OpenCV-第六话-图像混合

一.写在前面

线性混合理论：

g(x)=(1-α)f0 (x)+αf1 (x)

可以理解为：

f0，f1是待混合的两张图片

g是混合后的图片

其中α的取值范围是0~1

二.相关API

CV_EXPORTS_W void addWeighted(InputArray src1, double alpha, InputArray src2,
                              double beta, double gamma, OutputArray dst, int dtype = -1);

/** @brief Scales, calculates absolute values, and converts the result to 8-bit.

On each element of the input array, the function convertScaleAbs
performs three operations sequentially: scaling, taking an absolute
value, conversion to an unsigned 8-bit type:
\f[\texttt{dst} (I)= \texttt{saturate\_cast<uchar>} (| \texttt{src} (I)* \texttt{alpha} +  \texttt{beta} |)\f]
In case of multi-channel arrays, the function processes each channel
independently. When the output is not 8-bit, the operation can be
emulated by calling the Mat::convertTo method (or by using matrix
expressions) and then by calculating an absolute value of the result.
For example:
@code{.cpp}
    Mat_<float> A(30,30);
    randu(A, Scalar(-100), Scalar(100));
    Mat_<float> B = A*5 + 3;
    B = abs(B);
    // Mat_<float> B = abs(A*5+3) will also do the job,
    // but it will allocate a temporary matrix
@endcode
@param src input array.
@param dst output array.
@param alpha optional scale factor.
@param beta optional delta added to the scaled values.
@sa  Mat::convertTo, cv::abs(const Mat&)
*/

参数1：输入图像Mat – src1

参数2：输入图像src1的alpha值

参数3：输入图像Mat – src2

参数4：输入图像src2的alpha值

参数5：gamma值

参数6：输出混合图像

注意点：两张图像的大小和类型必须一致才可以

三.代码实现

/*
OpenCV 图像混合学习
Michael Jiang <sencom1997@outlook.com>
2019年7月24日11:07:56
*/

#include <opencv2/opencv.hpp>
#include <iostream>

using namespace cv;
int main()
{
	//读取图像p1.png和p2.png
	Mat p1 = imread("D:/p1.png", IMREAD_COLOR);
	Mat p2 = imread("D:/p2.png", IMREAD_COLOR);
	
	//判断是否读取成功
	if (!p1.data) {
		printf("p1 load failed!\n");
		return -1;
	}
	if (!p2.data) {
		printf("p2 load failed!\n");
		return -1;
	}

	namedWindow("p1", WINDOW_AUTOSIZE);
	namedWindow("p2", WINDOW_AUTOSIZE);

	imshow("p1", p1);
	imshow("p2", p2);

	//判断图片尺寸，格式是否相同
	if (p1.cols == p2.cols && p1.rows == p2.rows && p1.type() == p2.type()) {
		Mat mix;
		double alpha = 0.5;
		namedWindow("mix", WINDOW_AUTOSIZE);
		addWeighted(p1, alpha, p2, (1.0 - alpha), 1.0, mix);
		imshow("mix", mix);
	}
	else {
		printf("p1 p2 not same!\n");
		return -1;
	}
	waitKey(0);
	return 0;
}