blobs.size() != 0 in function 'virtual bool

Question

I write code in java using android studio to detection objects by camera and I have this error when I run my app

blobs.size() != 0 in function 'virtual bool

I use opencv for my code, can you help me pleas to solve this error

the line of error: tinyYolo.forward(result,outBlobNames);

the error in logcat

CvException [org.opencv.core.CvException: cv::Exception: OpenCV(3.4.5) /build/3_4_pack-android/opencv/modules/dnn/src/layers/convolution_layer.cpp:238: error: (-215:Assertion failed) blobs.size() != 0 in function 'virtual bool cv::dnn::ConvolutionLayerImpl::getMemoryShapes(const std::vector<std::vector<int> >&, int, std::vector<std::vector<int> >&, std::vector<std::vector<int> >&) const'
    at org.opencv.dnn.Net.forward_4(Native Method)

my code is

  public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {

    Mat frame = inputFrame.rgba();
    Size frame_size = new Size(416, 416);
    Scalar mean = new Scalar(127.5);
    if (startYolo == true) {



        Imgproc.cvtColor(frame, frame, Imgproc.COLOR_RGBA2RGB);

        Mat imageBlob = Dnn.blobFromImage(frame, 1.0 / 255.0, frame_size, mean, true, false);

        tinyYolo.setInput(imageBlob);



        List<Mat> result = new ArrayList<>();

        List<String> outBlobNames = tinyYolo.getUnconnectedOutLayersNames();

        tinyYolo.forward(result,outBlobNames);
        float confThreshold = 0.3f;
        List<Integer> clsIds = new ArrayList<>();
        List<Float> confs = new ArrayList<>();
        List<Rect> rects = new ArrayList<>();

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

            Mat level = result.get(i);

            for (int j = 0; j < level.rows(); ++j)
            {
                Mat row = level.row(j);
                Mat scores = row.colRange(5, level.cols());

                Core.MinMaxLocResult mm = Core.minMaxLoc(scores);

                float confidence = (float)mm.maxVal;

                Point classIdPoint = mm.maxLoc;
                if (confidence > confThreshold)
                {
                    int centerX = (int)(row.get(0,0)[0] * frame.cols());
                    int centerY = (int)(row.get(0,1)[0] * frame.rows());
                    int width   = (int)(row.get(0,2)[0] * frame.cols());
                    int height  = (int)(row.get(0,3)[0] * frame.rows());
                    int left    = centerX - width  / 2;
                    int top     = centerY - height / 2;

                    clsIds.add((int)classIdPoint.x);
                    confs.add((float)confidence);
                    rects.add(new Rect(left, top, width, height));
                }
            }
        }
        int ArrayLength = confs.size();

        if (ArrayLength>=1) {


            float nmsThresh = 0.2f;
            MatOfFloat confidences = new MatOfFloat(Converters.vector_float_to_Mat(confs));
            Rect[] boxesArray = rects.toArray(new Rect[0]);

            MatOfRect boxes = new MatOfRect(boxesArray);

            MatOfInt indices = new MatOfInt();

            Dnn.NMSBoxes(boxes, confidences, confThreshold, nmsThresh, indices);



            int[] ind = indices.toArray();
            for (int i = 0; i < ind.length; ++i) {

                int idx = ind[i];
                Rect box = boxesArray[idx];

                int idGuy = clsIds.get(idx);

                float conf = confs.get(idx);

                List<String> cocoNames = Arrays.asList("a person", "a bicycle", "a motorbike", "an airplane", "a bus", "a train", "a truck", "a boat", "a traffic light", "a fire hydrant", "a stop sign", "a parking meter", "a car", "a bench", "a bird", "a cat", "a dog", "a horse", "a sheep", "a cow", "an elephant", "a bear", "a zebra", "a giraffe", "a backpack", "an umbrella", "a handbag", "a tie", "a suitcase", "a frisbee", "skis", "a snowboard", "a sports ball", "a kite", "a baseball bat", "a baseball glove", "a skateboard", "a surfboard", "a tennis racket", "a bottle", "a wine glass", "a cup", "a fork", "a knife", "a spoon", "a bowl", "a banana", "an apple", "a sandwich", "an orange", "broccoli", "a carrot", "a hot dog", "a pizza", "a doughnut", "a cake", "a chair", "a sofa", "a potted plant", "a bed", "a dining table", "a toilet", "a TV monitor", "a laptop", "a computer mouse", "a remote control", "a keyboard", "a cell phone", "a microwave", "an oven", "a toaster", "a sink", "a refrigerator", "a book", "a clock", "a vase", "a pair of scissors", "a teddy bear", "a hair drier", "a toothbrush");

                int intConf = (int) (conf * 100);

                Imgproc.putText(frame,cocoNames.get(idGuy) + " " + intConf + "%",box.tl(),Core.FONT_HERSHEY_SIMPLEX, 2, new Scalar(255,255,0),2);

                Imgproc.rectangle(frame, box.tl(), box.br(), new Scalar(255, 0, 0), 2);
            }
        }
    }
    return frame;
}