# Uncategorized **URL:** https://forum.opencv.org/c/uncategorized/1.md?page=4 [Latest](https://forum.opencv.org/latest.md) · [Categories](https://forum.opencv.org/categories.md) · [Tags](https://forum.opencv.org/tags.md) **Page:** 5 --- ## [Template - rotation and translation](https://forum.opencv.org/t/template-rotation-and-translation/22227)
**Author:** [@sckp](https://forum.opencv.org/u/sckp)\ **Replies:** 4\ **Last updated:** [June 12, 2025, 11:59pm UTC](https://forum.opencv.org/t/template-rotation-and-translation/22227 "2025-06-12T23:59:30Z")
I have an image created from scan data and a target image for the “perfect” piece. The images are the same size (monochrome, 8 bpp) Is there a way to calculate the rotation and translation (no scaling!) to get the scan … --- ## [How to accurately segment overlapping rice grains in an image using OpenCV](https://forum.opencv.org/t/how-to-accurately-segment-overlapping-rice-grains-in-an-image-using-opencv/20618)
**Author:** [@Mary\_Joy](https://forum.opencv.org/u/Mary_Joy)\ **Replies:** 4\ **Last updated:** [May 22, 2025, 5:04pm UTC](https://forum.opencv.org/t/how-to-accurately-segment-overlapping-rice-grains-in-an-image-using-opencv/20618 "2025-05-22T17:04:31Z")
I am working on an image processing task using opencv python where I need to segment individual rice grains from an image. The challenge is that many grains are overlapping with each other. I tried watershed algorithm b… --- ## [I want to run opencv on my luckfox pico ultra w board supporting arm 32 bit architecture](https://forum.opencv.org/t/i-want-to-run-opencv-on-my-luckfox-pico-ultra-w-board-supporting-arm-32-bit-architecture/22206)
**Author:** [@docketrun](https://forum.opencv.org/u/docketrun)\ **Replies:** 0\ **Last updated:** [June 11, 2025, 5:27am UTC](https://forum.opencv.org/t/i-want-to-run-opencv-on-my-luckfox-pico-ultra-w-board-supporting-arm-32-bit-architecture/22206 "2025-06-11T05:27:31Z")
I want to run opencv on my luckfox pico ultra w board supporting arm 32 bit architecture, is their any documentation or examples for the same --- ## [Question about triangulation issues with OpenCV - gait analysis project](https://forum.opencv.org/t/question-about-triangulation-issues-with-opencv-gait-analysis-project/22050)
**Author:** [@NICCOLO\_VITO\_VACCA](https://forum.opencv.org/u/NICCOLO_VITO_VACCA)\ **Replies:** 0\ **Last updated:** [June 6, 2025, 2:12pm UTC](https://forum.opencv.org/t/question-about-triangulation-issues-with-opencv-gait-analysis-project/22050 "2025-06-06T14:12:21Z")
Hi everyone, I’m working on a university project in collaboration with two companies, where we are developing a gait analysis program to evaluate patients’ walking patterns during rehabilitation in a hospital. We are u… --- ## [Videowriter web camera logitech(1920x1080) with raspberry pi](https://forum.opencv.org/t/videowriter-web-camera-logitech-1920x1080-with-raspberry-pi/21948)
**Author:** [@nur92](https://forum.opencv.org/u/nur92)\ **Replies:** 1\ **Last updated:** [June 4, 2025, 8:02am UTC](https://forum.opencv.org/t/videowriter-web-camera-logitech-1920x1080-with-raspberry-pi/21948 "2025-06-04T08:02:06Z")
Hello, I have project related to capture a video and save the captured video with videowriter. I’m capturing a video with 1920x1080 quality with 30fps. I got problem as the captured video played fast. Is there a way to f… --- ## [Eye-to-Hand calibration in industrial robotics](https://forum.opencv.org/t/eye-to-hand-calibration-in-industrial-robotics/21943)
**Author:** [@louis2800](https://forum.opencv.org/u/louis2800)\ **Replies:** 0\ **Last updated:** [June 3, 2025, 7:50pm UTC](https://forum.opencv.org/t/eye-to-hand-calibration-in-industrial-robotics/21943 "2025-06-03T19:50:04Z")
Hi everyone, I’m working on an Eye-to-Hand calibration using a 6-DOF robot and a fixed external camera (infrared marker tracking system). For each acquisition, I have a synchronized pose pair: bTt: Pose of the robot … --- ## [Unable to load .BMP file correctly](https://forum.opencv.org/t/unable-to-load-bmp-file-correctly/21095)
**Author:** [@Franco67](https://forum.opencv.org/u/Franco67)\ **Replies:** 5\ **Last updated:** [May 28, 2025, 8:53am UTC](https://forum.opencv.org/t/unable-to-load-bmp-file-correctly/21095 "2025-05-28T08:53:12Z")
Hi. I have a task to perform and it’s not always working correctly: loading a 8-bit RGB color .BMP file from the filesystem, watermarking it and then save it. The watermarking process is just fine and also the imdecode… --- ## [Predicting lux values from RGB images](https://forum.opencv.org/t/predicting-lux-values-from-rgb-images/21062)
**Author:** [@abhivel16](https://forum.opencv.org/u/abhivel16)\ **Replies:** 2\ **Last updated:** [May 27, 2025, 5:38pm UTC](https://forum.opencv.org/t/predicting-lux-values-from-rgb-images/21062 "2025-05-27T17:38:20Z")
Are there any methods to predict lux values from an RGB image? I have a dataset of RGB images and lux values recorded using a luxmeter that can act as ground truth. My task is to build a model (I assume a CNN has the be… --- ## [A look at OpenCV's licensing](https://forum.opencv.org/t/a-look-at-opencvs-licensing/21096)
**Author:** [@Donatello\_Donini](https://forum.opencv.org/u/Donatello_Donini)\ **Replies:** 1\ **Last updated:** [May 26, 2025, 6:17pm UTC](https://forum.opencv.org/t/a-look-at-opencvs-licensing/21096 "2025-05-26T18:17:55Z")
I heard that OpenCV has a series of patented features (like the SIFT algorithm). I need to know which are the features that as of today (May 26, 2025) are patented. --- ## [OpenCV imshow Error: QSocketNotifier: Can only be used with threads started with QThread (No Qt Usage)](https://forum.opencv.org/t/opencv-imshow-error-qsocketnotifier-can-only-be-used-with-threads-started-with-qthread-no-qt-usage/21064)
**Author:** [@fdl](https://forum.opencv.org/u/fdl)\ **Replies:** 1\ **Last updated:** [May 23, 2025, 8:31am UTC](https://forum.opencv.org/t/opencv-imshow-error-qsocketnotifier-can-only-be-used-with-threads-started-with-qthread-no-qt-usage/21064 "2025-05-23T08:31:58Z")
When calling cv::imshow to display an image, the program throws the error: QSocketNotifier: Can only be used with threads started with QThread. I confirm that my code does not directly use the Qt library (no Qt headers… --- ## [GitHub - pvjosue/OpenCV-Spout: OpenCV & Spout C++ library. Shared GPU memory and](https://forum.opencv.org/t/github-pvjosue-opencv-spout-opencv-spout-c-library-shared-gpu-memory-and/21056)
**Author:** [@Carmatic\_frua](https://forum.opencv.org/u/Carmatic_frua)\ **Replies:** 0\ **Last updated:** [May 22, 2025, 10:15am UTC](https://forum.opencv.org/t/github-pvjosue-opencv-spout-opencv-spout-c-library-shared-gpu-memory-and/21056 "2025-05-22T10:15:18Z")
I am trying to incorporate Spout into my OpenCV Python project, and I found this… How useful is it? And how difficult would it be to get working, ideally keeping everything as UMat or even GPUMat (for CUDA) --- ## [How to pass parameters to Flann base matcher using Opencv JS](https://forum.opencv.org/t/how-to-pass-parameters-to-flann-base-matcher-using-opencv-js/21029)
**Author:** [@Borja\_Cano\_Barredo](https://forum.opencv.org/u/Borja_Cano_Barredo)\ **Replies:** 0\ **Last updated:** [May 16, 2025, 8:36am UTC](https://forum.opencv.org/t/how-to-pass-parameters-to-flann-base-matcher-using-opencv-js/21029 "2025-05-16T08:36:29Z")
Hi, After a lot of work trying to make flann matcher and sift to work on OpencvJS i finally have it working. Problem is i am trying to do feature matching for a streaming live cam in real-time and sift and flann are not… --- ## [Ice/frost detection?](https://forum.opencv.org/t/ice-frost-detection/13999)
**Author:** [@pineman](https://forum.opencv.org/u/pineman)\ **Replies:** 6\ **Last updated:** [May 15, 2025, 4:44pm UTC](https://forum.opencv.org/t/ice-frost-detection/13999 "2025-05-15T16:44:41Z")
Hi, I am trying to develop an application to detect frost/ice on commercial air conditioner’s evaporator coil. We can install cameras on site to take pictures of the coil periodically. My goal is to have a rough estimate… --- ## [Jagged floorplan points: How to split into clean line segments?](https://forum.opencv.org/t/jagged-floorplan-points-how-to-split-into-clean-line-segments/21010)
**Author:** [@gomdongdong2](https://forum.opencv.org/u/gomdongdong2)\ **Replies:** 1\ **Last updated:** [May 15, 2025, 7:51am UTC](https://forum.opencv.org/t/jagged-floorplan-points-how-to-split-into-clean-line-segments/21010 "2025-05-15T07:51:20Z")
I successfully detected the outer frame from the original floor plan, and the result is represented as a collection of points. I’m trying to convert these points into line segments. I’ve already tried using direction… --- ## [Non-planar stereo camera calibration (Two cameras with a physical Z-offset)](https://forum.opencv.org/t/non-planar-stereo-camera-calibration-two-cameras-with-a-physical-z-offset/20962)
**Author:** [@hex4def6](https://forum.opencv.org/u/hex4def6)\ **Replies:** 10\ **Last updated:** [May 14, 2025, 4:11pm UTC](https://forum.opencv.org/t/non-planar-stereo-camera-calibration-two-cameras-with-a-physical-z-offset/20962 "2025-05-14T16:11:15Z")
Hi all, I’m planning on creating a stereo camera that will have two camera modules on flexes. They will have different Z-offsets from each other, but will otherwise be pointed in the same direction (co-planar). Will I … --- ## [\[OpenCV.js\] Getting SIFT and FLANN to work](https://forum.opencv.org/t/opencv-js-getting-sift-and-flann-to-work/9987)
**Author:** [@Digizard](https://forum.opencv.org/u/Digizard)\ **Replies:** 7\ **Last updated:** [May 14, 2025, 9:26am UTC](https://forum.opencv.org/t/opencv-js-getting-sift-and-flann-to-work/9987 "2025-05-14T09:26:11Z")
Hi, all! I’m looking for help on how to use SIFT and FLANN with OpenCV.js. I basically want to translate this code from Python: needle = cv.imread('needle.png', 0) haystack = cv.imread('haystack.png', 0) sift = cv.SIF… --- ## [DirectML backend for dnn - confusion with G-API/onnx](https://forum.opencv.org/t/directml-backend-for-dnn-confusion-with-g-api-onnx/20989)
**Author:** [@JulienM](https://forum.opencv.org/u/JulienM)\ **Replies:** 0\ **Last updated:** [May 9, 2025, 8:05pm UTC](https://forum.opencv.org/t/directml-backend-for-dnn-confusion-with-g-api-onnx/20989 "2025-05-09T20:05:27Z")
Hi, I’m currently using opencv to perform inference on images using my trained model exported to onnx. It works pretty well and I take advantage of the stock, OpenVino and CUDA backends. My biggest complaint is the size… --- ## [How to setup project with both c++ and python dependencies of cv2?](https://forum.opencv.org/t/how-to-setup-project-with-both-c-and-python-dependencies-of-cv2/20983)
**Author:** [@clouds56](https://forum.opencv.org/u/clouds56)\ **Replies:** 0\ **Last updated:** [May 9, 2025, 5:08am UTC](https://forum.opencv.org/t/how-to-setup-project-with-both-c-and-python-dependencies-of-cv2/20983 "2025-05-09T05:08:45Z")
Now I’m creating a app that using some cv2 algorithms, the main part is in rust linked with cv2 built by vcpkg. But I’d like to also including a python interpreter with opencv-python so that we could do some quick protot… --- ## [Understanding the Philosophy Behind OpenCV's DNN Module](https://forum.opencv.org/t/understanding-the-philosophy-behind-opencvs-dnn-module/20906)
**Author:** [@radiantb](https://forum.opencv.org/u/radiantb)\ **Replies:** 0\ **Last updated:** [April 27, 2025, 3:10pm UTC](https://forum.opencv.org/t/understanding-the-philosophy-behind-opencvs-dnn-module/20906 "2025-04-27T15:10:35Z")
Hello everyone, Sometime back, I was working on a proposal for a GSoC project about integrating LightGlue and ALIKED into OpenCV by using the DNN module and extending Feature2D modules. While experimenting with LightGlu… --- ## [Photos of weeds](https://forum.opencv.org/t/photos-of-weeds/20905)
**Author:** [@piskora](https://forum.opencv.org/u/piskora)\ **Replies:** 1\ **Last updated:** [April 27, 2025, 10:37am UTC](https://forum.opencv.org/t/photos-of-weeds/20905 "2025-04-27T10:37:43Z")
Photos of weeds. I’m trying to write a processing for finding the coordinates of weeds. I’ll be grateful for your help. --- ## [Question of Telea Inpaint Source Code](https://forum.opencv.org/t/question-of-telea-inpaint-source-code/20902)
**Author:** [@Leo1212](https://forum.opencv.org/u/Leo1212)\ **Replies:** 0\ **Last updated:** [April 27, 2025, 9:26am UTC](https://forum.opencv.org/t/question-of-telea-inpaint-source-code/20902 "2025-04-27T09:26:14Z")
I’m reading the source code of Telea Inpaint method. The grandiant calculate code makes me confused. /modules/photo/src/inpaint.cpp #319 if (CV\_MAT\_ELEM(\*f,uchar,k,l+1)!=INSIDE) { if (CV\_MAT\_ELEM(\*f,uchar,k,l-1)!=I… --- ## [Opencv 4.11.0 on baremetal](https://forum.opencv.org/t/opencv-4-11-0-on-baremetal/20827)
**Author:** [@opencv\_user\_4110](https://forum.opencv.org/u/opencv_user_4110)\ **Replies:** 4\ **Last updated:** [April 27, 2025, 2:09am UTC](https://forum.opencv.org/t/opencv-4-11-0-on-baremetal/20827 "2025-04-27T02:09:55Z")
I have seen some posts asking about using opencv on arm baremetal environment. I would say yes, opencv can be compiled in arm cross compiler and used in arm baremetal environment which I did. I started trying on 2.4.8 … --- ## [Some problems with old OpenCV library and haarcascade](https://forum.opencv.org/t/some-problems-with-old-opencv-library-and-haarcascade/20899)
**Author:** [@RedCat](https://forum.opencv.org/u/RedCat)\ **Replies:** 3\ **Last updated:** [April 27, 2025, 12:47am UTC](https://forum.opencv.org/t/some-problems-with-old-opencv-library-and-haarcascade/20899 "2025-04-27T00:47:55Z")
Hi to all, I’m trying to run face recognition on an old version of the OpenCV library, but when uploading a file haarcascade\_frontalface\_alt.xml the library returns an error with the cvLoad function: OpenCV Error: Unsp… --- ## [Possible to save 1 bpp TIFF image?](https://forum.opencv.org/t/possible-to-save-1-bpp-tiff-image/20895)
**Author:** [@sofakng](https://forum.opencv.org/u/sofakng)\ **Replies:** 4\ **Last updated:** [April 26, 2025, 6:49pm UTC](https://forum.opencv.org/t/possible-to-save-1-bpp-tiff-image/20895 "2025-04-26T18:49:33Z")
Is it possible to save a 1 bpp TIFF image with OpenCV? I’m trying to load a grayscale image (8 bpp), binarize (threshold) the image and then save a 1 bpp TIFF using CCIT (Group 4) compression. It looks like grfmt\_tiff.… --- ## [Finding the asymptotic complexity of opencv algorithms](https://forum.opencv.org/t/finding-the-asymptotic-complexity-of-opencv-algorithms/20863)
**Author:** [@ibxx0402](https://forum.opencv.org/u/ibxx0402)\ **Replies:** 4\ **Last updated:** [April 23, 2025, 9:55am UTC](https://forum.opencv.org/t/finding-the-asymptotic-complexity-of-opencv-algorithms/20863 "2025-04-23T09:55:50Z")
As the title says, I want to compare the different complexities of the algorithms I want to use to use in a performance analysis between different denoise methods. The different methods I want to test is the following … --- ## [Issue with displaying live stream video using cv2.imshow (error :-215)](https://forum.opencv.org/t/issue-with-displaying-live-stream-video-using-cv2-imshow-error-215/16270)
**Author:** [@nipesh\_janghel](https://forum.opencv.org/u/nipesh_janghel)\ **Replies:** 5\ **Last updated:** [April 19, 2025, 2:37pm UTC](https://forum.opencv.org/t/issue-with-displaying-live-stream-video-using-cv2-imshow-error-215/16270 "2025-04-19T14:37:11Z")
Hello, I am currently working on a project where I am using OpenCV to capture frames from a video stream and display them using cv2.imshow. However, I am encountering an issue, and I would appreciate your assistance in … --- ## [Build OpenCV Framework - Mac osx error](https://forum.opencv.org/t/build-opencv-framework-mac-osx-error/2357)
**Author:** [@LisaG](https://forum.opencv.org/u/LisaG)\ **Replies:** 4\ **Last updated:** [April 17, 2025, 9:56am UTC](https://forum.opencv.org/t/build-opencv-framework-mac-osx-error/2357 "2025-04-17T09:56:00Z")
Hi there, I’m completely new to OpenCV and so yesterday I with installing it. I didn’t want to use Homebrew to install it on my Mac but I wanted to use the method of building the frameworks. I did this successfully for … --- ## [Recognizing a grid of letters from a phone display](https://forum.opencv.org/t/recognizing-a-grid-of-letters-from-a-phone-display/20821)
**Author:** [@Ralf\_71](https://forum.opencv.org/u/Ralf_71)\ **Replies:** 2\ **Last updated:** [April 16, 2025, 9:41am UTC](https://forum.opencv.org/t/recognizing-a-grid-of-letters-from-a-phone-display/20821 "2025-04-16T09:41:35Z")
Hello everybody! I want to build myself a program to solve a HASHTAG riddle. It is like the Wordle game, or mastermind, wrapped into one - and then you solve four of them in a grid together. This is what it looks like: … --- ## [Best method to create a video that plays frame by frame by default](https://forum.opencv.org/t/best-method-to-create-a-video-that-plays-frame-by-frame-by-default/20818)
**Author:** [@tonyman108](https://forum.opencv.org/u/tonyman108)\ **Replies:** 1\ **Last updated:** [April 15, 2025, 8:45pm UTC](https://forum.opencv.org/t/best-method-to-create-a-video-that-plays-frame-by-frame-by-default/20818 "2025-04-15T20:45:27Z")
Hi. We’ve developed an opencv-centric product inspection system that generates a lot of annotated images. Each image belongs to a batch. We currently store them as individual .png files. We’re trying to think of a co… --- ## [Creating training images](https://forum.opencv.org/t/creating-training-images/20808)
**Author:** [@curt](https://forum.opencv.org/u/curt)\ **Replies:** 1\ **Last updated:** [April 13, 2025, 5:40pm UTC](https://forum.opencv.org/t/creating-training-images/20808 "2025-04-13T17:40:32Z")
I am new to opencv and facial recognition. Is it reasonable to create training images with a webcam taking snapshots at regular intervals? Any suggestions such as face and camera angles, background, etc. Thanks, Curt [Previous page](https://forum.opencv.org/c/uncategorized/1.md?page=3) [Next page](https://forum.opencv.org/c/uncategorized/1.md?page=5)