OpenCV getPerspectiveTransform和Java透视

Question

我目前有一个ArrayList<MatOfPoint>存储图像的轮廓，并检索到最大的轮廓，这是我的透视目标

List<MatOfPoint> contours = new ArrayList<MatOfPoint>();
Imgproc.findContours(matOut, contours, new Mat(), Imgproc.RETR_LIST, Imgproc.CHAIN_APPROX_SIMPLE);

sort(contours);
MatOfPoint2f  m2f = MatOfPoint2f(contours.get(0).toArray());
double arc = Imgproc.arcLength(m2f, true);
MatOfPoint2f approx = new MatOfPoint2f();
Imgproc.approxPolyDP(m2f, approx, arc*0.02, true);

我在如何使用getPerspectiveTransform，然后应用WarpPerspectiveTransform来更改图像以使其适合450x450图像方面遇到了问题

我在python中找到了一个很好的例子，但是我对它不是很熟悉。有人能解释一下我将如何在java中进行纠正吗

def rectify(h):
    ''' this function put vertices of square we got, in clockwise order '''
    h = h.reshape((4,2))
    hnew = np.zeros((4,2),dtype = np.float32)

    add = h.sum(1)
    hnew[0] = h[np.argmin(add)]
    hnew[2] = h[np.argmax(add)]

    diff = np.diff(h,axis = 1)
    hnew[1] = h[np.argmin(diff)]
    hnew[3] = h[np.argmax(diff)]

    return hnew

以下是源链接：https://github.com/abidrahmank/OpenCV2-Python/blob/master/OpenCV_Python_Blog/sudoku_v_0.0.6/sudoku.py

Answer 1

简介：为了使用wrapPerspective，我们需要使用getPerspectiveTransform takes:mat src和mat dst计算包裹垫。这些是带有轮廓src（左上、右上、左下、右下）和相应的mat dst（0,0；0449；449,0；449449）的MatOfPoints2f（因此图像将为450x450-如果这是错误的，请纠正我）

opencv 3的Java解决方案是：

1. 整理积分 矩形轮廓为MatOfPoints2f约我们需要按照上面所述对点进行排序：

   //calculate the center of mass of our contour image using moments
   Moments moment = Imgproc.moments(approx.get(0));
   int x = (int) (moment.get_m10() / moment.get_m00());
   int y = (int) (moment.get_m01() / moment.get_m00());
   
   //SORT POINTS RELATIVE TO CENTER OF MASS 
   Point[] sortedPoints = new Point[4];
   
   double[] data;
   int count = 0;
   for(int i=0; i<approx.get(0).rows(); i++){
       data = approx.get(0).get(i, 0);
       double datax = data[0];
       double datay = data[1];
       if(datax < x && datay < y){
           sortedPoints[0]=new Point(datax,datay);
           count++;
       }else if(datax > x && datay < y){
           sortedPoints[1]=new Point(datax,datay);
           count++;
       }else if (datax < x && datay > y){
           sortedPoints[2]=new Point(datax,datay);
           count++;
       }else if (datax > x && datay > y){
           sortedPoints[3]=new Point(datax,datay);
           count++;
       }
   }
   

2. 准备材料src和det

           MatOfPoint2f src = new MatOfPoint2f(
                   sortedPoints[0],
                   sortedPoints[1],
                   sortedPoints[2],
                   sortedPoints[3]);
   
           MatOfPoint2f dst = new MatOfPoint2f(
                   new Point(0, 0),
                   new Point(450-1,0),
                   new Point(0,450-1),
                   new Point(450-1,450-1)      
                   );
   

3. 使用getPerspectiveTransform和WrapSpective

       Mat warpMat = Imgproc.getPerspectiveTransform(src,dst);
       //This is you new image as Mat
       Mat destImage = new Mat();
       Imgproc.warpPerspective(originalImg, destImage, warpMat, originalImg.size());
   

我刚刚完成了类似的项目，所以我相信这可以做得更好，但如果有人需要的话，这是一个有效的解决方案