How can I track the disappearance of a TV logo in a certain area in a frame...
Hi! I have a TV logo image and a rect where the logo is placed on almost all video frames. But there are also frames where the logo completely disappears (at least 10 consecutive seconds of running...
View Articlehistorical performance test cast data in build pipeline?
Hi all. Is there organized data/results kept for *performance* tests that are automatically run/collected by the OpenCV build pipeline? So that I can inspect and compare across builds/releases...
View Articlecv::dnn::blobFromImage() works in python but fails in c++
I am using opencv dnn.Net with the same network and with the same image in python and C++. While in python everything is ok, in C++ I get an access violation error from an opencv.dll. Here is my code...
View ArticleTriangulation with Ground Plane as Origin
Hello, I am working on a project where I have two calibrated cameras (c1, c2) mounted to the ceiling of my lab and I want to triangulate points on objects that I place in the capture volume. I want my...
View ArticleError building opencv with extra modules in Visual Studio 2013
I have configured and generated opencv 4.5.0 with extra modules on CMAKE successfully. However, when building this project in Visual Studio I get several errors. Below, you could find: small sample of...
View ArticleReading and Writing Videos: Python on GPU with CUDA - VideoCapture and...
I'm trying to crop a video, using Python 3+, by reading it frame-by-frame and write certain frames to a new video. I want to use GPU to speed up this process, as for a 1h video, it would take my CPU...
View ArticleProblem with building pose Mat from rotation and translation matrices
I have two images captured in the same space (scene), one with known pose. I need to calculate the pose of the second (query) image. I have obtained the relative camera pose using essential matrix. Now...
View Articlegetting out of arguments
The problem i'm trying to build something around the openvc advanced stitching solver. (the lower level API). However that asumes all is given in command line arguments, this is not practical for me....
View ArticleOptimizations on opencv hog implementation(interp_weight, gaussian)
Hello, I'm trying to implement hog descriptor algorithm on FPGA. I will use pure(without using any library) C++ code to synthesize design with Vivado HLS. So, i need to know what is the general...
View Articletvec and coordinate systems q
The output of solvePnp tvec and rvec: is tvec in world coordinates? I am guessing it is b/c the chessboard calibration is in mm. Second, what is tvec measuring from-to?
View Articleerrors when building opencv 4.5.0 wit extra modules using Mingw
please help!!!! I I am building opencv with extra modules for java using Mingw and cmake , and get some errors in the console what can be the reason !!!! 
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I am creating web application for face recognition using python flask app. I...
#camera.py import cv2 import os import time from flask import Response from pathlib import Path import uuid from contextlib import contextmanager from typing import Callable face_cascade =...
View Articlestitcher advanced api everything get wrapped arround
Hi, first i used the basic hihger level api, wich resulted in panorama pictures it worked But as i wanted to do some more i went for the deeper api with contrib opencv (i want transform txt outputs) i...
View ArticleDarknet makefile error when opencv=1, ubuntu 18.04
Hi, when i did this command: sudo apt install libopencv-dev And then, at the makefile of darknet: Opencv=1 (from opencv=0) After pressing the `make` command I get this: makefile:176: recipe for target...
View ArticleHow to avoid potential noise after Canny?
I have a time averaged grayscale frame of a video:  I applied Canny edge detector to that frame, but sometimes there is noise like this:...
View ArticleLot of Delay with my RTSP cam with OpenCV on Python
Good evening everyone. I have some concerns regarding a project that I am setting up. Indeed, when I display a simple Rtsp video stream via OpenCv, I have no problems. Everything is fluid. However I am...
View ArticleOpencv and OAK on Mac with new chip M1
I was wondering if opencv works (or will work) on the new MacBook Pros (2020)? These new laptops have their own apple chips (not intel based). I am also curious if the OAK( Opencv AI Kit) coming on...
View Articlebinary calibration pattern with XY recoverable features
Hi all I think I've seen this before, but it is also possible that such a thing does not exist and that I'm mistaken. I'm looking for a calibration pattern which looks like low resolution binary noise....
View Articlerecover pose scale
Is there a way to get a relative scale for the translation vector given from cv2.recoverpose(). e.g over 11 frames i get 10 different translation vectors, s(i) * t(i), 0 <= i < 9. Is there a way...
View ArticleHow to find surfance orientation (relative to camera) from single depth image?
Supposing I have access to the image stream of a depth camera, and there is a flat surface (e.g. floor, tabletop, etc) within the camera's FoV at all times, how could one estimate the floor vertical...
View ArticlefindCirclesGrid can't find sub-pattern with hollow insides
I'm trying to find a unique 2x2 hollow center sub-pattern inside a circle grid pattern. Using "detect", generates keypoints that indicate that the hollow circles are detected correctly, but the 2x2...
View ArticleRemoving translation from double camera facing the same direction
Hi all, I have a project for Android with which I take an image from the main camera as well as the "depth camera". The only problem is that the actual sensors are placed few centimeters away from...
View ArticleVideocapture RTSP cause very high cpu usage
i using OpenCV 3.4.12 VideoCapture in c++ with a simple read operation from a rtsp stream. A test with a 640x360 resolution runs with very high CPU usage 40-64% on my linux box with an i7 CPU. how can...
View ArticleHow to get bird view image which is synthized four side images?(get AVM:...
Hi I'm making avm(around view monitoring) image by getting four side images from four fisheye cameras. This process has three parts: 1. calibrate fisheye image/video/streaming 2. get top view(bird...
View ArticleProblem with undistortPoints() function in pose estimation of image
I have written about my task [here](https://answers.opencv.org/question/238792/problem-with-building-pose-mat-from-rotation-and-translation-matrices/). I have a set of images with known pose which...
View ArticleLineSegmentDetector
I need to show lines, but I have error this code: QImage temp = nPixDst->pixmap().toImage(); Mat image = QImage2Mat( temp ) ; cvtColor(image, image, COLOR_BGR2GRAY); Canny(image, image, 50, 150,...
View Articledeletion of useless posts
according to [previous discussion](https://github.com/opencv-infrastructure/answers.opencv.org/issues/45) some questions already deleted and there are [many question like tagged...
View ArticleHSV white color range in JS
I would like to track white color using webcam and Opencv.js. [Here](https://stackoverflow.com/questions/22588146/tracking-white-color-using-python-opencv) is the question/answer with python. I want to...
View ArticleHow can I check if the monitor is connected in Windows / Linux?
How can I check if the monitor is connected in Windows / Linux? The following program behavior is required, when I run my application: - if monitor is connected, then results will be showed in the...
View ArticleOpencv for pcb parts detection and angle calculation
Hi, I’m new in Opencv . I want to detect pcb parts (Es. capactors, resistors etc.) with opencv and calculate current rotation angle. There is an easy and optimized way to do this ?
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