One: OpenCV image reading and writing file help documentation

1.函数名：imread
定义：
Mat imread( const String& filename, int flags = IMREAD_COLOR );
def imread(filename, flags=None)
参数：
filename：文件名
flags：读取标识,枚举类型,
可以取以下值

enum ImreadModes {
    
       IMREAD_UNCHANGED  = -1, //!< If set, return the loaded image as is (with alpha channel, otherwise it gets cropped).
       IMREAD_GRAYSCALE  = 0,  //!< If set, always convert image to the single channel grayscale image (codec internal conversion).
       IMREAD_COLOR = 1,  //!< If set, always convert image to the 3 channel BGR color image.
       IMREAD_ANYDEPTH  = 2,  //!< If set, return 16-bit/32-bit image when the input has the corresponding depth, otherwise convert it to 8-bit.
       IMREAD_ANYCOLOR  = 4,  //!< If set, the image is read in any possible color format.
       IMREAD_LOAD_GDAL = 8,  //!< If set, use the gdal driver for loading the image.
       IMREAD_REDUCED_GRAYSCALE_2  = 16, //!< If set, always convert image to the single channel grayscale image and the image size reduced 1/2.
       IMREAD_REDUCED_COLOR_2  = 17, //!< If set, always convert image to the 3 channel BGR color image and the image size reduced 1/2.
       IMREAD_REDUCED_GRAYSCALE_4  = 32, //!< If set, always convert image to the single channel grayscale image and the image size reduced 1/4.
       IMREAD_REDUCED_COLOR_4  = 33, //!< If set, always convert image to the 3 channel BGR color image and the image size reduced 1/4.
       IMREAD_REDUCED_GRAYSCALE_8  = 64, //!< If set, always convert image to the single channel grayscale image and the image size reduced 1/8.
       IMREAD_REDUCED_COLOR_8  = 65, //!< If set, always convert image to the 3 channel BGR color image and the image size reduced 1/8.
       IMREAD_IGNORE_ORIENTATION   = 128 //!< If set, do not rotate the image according to EXIF's orientation flag.
     };

作用：读取图像,flags参数取“0”或“1”比较常见,取“0”is that the resulting image is a grayscale image.取“1”A three-channel color image is obtained.

python code
import cv2
#Read the grayscale image of the specified image
gray_image=cv2.imread(img_path,0)

#读取指定图片3通道
org_image=cv2.imread(img_path,1)

#-------------------------------------
#C code
#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;
int main(int argc, char** argv)
{
    
    //Read image file based on image file path and file name
    Mat src = imread("e:/TestImage/bike.jpg",1);
    //Create an image display window
    namedWindow("src", 0);
    //显示图像
    imshow("src", src);
    //等待用户按键触发,如果没有该语句,The window automatically closes after displaying the image.
    waitKey(0);
    return 0;
}

2.函数名：imwrite
定义：
bool imwrite( const String& filename, InputArray img, const std::vector& params = std::vector());
def imwrite(filename, img, params=None)
参数：
filename：文件名
img：要保存的图像
params：表示为特定格式保存的参数编码,Usually the default value is used directly.
作用：保存图像.

python code:
#save image to file
cv2.imwrite("xxx", image)

#---------------------------
C code：
#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;
int main(int argc, char** argv)
{
    
    Mat src = imread("e:/TestImage/bike.jpg", 1);
    namedWindow("src", 0);
    imshow("src", src);
    imwrite("e:/TestImage/bike_write.bmp", src);
    waitKey(0);
    return 0;
}

If the save file path has Chinese, you can use the following method to save:

cv2.imencode('.jpg', image)[1].tofile(save_img_path)

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