openCV KNN findNearest Error

Question

我试图实现KNN findNearest函数。我的程序应识别图片中的数字，但如果程序使用findNearest，我会收到错误。这是代码：

`private void searchingData() {

    img_gray = new Mat();
    img_blur = new Mat();
    img_thres = new Mat();

    Imgproc.cvtColor(img, img_gray, Imgproc.COLOR_BGR2GRAY);
    Imgproc.GaussianBlur(img_gray, img_blur, new Size(5,5), 0);
    //Imgproc.adaptiveThreshold(img_blur, img_thres, 255, Imgproc.ADAPTIVE_THRESH_MEAN_C, Imgproc.THRESH_BINARY, 7, 5);
    Imgproc.Canny(img_blur, img_thres, 10, 100); 

    Imgproc.findContours(img_thres, contours, new Mat(), Imgproc.RETR_LIST,Imgproc.CHAIN_APPROX_SIMPLE);

    for(int i=0; i< contours.size();i++){

        Rect rect = Imgproc.boundingRect(contours.get(i));

        if (rect.height < 50 && rect.height > 20){ 

            System.out.println(rect.x +","+rect.y+","+rect.height+","+rect.width);

            Mat subImg = new Mat();
            Imgproc.resize(img.submat(rect), subImg, new Size(10,10));

            //Found numbers then try to recognize it
            recognize(subImg);
        }
    }
}

public void learn() { //get the training data and train the KNN

    Mat sample, training_img = new Mat(), res = new Mat();

    for (int i = 1; i < 10; i++) {

        String path = String.format(".../Documents/numbers/%03d.png", i);
        sample = Imgcodecs.imread(path, Imgcodecs.CV_LOAD_IMAGE_GRAYSCALE);

        Mat m = new Mat(new Size(1,1), CvType.CV_32FC1);
        m.setTo(new Scalar(i));
        res.push_back(m);

        training_img.push_back(prepareImg(sample));
    }

    model = KNearest.create();
    model.train(training_img, Ml.ROW_SAMPLE, res);

}

private Mat prepareImg(Mat img) { //change image in the right format
    Mat sample = new Mat(), sized = new Mat();

    Imgproc.resize(img, sized, new Size(10,10));
    sized.reshape(1,1).convertTo(sample, CvType.CV_32FC1);

    return sample;
}

public void recognize(Mat getImg) {

    Mat results = new Mat();
    Mat dists   = new Mat();

    float result = model.findNearest(prepareImg(getImg), 2, results, new Mat(), dists);

    //result should be the number in getImg
    System.out.println(result);
}`

  

OpenCV错误：断言失败（test_samples.type（）== CV_32F＆amp;＆amp;   test_samples.cols == samples.cols）in   cv :: ml :: BruteForceImpl :: findNearest，file   C：\建立\ master_PackSlaveAddon-Win64的-VC12静电\的OpenCV \模块\毫升\ SRC \ knearest.cpp，   第325行线程“main”CvException中的异常   [org.opencv.core.CvException：cv :: Exception：   C：\建立\ master_PackSlaveAddon-Win64的-VC12静电\的OpenCV \模块\毫升\ SRC \ knearest.cpp：325：   错误：（ - 1515）test_samples.type（）== CV_32F＆amp;＆amp; test_samples.cols ==   函数cv :: ml :: BruteForceImpl :: findNearest]中的samples.cols

非常感谢！