[python]OpenCV之cvtColor

官方文档：https://docs.opencv.org/ 

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cvCvtColor是Opencv里的颜色空间转换函数

最常见的就是实现灰度转化，HSV转化

 

官方文档的解释：

§ cvtColor()

void cv::cvtColor	(	InputArray	src,
		OutputArray	dst,
		int	code,
		int	dstCn = 0
	)

Python:
	dst	=	cv.cvtColor(	src, code[, dst[, dstCn]]	)

Parameters（参数）

src	input image: 8-bit unsigned, 16-bit unsigned ( CV_16UC... ), or single-precision floating-point.
dst	output image of the same size and depth as src.
code	color space conversion code (see ColorConversionCodes).
dstCn	number of channels in the destination image; if the parameter is 0, the number of the channels is derived automatically from src and code.

 可以看到cvtColor的参数并不复杂

cvtColor(src,dst,code,dstCn)  ===>  (原图像，输出图像，color转化代码，输出通道) 

1，原图像：input image: 8-bit unsigned, 16-bit unsigned ( CV_16UC... ), or single-precision floating-point.，解释的很清楚8位无符号，16位无符号，或者单精浮点数。

2，输出图像：output image of the same size and depth as src. 输出与src相同大小和深度的图像。

3，code ：color转化代码

COLOR_BGR2BGRA  Python: cv.COLOR_BGR2BGRA	add alpha channel to RGB or BGR image（为rgb或bgr增加alpha通道）
COLOR_RGB2RGBA  Python: cv.COLOR_RGB2RGBA

COLOR_BGRA2BGR  Python: cv.COLOR_BGRA2BGR	remove alpha channel from RGB or BGR image(为rgb或bgr移除alpha通道)
COLOR_RGBA2RGB  Python: cv.COLOR_RGBA2RGB

 

COLOR_BGR2GRAY  Python: cv.COLOR_BGR2GRAY	convert between RGB/BGR and grayscale, color conversions
COLOR_RGB2GRAY  Python: cv.COLOR_RGB2GRAY
COLOR_GRAY2BGR  Python: cv.COLOR_GRAY2BGR
COLOR_GRAY2RGB  Python: cv.COLOR_GRAY2RGB

 

COLOR_BGR2HSV  Python: cv.COLOR_BGR2HSV	convert RGB/BGR to HSV (hue saturation value), color conversions
COLOR_RGB2HSV  Python: cv.COLOR_RGB2HSV

 

更多转化code，前往https://docs.opencv.org/trunk/d8/d01/group__imgproc__color__conversions.html#gga4e0972be5de079fed4e3a10e24ef5ef0aa4f6bc658bc546e1660fcab6bf7858f4查看

4，通道数：一般不写 ，参数说明number of channels in the destination image; if the parameter is 0, the number of the channels is derived automatically from src and code.  会自动根据src和code来自动导出通道数

 

实际使用：

cv.cvtColor(src, dst, cv.COLOR_RGB2HSV); //转为hsv图