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Questions tagged [opencv3.1]

Use this tag only for questions that are specific to version 3.1 of OpenCV, for general questions use the [opencv] tag.

OpenCV is an open source computer vision library

Version 3.1 released in December 2015. Its documentation can be found here.

For more information, see .

340 questions
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background subtractor for opencv=3.1.0

//cv::BackgroundSubtractorMOG2 bg = cv::BackgroundSubtractorMOG2(); cv::Ptr< BackgroundSubtractorMOG2 >createBackgroundSubtractorMOG2(); bg.set("history", 1000); bg.set("nmixtures", 3); bg.set("backgroundRatio", 0.7); bg.set("detectShadows",…
sophie
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Python2: Resize image plotted using Matplotlib

I'm coding using Jupyter Notebook with Python 2 + OpenCV 3, and I need to show my results using images. The images are very small and it's hard to observe the results. from matplotlib import pyplot as plt import cv2 thresh = 127 maxValue =…
Pat
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How to Choose which OpenCV to use in CMakeLists.txt when I have two OpenCV (same versions) in my computer?

I installed ROS in my computer. And ROS automatically installed opencv 3.2 in my computer. As I need to use functions in opencv's extra modules, I installed opencv again from source. Now I have a c++ project and I want to use the opencv I installed…
tczj
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Opencv3 x64 visual studio read image but only display empty window

I had worked with OPENCV2.4.7 for a long time. Everything worked fine on my windows10 computer. Today, I download OPENCV3.2 and want to start using this version. Unfortunately, it did not work correctly even with simply read an image file and show…
Yidian
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Partial human detection in OpenCV 3

I am working on a human detection program using OpenCV using Python. I saw this very good example and I ran it on the samples it had. It can detect people regardless where they are facing and has decent overlap detection as well as blurred motion as…
Razgriz
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Why is getAffineTransform producing such a weird matrix?

I want to creating an affine transform such that after the transform happens the image is still centered around the blue dot, and the top red dot is 45% from the top of the image, and the bottom red dot is 25% from the bottom of the image here is an…
YellowPillow
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How to set the parameters of OpenCV3 calcHist() using vectors?

I am calculating a histogram from a greyscale image using the above code; it is working fine. cv::Mat imgSrc = cv::imread("Image.jpg", cv::IMREAD_UNCHANGED); cv::Mat histogram; //Array for the histogram int channels[] = {0}; int binNumArray[] =…
szecsit
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Errors in building Opencv with extra modules in Visual Studio 2015

I have configured and generated opencv 3.2 with extra modules on CMAKE successfully using a 32-bit compiler of Visual Studio 2015 (vs14). However, when building this project in Visual Studio I get several errors. Below, you could find: small sample…
Ibrahim Khalil
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OpenCV 3.1.0 C++ predict function RAW_OUTPUT return values are sometimes inverse

I extract positive and negative descriptor vectors in the cv::Mat objects posSamples and negSamples of type CV_32FC1. Every row corresponds to a vector. I construct "samples" and "labels" cv::Mat objects to train an SVM. (2 class…
Alper Aydın
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OpenCV get coordinates / radius in pixel

I have the code that applies some transformations for image for detecting circles (GaussianBlur->cvtColor(gray)->canny->HoughCircles) and as for result i got vector circles; array. If I draw the result with OpenCV: cv::Point…
Siarhei
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OpenCV 3.2 hangs on cv2.cvtColor

I have a set of web APIs that I run on Apache with WSGI for image processing. Recently I upgraded my OpenCV to 3.2 (I'm using Python 2.7) OpenCV seems to work fine when I run it from console, but when I make web API calls openCV hangs on converting…
Dmitry Birulia
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opencv 3.1 detectmultiscale() for face detection

I am trying to detect faces using opencv detectmultiscale. The number of faces in the output is HUGE (faces { size=1152921366050660864 }...) although the input image has only one face. I tried to change the minNeighbors value in order to eliminate…
Fadwa
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OpenCV3 installation on Mac

I tried to install OpenCV3 for Mac with the following command in terminal: brew install opencv3 --with-contrib -with-ffmpeg It repeatedly gets stuck at this point: cmake .. -DCMAKE_C_FLAGS_RELEASE=-DNDEBUG -DCMAKE_CXX_FLAGS_RELEASE=-DNDEBUG…
Lakshay Sharma
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How can I know tracking is lost using KCF tracker

I am using KCF tracker to track a region selected by hand (mouse). Once it is selected, the tracker is able to do it but the tracker fails to stop tracking after the target has moved outside the image. Is there any way to know that the target…
user18441
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Affine transform in C++

I am currently making a project for school on image processing in visual Studio 2013, using Open CV 3.1. My goal (for now) is to transform an image, using affine transform, so that the trapezoidal board will be transformed into a rectangle. To do…
Jakub Oficjalski
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