【千律】OpenCV基础：图像二维直方图的绘制

import cv2 as cv
import numpy as np
import matplotlib.pyplot as plt


if __name__ == '__main__':

    # 读取原图
    img_lenna = cv.imread('lenna.png')

    # 绘制直方图
    plt.hist(img_lenna.ravel(), 256, [0, 256])
    plt.show()

    # 转换到HSV颜色空间
    img_hsv = cv.cvtColor(img_lenna, cv.COLOR_BGR2HSV)

    # HSV的二维直方图
    hist_hsv = cv.calcHist([img_hsv], [0, 1], None, [180, 256], [0, 180, 0, 256])

    # 取对数以增加对比度
    hist_hsv = np.log(1 + hist_hsv)

    # 显示二维直方图
    plt.imshow(hist_hsv, cmap='jet')
    plt.xlabel("S")
    plt.ylabel("H")
    plt.show()