主要内容

5-2 彩色图片直方图

1import cv2
2import numpy as np
3def ImageHist(image,type):
4    color = (255,255,255)
5    windowName = 'Gray'
6    if type == 31:
7        color = (255,0,0)
8        windowName = 'B Hist'
9    elif type == 32:
10        color = (0,255,0)
11        windowName = 'G Hist'
12    elif type == 33:
13        color = (0,0,255)
14        windowName = 'R Hist'
15    # 1 image 2 [0] 3 mask None 4 256 5 0-255
16    hist = cv2.calcHist([image],[0],None,[256],[0.0,255.0])
17    minV,maxV,minL,maxL = cv2.minMaxLoc(hist)
18    print(maxV)
19    histImg = np.zeros([256,256,3],np.uint8)
20    for h in range(256):
21        intenNormal = int(hist[h]*256/maxV)
22        cv2.line(histImg,(h,256),(h,256-intenNormal),color)
23    cv2.imshow(windowName,histImg)
24    return histImg
25
26img = cv2.imread('image0.jpg',1)
27channels = cv2.split(img)# RGB - R G B
28for i in range(0,3):
29    ImageHist(channels[i],31+i)
30cv2.waitKey(0)
31
32
33imGray = cv2.imread('image0.jpg', 0)
34ImageHist(imGray, 0)
35cv2.waitKey(0)
36
37#灰度 直方图均衡化
38import cv2
39import numpy as np
40img = cv2.imread('image0.jpg',1)
41gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
42cv2.imshow('src',gray)
43dst = cv2.equalizeHist(gray)
44cv2.imshow('dst',dst)
45cv2.waitKey(0)
46
47#彩色 直方图均衡化
48import cv2
49import numpy as np
50img = cv2.imread('image0.jpg',1)
51cv2.imshow('src',img)
52(b,g,r) = cv2.split(img)#通道分解
53bH = cv2.equalizeHist(b)
54gH = cv2.equalizeHist(g)
55rH = cv2.equalizeHist(r)
56result = cv2.merge((bH,gH,rH))# 通道合成
57cv2.imshow('dst',result)
58cv2.waitKey(0)
59
60#YUV 直方图均衡化
61import cv2
62import numpy as np
63img = cv2.imread('image0.jpg',1)
64imgYUV = cv2.cvtColor(img,cv2.COLOR_BGR2YCrCb)
65cv2.imshow('src',img)
66channelYUV = cv2.split(imgYUV)
67channelYUV[0] = cv2.equalizeHist(channelYUV[0])
68channels = cv2.merge(channelYUV)
69result = cv2.cvtColor(channels,cv2.COLOR_YCrCb2BGR)
70cv2.imshow('dst',result)
71cv2.waitKey(0)