如何用java在openCv中找到矩形的角

Question

我寫了這段檢測矩形的代碼，但我無法編寫檢測角的代碼。

public class RectDetection {
  public static void main(String[] args) {


 System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
 Mat rectengle=Imgcodecs.imread("D:\\sepano\\rect.png");
       Mat img =new Mat();
      img=rectengle.clone();
        Imgproc.cvtColor(rectengle, img, Imgproc.COLOR_BGR2GRAY);
        Imgproc.GaussianBlur(img, img, new  org.opencv.core.Size(1, 1), 2, 2);
    Imgproc.Canny(img,img,3, 3,5,false);

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

    MatOfPoint temp_contour = contours.get(0); //the largest is at the index 0 for starting point

    for (int idx = 0; idx < contours.size(); idx++) {
        temp_contour = contours.get(idx);
            MatOfPoint2f new_mat = new MatOfPoint2f( temp_contour.toArray() );
            int contourSize = (int)temp_contour.total();
            MatOfPoint2f approxCurve_temp = new MatOfPoint2f();
            Imgproc.approxPolyDP(new_mat, approxCurve_temp, contourSize*0.05, true);
     if (approxCurve_temp.total()==8) {
                MatOfPoint points = new MatOfPoint( approxCurve_temp.toArray() );
                Rect rect = Imgproc.boundingRect(points);
               Imgproc.rectangle(img, new Point(rect.x,rect.y), new Point(rect.x+rect.width,rect.y+rect.height), new Scalar(170,0,150,0), 5);}}

這是用於角點檢測的python代碼，但我無法將其轉換為java：

import numpy as np
import cv2
from matplotlib import pyplot as plt

img = cv2.imread('simple.jpg')
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)

corners = cv2.goodFeaturesToTrack(gray,25,0.01,10)
corners = np.int0(corners)

for i in corners:
    x,y = i.ravel()
    cv2.circle(img,(x,y),3,255,-1)

plt.imshow(img),plt.show()

有什么可以幫我的嗎？？？

Answer 1

仔細看看你的java代碼......

在這一行：

Imgproc.rectangle(img, new Point(rect.x,rect.y), new Point(rect.x+rect.width,rect.y+rect.height), new Scalar(170,0,150,0), 5);

Point(rect.x,rect.y)對應於矩形的左上角， Point(rect.x+rect.width,rect.y+rect.height)對應於矩形的右下角。

矩形檢測代碼應該就可以了，4個角如下：

Point(rect.x,rect.y) //左上角

Point(rect.x+rect.width,rect.y) //右上角

Point(rect.x,rect.y+rect.height) // Point(rect.x,rect.y+rect.height)

Point(rect.x+rect.width,rect.y+rect.height) // Point(rect.x+rect.width,rect.y+rect.height)