这是您需要遵循的方式...
为了方便起见,我已将您的图像调整为较小的尺寸,
- 计算源图像的四边形顶点,这里我手动查找,可以选择边缘检测,霍夫线等。
Q1=manual calculation;
Q2=manual calculation;
Q3=manual calculation;
Q4=manual calculation;
- 通过保持宽高比来计算目标图像中的四边形顶点,在这里您可以从源图像的四边形顶点上方获取卡片的宽度,并通过乘以宽高比来计算高度。
// compute the size of the card by keeping aspect ratio.
double ratio=1.6;
double cardH=sqrt((Q3.x-Q2.x)*(Q3.x-Q2.x)+(Q3.y-Q2.y)*(Q3.y-Q2.y)); //Or you can give your own height
double cardW=ratio*cardH;
Rect R(Q1.x,Q1.y,cardW,cardH);
- 现在您获得了源和目标的四边形顶点,然后应用 warpPerspective。
您可以参考下面的C++代码,
//Compute quad point for edge
Point Q1=Point2f(90,11);
Point Q2=Point2f(596,135);
Point Q3=Point2f(632,452);
Point Q4=Point2f(90,513);
// compute the size of the card by keeping aspect ratio.
double ratio=1.6;
double cardH=sqrt((Q3.x-Q2.x)*(Q3.x-Q2.x)+(Q3.y-Q2.y)*(Q3.y-Q2.y));//Or you can give your own height
double cardW=ratio*cardH;
Rect R(Q1.x,Q1.y,cardW,cardH);
Point R1=Point2f(R.x,R.y);
Point R2=Point2f(R.x+R.width,R.y);
Point R3=Point2f(Point2f(R.x+R.width,R.y+R.height));
Point R4=Point2f(Point2f(R.x,R.y+R.height));
std::vector<Point2f> quad_pts;
std::vector<Point2f> squre_pts;
quad_pts.push_back(Q1);
quad_pts.push_back(Q2);
quad_pts.push_back(Q3);
quad_pts.push_back(Q4);
squre_pts.push_back(R1);
squre_pts.push_back(R2);
squre_pts.push_back(R3);
squre_pts.push_back(R4);
Mat transmtx = getPerspectiveTransform(quad_pts,squre_pts);
int offsetSize=150;
Mat transformed = Mat::zeros(R.height+offsetSize, R.width+offsetSize, CV_8UC3);
warpPerspective(src, transformed, transmtx, transformed.size());
//rectangle(src, R, Scalar(0,255,0),1,8,0);
line(src,Q1,Q2, Scalar(0,0,255),1,CV_AA,0);
line(src,Q2,Q3, Scalar(0,0,255),1,CV_AA,0);
line(src,Q3,Q4, Scalar(0,0,255),1,CV_AA,0);
line(src,Q4,Q1, Scalar(0,0,255),1,CV_AA,0);
imshow("quadrilateral", transformed);
imshow("src",src);
waitKey();