blue, green, red = cv2.split(img)

hist = cv2.calcHist([green, blue], [0, 1], None, [32, 32],[0, 256, 0, 256])

# 导入所需库
import cv2
from matplotlib import pyplot as plt

# 读取输入图像
img = cv2.imread('blue-pool.jpg')

# 将图像分割成各自的蓝色、绿色和红色通道
blue, green, red = cv2.split(img)

# 绿色和蓝色通道的2D颜色直方图
plt.subplot(131)
hist1 = cv2.calcHist([green, blue], [0, 1], None, [32, 32],[0, 256, 0, 256])
p = plt.imshow(hist1, interpolation="nearest")
plt.title("G和B的2D直方图", fontsize=8)
plt.colorbar(p)

# 红色和绿色通道的2D颜色直方图
plt.subplot(132)
hist2 = cv2.calcHist([red, green], [0, 1], None, [32, 32],[0, 256, 0, 256])
p = plt.imshow(hist2, interpolation="nearest")
plt.title("R和G的2D直方图", fontsize=8)
plt.colorbar(p)

# 蓝色和红色通道的2D颜色直方图
plt.subplot(133)
hist3 = cv2.calcHist([blue, red], [0, 1], None, [32, 32],[0, 256, 0, 256])
p = plt.imshow(hist3, interpolation="nearest")
plt.title("B和R的2D直方图", fontsize=8)
plt.colorbar(p)
plt.show()