python+opencv直方图均衡化

短命女 2023-07-09 10:25 7阅读 0赞

# 前言 #

直方图均衡化的三种情况,分别是:  
\- 灰度图像直方图均衡化  
\- 彩色图像直方图均衡化  
\- YUV 直方图均衡化  
插入原图:

![原图][70]

## 灰度图像直方图均衡化 ##

对直方图均衡化主要使用opencv提供的一个equalizeHist()方法.

import cv2
    import numpy as np
    
    img = cv2.imread("1.jpg", 1)
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    cv2.imshow("src", gray)
    
    dst = cv2.equalizeHist(gray)
    cv2.imshow("dst", dst)
    
    cv2.waitKey(0)

将灰度图像作为参数传进equalizeHist()方法即可,效果如下:

![灰度图像直方图均衡化][70 1]

## 彩色图像直方图均衡化 ##

彩色图像的直方图均衡化和灰度图像略有不同,需要将彩色图像先用split()方法,将三个通道拆分,然后分别进行均衡化.最后使用merge()方法将均衡化之后的三个通道进行合并.操作如下:

import cv2
    import numpy as np
    
    img = cv2.imread("1.jpg", 1)
    cv2.imshow("src", img)
    
    # 彩色图像均衡化,需要分解通道 对每一个通道均衡化
    (b, g, r) = cv2.split(img)
    bH = cv2.equalizeHist(b)
    gH = cv2.equalizeHist(g)
    rH = cv2.equalizeHist(r)
    # 合并每一个通道
    result = cv2.merge((bH, gH, rH))
    cv2.imshow("dst", result)
    
    cv2.waitKey(0)

均衡化之后的效果如下:

![彩色图片直方图均衡化][70 2]

## YUV 直方图均衡化 ##

import cv2
    import numpy as np
    img = cv2.imread("1.jpg", 1)
    
    imgYUV = cv2.cvtColor(img, cv2.COLOR_BGR2YCrCb)
    cv2.imshow("src", img)
    
    channelsYUV = cv2.split(imgYUV)
    channelsYUV[0] = cv2.equalizeHist(channelsYUV[0])
    
    channels = cv2.merge(channelsYUV)
    result = cv2.cvtColor(channels, cv2.COLOR_YCrCb2BGR)
    cv2.imshow("dst", result)
    
    cv2.waitKey(0)

均衡化之后效果如下:

![yuv均衡化][yuv]

[70]: https://img-blog.csdn.net/20180813160753814?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21pc3N5b3Vnb29u/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[70 1]: https://img-blog.csdn.net/20180813161145603?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21pc3N5b3Vnb29u/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[70 2]: https://img-blog.csdn.net/2018081316182888?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21pc3N5b3Vnb29u/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70
[yuv]: https://img-blog.csdn.net/20180813162156812?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21pc3N5b3Vnb29u/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70