import cv2 as cv
import numpy as np
from matplotlib import pyplot as plt
def create_rgb_hist(image):
 """"創(chuàng)建 RGB 三通道直方圖（直方圖矩陣）"""
 h, w, c = image.shape
 # 創(chuàng)建一個(gè)（16*16*16,1）的初始矩陣，作為直方圖矩陣 
 # 16*16*16的意思為三通道每通道有16個(gè)bins
 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]
   # 人為構(gòu)建直方圖矩陣的索引，該索引是通過每一個(gè)像素點(diǎn)的三通道值進(jìn)行構(gòu)建
   index = int(b / bsize) * 16 * 16 + int(g / bsize) * 16 + int(r / bsize)
   # 該處形成的矩陣即為直方圖矩陣
   rgbhist[int(index), 0] += 1
 plt.ylim([0, 10000])
 plt.grid(color='r', linestyle='--', linewidth=0.5, alpha=0.3)
 return rgbhist
def hist_compare(image1, image2):
 """直方圖比較函數(shù)"""
 # 創(chuàng)建第一幅圖的rgb三通道直方圖（直方圖矩陣）
 hist1 = create_rgb_hist(image1)
 # 創(chuàng)建第二幅圖的rgb三通道直方圖（直方圖矩陣）
 hist2 = create_rgb_hist(image2)
 # 進(jìn)行三種方式的直方圖比較
 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("巴氏距離：%s, 相關(guān)性：%s, 卡方：%s" %(match1, match2, match3))
src1 = cv.imread("diff1.PNG")
cv.imshow("diff1", src1)
src2 = cv.imread("diff2.PNG")
cv.imshow("diff2", src2)
plt.subplot(1,2,1)
plt.title("diff1")
plt.plot(create_rgb_hist(src1))
plt.subplot(1,2,2)
plt.title("diff2")
plt.plot(create_rgb_hist(src2))
hist_compare(src1, src2)
plt.show()
cv.waitKey(0)
cv.destroyAllWindows()