Function correctIris

jni/venus/region_operation.cpp:289–377

}

static void correctIris(const Mat& image, std::vector<Point2f>& points)
{
	assert(image.channels() == 1);
	RoiInfo eye_info_r = calcuateEyeRegionInfo_r(points);
	RoiInfo eye_info_l = calcuateEyeRegionInfo_l(points);

	Mat eye_r = image(Rect(eye_info_r.origion, eye_info_r.mask.size()));
	Mat eye_l = image(Rect(eye_info_l.origion, eye_info_l.mask.size()));

	// roughly estimate iris radius
	const int iris_indices_r[] = {35, 37, 39, 41};
	const int iris_indices_l[] = {45, 47, 49, 51};
	float iris_r_radius = venus::distance(points[42], points[iris_indices_r[0]]);
	for(size_t i = 1; i < NELEM(iris_indices_r); ++i)
	{
		float dist = venus::distance(points[42], points[iris_indices_r[i]]);
		if(iris_r_radius > dist)
			iris_r_radius = dist;
	}
	
	float iris_l_radius = venus::distance(points[43], points[iris_indices_l[0]]);
	for(size_t i = 1; i < NELEM(iris_indices_l); ++i)
	{
		float dist = venus::distance(points[43], points[iris_indices_l[i]]);
		if(iris_l_radius > dist)
			iris_l_radius = dist;
	}

	// Morphological opening is performed to remove glint.
	int morph_radius = 1;
	int morph_size = morph_radius * 2 + 1;
	Mat element = getStructuringElement(cv::MORPH_RECT, Size(morph_size, morph_size), Point(morph_radius, morph_radius));
	Mat image_processed;
	morphologyEx(eye_r, eye_r, cv::MORPH_OPEN, element);
	morphologyEx(eye_l, eye_l, cv::MORPH_OPEN, element);

	// http://stackoverflow.com/questions/10716464/what-are-the-correct-usage-parameter-values-for-houghcircles-in-opencv-for-iris
	const float tolerance = 0.666f;
	std::vector<cv::Vec3f> circles_r, circles_l;
	for(int i = 8; i < 20; ++i)
	{
		cv::HoughCircles(eye_r, circles_r, cv::HOUGH_GRADIENT, 1, 30, 100, i, iris_r_radius*tolerance, iris_r_radius/tolerance);
		if(circles_r.size() <= 1)
			break;
	}
	for(int i = 8; i < 20; ++i)
	{
		cv::HoughCircles(eye_l, circles_l, cv::HOUGH_GRADIENT, 1, 30, 100, i, iris_l_radius*tolerance, iris_l_radius/tolerance);
		if(circles_l.size() <= 1)
			break;
	}

	if(circles_r.size() > 1 || circles_l.size() > 1)
		LOGW("multiple circles detected, need to be only one");

/*
	        36                  46
	      37  35              45  47