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Funvision opencv C++ tutorials

Funvision blog with OpenCV tutorials, source code from basics to advanced GStreamer video streaming and video processing. Lot of old school Cpencv LBP and HAAR cascades detectors for custom car and head detection and even modern mainly people and head deetction in DNN module. Tutorial source code is available mainly in C++ developped in Visual Studio and in WSL.

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Compile opencv 4 with Cuda and GStreamer on windows

on August 12, 2020

Compile opencv with gstreamer windows Install opencv with cuda Opencv cuda installation windows opencv gstreamer tutorial opencv gstreamer windows opencv with gstreamer

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Opencv 3.1 Tutorial Optical flow (calcOpticalFlowFarneback)

Farneback Optical flow Opencv simple C++ tutorial and code to achieve optical flow and farneback optical flow of moving an object in OpenCV video. Let's check the video example and the achieved result on my blog. Working and well describe code is included. Optical Flow Farneback parameters remarks You need 2 images at least to calculate optical flow, the previous image (prevgray) and the current image (img). !! The previous image must be initialized first !! Both images have to be grayscale. The result is stored in flowUmat which has the same size as inputs but the format is CV_32FC2 calcOpticalFlowFarneback (prevgray, img, flowUmat, 0.4 , 1 , 12 , 2 , 8 , 1.2 , 0 ); 0.4- image pyramid or simple image scale 1 is the number of pyramid layers. 1 means that flow is calculated only from the previous image. 12 is window size. Flow is computed over the window larger value is more robust to the noise. 2 mean number of iteration of the algorithm 8 is polyn

Fast Opencv people pedestrian detection Tutorial by CascadeClassifier

Simple Opencv C++ tutorial and example of people detection in video samples and pictures. There is nothing you cannot achieve in few simple steps. People detection and performace tasks in opencv could be solved if you have little bit knowledge of programing. Or just simple follow the steps.. Opencv tutorial instalation of opencv You can simple prepare the project inside the Visual Studio 2015 by Nuget Packages. This approach is easy for beginers and better than standard installation with all the environmental variables problems. Just follow the installation steps inside here Opencv is great and complex tools. There is lot of image processing and also machine learning features. You can simply learn your own detector. I would like to prepare some tutorial how to learn your own detector. It is long time run. All, you need to do, is some experience and basic opencv tools. under opencv/build/x64/vc14/bin opencv_createsamples.exe opencv_trainc

Opencv C++ Tutorial, Mat Roi, Region of interest

Opencv ROI, Region of Interest Simple opencv C++ tutorial how to work with ROI. Code example about selecting the rectangle region of interest inside the image and cut or display part of the image from the bigger picture. There is nothing what is difficult about this. Only trick is about one line of code. Rect RectangleToSelect(x,y,width,height) Mat source; Mat roiImage = source(RectangleToSelect); This is first post from this series. This simple opencv tutorials are all over the web. I would like to visualize all my steps through the code and //comment them. Each tutorial will contain small amount of step to keep reader focused. First tutorial about mat resizeing is available under that link Mat Resize I am using Visual Studio 2015, How to use Opencv 3.0.0 with Visual Studio can be found here install opencv visual studio 2015 . In Visual studio 2015 is best options to use NUGET packages, Here is described how to install Opencv by NUGET . It is easy. Working

Install opencv Visual Studio 2015

Install opencv for Visual Studio 2015 Opencv tutorial how to build opencv from source in Visual Studio 2015. This is usefull when the new version just release and there is no prebuild library awailable.. If you download prebuild libs for windows Visual studio some times agou there is problem the newest VS just mussing. Lets checkt the version of libraries and VS. Prebuild libs are only for version VC11 and VC12. This mean Visual Studio 2012 and 2013. This step helps you compile your own opencv libs for VC14 - Visual Studio 2015 Community edition. Important !! Now a days just use NUGET packages in Visual studio and you can code under 1 minutes. here . Prepare third party libs for opencv This step depends on your requirements. If you want python lets install python. But i can reccomend to install following parts. Intel © Threading Building Blocks ( TBB ) Intel © Integrated Performance Primitives ( IPP ) http://www.ffmpeg.org Build opencv 3.0.0 Downloa

Opencv VideoCapture File, Web Camera, RTSP stream

Opencv VideoCapture File, Camera and stream Opencv tutorial simple code in C++ to capture video from File, Ip camera stream and also the web camera plug into the computer. The key is to have installed the FFMPEG especially in case of reading the stream of IP cameras. In windows just use Opencv Installation by Nugets packages Here . Simple easy under 2 minutes of installation. In Linux, you need to follow the instruction below. If you are on Debian Like package system. Under Fedora Red hat dist just use a different approach. Code is simple and installation is the key.. Windows use nugets packages Linux you have to install and build Opencv With FFMPEG. Also simple. It is easy to capture video in OpenCV Video capture in OpenCV is a really easy task, but for a little bit experienced user. What is the problem? The problem is the installation of Opencv without recommended dependencies. Just install all basic libs that are recommended on the website. # Basic packa

Opencv C++ Tutorial Mat resize

Opencv Mat Resize Resize the Mat or Image in the Opencv C++ tutorial. It is obviously simple task and important to learn. This tutorial is visualized step by step and well-described each of them. The main trick is in that simple code. Mat Input; Mat Resized; int ColumnOfNewImage = 60; int RowsOfNewImage = 60; resize(Input, Resized, Size( ColumnOfNewImage , RowsOfNewImage )); This code just takes an Input image and resized save to output Mat. How big is the resized image is based on the Size? Size just contains two parameters. Simple numbers of how the result should be big. The simple number of columns (width) and rows (height). That is basically it. Enjoy Boring same face again and again. Load Image, resize and save Opencv C++ #include <Windows.h> #include "opencv2\highgui.hpp" #include "opencv2\imgproc.hpp" #include "opencv2\video\background_segm.hpp" #include &qu

Opencv reading IP camera, Video stream, Web camera, images and

Opencv reading video files, reading video stream, Images, IP and Web cameras. I would like to cover this all in one post. Yes, video writer is also important to store your results and achievements in video. There is couple of simple trick and if you follow them, you will never have a problem with the reading and writing video, stream, files in future. Basic opencv web camera reading There is couple think you need to take care. My favorite installation on windows platform is trough NUGET package system. It is easy in few steps. I describe this many times for example VS 2017 here . Nuget set up your project without any linking settings, library path selection, global environmental variables and you can directly start coding in few seconds. Just select and install nuget and compile code below. Nothing else. You need to take care if you have included several thinks. highgui.hpp core.hpp, imgproc.hpp, videoio, imgcodecs. All of them are not necessary to read the web camera but

Opencv build and install Visual Studio 2017 Contrib library

Easy install and build of Opencv 3+ tested on 3.2 version with contributor library and additional features described step by step, picture by picture. After this tutorial you can modify setting of CMAKE project according to HW possibilities and available libraries to build your own Opencv library. Most of the time, Prebuild libs with already generated DLL, LIBS are used to start project and coding. In case, that new visual studio 2017 is available there is no prebuild libraries for VS141, Thich is from my point of view confusing naming of Libraries compatible with Visual Studio 2017. Opencv VS 2017 install options Alternatives to this tutorial. You can skip this. There is possibility use some compatibility pack downloaded to VS140 and use same prebuild library as in case of Visual Studio 2015 this is described here The second way is to try use some prebuild NUGET package. I am using nugets a lot. Simple installation under one line of code inside nuget packages console. he

Head and people detection in opencv

LBP cascade for detect head and people in opencv LBP cascade free to download to use in opencv to detect people and heads. Code example and cascade description. All you need to write your own people head detector from the youtube video. Cascade is trained on my own people and head datasets. There are no perfect but in some cases are better then default opencv cascades. They are just different.. For example you can count that the head detector have much more false detection than the people detector.. The shape and feature space is much more common and close to others shapes than the whole people detector. Issues with opencv detectMultiScale head and people detector Please let me know if cascades worked as expected.. In code example there is ground threshold settings and reccomentation. LBP cascade head detection properties Sure you can find inside file. <!-- This is just basic 16 stage lbp cascade head detector develop by V.K. from https:

Opencv Web camera and Video streams in Windows subsystem for Linux WSL, by FFmpeg and GStreamer

Opencv in Windows Subsystem for Linux (WSL) is a compatibility layer designed to running Linux binary executables (in ELF format) natively on Windows 10. I love it. There are some limitations to mention. The first biggest is the lack of support of CUDA, which could be a limitation for deep learning application and learning in WSL. The second trouble for Opencv development is the lack of Web camera support. This suspends WSL almost on a useless level for me until now. VideoCapture cap; is not working in WSL for now cap.open(0); FFMPEG to WSL opencv program and back to WEB browser in windows This Video capture is right now not possible at in Ubuntu running under Windows (WSL). I will hit this limitation in this article. I will show you how to reach a video camera and learn something more about video streaming. Yes, the opencv processed frames will be stream to the web player on simple web site. Check the goal of this opencv tutorial on this video What you will learn

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