Highlight active rink area on the normalized rink image

figure 1

Let's do more adventure following yesterday's work. Highlight the rink to show the active play area as following:

figure 2

                                                                           

The red highlight area is exactly the active play area from figure 2.

In order to get it, firstly resize the rink image to match with play image. so we can use for pixel to pixel mapping.

create black/white mask from resized rink image:

figure 3

truncate the play image suing figure 3 and then create active red area

figure 4

Finally weightly add figure 4 to the normalized to generate figure 1.

Here is source code:

	# shift the image x = -100, y = -100 since the pic generated has 100, 100 offset.
	rows, cols, d3 = rink.shape
	M = np.float32([[1, 0, -offset], [0, 1, -offset]])
	transformedImage = cv2.warpAffine(image, M, (cols, rows))
	# resize the rink image to match with play image.
	transformedRink = cv2.resize(rink, None, fx=300.0 * 2 / rows, fy=610.0 * 2 / cols, interpolation=cv2.INTER_CUBIC)
	# covert the transformRink to black/white mask
	rinkMask = cv2.cvtColor(transformedRink, cv2.COLOR_BGR2GRAY)
	h, rinkMask = cv2.threshold(rinkMask, 10, 255, cv2.THRESH_BINARY)
	cv2.imshow("rinkMask", rinkMask)
	# use this mask to truncate the play rink image
	rows, cols = rinkMask.shape
	imageMask = cv2.bitwise_and(cv2.cvtColor(rinkMask, cv2.COLOR_GRAY2BGR), transformedImage[0:rows, 0:cols])
	# convert the truncated play image (only have the rink part) to black/white mask
	imageMask = cv2.cvtColor(imageMask, cv2.COLOR_BGR2GRAY)
	h, imageMask = cv2.threshold(imageMask, 10, 255, cv2.THRESH_BINARY)
	cv2.imshow("imageMask", imageMask)
	# create the red mask to merge with the normalized rink image.
	cropImage = transformedImage[0:rows, 0:cols]
	cropImage[imageMask != 0] = [0, 0, 255]
	cropImage[imageMask == 0] = [0, 0, 0]
	cv2.imshow("cropImage", cropImage)
	highlightRink = cv2.addWeighted(cropImage, 0.1, transformedRink, 0.9, 0)
	cv2.imshow("highlightRink", highlightRink)

view raw highlightRink.py hosted with ❤ by GitHub