背景画像に別の画像をはめ込む【OpenCV】

import cv2
 
fore_img = cv2.imread(r'C:\BioTech-Lab\lena.jpg')
back_img = cv2.imread(r'C:\BioTech-Lab\Lake.jpg')

dx = 100    # 横方向の移動距離
dy = 100    # 縦方向の移動距離
h, w = fore_img.shape[:2]
back_img[dy:dy+h, dx:dx+w] = fore_img

cv2.imshow('img',back_img)
cv2.waitKey(0)
cv2.destroyAllWindows()

import cv2

def overlay(fore_img, back_img, shift):

    '''
    fore_img：合成する画像
    back_img：背景画像
    shift：左上を原点としたときの移動量(x, y)
    '''

    shift_x, shift_y = shift

    fore_h, fore_w = fore_img.shape[:2]
    fore_x_min, fore_x_max = 0, fore_w
    fore_y_min, fore_y_max = 0, fore_h

    back_h, back_w = back_img.shape[:2]
    back_x_min, back_x_max = shift_y, shift_y+fore_h
    back_y_min, back_y_max = shift_x, shift_x+fore_w

    if back_x_min < 0:
        fore_x_min = fore_x_min - back_x_min
        back_x_min = 0
        
    if back_x_max > back_w:
        fore_x_max = fore_x_max - (back_x_max - back_w)
        back_x_max = back_w

    if back_y_min < 0:
        fore_y_min = fore_y_min - back_y_min
        back_y_min = 0
        
    if back_y_max > back_h:
        fore_y_max = fore_y_max - (back_y_max - back_h)
        back_y_max = back_h        

    back_img[back_y_min:back_y_max, back_x_min:back_x_max] = fore_img[fore_y_min:fore_y_max, fore_x_min:fore_x_max]

    return back_img

  
fore_img = cv2.imread(r'C:\BioTech-Lab\lena.jpg')
back_img = cv2.imread(r'C:\BioTech-Lab\Lake.jpg')

back_img = overlay(fore_img, back_img, (-100, 1200))

cv2.imshow('img',back_img)
cv2.waitKey(0)
cv2.destroyAllWindows()

import cv2
import numpy as np
 
fore_img = cv2.imread(r'C:\BioTech-Lab\lena.jpg')
back_img = cv2.imread(r'C:\BioTech-Lab\Lake.jpg')
h, w = back_img.shape[:2]

dx = 100
dy = 100
M = np.array([[1, 0, dx], [0, 1, dy]], dtype=float)
img_warped = cv2.warpAffine(fore_img, M, (w, h), back_img, borderMode=cv2.BORDER_TRANSPARENT)

cv2.imshow('img',img_warped)
cv2.waitKey(0)
cv2.destroyAllWindows()

import cv2
 
fore_img = cv2.imread(r'C:\BioTech-Lab\lena.jpg')
fore_h, fore_w = fore_img.shape[:2]

back_img = cv2.imread(r'C:\BioTech-Lab\Lake.jpg')
back_h, back_w = back_img.shape[:2]

M = cv2.getRotationMatrix2D((int(fore_w/2), int(fore_h/2)), 45, 0.5)
img_warped = cv2.warpAffine(fore_img, M, (back_w, back_h), back_img, borderMode=cv2.BORDER_TRANSPARENT)

cv2.imshow('img',img_warped)
cv2.waitKey(0)
cv2.destroyAllWindows()