彩色图像直方图均衡化Python

Question

我是Opencv的新人

我试着手工做直方图均衡化，不知怎么的我的输出是 this

首先，我将格式转换为YCR\u CB格式，然后将其拆分为y、cr和CB。然后我在y层做了直方图均衡化处理

我的代码是：

    from __future__ import division
    import cv2
    import numpy as np

    img1 = cv2.imread("sup.jpg")

    img2 = cv2.cvtColor(img1,cv2.COLOR_BGR2YCR_CB)

    y,cr,cb = cv2.split(img2)

    #y = cv2.equalizeHist(y)

    x =y

    height,width = y.shape

    hist = [0]*256
    pmf = [0]*256
    cdf = [0]*256
    levelBaru = [0]*256

    cv2.imshow("y before",x)
    cv2.waitKey(0)

    for i in range(0,height):  
        for j in range(0,width):
            hist[y.item(i,j)] += 1 
            #hist[y[i,j]] += 1

    for i in range(0,256):  
            #cari pmf
        pmf[i] = round(hist[i]/(height*width),4)

    print "pmf  done"

    cdf[0] = pmf[0]

    for i in range(1,256):              #cari cdf
        cdf[i] = cdf[i-1]+pmf[i]

    for i in range(1,256):              #cari levelBaru
        levelBaru[i] = int(cdf[i]*255)

    for i in range(0,height):           #baru
        for j in range(0,width):
            for k in range (0,256):
                if(y.item(i,j)==k):
                    #print i," ",levelBaru[i]
                    y.itemset((i,j),levelBaru[k])

    img2 = cv2.merge((y,cr,cb))
    img2 = cv2.cvtColor(img2,cv2.COLOR_YCR_CB2BGR) #supaya ga error pas di stack


    #cv2.namedWindow('result', cv2.WINDOW_NORMAL)
    cv2.imshow('result',img2)

    cv2.waitKey(0)
    cv2.destroyAllWindows

有点难找虫子，如果有人能帮我那就太棒了

Answer 1

根据问题标题，您希望通过在YCrCb域中拆分彩色图像的直方图来均衡它。编写自己的直方图均衡算法没有任何意义，正如所附的代码片段所示，OpenCV已经有了一个方法cv2.eqHist()来满足您的需要。在

import cv2

img = cv2.imread("path/to/Lenna.png")

img_y_cr_cb = cv2.cvtColor(img, cv2.COLOR_BGR2YCrCb)
y, cr, cb = cv2.split(img_y_cr_cb)

# Applying equalize Hist operation on Y channel.
y_eq = cv2.equalizeHist(y)

img_y_cr_cb_eq = cv2.merge((y_eq, cr, cb))
img_rgb_eq = cv2.cvtColor(img_y_cr_cb_eq, cv2.COLOR_YCR_CB2BGR)

输入：

输出：