performance tests in OpenCV 3.0 with OpenCL enabled
The performance scripts,e.g., opencv_perf_core and tutorial CPP examples in OpenCV 3.0 do not use UMat objects, how to enable OpenCL execution in this case?
View ArticleFace detect inconsistent performance
I'm using the cascade classifier with the front-face training data to detect faces in a still image (i.e. static jpg). I don't want to have to search the whole image for faces at once, so I send the...
View ArticleHow to find biggest white zone in an scanned image
Hi all, I have a project and I'm stuck... can you please help me to move on? I'm scanning some documents for a client and I have to apply a software barcode on the first page of the documents, but...
View ArticleBuilding OpenCV with CMake 3.3.2 causes ffmpeg error
Hi guys, Iam trying to build OpenCV with CMake. [opencv/master](https://github.com/Itseez/opencv/tree/master) While Downloading opencv_ffmpeg.dll through CMake, it causes an file DOWNLOAD HASH...
View ArticleStitching 2 images with different zooming setting
Hello, The Opencv stitching module can stitch 2 images with different zooming setting. My question is how the zoom setting of the output image (stitched image) decided?? What i mean is that, if i have...
View ArticleConverting from YUV420 to NV12 format with OpenCL acceleration
Hello folks, I wonder if the function/method YUV2RGB_NVx() in https://github.com/Itseez/opencv/blob/master/modules/imgproc/src/opencl/cvtcolor.cl does indeed convert YUV420 to NV12 or it just converts...
View ArticleHow is the OpenCV PCA mean calculated
I'm using OpenCV to calculate the PCA for a set of pixels represented as 2D points. But I'm unsure how PCA is calculating the mean of these points, as it is not what I would expect. If I have the...
View ArticleAndroid saving enormous Mat object (Java)
I'm writting andorid app where I use KNearest. I wrote code to train model, but every restart app, I must train data again, so I would like to save train data - `Mat(1000, 40 000, CvType.CV_32FC1);` I...
View ArticleCan't find "opencv2\contrib\contrib.hpp"
I need to add this library but It doesn't appear when I include it in my code: #include opencv2\contrib\contrib.hpp I use OpenCV 3.0.0.
View ArticleHow to overlay an PNG image with alpha channel to another PNG?
I have two PNG images (overlay.png and underlay.png) both with alpha channel. I tried the addWeight and copyTo API to mask overlay.png to underlay.png, but the result image is not what I want....
View ArticleImage Segmentation Algorithm
I have been given a piece of code by my supervisor but I don't understand the algorithm behind this code to make changes to it. I know this code using a block and finds contours within the block but...
View ArticleComparing 2 LBPs
I am using code from [bytefish.de](https://github.com/bytefish/opencv/tree/master/lbp) to generate my LBPs. If I generate 2 LBPs and their corresponding histograms, what is the best way to compare...
View ArticleIs it possible to get multiple prediction from FaceRecognizer
The task: 1) We have 1000+ face image database 2) For given image, we must detect top 10 most similar faces from database - in most cases face will not be exactly in database so large value for...
View ArticleMultithreading not effective for stereo vision with small images
I am building stereo camera device that should do the processing (=stereo matching) on board too. My requirement is to possibly do high FPS (=60 FPS) but the resolution can be as small as QVGA...
View ArticlemedianBlur KxK matrix size
Do anyone knows why medianBlur use a KxK size for the Matrix Kernel while Blur and Gaussian use a MxN matrix as Kernel? May be you @stevenputtemans know the answer ;)
View ArticleOpenCV failing to open camera
I have an OpenCV program that is supposed to use a webcam (in this case the built in laptop camera). The program compiles fine without error but when I run it the program seems to hang on the line:...
View ArticleShouldn't Mat::copyTo be documented with the type of mask?
I have just found that the `mask` in the `Mat::copyTo()` function should be of type `CV_8U`, with one or more channels (the same as `this`): // opencv/modules/src/copy.cpp: lines 270 and 271 int cn =...
View ArticleGives wrong number of faces
I am using following code to detect face. Basically in my ai project i want to add functionality like admin can only upload face image not other than that. so the alert will be displayed if the profile...
View Articlec++ fitLine function does not work correctly for three input points!
In development environment of VS2010, opencv 2.4.11, and a C++ console program, I found a while ago that the fitLine function did not output a correct result, when just three 2D points are inputted to...
View ArticleOpenCV 3.0 support Visual Studio 2010?
Sorry, I have a problem, I want to use OpenCV 3.0 at Visual Studio 2010, but I can't find the "VC10" folder under the build folder. Is OpenCV 3.0 not support Visual Studio 2010? thanks.
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