cisstStereoVision tutorial 4

Example 4 - Creating custom filters

List of files

• CMakeLists.txt: CMake script for creating compiler dependent projects
• CMyFilter1.h: Custom filter 1 class declaration
• CMyFilter1.cpp: Custom filter 1 class definition
• main.cpp: Application entry point (main() function)

Source code

All files can be found under cisstStereoVision/examples/tutorial3.

CMake

PROJECT(svlTutorial3)

FIND_PACKAGE(cisst REQUIRED)

IF(cisst_FOUND)

    INCLUDE(${CISST_USE_FILE})

    ADD_EXECUTABLE(${PROJECT_NAME}
                   CMyFilter1.h
                   CMyFilter1.cpp
                   main.cpp
                   )

    CISST_TARGET_LINK_LIBRARIES(${PROJECT_NAME} cisstCommon cisstVector cisstOSAbstraction cisstMultiTask cisstStereoVision)

ENDIF(cisst_FOUND)

Custom filter 1 class declaration

#include <cisstStereoVision/svlFilterBase.h>

class CMyFilter1 : public svlFilterBase
{
public:
    CMyFilter1();

protected:
    int Initialize(svlSample* syncInput, svlSample* &syncOutput);
    int Process(svlProcInfo* procInfo, svlSample* syncInput, svlSample* &syncOutput);
};

Custom filter 1 class implementation

#include "CMyFilter1.h"

CMyFilter1::CMyFilter1() :
    svlFilterBase()                                                       // Call baseclass' constructor
{                                                                         //
    AddInput("input", true);                                              // Create synchronous input connector
    AddInputType("input", svlTypeImageRGB);                               // Set sample type for input connector
                                                                          //
    AddOutput("output", true);                                            // Create synchronous ouput connector
    SetAutomaticOutputType(true);                                         // Set output sample type the same as input sample type
}

int CMyFilter1::Initialize(svlSample* syncInput, svlSample* &syncOutput)
{
    syncOutput = syncInput;                                               // Pass the input sample forward to the output
    return SVL_OK;                                                        //
}

int CMyFilter1::Process(svlProcInfo* procInfo, svlSample* syncInput, svlSample* &syncOutput)
{
    _OnSingleThread(procInfo)                                             // Execute the following block on one thread only
    {                                                                     //
        svlSampleImageRGB* image = (svlSampleImageRGB*)syncInput;         // Cast input sample to RGB image type
        svlRGB* pixel = (svlRGB*)image->GetUCharPointer();                // Get RGB pixel buffer for in-place modifications
        unsigned int pixelcount = image->GetWidth() * image->GetHeight(); // Get number of pixels in image
                                                                          //
        for (unsigned int i = 0; i < pixelcount; i ++, pixel ++) {        // for each pixel ...
            pixel->r = 255 - pixel->r;                                    //   process 'red' channel
            pixel->g = 255 - pixel->g;                                    //   process 'green' channel
            pixel->b = 255 - pixel->b;                                    //   process 'blue' channel
        }                                                                 //
    }                                                                     //
                                                                          //
    syncOutput = syncInput;                                               // Pass the modified sample forward to the output
                                                                          //
    return SVL_OK;                                                        //
}

Main program

#include <cisstStereoVision.h>
#include "CMyFilter1.h"

int main()
{
    svlInitialize();                                 // Discover supported devices and codecs
                                                     //
    svlStreamManager stream;                         // Instantiate SVL Stream
    svlFilterSourceVideoCapture source(1);           // Instantiate video capture filter
    CMyFilter1 filter1;                              // Instantiate user-implemented filter #1
    svlFilterImageWindow window;                     // Instantiate image window filter
                                                     //
    source.SetDevice(0);                             // Select first available capture device
                                                     //
    stream.SetSourceFilter(&source);                 // Assign source filter to stream
    source.GetOutput()->Connect(filter1.GetInput()); // Connect source filter to filter #1
    filter1.GetOutput()->Connect(window.GetInput()); // Connect filter #1 to window filter
                                                     //
    stream.Play();                                   // Initialize and Play video stream
                                                     //
    char ch;                                         //
    std::cin >> ch;                                  // (Wait for key-press)
                                                     //
    stream.Release();                                // Release stream
                                                     //
    return 0;                                        //
}