VideoWriter fails to open inside thread
Hello, I writing a C++ application for Windows that handles video streaming over sockets. In this program, the main thread listens for connection attempts, and creates a new thread for each client...
View ArticleCorrecting extrensic camera parameters
Hello, I'm attempting to use OpenCV to correct camera lens distortion and camera rotation/translation of an image before doing further processing. The image has a scale which needs to be read, and a...
View ArticleUnable to find contours in an image
Hi, I am using the following code : import numpy as np import cv2 import matplotlib.pyplot as plt im = cv2.imread('shapes.png') imgray = cv2.cvtColor(im,cv2.COLOR_BGR2GRAY) image, contours, hierarchy...
View ArticleMultiple Camera System Issue
As of now, I’ve successfully implemented 3 different systems involving up to 3 simple usb 2.0 webcams. The nature of each application is to receive a trigger from an embedded controller(via serial),...
View ArticleOpenCV stitching output is unstable
I am using opencv stitching class to make panorama. I am using the simplest code for stitching, just giving images, making pointer to stitcher class, creating default one and calling composePanorama...
View Articleundistort with only 2 parameter distortion coefficients.
Hi all, I am attempting to undistort some pre recorded footage, where I no longer have access to the camera. It was recorded with a camera system that calibrated and stored the intrinsic data. So far...
View ArticlefitEllipse - angle of resulting rotated rect
It seems that fitEllipse realization miss the result RotatedRect angle computing in some cases. ... box.center.x = (float)rp[0] + c.x; box.center.y = (float)rp[1] + c.y; box.size.width =...
View ArticleSimple OpenCV applicaton hangs after exe copied
I am running simple tutorial application compiled under Visual Studio 2013. It runs fine run from the command line. Unfortunately, when I copy the exe file to another location application hangs. There...
View ArticleHow to improve Edge Detection of Rectangular objects
Hello everyone. I'm using OpenCV to find biggest rectangular object(paper sheet A4). My work flow: 1. Apply filters(cvtColor/Canny/Blur) 2. via method **FindContours()** fill List with contours 3. loop...
View ArticlePose estimation using PNP: Strange wrong results
Hello, I am trying to use the PNP algorithm implementations in Open CV (EPNP, Iterative etc.) to get the metric pose estimates of cameras in a two camera pair (not a conventional stereo rig, the...
View Articlewmv vs mp4 process time. Which one is better for opencv?
Today I had accidentally converting a video file to mp4 instead of only using wmv. I found out that, if I'm using wmv, my processing time for each frame can go to 10ms perframes whereas the same video...
View ArticleHow to capture the camera View with video capture card in VB?
Hello everyone, I have a problem which is related to EmguCV to capture the camera view. My camera is 713x BDA analog capture, the card is UPMOST-UPG301B V. When I compile this code, the OpenCamera can...
View Articlehow optimize kaze descriptor
in opencv3 kaze/akaze descriptor is taking large time for execution? how to optimize this & reduce the execution time.
View Articleconvert grayscale to RGB?
Is it possible to convert a grayscale image to contain an RGB channel? And thereby manipulate those, and give some color to an grayscale image? I tried using cvtColor but, i seem to get an black image...
View ArticleOpencv+xbox one kinect+linux+libfreenect2/openni?
Hi guys, for a project that I got involved I will need to work with the new xbox one kinect sensor(be careful not the simple kinect from xbox 360 or microsoft kinect v2, though this one seems to be...
View Articlestitching images and homography
How can I change the Opencv stitching code to compute the homography once for the first image pair and subsequent pairs simply warp with it? Please provide some suggestions so that I can understand and...
View ArticleLucas Kanade feature tracker
I've built a new project using the file "lktdemo.cpp" provided in OpenCV folder. It builds successfully but when I run it, it uses the camera of my laptop. The camera of my laptop is ON but 'm unable...
View ArticleHSV Histogram or just SV?
Hello I have an image as in the picture, which only I care on the whiteness-greyness-black. The other Hue I don't really don't care. OpenCV uses H: 0 - 180, S: 0 - 255, V: 0 - 255 I just want to get...
View ArticleHow to make auto-adjustments(brightness and contrast) for image Android...
i'm using OpenCV for **Android**. I would like to know,how to make **image correction**(auto adjustments of brightness/contrast) for image(bitmap) in android via OpenCV or that can be done by native...
View ArticleSubdiv2D: get indices of vertices of all triangles
I know that Subdiv2D::getTriangleList() will return coordinates of vertices of a all triangles. But in my case, I'd like to get **indices**, instead of coordinates. So, does Subdiv2D provide some...
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