cvHaarDetectObjects()方法有什么作用？

Question

有些专家可以解释一下我是否可以使用cvHaarDetectObjects()方法来检测方块并获得宽度和高度？我找到了一个使用这种方法进行面部检测的代码,但我需要知道是否可以将它用于矩形检测.

    String src="src/squiredetection/MY.JPG";
    IplImage grabbedImage = cvLoadImage(src);
    IplImage grayImage    = IplImage.create(grabbedImage.width(),  grabbedImage.height(), IPL_DEPTH_8U, 1);

        cvCvtColor(grabbedImage, grayImage, CV_BGR2GRAY);

        CvSeq faces = cvHaarDetectObjects(grayImage, cascade, storage, 1.1, 3, 0);//*
        for (int i = 0; i < faces.total(); i++) {
            CvRect r = new CvRect(cvGetSeqElem(faces, i));
            cvRectangle(grabbedImage, cvPoint(r.x(), r.y()), cvPoint(r.x()+r.width(), r.y()+r.height()), CvScalar.RED, 1, CV_AA, 0);
         /*   hatPoints[0].x = r.x-r.width/10;    hatPoints[0].y = r.y-r.height/10;
            hatPoints[1].x = r.x+r.width*11/10; hatPoints[1].y = r.y-r.height/10;
            hatPoints[2].x = r.x+r.width/2;     hatPoints[2].y = r.y-r.height/2;*/
          //  cvFillConvexPoly(grabbedImage, hatPoints, hatPoints.length, CvScalar.GREEN, CV_AA, 0);
        }

当我使用上面的方法时,它抛出以下异常

OpenCV Error: Bad argument (Invalid classifier cascade) in unknown function, file C:\slave\WinInstallerMegaPack\src\opencv\modules\objdetect\src\haar.cpp, line 1036
Exception in thread "main" java.lang.RuntimeException: C:\slave\WinInstallerMegaPack\src\opencv\modules\objdetect\src\haar.cpp:1036: error: (-5) Invalid classifier cascade

    at com.googlecode.javacv.cpp.opencv_objdetect.cvHaarDetectObjects(Native Method)
    at com.googlecode.javacv.cpp.opencv_objdetect.cvHaarDetectObjects(opencv_objdetect.java:243)
    at squiredetection.Test2.main(Test2.java:52 I have put * on this line)

请善意为此提供简单的代码示例.

Answer 1

cvHaarDetectObjects()它不仅用于检测面部的物体或形状,还取决于HaarCascade分类器.

如果您通过face haarcascade xml那么它将返回对面的阵列或者也可以使用eye,nose等HaarCascade XML文件.您可以使用haarcascade xml创建自己的正面和负面样本来进行自定义opencv_traincascade.exe

CvSeq faces = cvHaarDetectObjects(grayImage, classifier, storage,
                1.1, 3, CV_HAAR_DO_CANNY_PRUNING);

for (int i = 0; i < faces.total(); i++) {
   // its ok
}

opencv doc上的详细信息

用于矩形检测:

有一个矩形检测的例子OpenCV,他们用它来检测棋盘中的方块.看看squares.c..\OpenCV\samples\c \目录.

在opencv中看到这个棋盘检测样本

未知函数错误中的无效分类器级联意味着您传递的分类器格式不正确或缺少某些内容.检查分类器xml文件是否有效.