public void TestStereoSGBMCorrespondence()
{
Image<Gray, Byte> left = EmguAssert.LoadImage<Gray, byte>("aloeL.jpg");
Image<Gray, Byte> right = EmguAssert.LoadImage<Gray, byte>("aloeR.jpg");
Size size = left.Size;
Image<Gray, Int16> disparity = new Image<Gray, Int16>(size);
StereoSGBM bm = new StereoSGBM(10, 64, 0, 0, 0, 0, 0, 0, 0, 0, StereoSGBM.Mode.SGBM);
Stopwatch watch = Stopwatch.StartNew();
bm.Compute(left, right, disparity);
watch.Stop();
EmguAssert.WriteLine(String.Format("Time used: {0} milliseconds", watch.ElapsedMilliseconds));
Matrix<double> q = new Matrix<double>(4, 4);
q.SetIdentity();
Image<Gray, Int16> disparityScaled = disparity * (-16);
MCvPoint3D32f[] points = PointCollection.ReprojectImageTo3D(disparityScaled.Mat, q);
float min = (float) 1.0e10, max = 0;
foreach (MCvPoint3D32f p in points)
{
if (p.Z < min)
min = p.Z;
else if (p.Z > max)
max = p.Z;
}
EmguAssert.WriteLine(String.Format("Min : {0}\r\nMax : {1}", min, max));
}
private void GetDisparityMap()
{
minDisparity = TBminDisparity.Value; //Minimum possible disparity value. Normally, it is zero but sometimes rectification algorithms can shift images, so this parameter needs to be adjusted accordingly.
//Default is zero, should be set to a negative value, if negative disparities are possible (depends on the angle between the cameras views and the distance of the measured object to the cameras).
numDisparities = TBnumDisparities.Value; //Maximum disparity minus minimum disparity. The value is always greater than zero. In the current implementation, this parameter must be divisible by 16.
SADWindowSize = TBSADWindowSize.Value; //(= blockSize) Matched block size. It must be an odd number >=1 . Normally, it should be somewhere in the 3..11 range. Use 0 for default.
P1 = TBp1.Value; //The first parameter controlling the disparity smoothness. It is the penalty on the disparity change by plus or minus 1 between neighbor pixels.
//Reasonably good value is 8*number_of_image_channels*SADWindowSize*SADWindowSize. Use 0 for default
P2 = TBp2.Value; //The second parameter controlling the disparity smoothness. It is the penalty on the disparity change by more than 1 between neighbor pixels.
//The algorithm requires p2 > p1. Reasonably good value is 32*number_of_image_channels*SADWindowSize*SADWindowSize. Use 0 for default
disp12MaxDiff = TBdisp12MaxDiff.Value; //Maximum allowed difference (in integer pixel units) in the left-right disparity check. Set it to a non-positive value to disable the check.
preFilterCap = TBpreFilterCap.Value; //Truncation value for the prefiltered image pixels. The algorithm first computes x-derivative at each pixel and clips its value by [-preFilterCap, preFilterCap] interval.
//The result values are passed to the Birchfield-Tomasi pixel cost function.
uniquenessRatio = TBuniquenessRatio.Value; //Margin in percentage by which the best (minimum) computed cost function value should “win” the second best value to consider the found match correct.
//Normally, a value within the 5-15 range is good enough.
speckleWindowSize = TBspeckleWindowSize.Value; //Maximum size of smooth disparity regions to consider their noise speckles and invalidate. Set it to 0 to disable speckle filtering. Otherwise, set it somewhere in the 50-200 range
speckleRange = TBspeckleRange.Value; //Maximum disparity variation within each connected component. If you do speckle filtering, set the parameter to a positive value,
//it will be implicitly multiplied by 16. Normally, 1 or 2 is good enough.
StereoSGBM.Mode mode = StereoSGBM.Mode.SGBM;
//mode (Optional) : Set it to HH to run the full-scale two-pass dynamic programming algorithm. It will consume O(W*H*numDisparities) bytes,
//which is large for 640x480 stereo and huge for HD-size pictures. By default, it is set to false.
StereoSGBM sgbm = new StereoSGBM(minDisparity, numDisparities, SADWindowSize, P1, P2, disp12MaxDiff, preFilterCap, uniquenessRatio, speckleWindowSize, speckleRange, mode);
//Computes disparity map for the specified stereo pair
sgbm.Compute(imageLeft, imageRight, disparity);
//Since Disparity will be either CV_16S or CV_32F, it needs to be compressed and normalized to CV_8U
CvInvoke.Normalize(disparity, disp8, 0, 255, Emgu.CV.CvEnum.NormType.MinMax, Emgu.CV.CvEnum.DepthType.Cv8U);
}
