文章选自：

一、imread说明

CV_EXPORTS_W Mat imread( const String& filename, int flags = IMREAD_COLOR );
功能：读取图像参数：@param filename 导入图像路径.@param flags 图像类型标识位enum ImreadModes {IMREAD_UNCHANGED            = -1, //!< If set, return the loaded image as is (with alpha channel, otherwise it gets cropped). Ignore EXIF orientation.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.};

目前支持的图像格式：

• Windows 位图 - *.bmp, *.dib

• JPEG 文件 - *.jpeg, *.jpg, *.jpe

• JPEG 2000 文件 - *.jp2

• 可移植网络图形 - *.png

• WebP - *.webp

• AVIF - *.avif

• 可移植图像格式 - *.pbm, *.pgm, *.ppm, *.pxm, *.pnm

• PFM 文件 - *.pfm

• Sun 光栅 - *.sr, *.ras

• TIFF 文件 - *.tiff, *.tif

• OpenEXR 图像文件 - *.exr

• Radiance HDR - *.hdr, *.pic

• GDAL 支持的光栅和矢量地理空间数据

二、imreadmulti说明

bool imreadmulti(const String& filename, CV_OUT std::vector<Mat>& mats, int flags = IMREAD_ANYCOLOR);功能：从指定文件加载多通道图像到 Mat对象的向量中参数：@param filename 要加载的文件名。@param mats 一个 Mat 对象的向量，用于存储每一通道。@param flags 可以取 cv::ImreadModes 的值，默认值为 cv::IMREAD_ANYCOLOR。