「 python 」不呼叫早就包好的 histogram equalization 函式，而是用公式推导

# -*- coding: utf-8 -*-import numpy as npimport cv2path = "photo.jpg"img = cv2.imread(path,0)#To display image before equalizationcv2.imshow('image',img)cv2.waitKey(0)a = np.zeros((256,),dtype=np.float16)b = np.zeros((256,),dtype=np.float16)height,width=img.shape#finding histogramfor i in range(width):    for j in range(height):        g = img[j,i]        a[g] = a[g]+1tmp = 1.0/(height*width)b = np.zeros((256,),dtype=np.float16)for i in range(256):    for j in range(i+1):        b[i] += a[j] * tmp;    b[i] = round(b[i] * 255);# b now contains the equalized histogramb=b.astype(np.uint8)#Re-map values from equalized histogram into the imagefor i in range(width):    for j in range(height):        g = img[j,i]        img[j,i]= b[g]cv2.imshow('image',img)cv2.waitKey(0)cv2.destroyAllWindows()