在轮廓JavaCV周围绘制边界框？

Posted 2023-03-28

【中文标题】在轮廓JavaCV周围绘制边界框？

【英文标题】：Drawing bounding box around contours JavaCV?

【发布时间】：2016-11-20 11:35:00

【问题描述】：

我想知道如何使用 JavaCV 在轮廓周围绘制边界框。我知道像素面积和中心点。我还找到了一种查找像素宽度以查找距离的方法。我觉得边界框可以更准确地找到像素宽度以找到距离然后我正在做的事情。任何帮助都会很棒，或者如果您知道另一种方法可以找到很棒的距离。谢谢...

import org.bytedeco.javacpp.*;
import org.bytedeco.javacpp.opencv_core.CvMemStorage;
import org.bytedeco.javacpp.opencv_core.IplImage;
import org.bytedeco.javacpp.opencv_videoio.CvCapture;
import static org.bytedeco.javacpp.opencv_core.*;
import static org.bytedeco.javacpp.opencv_imgproc.*;
public class Webcam 
   public static void main(String[] args) throws Exception 
       CvCapture capture = opencv_videoio.cvCreateCameraCapture(0);

       IplImage img1, imghsv, imgbin;
       CvScalar minc = cvScalar(95,125,75,0), maxc = cvScalar(145,255,255,0);
       CvSeq contour1 = new CvSeq(), contour2;
       CvMemStorage storage = CvMemStorage.create();
       CvMoments moments = new CvMoments(Loader.sizeof(CvMoments.class));
       double areaMax = 1000, areaC = 0;
       double m01, m10, m_area, focal, width, obj_width, obj_height;
       double distance;

       //focal is (pixel width * distance in inches) / object width 
       focal = 144.4;
       //Real objects width in inches
       obj_width = 3.5;
     //Real objects height in inches
       obj_height = 3.5;

       int posX=0, posY=0;

       int cRad = 100;

       while(true)
       
       img1 = opencv_videoio.cvQueryFrame(capture); 
       opencv_imgproc.cvSmooth(img1, img1, CV_MEDIAN, 13, 0, 0, 0);
       imgbin = IplImage.create(cvGetSize(img1), 8, 1);
       imghsv = IplImage.create(cvGetSize(img1), 8, 3);


       if(img1 == null) break;

       cvCvtColor(img1, imghsv, CV_BGR2HSV);
       cvInRangeS(imghsv, minc, maxc, imgbin);

       contour1 = new CvSeq();
       areaMax = 1000;

       cvFindContours(imgbin, storage, contour1, Loader.sizeof(CvContour.class), CV_RETR_LIST, CV_LINK_RUNS, cvPoint(0,0));

       contour2 = contour1;

       while(contour1 != null && !contour1.isNull())
       
           areaC = cvContourArea(contour1, CV_WHOLE_SEQ, 1);

           if(areaC > areaMax)
           
               areaMax = areaC;
           

           contour1 = contour1.h_next();
       

       while(contour2 != null && !contour2.isNull())
       
           areaC = cvContourArea(contour2, CV_WHOLE_SEQ, 1);

           if(areaC < areaMax)
           
               cvDrawContours(imgbin, contour2, CV_RGB(0,0,0),CV_RGB(0,0,0),0,CV_FILLED,8,cvPoint(0,0));
           
           contour2 = contour2.h_next();
       

       cvMoments(imgbin, moments, 1);
       m10 = cvGetSpatialMoment(moments, 1, 0);
       m01 = cvGetSpatialMoment(moments, 0, 1);
       m_area = cvGetCentralMoment(moments, 0, 0);

       posX = (int) (m10/m_area);
       posY = (int) (m01/m_area);

       if(posX > 0 && posY > 0)
       
           cRad = (int) (100 / (5000/m_area));
           cvCircle(img1, cvPoint(posX, posY), 5, cvScalar(0,255,0,0), 9, 0, 0);
       
       //Change numbers after m_area to size of object
       width =  java.lang.Math.sqrt((m_area/(obj_height*obj_width)));

       distance = (obj_width * focal) / width;

       cvFlip(img1, img1, 1);
       cvFlip(imgbin, imgbin , 1);
       opencv_highgui.cvShowImage("Color",img1);
       opencv_highgui.cvShowImage("CF",imgbin);
       char c = (char) opencv_highgui.cvWaitKey(15);
       if(c == 27) break;
       if(c == 'q')
       
           System.out.print("Width in pixels ");
           System.out.println(width);
           System.out.print("Distance in inches ");
           System.out.println(distance);

       
       

   

This is what I haveThis is what I want 。我能够找到所有蓝色轮廓并将背景变为黑色。我只想在蓝色像素周围绘制一个边界框，以帮助更好地找到与对象的距离，并确保我们正在跟踪正确的对象。

【问题讨论】：

你能分享原始图像及其所需的输出吗？

当然可以。感谢您提供帮助。

【参考方案1】：

如果你想在轮廓周围画一个边界框，你可以这样做：

Rect rect = opencv_imgproc.boundingRect(contour);
opencv_imgproc.rectangle(src, rect, Scalar.GREEN);