private void FindDefects(Mat maskImage, ref int cx, ref int cy, int min_defects_count, int max_defects_count)
{
int erosion_size = 1;
Mat element = Imgproc.getStructuringElement(
Imgproc.MORPH_ELLIPSE,
new Size(2 * erosion_size + 1, 2 * erosion_size + 1),
new Point(erosion_size, erosion_size));
// dilate and erode
Imgproc.dilate(maskImage, maskImage, element);
Imgproc.erode(maskImage, maskImage, element);
element.Dispose();
//Find Contours in image
List <MatOfPoint> contours = new List <MatOfPoint>();
Imgproc.findContours(maskImage, contours, new MatOfPoint(), Imgproc.RETR_EXTERNAL, Imgproc.CHAIN_APPROX_SIMPLE);
//Loop to find the biggest contour; If no contour is found index=-1
int index = -1;
double area = 2000;
for (int i = 0; i < contours.Count; i++)
{
var tempsize = Imgproc.contourArea(contours[i]);
if (tempsize > area)
{
area = tempsize;
index = i;
}
}
if (index == -1)
{
return;
}
else
{
var points = new MatOfPoint(contours[index].toArray());
var hull = new MatOfInt();
Imgproc.convexHull(points, hull, false);
var defects = new MatOfInt4();
Imgproc.convexityDefects(points, hull, defects);
var start_points = new MatOfPoint2f();
var far_points = new MatOfPoint2f();
for (int i = 0; i < defects.size().height; i++)
{
int ind_start = (int)defects.get(i, 0)[0];
int ind_end = (int)defects.get(i, 0)[1];
int ind_far = (int)defects.get(i, 0)[2];
double depth = defects.get(i, 0)[3] / 256;
double a = Core.norm(contours[index].row(ind_start) - contours[index].row(ind_end));
double b = Core.norm(contours[index].row(ind_far) - contours[index].row(ind_start));
double c = Core.norm(contours[index].row(ind_far) - contours[index].row(ind_end));
double angle = Math.Acos((b * b + c * c - a * a) / (2 * b * c)) * 180.0 / Math.PI;
double threshFingerLength = ((double)maskImage.height()) / 8.0;
double threshAngle = 80;
if (angle < threshAngle && depth > threshFingerLength)
{
//start point
var aa = contours[index].row(ind_start);
start_points.push_back(contours[index].row(ind_start));
far_points.push_back(contours[index].row(ind_far));
}
}
points.Dispose();
hull.Dispose();
defects.Dispose();
// when no finger found
if (far_points.size().height < min_defects_count || far_points.size().height > max_defects_count)
{
return;
}
var cnts = new List <MatOfPoint>();
cnts.Add(contours[index]);
Mat mm = new Mat();
Imgproc.cvtColor(maskImage, mm, Imgproc.COLOR_GRAY2BGR);
Imgproc.drawContours(mm, cnts, 0, new Scalar(0, 0, 255));
// OpenCVForUnity.ImgcodecsModule.Imgcodecs.imwrite("D:/tempImg.jpg", mm)
//var rotatedRect = Imgproc.minAreaRect(far_points);
var boundingRect = Imgproc.boundingRect(far_points);
cx = (int)(boundingRect.x + boundingRect.width / 2);
cy = (int)(boundingRect.y + boundingRect.height / 2);
}
}