import cv2
import numpy as np
import matplotlib.pyplot as plt
img = cv2.imread("gpu.bmp")

# 格式转换
# img_out = cv2.cvtColor(img, cv2.COLOR_RGB2GRAY)
img_out = cv2.cvtColor(img, cv2.COLOR_RGB2BGR)

plt.imshow(img_out)
# plt.imshow(img_out, cmap="gray")
plt.show()