OpenCV | OpenCV彩色图像直方图算法实现

彩色图像直方图和灰度图像直方图的原理是一样的，不同的是彩色图像需要分别计算BGR三个通道。

Cerasus.JPG

  

   

    

     

    
    

     

      import cv2
     
    
   

    

     

    
    

     

      import numpy as np
     
    
   

    

     

    
    

     

      import matplotlib.pyplot as plt
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      img = cv2.imread('Cerasus.JPG', 1)
     
    
   

    

     

    
    

     

      imgInfo = img.shape
     
    
   

    

     

    
    

     

      height = imgInfo[0]
     
    
   

    

     

    
    

     

      width = imgInfo[1]
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      count_b = np.zeros(256, np.float)
     
    
   

    

     

    
    

     

      count_g = np.zeros(256, np.float)
     
    
   

    

     

    
    

     

      count_r = np.zeros(256, np.float)
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      for i in range(height):
     
    
   

    

     

    
    

     
 for j in range(width):
     
    
   

    

     

    
    

     

       (b, g, r) = img[i, j]
     
    
   

    

     

    
    

     

       index_b = int(b)
     
    
   

    

     

    
    

     

       index_g = int(g)
     
    
   

    

     

    
    

     

       index_r = int(r)
     
    
   

    

     

    
    

     

       count_b[index_b] = count_b[index_b] + 1
     
    
   

    

     

    
    

     

       count_g[index_g] = count_g[index_g] + 1
     
    
   

    

     

    
    

     

       count_r[index_r] = count_r[index_r] + 1
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      # 计算每一个通道的概率
     
    
   

    

     

    
    

     

      total = height * width
     
    
   

    

     

    
    

     

      count_b = count_b / total
     
    
   

    

     

    
    

     

      count_g = count_g / total
     
    
   

    

     

    
    

     

      count_r = count_r / total
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      # 绘图
     
    
   

    

     

    
    

     

      x = np.linspace(0, 256, 256)
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      y1 = count_b
     
    
   

    

     

    
    

     

      plt.figure()
     
    
   

    

     

    
    

     

      plt.bar( x, y1, 0.9, alpha = 1, color = 'b' )
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      y2 = count_g
     
    
   

    

     

    
    

     

      plt.figure()
     
    
   

    

     

    
    

     

      plt.bar( x, y2, 0.9, alpha = 1, color = 'g' )
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      y3 = count_r
     
    
   

    

     

    
    

     

      plt.figure()
     
    
   

    

     

    
    

     

      plt.bar( x, y3, 0.9, alpha = 1, color = 'r' )
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      plt.show()
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      cv2.waitKey(0)
     
    
  
 

三个通道直方图如下：

文章来源: drugai.blog.csdn.net，作者：DrugAI，版权归原作者所有，如需转载，请联系作者。

原文链接：drugai.blog.csdn.net/article/details/102993952