python 实现将小图片放到另一个较大的白色或黑色背景图片中

将图片放入到白色或黑色背景图中，前提是图片小于背景图片的尺寸，原图为如下，长为192，宽为64。

1.将图片放入到白色背景图（224,224）中

import cv2
import numpy as np

def img_resize_to_target_white(image):
target = np.ones((224,224),dtype=np.uint8)*255

ret = cv2.cvtColor(target, cv2.COLOR_GRAY2BGR)

h = image.shape[0]
w = image.shape[1]
for i in range(224):
 for j in range(224):
  if(i < h) and (j < w):

ret[i, j, 0] = image[i, j, 0]
   ret[i, j, 1] = image[i, j, 1]
   ret[i, j, 2] = image[i, j, 2]
  else:
   ret[i, j, 0] = 255
   ret[i, j, 1] = 255
   ret[i, j, 2] = 255

return ret

if __name__ == '__main__':
image = cv2.imread('/home/yasin/桌面/test.png')
img_new_white = img_resize_to_target_white(image)
cv2.imshow("img_new_white", img_new_white)
cv2.waitKey()

运行结果为：

2.将图片放入到黑色背景图（224,224）中

import cv2

def img_resize_to_target_black(image):
target = np.zeros((224,224),dtype=np.uint8)

bgr_img = cv2.cvtColor(target, cv2.COLOR_GRAY2BGR)

h = image.shape[0]
w = image.shape[1]
for i in range(h):
 for j in range(w):

bgr_img[i, j, 0] = image[i, j, 0]
  bgr_img[i, j, 1] = image[i, j, 1]
  bgr_img[i, j, 2] = image[i, j, 2]

return bgr_img

if __name__ == '__main__':
image = cv2.imread('/home/yasin/桌面/test.png')
img_new_black = img_resize_to_target_black(image)
cv2.imshow("img_new_black", img_new_black)
cv2.waitKey()

运行结果为：

来源：https://blog.csdn.net/zhou4411781/article/details/95451476