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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 .

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Error in installing opencv3 with homebrew and python3

I'm using homebrew installing opencv3 on OSX(EI Captain), brew install opencv3 --with-contrib --with-python3 --HEAD and an error occurred: Updating Homebrew... ==> Installing opencv3 from homebrew/science ==> Cloning…
SKSKSKSK
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How to Cut an Image Vertically into Two Equal Sized Images

So I have an 800 x 600 image that I want to cut vertically into two equally sized pictures using OpenCV 3.1.0. This means that at the end of the cut, I should have two images that are 400 x 600 each and are stored in their own PIL variables. Here's…
Elliot Killick
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In the context of OpenCV, what is `ippicv`?

While building OpenCV 3.1.0 on CentOS I've been getting a hash mismatch error caused by a file called ippicv_linux_20151201.tgz. After some research I have found that the two prevailing solutions suggested by several people (for example here) are…
Ray
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Cannot install openCV 3.1.0 with python3. CMAKE not including or linking python correctly

I'm trying to get OpenCV 3.1.0 installed with Python3 on my machine. Because I have Ubuntu 16.04, I am following this guide exactly: http://www.pyimagesearch.com/2016/10/24/ubuntu-16-04-how-to-install-opencv/ However, I have trouble in step 4, after…
user3667125
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Error installing OpenCV on Ubuntu 16.04

I have being trying to install OpenCV on Ubuntu 16.04 unsing several tutorials and i always end up with an error. This is the last one i've got following this…
Rafael Reis
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OpenCV lines/ruler detection

I'm trying to detect ruler on the image, and I'm going to follow the next process: 1) prepare image (blur,Canny, ect.) 2) detect lines 3) prepare set of parallel lines so, I have an image: that app converts to this: next I've tried HoughLinesP…
Siarhei
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Difference Between OpenCV's Haar Cascade Classifiers

OpenCV provides several Haar Cascade classidiers for face detection: - haarcascade_frontalface_alt.xml - haarcascade_frontalface_alt2.xml - haarcascade_frontalface_alt_tree.xml - haarcascade_frontalface_default.xml I wonder what is the difference…
mohaghighat
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Image loses quality with cv2.warpPerspective

I am working with OpenCV 3.1 and with Python. My problem comes when I try to deskew (fix the tilt of) an image with text. I am using cv2.warpPerspective to make it possible, but the image loses a lot of quality. You can see here the original part…
Chuck Aguilar
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OpenCV 3 Python - Haar Cascade Upper Body Detector doesn't work on a half body (waist up) photo?

I've been trying to detect people in photos and I've had some success with pedestrians. However, for my use case scenario, I need to be able to detect half body/upper body (waist up) or heads in photo. I tried the haar cascade for the upper body.…
Razgriz
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Advantage of using a CUDA Stream

I am trying to understand where a Stream might help me with processing multiple Regions of Interest on a video frame. If using NPP functions that support a stream, is this a case where one would launch as many streams as there are ROIs? Possibly…
AeroClassics
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How to calibrate camera focal length, translation and rotation given four points?

I'm trying to find the focal length, position and orientation of a camera in world space. Because I need this to be resolution-independent, I normalized my image coordinates to be in the range [-1, 1] for x, and a somewhat smaller range for y…
Thomas
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Unable to pass IplImage class as arguments

I am trying to pass the IplImage object to another program as arguments using the system library call. The code snippet is as shown below. #include #include #include #include "libuvc/libuvc.h" …
Eswar
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ClassNotFoundException: android.hardware.camera2.CameraAccessException with OpenCV 3.1.0

I am working in an android project with Android Studio 2.2 that uses OpenCV 3.1.0 library. I imported the library according to this answer. The situation is the following: When I compile the project for a device with API >= 21 (exactly API 23),…
David Miguel
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Working OpenCV HoG SVM Predict code from 2.4 does not work in 3.4.1

I am resurrecting some of my old code for OpenCV 2.4.1 which worked and allowed me to train my own HoG ( Histogram of Oriented Gradients ) descriptors for OpenCV's SVM. I am now porting this old working code to OpenCV 3.4.1 and I have noticed that…
PhilBot
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Multi-Layer Perceptrons in EmguCV

I'm trying to implement Multi-Layer Perceptrons (MLP) neural networks using EmguCV 3.1 (a dot NET wrapper for OpenCV library) in C#(Windows Form). In order to practice with this library I decide to implement OR operation using MLP. I create MLP…
Babak.Abad
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