Photo Collage from Webcam

gistfile1.txt

import cv2
import numpy as np
import random
import math
#capture webcam
cap = cv2.VideoCapture(0)
#mmm determines the size of the collage.
#mmm must be >3000
mmm = 3000
b = mmm/8
global mmm
#create background for collage
collage  =  np.zeros((mmm,mmm,3), np.uint8)
#overlays a picture onto the collage
def overlay(img, bg):
    imgray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
    _ ,mask = cv2.threshold(imgray,2,255,0)
    mask_inv = 255-mask
    img1_bg = cv2.bitwise_and(bg,bg,mask = mask_inv)
    img2_fg = cv2.bitwise_and(img,img,mask = mask)
    res = cv2.add(img1_bg,img2_fg)
    return res
#rotates an image
def rotate(img):
    global mmm
    bg = np.zeros((mmm,mmm,3), np.uint8)
    scale = random.random()*2
    h,w = img.shape[:2]
    if scale<.1: scale = .5
    img = cv2.resize(img, (int(w*scale), int(h*scale)))
    h,w = img.shape[:2]
    xxx = mmm/4
    a,b = random.randint(-xxx,xxx),random.randint(-xxx,xxx)
    try: bg[mmm/2+a-mmm/10:mmm/2+h+a-mmm/10, mmm/2+b-mmm/10:mmm/2+w+b-mmm/10] = img
    except: pass
    img = bg
    h,w = img.shape[:2]
    M = cv2.getRotationMatrix2D((w/2, h/2), random.randint(-50,50), 1)
    dst = cv2.warpAffine(img, M, (w,h))
    if random.random>.5: dst = cv2.flip(dst, 1)
    return dst
#main loop
while True:
    _, img = cap.read()
    cv2.imshow('img', cv2.resize(img, (300,300)))
    cv2.imshow('collage', cv2.resize(collage[b:mmm-b, b:mmm-b], (600,600)))
    k = cv2.waitKey(1)
    if k == 115:
        img = rotate(img)
        collage = overlay(img, collage)
    if k == 27: break
cv2.destroyAllWindows()
cap.release()
cv2.imwrite('collage.png', collage)