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Total newbie to OpenCV. I am trying to place a png image (of sunglasses) over the eyes in a webcam feed. While running the program, the transparent regions of the image is white. Here's the part of my code- 

# Create the mask for the glasses
imgGlassesGray = cv2.cvtColor(imgGlasses, cv2.COLOR_BGR2GRAY)
ret, orig_mask = cv2.threshold(imgGlassesGray, 10, 255, cv2.THRESH_BINARY)
#orig_mask = imgGlasses[:,:,3]

# Create the inverted mask for the glasses
orig_mask_inv = cv2.bitwise_not(orig_mask)

# Convert glasses image to BGR
# and save the original image size (used later when re-sizing the image)
imgGlasses = imgGlasses[:,:,0:3]
origGlassesHeight, origGlassesWidth = imgGlasses.shape[:2]

video_capture = cv2.VideoCapture(0)

while True:

    ret, frame = video_capture.read()

    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    faces = face_cascade.detectMultiScale(gray, 1.3, 5)

    for (x,y,w,h) in faces:
        #cv2.rectangle(frame,(x,y),(x+w,y+h),(255,0,0),2)
            roi_gray = gray[y:y+h, x:x+w]
            roi_color = frame[y:y+h, x:x+w]

            eyes = eye_cascade.detectMultiScale(roi_gray)

            for (ex,ey,ew,eh) in eyes:
            cv2.rectangle(roi_color,(ex,ey),(ex+ew,ey+eh),(0,255,0),1)

        for (ex, ey, ew, eh) in eyes:
            glassesWidth = 2*ew
            glassesHeight = glassesWidth * origGlassesHeight / origGlassesWidth

            # Center the glasses
            x1 = ex - (glassesWidth/4)
            x2 = ex + ew + (glassesWidth/4)
            y1 = ey + eh - (glassesHeight/2)
            y2 = ey + eh + (glassesHeight/2)

            # Re-calculate the width and height of the glasses image
            glassesWidth = x2 - x1
            glassesHeight = y2 - y1

            # Re-size the original image and the masks to the glasses sizes
            # calcualted above
            glasses = cv2.resize(imgGlasses, (glassesWidth,glassesHeight), interpolation = cv2.INTER_AREA)
            mask = cv2.resize(orig_mask, (glassesWidth,glassesHeight), interpolation = cv2.INTER_AREA)
            mask_inv = cv2.resize(orig_mask_inv, (glassesWidth,glassesHeight), interpolation = cv2.INTER_AREA)

            # take ROI for glasses from background equal to size of glasses image
            roi = roi_color[y1:y2, x1:x2]

            # roi_bg contains the original image only where the glasses is not
            # in the region that is the size of the glasses.
            roi_bg = cv2.bitwise_and(roi,roi,mask = mask_inv)

            # roi_fg contains the image of the glasses only where the glasses is
            roi_fg = cv2.bitwise_and(glasses,glasses,mask = mask)

            # join the roi_bg and roi_fg
            dst = cv2.add(roi_bg,roi_fg)

            # place the joined image, saved to dst back over the original image
            roi_color[y1:y2, x1:x2] = dst

            break

There are indentation issues here, but they are right on my program. Also, I'll post the full code if that's required.

This is the image I'm trying to mask and overlay -

enter image description here

Thanks in advance!

user3699912
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1 Answers1

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You need to load the image as follows to get all 4 channels:

import cv2

imgGlasses = cv2.imread(filename, cv2.CV_LOAD_IMAGE_UNCHANGED)

or

imgGlasses = cv2.imread(filename, -1)

If this doesn't work, you could try setting the colour using this example.

Community
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Ed Smith
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