CVTrackedChessboard Class Reference

OpenCV chessboard tracker class derived from CVTracked. More...

#include <CVTrackedChessboard.h>

Inheritance diagram for CVTrackedChessboard:

Public Member Functions
	CVTrackedChessboard (string calibIniPath)
bool	track (CVMat imageGray, CVMat imageBgr, CVCalibration *calib) final
	Tracks the chessboard image in the given image for the first sceneview. More...
Public Member Functions inherited from CVTracked
	CVTracked ()
virtual	~CVTracked ()=default
void	drawDetection (bool draw)
bool	isVisible ()
bool	drawDetection ()
CVMatx44f	objectViewMat ()

Private Member Functions
void	calcBoardCorners3D (const CVSize &boardSize, float squareSize, CVVPoint3f &objectPoints3D)
bool	loadCalibParams ()

Private Attributes
string	_calibParamsFileName
float	_edgeLengthM
CVVPoint3f	_boardPoints3D
CVSize	_boardSize
bool	_solved
CVMat	_rVec
CVMat	_tVec
string	_calibIniPath

Additional Inherited Members
Static Public Member Functions inherited from CVTracked
static cv::Matx44f	createGLMatrix (const CVMat &tVec, const CVMat &rVec)
	Create an OpenGL 4x4 matrix from an OpenCV translation & rotation vector. More...
static void	createRvecTvec (const CVMatx44f &glMat, CVMat &tVec, CVMat &rVec)
	Creates the OpenCV rvec & tvec vectors from an column major OpenGL 4x4 matrix. More...
static CVMatx44f	calcObjectMatrix (const CVMatx44f &cameraObjectMat, const CVMatx44f &objectViewMat)
static CVVec3f	averageVector (vector< CVVec3f > vectors, vector< float > weights)
static SLQuat4f	averageQuaternion (vector< SLQuat4f > quaternions, vector< float > weights)
static void	resetTimes ()
	Resets all static variables. More...
Static Public Attributes inherited from CVTracked
static AvgFloat	trackingTimesMS
	Averaged time for video tracking in ms. More...
static AvgFloat	detectTimesMS
	Averaged time for video feature detection & description in ms. More...
static AvgFloat	detect1TimesMS
	Averaged time for video feature detection subpart 1 in ms. More...
static AvgFloat	detect2TimesMS
	Averaged time for video feature detection subpart 2 in ms. More...
static AvgFloat	matchTimesMS
	Averaged time for video feature matching in ms. More...
static AvgFloat	optFlowTimesMS
	Averaged time for video feature optical flow tracking in ms. More...
static AvgFloat	poseTimesMS
	Averaged time for video feature pose estimation in ms. More...
Protected Attributes inherited from CVTracked
bool	_isVisible
	Flag if marker is visible. More...
bool	_drawDetection
	Flag if detection should be drawn into image. More...
CVMatx44f	_objectViewMat
	view transformation matrix More...
HighResTimer	_timer
	High resolution timer. More...

Detailed Description

OpenCV chessboard tracker class derived from CVTracked.

The chessboard tracker uses the same chessboard pattern as the calibration class defined in CVCalibration. See CVTrackedChessboard::track for the core tracking implementation.

Definition at line 31 of file CVTrackedChessboard.h.

Constructor & Destructor Documentation

CVTrackedChessboard()

CVTrackedChessboard::CVTrackedChessboard ( string  calibIniPath )

explicit

Definition at line 24 of file CVTrackedChessboard.cpp.

  : _calibParamsFileName("calib_in_params.yml"),
    _calibIniPath(calibIniPath)
{
    if (!loadCalibParams())
    {
        Utils::exitMsg("SLProject",
                       "CVTrackedChessboard: could not load calibration parameter",
                       __LINE__,
                       __FILE__);
    }
 
    calcBoardCorners3D(_boardSize,
                       _edgeLengthM,
                       _boardPoints3D);
    _solved = false;
}

Member Function Documentation

calcBoardCorners3D()

void CVTrackedChessboard::calcBoardCorners3D ( const CVSize &  boardSize, float  squareSize, CVVPoint3f &  objectPoints3D  )

private

Definition at line 65 of file CVTrackedChessboard.cpp.

{
    // Because OpenCV image coords are top-left we define the according
    // 3D coords also top-left.
    objectPoints3D.clear();
    for (int y = boardSize.height - 1; y >= 0; --y)
        for (int x = 0; x < boardSize.width; ++x)
            objectPoints3D.push_back(CVPoint3f((float)x * squareSize,
                                               (float)y * squareSize,
                                               0));
}

loadCalibParams()

bool CVTrackedChessboard::loadCalibParams ( )

private

Definition at line 42 of file CVTrackedChessboard.cpp.

{
    string        fullCalibIniFile = _calibIniPath + _calibParamsFileName;
    SLstring      configString     = SLFileStorage::readIntoString(fullCalibIniFile, IOK_config);
    CVFileStorage fs(configString, CVFileStorage::READ | CVFileStorage::MEMORY);
 
    if (!fs.isOpened())
    {
        Utils::log("SLProject", "Could not open the calibration parameter file: %s", fullCalibIniFile.c_str());
        return false;
    }
 
    // assign paramters
    fs["numInnerCornersWidth"] >> _boardSize.width;
    fs["numInnerCornersHeight"] >> _boardSize.height;
    // load edge length in MM
    fs["squareSizeMM"] >> _edgeLengthM;
    // convert to M
    _edgeLengthM *= 0.001f;
 
    return true;
}

track()

bool CVTrackedChessboard::track ( CVMat  imageGray, CVMat  imageBgr, CVCalibration *  calib  )

finalvirtual

Tracks the chessboard image in the given image for the first sceneview.

Implements CVTracked.

Definition at line 81 of file CVTrackedChessboard.cpp.

{
    assert(!imageGray.empty() && "ImageGray is empty");
    assert(!imageBgr.empty() && "ImageBGR is empty");
    assert(!calib->cameraMat().empty() && "Calibration is empty");
 
    ////////////
    // Detect //
    ////////////
 
    float startMS = _timer.elapsedTimeInMilliSec();
 
    // detect chessboard corners
    int flags = cv::CALIB_CB_FAST_CHECK;
 
    CVVPoint2f corners2D;
 
    _isVisible = cv::findChessboardCorners(imageGray,
                                           _boardSize,
                                           corners2D,
                                           flags);
 
    CVTracked::detectTimesMS.set(_timer.elapsedTimeInMilliSec() - startMS);
 
    if (_isVisible)
    {
 
        if (_drawDetection)
        {
            cv::drawChessboardCorners(imageBgr, _boardSize, corners2D, true);
        }
 
        /////////////////////
        // Pose Estimation //
        /////////////////////
 
        startMS = _timer.elapsedTimeInMilliSec();
 
        // find the camera extrinsic parameters (rVec & tVec)
        _solved = solvePnP(CVMat(_boardPoints3D),
                           CVMat(corners2D),
                           calib->cameraMat(),
                           calib->distortion(),
                           _rVec,
                           _tVec,
                           _solved,
                           cv::SOLVEPNP_ITERATIVE);
 
        CVTracked::poseTimesMS.set(_timer.elapsedTimeInMilliSec() - startMS);
 
        if (_solved)
        {
            _objectViewMat = createGLMatrix(_tVec, _rVec);
            return true;
        }
    }
 
    return false;
}

Member Data Documentation

_boardPoints3D

CVVPoint3f CVTrackedChessboard::_boardPoints3D

private

Definition at line 48 of file CVTrackedChessboard.h.

_boardSize

CVSize CVTrackedChessboard::_boardSize

private

Definition at line 49 of file CVTrackedChessboard.h.

_calibIniPath

string CVTrackedChessboard::_calibIniPath

private

Definition at line 53 of file CVTrackedChessboard.h.

_calibParamsFileName

string CVTrackedChessboard::_calibParamsFileName

private

Definition at line 46 of file CVTrackedChessboard.h.

_edgeLengthM

float CVTrackedChessboard::_edgeLengthM

private

Definition at line 47 of file CVTrackedChessboard.h.

_rVec

CVMat CVTrackedChessboard::_rVec

private

Definition at line 51 of file CVTrackedChessboard.h.

_solved

bool CVTrackedChessboard::_solved

private

Definition at line 50 of file CVTrackedChessboard.h.

_tVec

CVMat CVTrackedChessboard::_tVec

private

Definition at line 52 of file CVTrackedChessboard.h.

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The documentation for this class was generated from the following files:

• CVTrackedChessboard.h
• CVTrackedChessboard.cpp