OpenCV_OpticalFlowPyrLK.java
import org.opencv.core.*;
import org.opencv.imgproc.Imgproc;
import org.opencv.video.Video;
import org.opencv.videoio.VideoCapture;
import javax.swing.*;
import java.util.List;
public class OpenCV_OpticalFlowPyrLK {
static{ System.loadLibrary(Core.NATIVE_LIBRARY_NAME); }
public static void main(String arg[]) throws Exception{
JFrame frame2 = new JFrame("OpticalFlowPyrLK");
frame2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame2.setSize(640,480);
frame2.setBounds(300,100, frame2.getWidth()+50, 50+frame2.getHeight());
Panel panel2 = new Panel();
frame2.setContentPane(panel2);
frame2.setVisible(true);
//-- 2. Read the video stream
VideoCapture capture = new VideoCapture();
capture.open(0); //0 Table 1st branch CCD,1 second branch
Mat webcam_image=new Mat();
MatOfPoint2f mMOP2fptsThis=new MatOfPoint2f();
MatOfPoint2f mMOP2fptsPrev=new MatOfPoint2f();
MatOfPoint2f mMOP2fptsSafe = new MatOfPoint2f();
MatOfFloat mMOFerr=new MatOfFloat();
MatOfByte mMOBStatus=new MatOfByte();
Mat matOpFlowThis = new Mat();
Mat matOpFlowPrev = new Mat();
List<Point> pts, corners, cornersThis, cornersPrev;
List<Byte> byteStatus;
int x, y,iLineThickness = 3;
Point pt, pt1, pt2;
Scalar colorOpticalFlow = new Scalar(0, 255,0);
Mat mRgba;
capture.read(webcam_image);
frame2.setSize(webcam_image.width()+40,webcam_image.height()+60);
if( capture.isOpened())
{
while( true )
{
Thread.sleep(200);
capture.read(webcam_image);
if( !webcam_image.empty() )
{
mRgba=webcam_image.clone();
int qualityLevel = 40;
MatOfPoint MOPcorners = new MatOfPoint();
if (mMOP2fptsPrev.rows() == 0) {
// first time through the loop so we need prev and this mats
// plus prev points
// get this mat
Imgproc.cvtColor(mRgba, matOpFlowThis, Imgproc.COLOR_RGBA2GRAY);
// copy that to prev mat
matOpFlowThis.copyTo(matOpFlowPrev);
// get prev corners
Imgproc.goodFeaturesToTrack(matOpFlowPrev, MOPcorners, qualityLevel, 0.05, 20);
mMOP2fptsPrev.fromArray(MOPcorners.toArray());
// get safe copy of this corners
mMOP2fptsPrev.copyTo(mMOP2fptsSafe);
}
else
{
//Log.d("Baz", "Opflow");
// we've been through before so
// this mat is valid. Copy it to prev mat
matOpFlowThis.copyTo(matOpFlowPrev);
// get this mat
Imgproc.cvtColor(mRgba, matOpFlowThis, Imgproc.COLOR_RGBA2GRAY);
// get the corners for this mat
Imgproc.goodFeaturesToTrack(matOpFlowThis, MOPcorners, qualityLevel, 0.05, 20);
mMOP2fptsThis.fromArray(MOPcorners.toArray());
// retrieve the corners from the prev mat
// (saves calculating them again)
mMOP2fptsSafe.copyTo(mMOP2fptsPrev);
// and save this corners for next time through
mMOP2fptsThis.copyTo(mMOP2fptsSafe);
}
// Parameters:
// prevImg first 8-bit input image
// nextImg second input image
// prevPts vector of 2D points for which the flow needs to be found; point coordinates must be single-precision floating-point numbers.
// nextPts output vector of 2D points (with single-precision floating-point coordinates) containing the calculated new positions of input features in the second image; when OPTFLOW_USE_INITIAL_FLOW flag is passed, the vector must have the same size as in the input.
// status output status vector (of unsigned chars); each element of the vector is set to 1 if the flow for the corresponding features has been found, otherwise, it is set to 0.
// err output vector of errors; each element of the vector is set to an error for the corresponding feature, type of the error measure can be set in flags parameter; if the flow wasn't found then the error is not defined (use the status parameter to find such cases).
Video.calcOpticalFlowPyrLK(matOpFlowPrev, matOpFlowThis, mMOP2fptsPrev, mMOP2fptsThis, mMOBStatus, mMOFerr);
cornersPrev = mMOP2fptsPrev.toList();
cornersThis = mMOP2fptsThis.toList();
byteStatus = mMOBStatus.toList();
y = byteStatus.size() - 1;
for (x = 0; x < y; x++) {
if (byteStatus.get(x) == 1) {
pt = cornersThis.get(x);
pt2 = cornersPrev.get(x);
Imgproc.circle(mRgba, pt, 5, colorOpticalFlow, iLineThickness - 1);
Imgproc.line(mRgba, pt, pt2, colorOpticalFlow, iLineThickness);
}
}
panel2.setimagewithMat(mRgba); //
frame2.repaint();
}
else
{
System.out.println("No supplementary appointment!");
break;
}
}
}
return;
}
}
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