Python+OpenCV（七）——直方图及其应用

学习视频：python+opencv3.3视频教学基础入门
其他学习记录：
Python+OpenCV（一）——基础操作
 Python+OpenCV（二）——Numpy模块
 Python+OpenCV（三）——色彩空间
 Python+OpenCV（四）——像素运算
 Python+OpenCV（五）——ROI和泛洪填充
 Python+OpenCV（六）——均值/中值/自定义/高斯模糊、高斯噪声处理、高斯双边滤波
源码如下：

# -*- coding = utf-8 -*-
# @Time : 2021/8/2 19:08
# @Author : 西兰花
# @File : OpenCV02.py
# @Software : PyCharm


import cv2 as cv    # 引入OpenCV模块
import numpy as np
import matplotlib.pyplot as plt


def plot_dome(image):
    plt.hist(image.ravel(), 256, [0, 256])
    plt.show()


def image_hist(image):
    color = ('blue', 'green', 'red')
    for i, color in enumerate(color):
        hist = cv.calcHist([image], [1], None, [256], [0, 256])
        plt.plot(hist, color=color)
        plt.xlim([0, 256])
    plt.show()


def equalHist_demo(image):  # 全局均衡化（灰度图像），增强对比度
    gray = cv.cvtColor(image, cv.COLOR_BGR2GRAY)
    dst = cv.equalizeHist(gray)
    cv.imshow("equalHist_demo", dst)


def clahe_demo(image):      # 局部均衡化（灰度图像），增强了对比度
    gray = cv.cvtColor(image, cv.COLOR_BGR2GRAY)
    clahe = cv.createCLAHE(clipLimit=0.5, tileGridSize=(8, 8))
    dst = clahe.apply(gray)
    cv.imshow("clahe_demo:", dst)


def create_rgb_hist(image):
    h, w, c = image.shape
    rgbHist = np.zeros([16 * 16 * 16, 1], np.float32)
    bsize = 256 / 16
    for row in range(h):
        for col in range(w):
            b = image[row, col, 0]
            g = image[row, col, 1]
            r = image[row, col, 2]
            index = np.int(b / bsize) * 16 * 16 + np.int(g / bsize) * 16 + np.int(r / bsize)
            rgbHist[np.int(index), 0] = rgbHist[np.int(index), 0] + 1
    return rgbHist


def hist_compare(image1, image2):
    hist1 = create_rgb_hist(image1)
    hist2 = create_rgb_hist(image2)
    match1 = cv.compareHist(hist1, hist2, cv.HISTCMP_BHATTACHARYYA)
    match2 = cv.compareHist(hist1, hist2, cv.HISTCMP_CORREL)
    match3 = cv.compareHist(hist1, hist2, cv.HISTCMP_CHISQR)
    print("巴氏距离: %s, 相关性: %s, 卡方: %s " %(match1, match2, match3))


print("------ Hello OpenCV ------")
src1 = cv.imread("C:/Users/Administrator/Pictures/PS/4.jpg")     # 读取图像
cv.imshow("input image_12.jpg", src1)    # 显示图像
# plot_dome(src)
# image_hist(src)
# equalHist_demo(src)
# clahe_demo(src)

src2 = cv.imread("C:/Users/Administrator/Pictures/PS/3.jpg")     # 读取图像
src3 = cv.imread("C:/Users/Administrator/Pictures/PS/image_3.jpg----after.jpg")     # 读取图像
cv.imshow("input image_3.jpg", src2)    # 显示图像
cv.imshow("input image_image_3.jpg----after.jpg", src3)    # 显示图像
hist_compare(src2, src3)

cv.waitKey(0)

cv.destroyAllWindows()  # 销毁/关闭所有窗口