OpenCV¶

Overview¶

OpenCV

OpenCV is a library of programming functions mainly aimed at real-time computer vision, originally developed by Intel. It is free for use under the open source BSD license.
The library is cross-platform and focuses mainly on real-time image processing.
If the library finds Intel's Integrated Performance Primitives on the system, it will use these commercial optimized routines to accelerate itself.
Our cameras support this Vision Library by usage of XIMEA xiApiPlusOcv.

xiApiPlusOcv API¶

The XIMEA xiApiPlusOcv is an application interface which allows to easily create applications in CPP capable to get images from a camera and use them together with standard OpenCV library.

OpenCV Installation¶

The sample application for OpenCV Library requires the headers and binaries to be installed before it can be successfully built.
Please follow these guidelines depending on your OS:

Sample Application¶

XIMEA OpenCV sample application captures a sequence of images and displays it on the screen using OpenCV Mat format.

OpenCV sample code - See this section with various OpenCV examples.
If XIMEA API Software Package is installed, sample applications with XIMEA OpenCV Library are located:

Windows - in XIMEA\Examples\xiApiPlusOcv as a Visual Studio .vcxproj or in XIMEA\Examples\Sources\xiAPIplusOpenCV
Linux - in /opt/XIMEA/examples/xiApiPlusOpenCV directory as a Makefile project or in /opt/XIMEA/samples/xiAPIplusOpenCV
macOS - in examples as a Makefile project

To run this application, please follow these steps:

Download and install XIMEA API Software Package
Install OpenCV
Check the sample application dependencies.
In Visual Studio project settings it is necessary to check OpenCV paths, and also Ximea libraries. Our configuration uses environment variable $(OPENCV_DIR) as path where OpenCV is built (e.g. C:\opencv\build\x64\vc12).
These setting should be checked in the project settings:
- Configuration properties --> C/C++ --> General --> Additional Include Directories
- Configuration properties --> Linker --> General --> Additional Library Directories
- Configuration properties --> Linker --> Input --> Additional Dependencies. The default settings use the opencv_world310.lib.
Build our OpenCV sample application

The Sample application uses the OpenCV xiApiPlusOcv.hpp library interface to capture series of frames from the camera and converts each frame to the OpenCV Mat format and shows it on the display.
It uses a xiAPIplusCameraOcv class to handle the camera and its features.

When compiling on 64-bit Windows systems the Solution platform in Visual Studio should be set to x64.

How to write applications¶

#include <stdio.h>
#include "xiApiPlusOcv.hpp" 

using namespace cv;
using namespace std;

int main (void)
{
 try
 {
   xiAPIplusCameraOcv cam;
   cam.OpenFirst();
   cam.SetExposureTime(10000); //10000 us = 10 ms
   cam.StartAcquisition();

   // Read and convert a frame from the camera
   Mat cv_mat_image = cam.GetNextImageOcvMat();
   // Show image on display
   cv::imshow("Image from camera",cv_mat_image);

   cam.StopAcquisition();
   cam.Close();
 }
 catch(xiAPIplus_Exception& exp)
 {
   exp.PrintError(); // report error if some call fails
 }
}

The xiAPIplusCameraOcv class is used to handle the camera.
In an application, an instance of this class has to be created.
Then the class should be initialized by calling an opening method (e.g. OpenFirst()).
Camera parameters can be set by calling set methods or read by calling get methods.
The camera acquisition starts after StartAcquisition() is called.
The captured frames can be read by calling GetNextImageOcvMat() - a method that reads a frame from the camera and converts it into OpenCV Mat format that can be directly used for OpenCV processing.

Documentation¶

XIMEA OpenCV Library is documented at xiApiPlusOcv.hpp file.
OpenCV is documented in OpenCV Online C++ Reference

Offline Processing¶

xiApiPlusOcv allows to process already captured and stored images using Offline Processing. Please read more at xiApiPlusOcv Offline Processing.