count.py

# -*- coding: utf-8 -*-
"""
Created on Fri Jul  5 22:03:01 2019

@author: Lusijay
"""

# Function - To count the number of fingers in the segmented hand region
#-------------------------------------------------------------------------------
def count(thresholded, segmented):
	# find the convex hull of the segmented hand region
	chull = cv2.convexHull(segmented)

	# find the most extreme points in the convex hull
	extreme_top    = tuple(chull[chull[:, :, 1].argmin()][0])
	extreme_bottom = tuple(chull[chull[:, :, 1].argmax()][0])
	extreme_left   = tuple(chull[chull[:, :, 0].argmin()][0])
	extreme_right  = tuple(chull[chull[:, :, 0].argmax()][0])

	# find the center of the palm
	cX = (extreme_left[0] + extreme_right[0]) // 2
	cY = (extreme_top[1] + extreme_bottom[1]) // 2

	# find the maximum euclidean distance between the center of the palm
	# and the most extreme points of the convex hull
	distance = pairwise.euclidean_distances([(cX, cY)], Y=[extreme_left, extreme_right, extreme_top, extreme_bottom])[0]
	maximum_distance = distance[distance.argmax()]
	
	# calculate the radius of the circle with 80% of the max euclidean distance obtained
	radius = int(0.8 * maximum_distance)
	
	# find the circumference of the circle
	circumference = (2 * np.pi * radius)

	# take out the circular region of interest which has 
	# the palm and the fingers
	circular_roi = np.zeros(thresholded.shape[:2], dtype="uint8")
	
	# draw the circular ROI
	cv2.circle(circular_roi, (cX, cY), radius, 255, 1)
	
	# take bit-wise AND between thresholded hand using the circular ROI as the mask
	# which gives the cuts obtained using mask on the thresholded hand image
	circular_roi = cv2.bitwise_and(thresholded, thresholded, mask=circular_roi)

	# compute the contours in the circular ROI
	(_, cnts, _) = cv2.findContours(circular_roi.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)

	# initalize the finger count
	count = 0

	# loop through the contours found
	for c in cnts:
		# compute the bounding box of the contour
		(x, y, w, h) = cv2.boundingRect(c)

		# increment the count of fingers only if -
		# 1. The contour region is not the wrist (bottom area)
		# 2. The number of points along the contour does not exceed
		#     25% of the circumference of the circular ROI
		if ((cY + (cY * 0.25)) > (y + h)) and ((circumference * 0.25) > c.shape[0]):
			count += 1

	return count