📅 最后修改于: 2020-11-23 03:37:05 🧑 作者: Mango
OpenCV支持各种类型的图像，例如彩色，二进制，灰度等。使用imread()方法和Imgcodecs类的预定义字段，可以将给定图像读取为另一种类型。
在前面的章节中，我们已经了解了Imgcodecs类的imread()方法的语法。它接受一个表示要读取图像位置的字符串参数。
imread(filename)
imread()方法具有另一种语法。
imread(filename, int flags)
此语法接受两个参数-
filename-它接受参数(文件名) ，这是String类型的变量，表示要读取的文件的路径。
flags-代表预定义标志值的整数值。对于每个值，这会将给定图像读取为特定类型(灰度颜色等)。
下表列出了Imgproc类中作为此参数值提供的各个字段。
| S.No | Fields and Description |
|---|---|
| 1 |
IMREAD_COLOR If the flag is set to this value, the loaded image will be converted to a 3-channel BGR (Blue Green Red) color image. |
| 2 |
IMREAD_GRAYSCALE If the flag is set to this value, the loaded image will be converted to a single-channel grayscale image. |
| 3 |
IMREAD_LOAD_GDAL If the flag is set to this value, you can load the image using the gdal driver. |
| 4 |
IMREAD_ANYCOLOR If the flag is set to this value, the image is read in any possible color format. |
| 5 |
IMREAD_REDUCED_COLOR_2 IMREAD_REDUCED_COLOR_4 IMREAD_REDUCED_COLOR_8 If the flag is set to this value, the image is read as three-channel BGR, and the size of the image is reduced to ½, ¼th or ⅛th of the original size of the image with respect to the field used. |
| 6 |
IMREAD_REDUCED_GRAYSCALE_2 IMREAD_REDUCED_GRAYSCALE_4 IMREAD_REDUCED_GRAYSCALE_8 If the flag is set to this value, the image is read as a single-channel grayscale image, and the size of the image is reduced to ½, ¼th or ⅛th of the original size of the image with respect to the field used. |
| 7 |
IMREAD_UNCHANGED If the flag is set to this value, the loaded image is returned as it is. |