What is the saturate operation in opencv

OpenCV Medium saturate operation ( Saturation operation ) What the hell is going on ？

Just try with two practical examples .

We use it CV_8U Type to try ,CV_8U For the range of 0~255

First example ：

//OpenCV edition ：3.0.0
//VS edition ：2013

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#include <opencv2/opencv.hpp>
#include <iostream>
using namespace std;


int main()
{
    

	cv::Mat A1(2, 3, CV_8UC1, cv::Scalar(254));
	cout << "A1 The data in is ：\n" << A1 << endl << endl;

	cv::Mat B1(2, 3, CV_8UC1, cv::Scalar(2));
	cout << "B1 The data in is ：\n" << B1 << endl << endl;

	cv::Mat C1;
	cv::add(A1, B1, C1);
	cout << "C1 The data in is ：\n" << C1 << endl << endl;

	return(0);
}

The operation results are as follows ：

According to the truth , The result should be 256, But because the type of output matrix is also CV_8U, and CV_8U For the range of 0~255, So the value is set to 255.

Second example ：

//OpenCV edition ：3.0.0
//VS edition ：2013

#include <opencv2/opencv.hpp>

#include <iostream>
using namespace std;


int main()
{
    

	cv::Mat A1(2, 3, CV_8UC1, cv::Scalar(254));
	cout << "A1 The data in is ：\n" << A1 << endl << endl;

	cv::Mat B1(2, 3, CV_8UC1, cv::Scalar(2));
	cout << "B1 The data in is ：\n" << B1 << endl << endl;

	cv::Mat C1;
	cv::subtract(B1, A1, C1);
	cout << "C1 The data in is ：\n" << C1 << endl << endl;

	return(0);
}

The operation results are as follows ：

According to the truth , The result should be -252, But because the type of output matrix is also CV_8U, and CV_8U For the range of 0~255, So the value is set to 0.
Through these two examples , You should understand OpenCV Medium saturate operation ( Saturation operation ) What the hell is going on .