Getting Started with OpenCV in C++ 002: Loading, Modifying, and Saving Images

 1 #include <opencv2/>
 2 #include <iostream>
 3 
 4 using namespace cv;
 5 using namespace std;
 6 
 7 /// <summary>
 8 /// image processing
 9 /// 1, load image imread( const String& filename, int flags = IMREAD_COLOR )
10 /// 2、Create a window void namedWindow(const String& winname, int flags = WINDOW_AUTOSIZE)
11 /// 3、Show image void imshow(const String& winname, InputArray mat)
12 /// 4、Modify image void cvtColor( InputArray src, OutputArray dst, int code, int dstCn = 0 )
13 /// 5、Save Image imwrite( const String& filename, InputArray img,const std::vector<int>& params = std::vector<int>())
14 /// </summary>
15 /// <returns></returns>
16 int main()
17 {
18     //1. Load image
19     //Mat imread( const String& filename, int flags = IMREAD_COLOR ): the first parameter is the address of the image, the second parameter is the way to load the image.
20     //IMREAD_UNCHANGED(<0) means load the original image without any modification.
21     //IMREAD_GRAYSCALE(0) indicates that the original image is loaded in as a grayscale image.
22     //IMREAD_COLOR(>0) means load in the original image as an RGB image.
23     // opencv supports jpg, png, tiff and other common image formats.
24     Mat src = imread("D:\\360MoveData\\Users\\Administrator\\Desktop\\TestImage\\", IMREAD_UNCHANGED);
25 
26     //Load the original image as a grayscale image
27     Mat src2 = imread("D:\\360MoveData\\Users\\Administrator\\Desktop\\TestImage\\", IMREAD_GRAYSCALE);
28 
29     //2、Create window
30     //void namedWindow(const String& winname, int flags = WINDOW_AUTOSIZE): winname denotes the name of the window. flags denotes the window characteristics.
31     // namedWindow: indicates the creation of a window with the specified name and characteristics, which is used to display the image. It is created and destroyed automatically by OpenCV and does not need to be released manually.
32     //flags:list of window features
33     //WINDOW_AUTOSIZE: Adaptive image size, user can't modify the window size.
34     //WINDOW_FREERATIO: Window size adaptive scale
35     //WINDOW_FULLSCREEN: full screen display
36     //WINDOW_GUI_NORMAL: is the old way of drawing windows without status bar and toolbar, while WINDOW_GUI_EXPANDED is a new enhanced GUI.
37     //WINDOW_KEEPRATIO: Keeps the image proportional.
38     //WINDOW_NORMAL: used when integrating with QT, allows to modify the window size.
39     //
40 
41     namedWindow("OrigianImage", WINDOW_AUTOSIZE);
42     namedWindow("GrayImage", WINDOW_AUTOSIZE);
43 
44     //3. Display image
45     //void imshow(const String& winname, InputArray mat): winname The name of the window created using namedWindow; mat The image object to be displayed.
46     //imshow: a window created using namedWindow to display the specified image.
47 
48     imshow("OrigianImage", src);
49     imshow("GrayImage", src2);
50 
51     //4、Modify the image
52     //void cvtColor( InputArray src, OutputArray dst, int code, int dstCn = 0 ): src the source image, the image to be converted; dst the image after the color space conversion; code the conversion method of the source color space and the target color space; dstCn
53     //cvtColor: Converts an image from one color space to another.
54     //code list:
55     //COLOR_BGR2GRAY: Converts from RGB to Gray, from color to gray.
56     //
57 
58     Mat des;
59     cvtColor(src, des, COLOR_BGR2HSV);
60 
61     namedWindow("cvtColorImage", WINDOW_AUTOSIZE);
62     imshow("cvtColorImage", des);
63 
64 
65     //5. Saving images
66     //imwrite( const String& filename, InputArray img,const std::vector<int>& params = std::vector<int>()): filename The name of the file where the image is to be saved , contains the full path and file name and extension, the extension is different, the generated image is different; img The image to be saved.
67     //imwrite: used to save as an image with the specified name.
68     //Only images in 8-bit, 16-bit PNG, JPG, TIFF file formats and single-channel or three-channel BGR can be saved in this way.
69     //You can save the image of the transparent channel when saving the PNG format.
70     //Compression parameters can be specified.
71 
72     //Saves three formats, realized by suffix names.
73     imwrite("D:\\ScanImages\\",des);
74     imwrite("D:\\ScanImages\\", des);
75     imwrite("D:\\ScanImages\\", des);
76 
77     waitKey(0);
78 
79     return 0;
80 }

1 Mat src = imread("D:\\360MoveData\\Users\\Administrator\\Desktop\\TestImage\\", IMREAD_UNCHANGED);

2 namedWindow("OrigianImage", WINDOW_AUTOSIZE);

3 imshow("OrigianImage", src);

1 Mat src2 = imread("D:\\360MoveData\\Users\\Administrator\\Desktop\\TestImage\\", IMREAD_GRAYSCALE);
2 namedWindow("GrayImage", WINDOW_AUTOSIZE);
3 imshow("GrayImage", src2);

1 Mat des;
2 cvtColor(src, des, COLOR_BGR2HSV);
3 
4 namedWindow("cvtColorImage", WINDOW_AUTOSIZE);
5 imshow("cvtColorImage", des);