OpenCV之warpPerspective--透视变换

OpenCV之warpPerspective–透视变换

参考博客链接：https://blog.csdn.net/liuphahaha/article/details/50719275

为了记录自己的学习：

一

OpenCV透视变化进行图像中的关键图提取（抠图）
上代码：

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

using namespace std;
using namespace cv;

struct userdata {
	Mat im;
	vector<Point2f> points;
};

void mouseHandle(int event, int x, int y, int flags,void* ptr)
{
	if (event == EVENT_LBUTTONDOWN)
	{
		userdata *data = (userdata*)ptr;
		circle(data->im, Point(x, y), 3, Scalar(0, 0, 255), 3, CV_AA);
		imshow("dst", data->im);
		if (data->points.size() < 4)
		{
			data->points.push_back(Point2f(x, y));
		}
	}
}

int main()
{
	Mat Image = imread("E:/Images/book1.jpg");
	imshow("Image", Image);
	Mat result = Mat::zeros(400, 300, CV_8UC3);

	vector<Point2f> obj;
	obj.push_back(Point2f(0, 0));
	obj.push_back(Point2f(300, 0));
	obj.push_back(Point2f(300, 400));
	obj.push_back(Point2f(0, 400));

	Mat dst = Image.clone();
	
	userdata data;
	data.im = dst;
	imshow("dst", dst);
	setMouseCallback("dst", mouseHandle, &data);
	waitKey(0);

	Mat H = findHomography(data.points, obj, CV_RANSAC);;
	warpPerspective(Image, result, H, result.size());
	imshow("result", result);

	waitKey(0);
}
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效果图如下：
原图：

结果图为：

OK！！！

二

换广告牌（抠图）

上代码：

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

using namespace std;
using namespace cv;

struct userdata {
	Mat im;
	vector<Point2f> points;
};

void mouseHandle(int event, int x, int y, int flags,void* ptr)
{
	if (event == EVENT_LBUTTONDOWN)
	{
		userdata *data = (userdata*)ptr;
		circle(data->im, Point(x, y), 3, Scalar(0, 0, 255), 3, CV_AA);
		imshow("dst", data->im);
		if (data->points.size() < 4)
		{
			data->points.push_back(Point2f(x, y));
		}
	}
}

int main()
{
	Mat Image = imread("E:/Images/photo1.jpg");
	imshow("Image", Image);

	vector<Point2f> obj;
	obj.push_back(Point2f(0, 0));
	obj.push_back(Point2f(Image.cols, 0));
	obj.push_back(Point2f(Image.cols, Image.rows));
	obj.push_back(Point2f(0, Image.rows));

	Mat Image2 = imread("E:/Images/photo.jpg");
	imshow("Image2", Image2);
	Mat dst = Image2.clone();
	
	userdata data;
	data.im = dst;
	imshow("dst", dst);
	setMouseCallback("dst", mouseHandle, &data);
	waitKey(0);
	

	//将需要替换的图透视变换到大图进行变换
	Mat H = findHomography(obj, data.points, CV_RANSAC);
	warpPerspective(Image, dst, H, dst.size());
	imshow("result", dst);

	Point pts[4];
	for (int i = 0; i < 4; i++)
	{
		pts[i] = data.points[i];
	}

	//进行填充（0，0，0）
	fillConvexPoly(Image2, pts, 4, Scalar(0), CV_AA);
	imshow("....", Image2);

	//进行或操作
	Image2 += dst;
	imshow("finally", Image2);
	imwrite("E:/Images/phototest.jpg", Image2);


	waitKey(0);
}
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原图：

模板图：

最后换好的图：

效果不错！！！ 留着学习

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