利用opencv、vs2015自带的矫正功能矫正车牌

1.打开VS2015选择文件，然后新建项目，选择新建一个Win32控制台应用程序，并选择空项目并在源文件中添加一个名为rotate的CPP文件 

在该rotate.cpp文件中输入一下代码

#include "cv.h"                             //  OpenCV 文件头

#include "highgui.h"

#include "cvaux.h"

#include "cxcore.h"

#include "opencv2/opencv.hpp"

#include "opencv2/imgproc.hpp"

#include <iostream>

#include <string>

using namespace cv;

using namespace std;

Mat rotateImage1(Mat img, int degree)

{

degree = -degree;

double angle = degree  * CV_PI / 180.; // 弧度  

double a = sin(angle), b = cos(angle);

int width = img.cols;

int height = img.rows;

int width_rotate = int(height * fabs(a) + width * fabs(b));

int height_rotate = int(width * fabs(a) + height * fabs(b));

//旋转数组map

// [ m0  m1  m2 ] ===>  [ A11  A12   b1 ]

// [ m3  m4  m5 ] ===>  [ A21  A22   b2 ]

float map[6];

Mat map_matrix = Mat(2, 3, CV_32F, map);

// 旋转中心

CvPoint2D32f center = cvPoint2D32f(width / 2, height / 2);

CvMat map_matrix2 = map_matrix;

cv2DRotationMatrix(center, degree, 1.0, &map_matrix2);

map[2] += (width_rotate - width) / 2;

map[5] += (height_rotate - height) / 2;

Mat img_rotate;

//对图像做仿射变换

//CV_WARP_FILL_OUTLIERS - 填充所有输出图像的象素。

//如果部分象素落在输入图像的边界外，那么它们的值设定为 fillval.

//CV_WARP_INVERSE_MAP - 指定 map_matrix 是输出图像到输入图像的反变换，

warpAffine(img, img_rotate, map_matrix, Size(width_rotate, height_rotate), 1, 0, 0);

return img_rotate;

}

int main(int argc, char *argv[])

{

int degree;

Mat m_SrcImg;

m_SrcImg = imread("C:\\Users\\lidabao\\Desktop\\Lena1.bmp");

namedWindow("原图像", 1);

imshow("原图像", m_SrcImg);

cout << "请输入旋转的度数：";

cin >> degree;

Mat m_ResImg = rotateImage1(m_SrcImg, degree);

namedWindow("旋转后图像", 1);