The following code can be used to make a chessboard image given the number of rows and columns of the chessboard, square size in pixel, and two colors.

The default size of the square is 100 pixels and default colors are black and white.

Use an image viewer like Irfanview to print the saved chessboard pattern to a paper maintaining the required size of the chessboard in metric measurements.

As an example, if you want to print a 5×7 chessboard pattern where one square should be 3cm×3cm, select the options as follows.

Here is a code snippet we can use for converting an image from RGB colour space to HSV colour space. OpenCV uses BGR format instead of RGB. Therefore, we have to use the CV_BGR2HSV flag to convert the image to HSV space and then the “split” method to separate the hue, saturation and value channels.

These are the data types we can use with OpenCV Matrices.

	DATA TYPE	RANGE	IPL IMAGES	CV::MAT
Unsigned 8bits	uchar	0 ~ 255	IPL_DEPTH_8U	CV_8UC1 CV_8UC2 CV_8UC3 CV_8UC4
Signed 8bits	char	-128 ~ 127	IPL_DEPTH_8S	CV_8SC1 CV_8SC2 CV_8SC3 CV_8SC4
Unsigned 16bits	ushort	0 ~ 65535	IPL_DEPTH_16U	CV_16UC1 CV_16UC2 CV_16UC3 CV_16UC4
Signed 16bits	short	-32768 ~ 32767	IPL_DEPTH_16S	CV_16SC1 CV_16SC2 CV_16SC3 CV_16SC4
Signed 32bits	int	-2147483648 ~ 2147483647	IPL_DEPTH_32S	CV_32SC1 CV_32SC2 CV_32SC3 CV_32SC4
Float 32bits	float	-1.18e-38 ~ 3.40e-38	IPL_DEPTH_32F	CV_32FC1 CV_32FC2 CV_32FC3 CV_32FC4
Double 64bits	double	-1.7e+308 ~ +1.7e+308	IPL_DEPTH_64F	CV_64FC1 CV_64FC2 CV_64FC3 CV_64FC4
Unsigned 1bit	bool	0 and 1	IPL_DEPTH_1U

‘C’ represents the number of channels

• C1: 1 channel
• C2: 2 channels
• C3: 3 channels
• C4: 4 channels

We can check the Data Type of a cv::Mat using “type()” method.

This is a method you can use for checking the type of an cv::Mat.

The following method can be used to print any type of single channel cv::Mat

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src: StackOverflaw