Added Python interface

CmakeProject/source/anms.h

@@ -105,11 +105,11 @@ vector<cv::KeyPoint> Sdc(vector<cv::KeyPoint> keyPoints, int numRetPoints, float
         else if (result.size()<Kmin) high = radius-1; //update binary search range
         else low = radius+1;
     }
-        // retrieve final keypoints
-        vector<cv::KeyPoint> kp;
-        for (unsigned int i = 0; i<ResultVec.size(); i++) kp.push_back(keyPoints[ResultVec[i]]);
+    // retrieve final keypoints
+    vector<cv::KeyPoint> kp;
+    for (unsigned int i = 0; i<ResultVec.size(); i++) kp.push_back(keyPoints[ResultVec[i]]);
 
-        return kp;
+    return kp;
 }
 
 
@@ -347,11 +347,11 @@ vector<cv::KeyPoint> Ssc(vector<cv::KeyPoint> keyPoints, int numRetPoints,float
         else low = width+1;
         prevWidth = width;
     }
-        // retrieve final keypoints
-        vector<cv::KeyPoint> kp;
-        for (unsigned int i = 0; i<ResultVec.size(); i++) kp.push_back(keyPoints[ResultVec[i]]);
+    // retrieve final keypoints
+    vector<cv::KeyPoint> kp;
+    for (unsigned int i = 0; i<ResultVec.size(); i++) kp.push_back(keyPoints[ResultVec[i]]);
 
-        return kp;
+    return kp;
 }
 
 

Python/README.md

@@ -0,0 +1,5 @@
+# Python
+
+To run this code set parameters in run_demo.sh and execute `./run_demo.sh` from your terminal.
+
+We have tested with Python 2.7.6 and OpenCV 2.4.8

Python/demo.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python
+
+import argparse
+import cv2
+import numpy
+from random import shuffle
+from ssc import *
+
+def main():
+	parser = argparse.ArgumentParser()
+	parser.add_argument('--image_path', type=str, default="../Images/test.png")
+	parser.add_argument('--num_ret_points', type=int, default=10)
+	parser.add_argument('--tolerance', type=float, default=0.1)
+	args = parser.parse_args()
+
+	img = cv2.imread(args.image_path)
+	cv2.imshow('Input Image', img)
+	cv2.waitKey(0)
+
+	fast = cv2.FastFeatureDetector()
+	keypoints = fast.detect(img, None)
+	img2 = cv2.drawKeypoints(img, keypoints, color=(255,0,0))
+	cv2.imshow('Detected FAST keypoints', img2)
+	cv2.waitKey(0)
+
+	# keypoints should be sorted by strength in descending order before feeding to SSC to work correctly
+	shuffle(keypoints) # simulating sorting by score with random shuffle
+
+	selected_keypoints = SSC(keypoints, args.num_ret_points, args.tolerance, img.shape[1], img.shape[0])
+
+	img3 = cv2.drawKeypoints(img, selected_keypoints, color=(255,0,0))
+	cv2.imshow('Selected keypoints', img3)
+	cv2.waitKey(0)
+
+if __name__ == '__main__':
+	main()

Python/run_demo.sh

@@ -0,0 +1,4 @@
+python demo.py \
+    --image_path='../Images/test.png' \
+    --num_ret_points=750 \
+    --tolerance=0.1 \

Python/ssc.py

@@ -0,0 +1,62 @@
+import math
+
+def SSC(keypoints, num_ret_points, tolerance, cols, rows):
+	exp1 = rows + cols + 2*num_ret_points
+	exp2 = 4*cols + 4*num_ret_points + 4*rows*num_ret_points + rows*rows + cols*cols - 2*rows*cols + 4*rows*cols*num_ret_points
+	exp3 = math.sqrt(exp2)
+	exp4 = (2*(num_ret_points - 1))
+
+	sol1 = -round(float(exp1+exp3)/exp4) # first solution
+	sol2 = -round(float(exp1-exp3)/exp4) # second solution
+
+	high = sol1 if (sol1>sol2) else sol2 #binary search range initialization with positive solution
+	low = math.floor(math.sqrt(len(keypoints)/num_ret_points))
+
+	prevWidth = -1
+	selected_keypoints = []
+	ResultVec = []
+	result = []
+	complete = False
+	K = num_ret_points
+	Kmin = round(K-(K*tolerance))
+	Kmax = round(K+(K*tolerance))
+
+	while(~complete):
+		width = low+(high-low)/2
+		if (width == prevWidth or low>high): #needed to reassure the same radius is not repeated again
+			ResultVec = result #return the keypoints from the previous iteration
+			break
+
+		c = width/2; #initializing Grid
+		numCellCols = int(math.floor(cols/c));
+		numCellRows = int(math.floor(rows/c));
+		coveredVec = [ [False for i in range(numCellCols+1)] for j in range(numCellCols+1)]
+		result = []
+
+		for i in range(len(keypoints)):
+			row = int(math.floor(keypoints[i].pt[1]/c)) #get position of the cell current point is located at
+			col = int(math.floor(keypoints[i].pt[0]/c))
+			if (coveredVec[row][col]==False): # if the cell is not covered
+				result.append(i)
+				rowMin = int((row-math.floor(width/c)) if ((row-math.floor(width/c))>=0) else 0) #get range which current radius is covering
+				rowMax = int((row+math.floor(width/c)) if ((row+math.floor(width/c))<=numCellRows) else numCellRows)
+				colMin = int((col-math.floor(width/c)) if ((col-math.floor(width/c))>=0) else 0)
+				colMax = int((col+math.floor(width/c)) if ((col+math.floor(width/c))<=numCellCols) else numCellCols)
+				for rowToCov in range(rowMin, rowMax+1):
+					for colToCov in range(colMin, colMax+1):
+						if (~coveredVec[rowToCov][colToCov]):
+							coveredVec[rowToCov][colToCov] = True #cover cells within the square bounding box with width w
+
+		if (len(result)>=Kmin and len(result)<=Kmax): #solution found
+			ResultVec = result
+			complete = True
+		elif (len(result)<Kmin): 
+			high = width-1 #update binary search range
+		else: 
+			low = width+1
+		prevWidth = width
+
+	for i in range(len(ResultVec)):
+		selected_keypoints.append(keypoints[ResultVec[i]])
+
+	return selected_keypoints

QtProject/anms.h

@@ -106,11 +106,11 @@ vector<cv::KeyPoint> Sdc(vector<cv::KeyPoint> keyPoints, int numRetPoints, float
         else if (result.size()<Kmin) high = radius-1; //update binary search range
         else low = radius+1;
     }
-        // retrieve final keypoints
-        vector<cv::KeyPoint> kp;
-        for (unsigned int i = 0; i<ResultVec.size(); i++) kp.push_back(keyPoints[ResultVec[i]]);
+    // retrieve final keypoints
+    vector<cv::KeyPoint> kp;
+    for (unsigned int i = 0; i<ResultVec.size(); i++) kp.push_back(keyPoints[ResultVec[i]]);
 
-        return kp;
+    return kp;
 }
 
 
@@ -348,11 +348,11 @@ vector<cv::KeyPoint> Ssc(vector<cv::KeyPoint> keyPoints, int numRetPoints,float
         else low = width+1;
         prevWidth = width;
     }
-        // retrieve final keypoints
-        vector<cv::KeyPoint> kp;
-        for (unsigned int i = 0; i<ResultVec.size(); i++) kp.push_back(keyPoints[ResultVec[i]]);
+    // retrieve final keypoints
+    vector<cv::KeyPoint> kp;
+    for (unsigned int i = 0; i<ResultVec.size(); i++) kp.push_back(keyPoints[ResultVec[i]]);
 
-        return kp;
+    return kp;
 }