frominit.py：
opencv版本4.1.0，不同版本也许doc稍有不同
def imwrite(filename, img, params=None): # real signature unknown; restored from __doc__"""imwrite(filename, img[, params]) -> retval. @brief Saves an image to a specified file. 将图像保存到指定文件. . The function imwrite saves the image to the specified file. The image format is chosen based on the. filename extension (see cv::imread for the list of extensions). In general, only 8-bit. single-channel or 3-channel (with 'BGR' channel order) images. can be saved using this function, with these exceptions:· imwrite函数将图像保存到指定文件。 图像格式是根据文件扩展名选择的（扩展名列表请参见cv :: imread）。 · 通常，使用此功能只能保存8位单通道或3通道（具有“ BGR”通道顺序）图像，但以下情况除外：. - 16-bit unsigned (CV_16U) images can be saved in the case of PNG, JPEG 2000, and TIFF formats. - 32-bit float (CV_32F) images can be saved in PFM, TIFF, OpenEXR, and Radiance HDR formats;· 对于PNG，JPEG 2000和TIFF格式，可以保存16位无符号（CV_16U）图像；·可以PFM，TIFF，OpenEXR和Radiance HDR格式保存32位浮点（CV_32F）图像；. 3-channel (CV_32FC3) TIFF images will be saved using the LogLuv high dynamic range encoding. (4 bytes per pixel). - PNG images with an alpha channel can be saved using this function. To do this, create. 8-bit (or 16-bit) 4-channel image BGRA, where the alpha channel goes last. Fully transparent pixels. should have alpha set to 0, fully opaque pixels should have alpha set to 255/65535 (see the code sample below).·使用LogLuv高动态范围编码（每像素4个字节）将保存3通道（CV_32FC3）TIFF图像-使用此功能可以保存具有alpha通道的PNG图像。 ·为此，创建8位（或16位）4通道图像BGRA，其中alpha通道位于最后。 ·完全透明的像素应将alpha设置为0，完全不透明的像素应将alpha设置为255/65535（请参见下面的代码示例）。. . If the format, depth or channel order is different, use. Mat::convertTo and cv::cvtColor to convert it before saving. Or, use the universal FileStorage I/O. functions to save the image to XML or YAML format.··如果格式，深度或通道顺序不同，请在保存之前使用Mat :: convertTo和cv :: cvtColor进行转换。 ·或者，使用通用的FileStorage I / O功能将图像保存为XML或YAML格式。. . The sample below shows how to create a BGRA image and save it to a PNG file. It also demonstrates how to set custom. compression parameters:·下面的示例演示如何创建BGRA图像并将其保存到PNG文件。 它还演示了如何设置自定义压缩参数：. @include snippets/imgcodecs_imwrite.cpp. @param filename Name of the file. 文件名。. @param img Image to be saved. 要保存的图像。. @param params Format-specific parameters encoded as pairs (paramId_1, paramValue_1, paramId_2, paramValue_2, ... .) see cv::ImwriteFlags特定格式的参数编码为对（paramId_1，paramValue_1，paramId_2，paramValue_2等）。请参见cv :: ImwriteFlags"""pass
Doc中所指cv :: ImwriteFlags：链接
参考文章：OpenCV笔记1：用imwrite函数来保存图片
