變為黑白影象

將彩色圖片變成黑白灰度影象的演算法，一般是：Gray = Red * 0.299 + Green * 0.587 + Blue * 0.114

 1 #include <iostream>
 2 #include "opencv2/core.hpp"
 3 #include "opencv2/imgproc.hpp"
 4 #include "opencv2/highgui.hpp"
 5  
 6 #include "BlackWhite.hpp"
 7  
 8 using namespace
 
 std;
 9 using namespace cv;
10  
11  
12 #define BASE 200
13  
14 static string window_name = "photo";
15 static Mat src;
16 static int red     = 40 + BASE;
17 static int yellow  = 60 + BASE;
18 static int green   = 40 + BASE;
19 static int magenta = 60 + BASE;
20 static int blue    = 20 + BASE;
21 static int
 
 cyan    = 80 + BASE;
22  
23 static void callbackAdjust(int , void *)
24 {
25     Mat dst;
26     BlackWhite b;
27  
28     //set params
29     b.red = (red - BASE) / 100.0;
30     b.yellow = (yellow - BASE) / 100.0;
31     b.green = (green - BASE) / 100.0;
32     b.magenta = (magenta - BASE) / 100.0;
33     b.blue = (blue - BASE) / 100.0;
34     b.cyan = (cyan - BASE) / 100.0;
35  
36     //adjust Black White
37     b.adjust(src, dst);
38  
39     imshow(window_name, dst);
40 }
41  
42  
43 int main()
44 {
45     src = imread("girl.jpg");
46  
47     if ( !src.data ) {
48         cout << "error read image" << endl;
49         return -1;
50     }
51  
52     namedWindow(window_name);
53  
54     //create trackbars
55     createTrackbar("red", window_name, &red, 500, callbackAdjust);
56     createTrackbar("yellow", window_name, &yellow, 500, callbackAdjust);
57     createTrackbar("green", window_name, &green, 500, callbackAdjust);
58     createTrackbar("cyan", window_name, &cyan, 500, callbackAdjust);
59     createTrackbar("blue", window_name, &blue, 500, callbackAdjust);
60     createTrackbar("magenta", window_name, &magenta, 500, callbackAdjust);
61  
62     callbackAdjust(0, 0);
63  
64     waitKey();
65     return 0;
66 }

調整引數值後的黑白圖片效果（暗化綠背景、突出人臉（紅））：