Pimp my webcam (stream) project
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

62 lines
2.2 KiB

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
Add a PNG image to a frame
25.05.20/KQ Initial (modularized) version
27.05.20/KQ Variable naming corrected
import numpy as np
import cv2
import sys
# My own new version w/ transparency effect (& reasonable performance)
def overlay_png(frame, x_offset, y_offset, png, alpha_mask):
"""Overlay a png on an OpenCV frame @x_offset/y_offset w/ transparency effect based on png alpha channel
_scr_height = png.shape[0]
_scr_width = png.shape[1]
_frame_roi = frame[y_offset:y_offset+_scr_height, x_offset:x_offset+_scr_width, 0:3] # Source original region
_all_square_bg_fg = cv2.bitwise_or(_frame_roi >> 2, png, mask=alpha_mask) # Both added, background somewhat reduced ...
_mask_inv = cv2.bitwise_not(alpha_mask) # Negate mask (inverse)
_surrounding_bg = cv2.bitwise_or(_frame_roi, png, mask=_mask_inv) # This yields the original background at transparent regions
frame[y_offset:y_offset+_scr_height, x_offset:x_offset+_scr_width, 0:3] = _all_square_bg_fg + _surrounding_bg # Now add both: Transparent add achieved!
# Ref.: https://stackoverflow.com/questions/14063070/overlay-a-smaller-image-on-a-larger-image-python-opencv
def overlay_image_alpha(img, img_overlay, pos, alpha_mask):
"""Overlay img_overlay on top of img at the position specified by
pos and blend using alpha_mask.
Alpha mask must contain values within the range [0, 1] and be the
same size as img_overlay.
x, y = pos
# Image ranges
y1, y2 = max(0, y), min(img.shape[0], y + img_overlay.shape[0])
x1, x2 = max(0, x), min(img.shape[1], x + img_overlay.shape[1])
# Overlay ranges
y1o, y2o = max(0, -y), min(img_overlay.shape[0], img.shape[0] - y)
x1o, x2o = max(0, -x), min(img_overlay.shape[1], img.shape[1] - x)
# Exit if nothing to do
if y1 >= y2 or x1 >= x2 or y1o >= y2o or x1o >= x2o:
channels = img.shape[2]
alpha = alpha_mask[y1o:y2o, x1o:x2o] # Alpha channel only: 0..1 where <>0 means NOT transparent!
alpha_inv = 1.0 - alpha
for c in range(channels):
img[y1:y2, x1:x2, c] = (alpha * img_overlay[y1o:y2o, x1o:x2o, c] +
alpha_inv * img[y1:y2, x1:x2, c])