protected FindCornersCalibrationResult FindCorners(Image<Bgr, byte> image, StereoCameraCalibrationData calibData, ref Size? imgSize)
{
if (imgSize == null)
{
imgSize = image.Size;
}
else if (!image.Size.Equals(imgSize.Value))
{
return new FindCornersCalibrationResult()
{
Found = false
};
}
PointF[] corners = null;
var tImg = image;
corners = CameraCalibration.FindChessboardCorners(
tImg.Convert<Gray, byte>(),
calibData.BoardSquareSize,
CALIB_CB_TYPE.ADAPTIVE_THRESH | CALIB_CB_TYPE.NORMALIZE_IMAGE
);
var leftFound = (corners != null && corners.Count() != 0);
if (leftFound)
{
var subCorners = new PointF[1][];
subCorners[0] = corners.ToArray();
image.Convert<Gray, byte>().FindCornerSubPix(
subCorners,
new Size(11, 11),
new Size(-1, -1),
new MCvTermCriteria(30, 0.01));
corners = subCorners[0];
}
else
{
return new FindCornersCalibrationResult()
{
Found = false
};
}
return new FindCornersCalibrationResult()
{
Found = true,
Corners = corners
};
}
public StereoCameraParams CalibrateStereo(StereoCameraCalibrationData calibData)
{
var imgCount = calibData.GetCalibListSize();
var leftImagePoints = new List<List<PointF>>();
var rightImagePoints = new List<List<PointF>>();
int foundImagesCount = 0;
Size? imgSize = null;
for (int i = 0; i < imgCount; ++i)
{
//left
var leftFileName = calibData.GetFrameById(i).LeftRawFrame;
var leftImage = new Image<Bgr, byte>(leftFileName);
var leftRes = FindCorners(leftImage, calibData, ref imgSize);
if (!leftRes.Found)
{
continue;
}
////
//right
var rightFileName = calibData.GetFrameById(i).RightRawFrame;
var rightImage = new Image<Bgr, byte>(rightFileName);
var rightRes = FindCorners(rightImage, calibData, ref imgSize);
if (!rightRes.Found)
{
continue;
}
////
if (leftRes.Found && rightRes.Found)
{
leftImagePoints.Add(new List<PointF>(leftRes.Corners));
rightImagePoints.Add(new List<PointF>(rightRes.Corners));
++foundImagesCount;
}
}
var objectPoints = new List<List<MCvPoint3D32f>>();
for (int i = 0; i < foundImagesCount; ++i)
{
objectPoints.Add(new List<MCvPoint3D32f>());
for (int j = 0; j < calibData.BoardSquareSize.Height; ++j)
{
for (int k = 0; k < calibData.BoardSquareSize.Width; ++k)
{
objectPoints[i].Add(new MCvPoint3D32f((float)(j * calibData.SquareSize), (float)(k * calibData.SquareSize), 0));
}
}
}
var objectPointsArray = objectPoints.Select(x => x.ToArray()).ToArray();
var leftImagePointsArray = leftImagePoints.Select(x => x.ToArray()).ToArray();
var rightImagePointsArray = rightImagePoints.Select(x => x.ToArray()).ToArray();
IntrinsicCameraParameters leftIntrinsicCameraParameters = new IntrinsicCameraParameters(8);
IntrinsicCameraParameters rightIntrinsicCameraParameters = new IntrinsicCameraParameters(8);
ExtrinsicCameraParameters extrinsic;
Matrix<double> foundamental;
Matrix<double> essential;
CameraCalibration.StereoCalibrate(
objectPoints: objectPointsArray,
imagePoints1: leftImagePointsArray,
imagePoints2: rightImagePointsArray,
intrinsicParam1: leftIntrinsicCameraParameters,
intrinsicParam2: rightIntrinsicCameraParameters,
imageSize: imgSize.Value,
flags: CALIB_TYPE.DEFAULT,
termCrit: new MCvTermCriteria(100, 1e-5),
extrinsicParams: out extrinsic,
foundamentalMatrix: out foundamental,
essentialMatrix: out essential
);
//rectification
Rectangle Rec1 = new Rectangle(); //Rectangle Calibrated in camera 1
Rectangle Rec2 = new Rectangle(); //Rectangle Caliubrated in camera 2
Matrix<double> Q = new Matrix<double>(4, 4); //This is what were interested in the disparity-to-depth mapping matrix
Matrix<double> R1 = new Matrix<double>(3, 3); //rectification transforms (rotation matrices) for Camera 1.
Matrix<double> R2 = new Matrix<double>(3, 3); //rectification transforms (rotation matrices) for Camera 1.
Matrix<double> P1 = new Matrix<double>(3, 4); //projection matrices in the new (rectified) coordinate systems for Camera 1.
Matrix<double> P2 = new Matrix<double>(3, 4); //projection matrices in the new (rectified) coordinate systems for Camera 2.
CvInvoke.cvStereoRectify(
cameraMatrix1: leftIntrinsicCameraParameters.IntrinsicMatrix,
cameraMatrix2: rightIntrinsicCameraParameters.IntrinsicMatrix,
distCoeffs1: leftIntrinsicCameraParameters.DistortionCoeffs,
distCoeffs2: rightIntrinsicCameraParameters.DistortionCoeffs,
imageSize: imgSize.Value,
R: extrinsic.RotationVector.RotationMatrix,
T: extrinsic.TranslationVector,
R1: R1,
R2: R2,
P1: P1,
P2: P2,
Q: Q,
flags: STEREO_RECTIFY_TYPE.DEFAULT,
alpha: -1,
newImageSize: Size.Empty,
validPixROI1: ref Rec1,
validPixROI2: ref Rec2
);
var leftMapX = new Matrix<float>(imgSize.Value.Height, imgSize.Value.Width);
var rightMapX = new Matrix<float>(imgSize.Value.Height, imgSize.Value.Width);
var leftMapY = new Matrix<float>(imgSize.Value.Height, imgSize.Value.Width);
var rightMapY = new Matrix<float>(imgSize.Value.Height, imgSize.Value.Width);
CvInvoke.cvInitUndistortRectifyMap(
cameraMatrix: leftIntrinsicCameraParameters.IntrinsicMatrix,
distCoeffs: leftIntrinsicCameraParameters.DistortionCoeffs,
R: R1,
newCameraMatrix: P1,
mapx: leftMapX,
mapy: leftMapY
);
CvInvoke.cvInitUndistortRectifyMap(
cameraMatrix: rightIntrinsicCameraParameters.IntrinsicMatrix,
distCoeffs: rightIntrinsicCameraParameters.DistortionCoeffs,
R: R2,
newCameraMatrix: P2,
mapx: rightMapX,
mapy: rightMapY
);
////
return new StereoCameraParams()
{
EssentialMatrix = essential,
ExtrinsicCameraParams = extrinsic,
FoundamentalMatrix = foundamental,
LeftIntrinsicCameraParameters = leftIntrinsicCameraParameters,
RightIntrinsicCameraParameters = rightIntrinsicCameraParameters,
Rec1 = Rec1,
Rec2 = Rec2,
Q = Q,
R1 = R1,
R2 = R2,
P1 = P1,
P2 = P2,
LeftMapX = leftMapX,
LeftMapY = leftMapY,
RightMapX = rightMapX,
RightMapY = rightMapY
};
}