OpenCV - Java - 如何删除集群周围的一些像素

Question

我正在做一个项目，我需要识别图像的某些区域。在处理图像并删除所有不必要的东西后，我终于得到了我需要的区域，如图所示（绿色圆圈内的区域）。

我无法使用 OpenCV 在该区域周围画一个圆圈。我目前正在使用 Java 版本的 OpenCV。如果有人可以为我指出如何在图像上实现绿色圆圈的正确方向，那将非常有帮助。

我试图检测该区域的事情。 斑点检测器 - 没有取得多大成就。 Cluster - 与 blob 检测器相同。 HoughCircles - 在图像中绘制不必要的圆圈。 FindContour - 没有绘制任何东西，因为它不是一个完美的圆形、椭圆或任何其他众所周知的多边形。

感谢您的帮助。

Answer 1

这里有一个解决方案：

1. 打开以清除所有细长/细长图案中的图像。
2. 连接组件标签以计算剩余模式
3. 每个剩余图案的大小计数
4. 最大的图案是您要圈出的图案。

注意：如果要完美保留图案，可以通过重建（侵蚀+测地线重建）将开口替换为开口。

Answer 2

我终于找到了解决问题的方法。我使用了 OpenCV 库中的特征检测器，并为检测器提供了正确的阈值。这对我有用。 Java 中的代码如下所示。

public static void main(String[] args){
    try{
        //Validation whether a file name is passed to the function
        if(args.length == 0){
            System.out.println("here...");
            log.error("No file was passed to the function");
            throw new IOException();
        }

        //Read the image from the input
        Mat inputMat = Highgui.imread(args[0],Highgui.CV_LOAD_IMAGE_GRAYSCALE);

        //Create a feature detector. In this case we are using SURF (Speeded-Up Robust Features) detector. 
        MatOfKeyPoint objectKeyPoints = new MatOfKeyPoint();
        FeatureDetector featureDetector = FeatureDetector.create(FeatureDetector.SURF);

        //A temporary file is created to input Hessian Threshold to the SURF detector
        File tempFile = File.createTempFile("config", ".yml");
        String settings = "%YAML:1.0\nhessianThreshold: 7000.\noctaves: 3\noctaveLayers: 4\nupright: 0\n";
        FileWriter writer = new FileWriter(tempFile, false);
        writer.write(settings);
        writer.close();

        //Read the configuration from the temporary file to assign the threshold for the detector
        featureDetector.read(tempFile.getPath());

        //Detect the features in the image provided
        featureDetector.detect(inputMat, objectKeyPoints);

        //Iterate through the list of key points detected in the previous step and find the Key Point with the largest size
        List<KeyPoint> objectKeyPointList = objectKeyPoints.toList();
        KeyPoint impKeyPoint = new KeyPoint();

        for(int i=0; i<objectKeyPointList.size(); i++){
            if(impKeyPoint == null){
                impKeyPoint = objectKeyPointList.get(i);
            }
            else if(impKeyPoint.size < objectKeyPointList.get(i).size){
                impKeyPoint = objectKeyPointList.get(i);
            }
        }

        //If the size of the Key Point is greater than 120 then reduce the size to 120 and if the size is less than 120 then increase to 120 
        if(impKeyPoint.size > 120){
            KeyPoint tempKeyPoint = new KeyPoint();
            tempKeyPoint = impKeyPoint;
            tempKeyPoint.size = 120;
            impKeyPoint = tempKeyPoint;
        }
        else if(impKeyPoint.size < 120){
            KeyPoint tempKeyPoint = new KeyPoint();
            tempKeyPoint = impKeyPoint;
            tempKeyPoint.size = 120;
            impKeyPoint = tempKeyPoint;
        }

        //Convert the Key Point to MatOfKeyPoint since drawKeyPoints accepts only MatOfKeyPoint
        MatOfKeyPoint impMatOfKeyPoint = new MatOfKeyPoint(impKeyPoint);

        //Mat for drawing the circle in the image
        Mat outputImage = new Mat(inputMat.rows(), inputMat.cols(), Highgui.CV_LOAD_IMAGE_COLOR);

        //Green color for the circle
        Scalar greenCircle = new Scalar(0, 255, 0);

        //Draw the circle around the optic nerve when detected
        Features2d.drawKeypoints(inputMat, impMatOfKeyPoint, outputImage, greenCircle, Features2d.DRAW_RICH_KEYPOINTS);

        //Write the image to a file
        Highgui.imwrite("surf_keypoints.png", outputImage);
    }catch(Exception e){
        log.fatal(e.getMessage());
    }

}

希望这对其他人有帮助。