cherry pick new point extractor from Patrick

1 files changed, 63 insertions, 65 deletions

diff --git a/ftnoir_tracker_pt/point_extractor.cpp b/ftnoir_tracker_pt/point_extractor.cpp
index 4213eb06..61e86bec 100644
--- a/ftnoir_tracker_pt/point_extractor.cpp
+++ b/ftnoir_tracker_pt/point_extractor.cpp
@@ -11,87 +11,85 @@
 using namespace cv;

 using namespace std;

 

-struct BlobInfo

-{

-    BlobInfo() : m00(0), m10(0), m01(0) {}

-    long m00;

-    long m10;

-    long m01;

-};

-

 // ----------------------------------------------------------------------------

 const vector<Vec2f>& PointExtractor::extract_points(Mat frame, float dt, bool draw_output)

 {

-	/*

-	// sensitivity test for tracker

-	static int n = 0;

-	if (points.size() == 3)

-	{

-		for (int i=0; i<3; ++i)

-		{

-			points[i][0] -= 1e-4*sin(n/100.0);

-			points[i][1] -= 1e-4*cos(n/100.0);

-		}

-		++n;

-		return points;

-	}

-	*/

+    const int W = frame.cols;

+	const int H = frame.rows; 

+

+	// clear old points

+	points.clear();

 

 	// convert to grayscale

-	Mat frame_bw;

-    cvtColor(frame, frame_bw, COLOR_BGR2GRAY);

+	Mat frame_grey;

+	cvtColor(frame, frame_grey, COLOR_BGR2GRAY);

 

 	// convert to binary

-	threshold(frame_bw, frame_bw, threshold_val, 255, THRESH_BINARY);

-	//erode(frame_bw, frame_bw, Mat(), Point(-1,-1), min_size); //destroys information -> bad for subpixel accurarcy

+	Mat frame_bin;

+	threshold(frame_grey, frame_bin, threshold_val, 255, THRESH_BINARY);

 

-	// find connected components...

-	// extract blobs with floodfill

-	vector<BlobInfo> blobs;

-    int blob_count = 1;

+	unsigned int region_size_min = 3.14*min_size*min_size;

+    unsigned int region_size_max = 3.14*max_size*max_size;

 

-    for (int y=0; y < frame_bw.rows; y++) {

-        for (int x=0; x < frame_bw.cols; x++) {

-			if (frame_bw.at<unsigned char>(y,x) != 255) continue;

+    int blob_index = 1;

+    for (int y=0; y<H; y++)

+	{

+        for (int x=0; x<W; x++)

+		{

+			// find connected components with floodfill

+			if (frame_bin.at<unsigned char>(y,x) != 255) continue;

             Rect rect;

-            floodFill(frame_bw, Point(x,y), Scalar(blob_count), &rect, Scalar(0), Scalar(0), 4);

-			BlobInfo blob;

-            for (int i=rect.y; i < (rect.y+rect.height); i++) {

-                for (int j=rect.x; j < (rect.x+rect.width); j++) {

-                    if (frame_bw.at<unsigned char>(i,j) != blob_count) continue;

-                    blob.m00++;

-					blob.m01+=i;

-					blob.m10+=j;

+            floodFill(frame_bin, Point(x,y), Scalar(blob_index), &rect, Scalar(0), Scalar(0), FLOODFILL_FIXED_RANGE);

+			blob_index++;

+

+			// calculate the size of the connected component

+			unsigned int region_size = 0;

+            for (int i=rect.y; i < (rect.y+rect.height); i++)

+			{

+                for (int j=rect.x; j < (rect.x+rect.width); j++)

+				{

+                    if (frame_bin.at<unsigned char>(i,j) != blob_index-1) continue;

+					region_size++;

                 }

             }

-            blobs.push_back(blob);

-            blob_count++;

-			if (blob_count >= 255) break;

+			

+			if (region_size < region_size_min || region_size > region_size_max) continue; 

+

+			// calculate the center of mass:

+			// mx = (sum_ij j*f(frame_grey_ij)) / (sum_ij f(frame_grey_ij))

+			// my = ...

+			// f maps from [threshold,256] -> [0, 1], lower values are mapped to 0 

+			float m = 0;

+			float mx = 0;

+			float my = 0;

+			for (int i=rect.y; i < (rect.y+rect.height); i++)

+			{

+                for (int j=rect.x; j < (rect.x+rect.width); j++)

+				{

+                    if (frame_bin.at<unsigned char>(i,j) != blob_index-1) continue;

+					float val = frame_grey.at<unsigned char>(i,j);

+					val = float(val - threshold_val)/(256 - threshold_val);

+					val = val*val; // makes it more stable (less emphasis on low values, more on the peak)

+					m  +=     val;

+					mx += j * val;

+					my += i * val; 

+                }

+            }

+

+			// convert to centered camera coordinate system with y axis upwards 

+			Vec2f c;

+			c[0] =  (mx/m - W/2)/W;

+			c[1] = -(my/m - H/2)/W;

+			points.push_back(c);

+            

+			if (blob_index >= 255) break;

         }

-		if (blob_count >= 255) break;

+		if (blob_index >= 255) break;

     }

-

-	// extract points

-	Vec2f c;

-	points.clear();

-	float m00_min = 3.14*min_size*min_size;

-	float m00_max = 3.14*max_size*max_size;

-	for (vector<BlobInfo>::iterator iter = blobs.begin();

-		 iter!= blobs.end();

-		 ++iter)

-	{

-		const BlobInfo& m = *iter;

-		if (m.m00 < m00_min || m.m00 > m00_max) continue;

-		// convert to centered camera coordinate system with y axis upwards

-		c[0] =  (m.m10/float(m.m00) - frame.cols/2)/frame.cols;

-		c[1] = -(m.m01/float(m.m00) - frame.rows/2)/frame.cols;

-		points.push_back(c);

-	}

 	

 	// draw output image

-	if (draw_output)

-	{	

-		frame.setTo(Scalar(255,0,0), frame_bw);

+	if (draw_output) {	

+		frame.setTo(Scalar(255,0,0), frame_bin);

 	}

 

 	return points;