# \#contrib **URL:** https://forum.opencv.org/tag/contrib/273.md [Latest](https://forum.opencv.org/latest.md) · [Categories](https://forum.opencv.org/categories.md) · [Tags](https://forum.opencv.org/tags.md) --- ## [builtins.AttributeError: module 'cv2' has no attribute 'legacy'](https://forum.opencv.org/t/builtins-attributeerror-module-cv2-has-no-attribute-legacy/13655)
**Author:** [@jvkloc](https://forum.opencv.org/u/jvkloc)\ **Replies:** 5\ **Last updated:** [September 13, 2025, 1:12pm UTC](https://forum.opencv.org/t/builtins-attributeerror-module-cv2-has-no-attribute-legacy/13655 "2025-09-13T13:12:48Z")
I installed opencv-python version 4.7.0.72 with pip3 and I get builtins.AttributeError: module 'cv2' has no attribute 'legacy' error when trying to use MOSSE tracker. If I go without legacy, then I’ll get builtins.Att… --- ## [Thin plate spline warpImage produces only zeros](https://forum.opencv.org/t/thin-plate-spline-warpimage-produces-only-zeros/1125)
**Author:** [@pakoun](https://forum.opencv.org/u/pakoun)\ **Replies:** 14\ **Last updated:** [September 4, 2025, 2:52am UTC](https://forum.opencv.org/t/thin-plate-spline-warpimage-produces-only-zeros/1125 "2025-09-04T02:52:37Z")
Dear all, I am trying to warp an image using the thinplatespline but after warping, the image contains only 0 values. I am attaching a working code example and the datasets as well. I hope for some help to show me the r… --- ## [Vcpkg and CLion: ximgproc cannot be found](https://forum.opencv.org/t/vcpkg-and-clion-ximgproc-cannot-be-found/23745)
**Author:** [@Mateusz\_PL](https://forum.opencv.org/u/Mateusz_PL)\ **Replies:** 2\ **Last updated:** [August 13, 2025, 11:27am UTC](https://forum.opencv.org/t/vcpkg-and-clion-ximgproc-cannot-be-found/23745 "2025-08-13T11:27:46Z")
Hi! I’m currently working on a project that uses OpenCV. I’m using CLion and Vcpkg to install OpenCV. I have a problem with ximgproc — CLion doesn’t recognize this directory, so I cannot access it, although it has no pro… --- ## [Open cv contrib with gs streamer enable support](https://forum.opencv.org/t/open-cv-contrib-with-gs-streamer-enable-support/22900)
**Author:** [@Abdullah\_Khalid](https://forum.opencv.org/u/Abdullah_Khalid)\ **Replies:** 1\ **Last updated:** [July 4, 2025, 7:25am UTC](https://forum.opencv.org/t/open-cv-contrib-with-gs-streamer-enable-support/22900 "2025-07-04T07:25:49Z")
can soneone tell me ehere to get or how to compile open cv gs streamer support over j4012 industrial recomputer. --- ## [How to use MapperGradEuclid](https://forum.opencv.org/t/how-to-use-mappergradeuclid/22523)
**Author:** [@Steve\_Best](https://forum.opencv.org/u/Steve_Best)\ **Replies:** 3\ **Last updated:** [June 18, 2025, 2:02pm UTC](https://forum.opencv.org/t/how-to-use-mappergradeuclid/22523 "2025-06-18T14:02:48Z")
I’ve seen a function MapperGradEuclid and I’d like to see if it is useful, but, despite it being in the docs I can’t seem to access it from python. I’ve seen some StackOverflow questions, none very recent, where people … --- ## [MultiTracker\_create not in module of openCV vers 4.11.0 (openCV\_contrib\_python)](https://forum.opencv.org/t/multitracker-create-not-in-module-of-opencv-vers-4-11-0-opencv-contrib-python/20625)
**Author:** [@Thorvaldur\_Petursson](https://forum.opencv.org/u/Thorvaldur_Petursson)\ **Replies:** 10\ **Last updated:** [March 26, 2025, 11:18am UTC](https://forum.opencv.org/t/multitracker-create-not-in-module-of-opencv-vers-4-11-0-opencv-contrib-python/20625 "2025-03-26T11:18:47Z")
even though the documentation of openCV 4.11.0 says it has the class / function MultiTracker\_create() , the cv2.getBuildInformation() says AttributeError: module ‘cv2’ has no attribute ‘MultiTracker\_create’ How come th… --- ## [Build opencv\_cvv and opencv\_world failed](https://forum.opencv.org/t/build-opencv-cvv-and-opencv-world-failed/20534)
**Author:** [@WWjh](https://forum.opencv.org/u/WWjh)\ **Replies:** 4\ **Last updated:** [March 17, 2025, 1:53am UTC](https://forum.opencv.org/t/build-opencv-cvv-and-opencv-world-failed/20534 "2025-03-17T01:53:06Z")
my version is opencv-4.9.0,so is the opencv\_contrib;build in VS2022，Qt version is 5.14.0; It will build failed when I both check “Build\_opencv\_world” and “Build\_opencv\_cvv”。the compiler give link errors inthe picture; … --- ## [NVIDIA Xavier OpenCV built from source tests fail](https://forum.opencv.org/t/nvidia-xavier-opencv-built-from-source-tests-fail/19448)
**Author:** [@mfatih7](https://forum.opencv.org/u/mfatih7)\ **Replies:** 15\ **Last updated:** [December 11, 2024, 4:40pm UTC](https://forum.opencv.org/t/nvidia-xavier-opencv-built-from-source-tests-fail/19448 "2024-12-11T16:40:50Z")
Hello, In order to build opencv from source for Xavier Dev Board with Jetpack 5.1.2, I modified and used the script here, which is referenced by Jetson Zoo. I enabled cuda and include contrib in my modified built scrip… --- ## [How to use Thin Plate Spline Shape Transformer correctly?](https://forum.opencv.org/t/how-to-use-thin-plate-spline-shape-transformer-correctly/19147)
**Author:** [@wl2776](https://forum.opencv.org/u/wl2776)\ **Replies:** 6\ **Last updated:** [October 30, 2024, 1:11pm UTC](https://forum.opencv.org/t/how-to-use-thin-plate-spline-shape-transformer-correctly/19147 "2024-10-30T13:11:52Z")
I’ve got a grid of 9 landmarks, shown in the picture below My goal is to obtain warped image of a palm region, like this Here, L1 on the source image is translated to point 0, 0 in the resulting image, L9 in the s… --- ## [Help configuring CMake to build with contrib modules](https://forum.opencv.org/t/help-configuring-cmake-to-build-with-contrib-modules/18460)
**Author:** [@zabsy](https://forum.opencv.org/u/zabsy)\ **Replies:** 2\ **Last updated:** [August 9, 2024, 3:44pm UTC](https://forum.opencv.org/t/help-configuring-cmake-to-build-with-contrib-modules/18460 "2024-08-09T15:44:23Z")
Hello, I’m building OpenCV from source on Ubuntu 22.04.4 in order to use the SFM module, following the instructions here exactly, except replacing “4.x” with “4.10.0” After getting to the configuration step and running… --- ## [Unable to build ximgproc module from contrib for opencv\_js](https://forum.opencv.org/t/unable-to-build-ximgproc-module-from-contrib-for-opencv-js/18464)
**Author:** [@ceniei](https://forum.opencv.org/u/ceniei)\ **Replies:** 0\ **Last updated:** [August 9, 2024, 1:24pm UTC](https://forum.opencv.org/t/unable-to-build-ximgproc-module-from-contrib-for-opencv-js/18464 "2024-08-09T13:24:49Z")
I am trying to use the procedure at (OpenCV: Build OpenCV.js) to build opencv\_js with the opencv\_contrib modules, but I am not able to do so successfully. I noticed that the imgcodecs module is disabled by default in th… --- ## [AttributeError: module 'cv2.xfeatures2d' has no attribute 'SURF\_create'](https://forum.opencv.org/t/attributeerror-module-cv2-xfeatures2d-has-no-attribute-surf-create/18450)
**Author:** [@Andre\_Silva](https://forum.opencv.org/u/Andre_Silva)\ **Replies:** 7\ **Last updated:** [August 7, 2024, 3:10pm UTC](https://forum.opencv.org/t/attributeerror-module-cv2-xfeatures2d-has-no-attribute-surf-create/18450 "2024-08-07T15:10:57Z")
I’m trying to use the SURF feature extractor, but I’m encountering the error: “AttributeError: module ‘cv2.xfeatures2d’ has no attribute ‘SURF\_create’”. I’ve already tried manually compiling OpenCV to enable OPENCV\_ENABL… --- ## [Where is the dnn\_superres.hpp located?](https://forum.opencv.org/t/where-is-the-dnn-superres-hpp-located/18434)
**Author:** [@Trylz](https://forum.opencv.org/u/Trylz)\ **Replies:** 2\ **Last updated:** [August 6, 2024, 6:00pm UTC](https://forum.opencv.org/t/where-is-the-dnn-superres-hpp-located/18434 "2024-08-06T18:00:12Z")
I am trying to add super sampling to my application using this tutorial: https://docs.opencv.org/4.x/d5/d29/tutorial\_dnn\_superres\_upscale\_image\_single.html Unfortunately I can’t find the opencv2/dnn\_superres.hpp to inc… --- ## [OpenCV-Contrib in Android Application](https://forum.opencv.org/t/opencv-contrib-in-android-application/18109)
**Author:** [@ap68275](https://forum.opencv.org/u/ap68275)\ **Replies:** 0\ **Last updated:** [June 28, 2024, 9:06am UTC](https://forum.opencv.org/t/opencv-contrib-in-android-application/18109 "2024-06-28T09:06:22Z")
Hi! I am currently trying to implement object tracking in an Android application using Dart’s FFI and OpenCV-contrib’s tracking modules. I have built opencv 4.9.0 with the contrib module using the build\_sdk.py script an… --- ## [Can't use part of conarlib files](https://forum.opencv.org/t/cant-use-part-of-conarlib-files/17254)
**Author:** [@lalitesler](https://forum.opencv.org/u/lalitesler)\ **Replies:** 3\ **Last updated:** [April 11, 2024, 9:33am UTC](https://forum.opencv.org/t/cant-use-part-of-conarlib-files/17254 "2024-04-11T09:33:47Z")
Hi, I have a problem with the trackers, I installed the contrib folder, I can access the tracking\_legacy.hpp file but not use its classes, but tracking.hpp working, what could be the problem? I use opencv 4.9.0 --- ## [Opencv contrib SFM CERES ERROR!](https://forum.opencv.org/t/opencv-contrib-sfm-ceres-error/17134)
**Author:** [@fuc](https://forum.opencv.org/u/fuc)\ **Replies:** 1\ **Last updated:** [April 3, 2024, 8:53am UTC](https://forum.opencv.org/t/opencv-contrib-sfm-ceres-error/17134 "2024-04-03T08:53:36Z")
There is a problem occurring during the installation process of opencv-contrib. Ceres-solver is clearly installed. However, errors related to Ceres persistently occur. This is result of find ceres. root@b1201fc87717:… --- ## [Opencv2.framework for iOS is missing +contrib](https://forum.opencv.org/t/opencv2-framework-for-ios-is-missing-contrib/16584)
**Author:** [@wolf359](https://forum.opencv.org/u/wolf359)\ **Replies:** 1\ **Last updated:** [February 24, 2024, 7:54pm UTC](https://forum.opencv.org/t/opencv2-framework-for-ios-is-missing-contrib/16584 "2024-02-24T19:54:17Z")
I’m developing an iPhone app that requires ximgproc, which is in the +contrib branch. Unfortunately, opencv2.framework for iOS seems to be built without +contrib. Is there a way to add it, or to request OpenCV to includ… --- ## [Can I build the extra modules with OpenCV already installed?](https://forum.opencv.org/t/can-i-build-the-extra-modules-with-opencv-already-installed/15935)
**Author:** [@Zhang](https://forum.opencv.org/u/Zhang)\ **Replies:** 0\ **Last updated:** [December 22, 2023, 7:17am UTC](https://forum.opencv.org/t/can-i-build-the-extra-modules-with-opencv-already-installed/15935 "2023-12-22T07:17:01Z")
I find the device(jetson NX) has alreadey installed OpenCV. Is it possible to install openCV contrib without remove already installed OpenCV? --- ## [Unable to build OpenCV with the contrib modules](https://forum.opencv.org/t/unable-to-build-opencv-with-the-contrib-modules/15923)
**Author:** [@Hercules\_Holmes](https://forum.opencv.org/u/Hercules_Holmes)\ **Replies:** 1\ **Last updated:** [December 21, 2023, 7:25am UTC](https://forum.opencv.org/t/unable-to-build-opencv-with-the-contrib-modules/15923 "2023-12-21T07:25:47Z")
I am using CMake gui, opencv\_contrib 4.x and tried both opencv 4.7 and 4.8. Everytime i build ALL\_BUILD in VS2019 (x64). I get a ton of errors mostly from cv::hal\_baseline and most in the form of overloading or differen… --- ## [Is there a reason why the tracking code was moved to a legacy module starting from 4.5.1?](https://forum.opencv.org/t/is-there-a-reason-why-the-tracking-code-was-moved-to-a-legacy-module-starting-from-4-5-1/15784)
**Author:** [@leeareum566](https://forum.opencv.org/u/leeareum566)\ **Replies:** 2\ **Last updated:** [December 9, 2023, 8:34am UTC](https://forum.opencv.org/t/is-there-a-reason-why-the-tracking-code-was-moved-to-a-legacy-module-starting-from-4-5-1/15784 "2023-12-09T08:34:18Z")
Hello Is there a special reason why the tracking code was moved to a legacy module starting from 4.5.1? And for what reason is it usually moved to a legacy module? I am a developer on a C# project. I use opencv… --- ## [Freetype2 module unavailable](https://forum.opencv.org/t/freetype2-module-unavailable/15557)
**Author:** [@zhouzhi123.8](https://forum.opencv.org/u/zhouzhi123.8)\ **Replies:** 1\ **Last updated:** [November 17, 2023, 8:28am UTC](https://forum.opencv.org/t/freetype2-module-unavailable/15557 "2023-11-17T08:28:14Z")
I build OpenCV 4.6.0 from source code on Ubuntu 18.04, all extra modules which I need installed successfully except freetype2, How to fix it? thanks below is my build info Should I install any dependence before free… --- ## [Compilation errors](https://forum.opencv.org/t/compilation-errors/14927)
**Author:** [@Shersoni](https://forum.opencv.org/u/Shersoni)\ **Replies:** 4\ **Last updated:** [November 11, 2023, 12:46pm UTC](https://forum.opencv.org/t/compilation-errors/14927 "2023-11-11T12:46:17Z")
Hello, I am trying to build OpenCV 4.8.1 on Linux 22.04 on Nvidia 4070 card. The machine has Xeon processor. While enabling CUDA==On, I get the following errors: /home/csverma/Downloads/opencv-4.8.1/modules/core/incl… --- ## [OpenCV build from source error](https://forum.opencv.org/t/opencv-build-from-source-error/14616)
**Author:** [@mfatih7](https://forum.opencv.org/u/mfatih7)\ **Replies:** 8\ **Last updated:** [September 25, 2023, 11:26am UTC](https://forum.opencv.org/t/opencv-build-from-source-error/14616 "2023-09-25T11:26:57Z")
Hello I am trying to build OpenCV 4.7 and 4.8 from source code using CMAKE GUI. If I build without setting OPENCV\_EXTRA\_MODULES\_PATH the CMAKE build and generate succeeds and in Visual Studio I can build and install wi… --- ## [How to get opencv-contrib binary package with CUDA](https://forum.opencv.org/t/how-to-get-opencv-contrib-binary-package-with-cuda/6708)
**Author:** [@aipatrone](https://forum.opencv.org/u/aipatrone)\ **Replies:** 5\ **Last updated:** [December 13, 2021, 3:35pm UTC](https://forum.opencv.org/t/how-to-get-opencv-contrib-binary-package-with-cuda/6708 "2021-12-13T15:35:28Z")
Could please tell me how you manage to have this method? The only opencv\_contrib that I find available is only for cpu and if I use the opencv\_python it doesn´t recognize this method. Thanks in advance --- ## [How do I resolve the linker error with 'cv::face::LBPHFaceRecognizer' in my OpenCV C++ code?](https://forum.opencv.org/t/how-do-i-resolve-the-linker-error-with-cv-lbphfacerecognizer-in-my-opencv-c-code/13377)
**Author:** [@MaestroFries](https://forum.opencv.org/u/MaestroFries)\ **Replies:** 6\ **Last updated:** [June 1, 2023, 5:41am UTC](https://forum.opencv.org/t/how-do-i-resolve-the-linker-error-with-cv-lbphfacerecognizer-in-my-opencv-c-code/13377 "2023-06-01T05:41:54Z")
Unresolved External Source in OPENCV C++ Code with cv::face::LBPHFaceRecognizer I have OPENCV code which acts a trainer that takes a directory full of face images. I am running this on OpenCV 4.2.0 with the OPENCV contr… --- ## [DNN\_superres does not work even on OpenCV version 4.7.0](https://forum.opencv.org/t/dnn-superres-does-not-work-even-on-opencv-version-4-7-0/12883)
**Author:** [@Anish\_Nethi](https://forum.opencv.org/u/Anish_Nethi)\ **Replies:** 5\ **Last updated:** [April 20, 2023, 10:09pm UTC](https://forum.opencv.org/t/dnn-superres-does-not-work-even-on-opencv-version-4-7-0/12883 "2023-04-20T22:09:08Z")
import cv2 from cv2 import dnn\_superres sr = dnn\_superres.DnnSuperResImpl\_create() path = ‘LapSRN\_x8.pb’ sr.readModel(path) sr.setModel(‘lapsrn’, 8) image = cv2.imread(‘1\_output\_face\_0.jpg’) upscaled = sr.upsampl… --- ## [Image quality assessment](https://forum.opencv.org/t/image-quality-assessment/12827)
**Author:** [@Visionary](https://forum.opencv.org/u/Visionary)\ **Replies:** 3\ **Last updated:** [April 18, 2023, 5:25am UTC](https://forum.opencv.org/t/image-quality-assessment/12827 "2023-04-18T05:25:46Z")
Hi! I am quite new to OpenCV, image quality assessment, machine learning etc. I have a task to analyze which image has better quality comparing 2 images. Currently I want to implement it using Reduced-reference or No-… --- ## [Object Detection - Waldboost](https://forum.opencv.org/t/object-detection-waldboost/7293)
**Author:** [@VDL](https://forum.opencv.org/u/VDL)\ **Replies:** 0\ **Last updated:** [January 26, 2022, 3:18pm UTC](https://forum.opencv.org/t/object-detection-waldboost/7293 "2022-01-26T15:18:58Z")
In the Extra modules, there is Object Detection using Waldboost. I tried it and it did not detect anything. I have read somewhere else, that it is non-working. If so why is it there, without this mention, for this amou… --- ## [Some opencv Trackers dont appear to be implemented](https://forum.opencv.org/t/some-opencv-trackers-dont-appear-to-be-implemented/12753)
**Author:** [@rmarlborough](https://forum.opencv.org/u/rmarlborough)\ **Replies:** 1\ **Last updated:** [April 10, 2023, 8:02pm UTC](https://forum.opencv.org/t/some-opencv-trackers-dont-appear-to-be-implemented/12753 "2023-04-10T20:02:52Z")
I am using opencv 4.6.0 on Ubuntu22. There is sample code on using trackers that can be downloaded from learnopencv.com. A few of them dont appear to be implemented even though they appear in the docs. These are TrackerB… --- ## [Is there a version of opencv\_contrib to use with OpenCV 4.6.0](https://forum.opencv.org/t/is-there-a-version-of-opencv-contrib-to-use-with-opencv-4-6-0/12666)
**Author:** [@rmarlborough](https://forum.opencv.org/u/rmarlborough)\ **Replies:** 1\ **Last updated:** [April 4, 2023, 1:27pm UTC](https://forum.opencv.org/t/is-there-a-version-of-opencv-contrib-to-use-with-opencv-4-6-0/12666 "2023-04-04T13:27:37Z")
and if so how do I get that? [Next page](https://forum.opencv.org/tag/contrib/273.md?match_all_tags=true&page=1&tags%5B%5D=contrib)