How to correctly determine the corners of a white sheet of paper?

Question

Java

Trying to find the corners of a white sheet of paper.
The fourth corner is not where it is needed.
What's wrong?

The code

package com;

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.MatOfPoint;
import org.opencv.core.Point;
import org.opencv.core.Rect;
import org.opencv.core.Scalar;
import org.opencv.core.Size;
import org.opencv.highgui.HighGui;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;  

public class Main {

  public static void main(String[] args) {
    //Loading the OpenCV core library  
      System.loadLibrary( Core.NATIVE_LIBRARY_NAME );
      System.out.println("Версия OpenCV: " + Core.VERSION);
        
    String file = "images\\white3.png"; 
      Mat imageOriginal = Imgcodecs.imread(file);
     
      Mat imageOriginalResize = new Mat();
      Size minScaleSize = new Size(imageOriginal.width()/4, imageOriginal.height()/4);
      Imgproc.resize(imageOriginal, imageOriginalResize, minScaleSize , 0, 0, Imgproc.INTER_AREA);
      
      Mat imageGray = new Mat();
      Imgproc.cvtColor(imageOriginalResize, imageGray, Imgproc.COLOR_BGR2GRAY);
      
      Mat imageGaussianBlur = new Mat();
        Imgproc.GaussianBlur(imageGray, imageGaussianBlur, new Size(3, 3), 3);
        
        Mat imageCanny = new Mat();
        Imgproc.Canny(imageGaussianBlur, imageCanny, 120, 250, 3, true);
        
        
        MatOfPoint corners = new MatOfPoint();
        System.out.println("Поиск углов");
        Imgproc.goodFeaturesToTrack(imageCanny, corners, 4, 0.01, 500);
        
        if (corners.toArray().length == 4) {
        	System.out.println("Найденно углов: " + corners.toArray().length);
        
        	Point[] cornerPoints = corners.toArray();
        	Point tl = cornerPoints[3];
        	Point br = cornerPoints[0];
        
        
        	Rect rect = new Rect(tl, new Size(br.x, br.y));
        	System.out.println("Будущий квадрат: " + rect);
        
        	//Mat mat = new Mat(cornerpoints[0], cornerpoints[1], cornerpoints[2], cornerpoints[3]);
        	// Rect rect = Imgproc.boundingRect();
        

        	for (Point points : cornerPoints) {
        		System.out.println(points);
        		int pointXI = (int) points.x;
        		String pointXS = Integer.toString(pointXI);
        		int pointYI = (int) points.y;
        		String pointYS = Integer.toString(pointYI);
        	
        		Imgproc.circle(imageOriginalResize, points, 5, new Scalar(0,0,255), 3);
        		Imgproc.putText(imageOriginalResize, pointXS + " " + pointYS, 
            		new Point(points.x-20, points.y+20) , 1, 1, new Scalar(0, 0, 255), 2);
        		// Imgproc.rectangle(imageOriginalResize, rect, new Scalar(255, 0, 0), 5);
        		}
        	
        }else {
        	System.out.println("Углы не найдены");
        }
        
        HighGui.namedWindow( "Image original", HighGui.WINDOW_AUTOSIZE );
    HighGui.imshow( "Image original", imageOriginalResize);
    
    HighGui.namedWindow( "Image Canny", HighGui.WINDOW_AUTOSIZE );
    HighGui.imshow( "Image Canny", imageCanny);
        
        if (HighGui.waitKey(0) == 27) {

        	HighGui.destroyAllWindows();
        	imageOriginal.release();
            imageGray.release();
            imageGaussianBlur.release();
            imageCanny.release();
            imageOriginalResize.release();
            
        } else {
        	HighGui.destroyAllWindows();
        	imageOriginal.release();
            imageGray.release();
            imageGaussianBlur.release();
            imageCanny.release();
            imageOriginalResize.release();
        	
        }
        System.exit(0);
        

  }

}