, I’m trying to use “goodFeaturesToTrack” to detect features in my image. As far as I understand, it is supposed to look for corner-like features. However, I’ve got the impression that it is mainly detecting bright … --- ## [OpenCV Python implementation for finding correspondences between two images](https://forum.opencv.org/t/opencv-python-implementation-for-finding-correspondences-between-two-images/6791)
**Author:** [@rllyryan](https://forum.opencv.org/u/rllyryan)\ **Replies:** 1\ **Last updated:** [January 12, 2022, 12:11am UTC](https://forum.opencv.org/t/opencv-python-implementation-for-finding-correspondences-between-two-images/6791 "2022-01-12T00:11:45Z")
Hello! Does anyone know if there is an existing function in OpenCV Python that can calculate the correspondences between two images given a set of the two images and the keypoints detected (no descriptors)? According to…