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Deploying a YOLOv7 trained model using C++


I have trained a YOLOv7 model on a custom dataset. I want to use the trained model in my C++ project. I tried to do so using .pt weights and .onnx weights, but I'm continuously getting errors.

As advised here, I performed 'Reparameterization' on the .pt file, before converting it into .onnx.

In the current trial, I followed this repository, and I used the following code:

#include <fstream>
#include <sstream>
#include <iostream>
#include <opencv2/dnn.hpp>
#include <opencv2/imgproc.hpp>
#include <opencv2/highgui.hpp>

using namespace cv;
using namespace dnn;
using namespace std;

struct Net_config
{
    float confThreshold; // Confidence threshold
    float nmsThreshold;  // Non-maximum suppression threshold
    string modelpath;
};

class YOLOV7
{
public:
    YOLOV7(Net_config config);
    void detect(Mat& frame);
private:
    int inpWidth;
    int inpHeight;
    vector<string> class_names;
    int num_class;

    float confThreshold;
    float nmsThreshold;
    Net net;
    void drawPred(float conf, int left, int top, int right, int bottom, Mat& frame, int classid);
};

YOLOV7::YOLOV7(Net_config config)
{
    this->confThreshold = config.confThreshold;
    this->nmsThreshold = config.nmsThreshold;

    //this->net = readNetFromONNX(config.modelpath);
    this->net = readNetFromONNX("yolov7.onnx");
    ifstream ifs("coco.names");
    string line;
    while (getline(ifs, line)) this->class_names.push_back(line);
    this->num_class = class_names.size();

    size_t pos = config.modelpath.find("_");
    int len = config.modelpath.length() - 6 - pos;
    string hxw = config.modelpath.substr(pos + 1, len);
    pos = hxw.find("x");
    string h = hxw.substr(0, pos);
    len = hxw.length() - pos;
    string w = hxw.substr(pos + 1, len);
    this->inpHeight = stoi(h);
    this->inpWidth = stoi(w);
}

void YOLOV7::drawPred(float conf, int left, int top, int right, int bottom, Mat& frame, int classid)   // Draw the predicted bounding box
{
    //Draw a rectangle displaying the bounding box
    rectangle(frame, Point(left, top), Point(right, bottom), Scalar(0, 0, 255), 2);

    //Get the label for the class name and its confidence
    string label = format("%.2f", conf);
    label = this->class_names[classid] + ":" + label;

    //Display the label at the top of the bounding box
    int baseLine;
    Size labelSize = getTextSize(label, FONT_HERSHEY_SIMPLEX, 0.5, 1, &baseLine);
    top = max(top, labelSize.height);
    //rectangle(frame, Point(left, top - int(1.5 * labelSize.height)), Point(left + int(1.5 * labelSize.width), top + baseLine), Scalar(0, 255, 0), FILLED);
    putText(frame, label, Point(left, top), FONT_HERSHEY_SIMPLEX, 0.75, Scalar(0, 255, 0), 1);
}

void YOLOV7::detect(Mat& frame)
{
    Mat blob = blobFromImage(frame, 1 / 255.0, Size(this->inpWidth, this->inpHeight), Scalar(0, 0, 0), true, false);
    this->net.setInput(blob);
    vector<Mat> outs;
    this->net.forward(outs, this->net.getUnconnectedOutLayersNames());

    int num_proposal = outs[0].size[0];
    int nout = outs[0].size[1];
    if (outs[0].dims > 2)
    {
        num_proposal = outs[0].size[1];
        nout = outs[0].size[2];
        outs[0] = outs[0].reshape(0, num_proposal);
    }
    /////generate proposals
    vector<float> confidences;
    vector<Rect> boxes;
    vector<int> classIds;
    float ratioh = (float)frame.rows / this->inpHeight, ratiow = (float)frame.cols / this->inpWidth;
    int n = 0, row_ind = 0; ///cx,cy,w,h,box_score,class_score
    float* pdata = (float*)outs[0].data;
    for (n = 0; n < num_proposal; n++)   ///ÌØÕ÷ͼ³ß¶È
    {
        float box_score = pdata[4];
        if (box_score > this->confThreshold)
        {
            Mat scores = outs[0].row(row_ind).colRange(5, nout);
            Point classIdPoint;
            double max_class_socre;
            // Get the value and location of the maximum score
            minMaxLoc(scores, 0, &max_class_socre, 0, &classIdPoint);
            max_class_socre *= box_score;
            if (max_class_socre > this->confThreshold)
            {
                const int class_idx = classIdPoint.x;
                float cx = pdata[0] * ratiow;  ///cx
                float cy = pdata[1] * ratioh;   ///cy
                float w = pdata[2] * ratiow;   ///w
                float h = pdata[3] * ratioh;  ///h

                int left = int(cx - 0.5 * w);
                int top = int(cy - 0.5 * h);

                confidences.push_back((float)max_class_socre);
                boxes.push_back(Rect(left, top, (int)(w), (int)(h)));
                classIds.push_back(class_idx);
            }
        }
        row_ind++;
        pdata += nout;
    }

    // Perform non maximum suppression to eliminate redundant overlapping boxes with
    // lower confidences
    vector<int> indices;
    dnn::NMSBoxes(boxes, confidences, this->confThreshold, this->nmsThreshold, indices);
    for (size_t i = 0; i < indices.size(); ++i)
    {
        int idx = indices[i];
        Rect box = boxes[idx];
        this->drawPred(confidences[idx], box.x, box.y,
            box.x + box.width, box.y + box.height, frame, classIds[idx]);
    }
}

int main()
{
    Net_config YOLOV7_nets = { 0.3, 0.5, "yolov7.onnx" };   ////choices=["models/yolov7_640x640.onnx", "models/yolov7-tiny_640x640.onnx", "models/yolov7_736x1280.onnx", "models/yolov7-tiny_384x640.onnx", "models/yolov7_480x640.onnx", "models/yolov7_384x640.onnx", "models/yolov7-tiny_256x480.onnx", "models/yolov7-tiny_256x320.onnx", "models/yolov7_256x320.onnx", "models/yolov7-tiny_256x640.onnx", "models/yolov7_256x640.onnx", "models/yolov7-tiny_480x640.onnx", "models/yolov7-tiny_736x1280.onnx", "models/yolov7_256x480.onnx"]
    YOLOV7 net(YOLOV7_nets);
    string imgpath = "frame1.png";
    Mat srcimg = imread(imgpath);
    net.detect(srcimg);

    static const string kWinName = "Deep learning object detection in OpenCV";
    namedWindow(kWinName, WINDOW_NORMAL);
    imshow(kWinName, srcimg);
    system("pause");
    waitKey(0);
    destroyAllWindows();
}

However, I got the following error:

OpenCV: terminate handler is called! The last OpenCV error is:
OpenCV(4.1.1) Error: Unsupported format or combination of formats (Failed to parse onnx model) in cv::dnn::dnn4_v20190621::ONNXImporter::ONNXImporter, file C:\opencv-4.1.1\modules\dnn\src\onnx\onnx_importer.cpp, line 57

Here is a link to my 'yolov7.onnx' file, and here is a link to 'frame1.png'

The model is trained to detect 1 class, which is 'Potholes' in roads.

Currently, I have visual studio 2019, and opencv 4.1.1.

Should I upgrade to another opencv version?

Pls guide me to any possible solutions, so that I can successfully deploy the YOLOv7 model using C++.


Solution

  • I upgraded to Opencv 4.6.0.

    Also, I discovered that I wasn't placing the .onnx and the image files in the same folder as the .exe file.

    The following is the code in it's final status (but as I said above, the paths of the .onnx file, and the image files should be specified correctly):

    #include <fstream>
    #include <sstream>
    #include <iostream>
    #include <opencv2/dnn.hpp>
    #include <opencv2/imgproc.hpp>
    #include <opencv2/highgui.hpp>
    
    using namespace cv;
    using namespace dnn;
    using namespace std;
    
    struct Net_config
    {
        float confThreshold; // Confidence threshold
        float nmsThreshold;  // Non-maximum suppression threshold
        string modelpath;
    };
    
    class YOLOV7
    {
    public:
        YOLOV7(Net_config config);
        void detect(Mat& frame);
    private:
        int inpWidth;
        int inpHeight;
        vector<string> class_names;
        int num_class;
    
        float confThreshold;
        float nmsThreshold;
        Net net;
        void drawPred(float conf, int left, int top, int right, int bottom, Mat& frame, int classid);
    };
    
    YOLOV7::YOLOV7(Net_config config)
    {
        this->confThreshold = config.confThreshold;
        this->nmsThreshold = config.nmsThreshold;
    
        //this->net = readNetFromONNX(config.modelpath);
        this->net = readNetFromONNX("yolov7.onnx");
        //ifstream ifs("coco.names");
        ifstream ifs("Potholes.names");
        string line;
        while (getline(ifs, line)) this->class_names.push_back(line);
        this->num_class = class_names.size();
    
        this->inpHeight = 640;//stoi(h);
        this->inpWidth = 640;//stoi(w);
    }
    
    void YOLOV7::drawPred(float conf, int left, int top, int right, int bottom, Mat& frame, int classid)   // Draw the predicted bounding box
    {
        //Draw a rectangle displaying the bounding box
        rectangle(frame, Point(left, top), Point(right, bottom), Scalar(0, 0, 255), 2);
    
        //Get the label for the class name and its confidence
        string label = format("%.2f", conf);
        label = this->class_names[classid] + ":" + label;
    
        //Display the label at the top of the bounding box
        int baseLine;
        Size labelSize = getTextSize(label, FONT_HERSHEY_SIMPLEX, 0.5, 1, &baseLine);
        top = max(top, labelSize.height);
        //rectangle(frame, Point(left, top - int(1.5 * labelSize.height)), Point(left + int(1.5 * labelSize.width), top + baseLine), Scalar(0, 255, 0), FILLED);
        putText(frame, label, Point(left, top), FONT_HERSHEY_SIMPLEX, 0.75, Scalar(0, 255, 0), 1);
    }
    
    void YOLOV7::detect(Mat& frame)
    {
        Mat blob = blobFromImage(frame, 1 / 255.0, Size(this->inpWidth, this->inpHeight), Scalar(0, 0, 0), true, false);
        this->net.setInput(blob);
        vector<Mat> outs;
        this->net.forward(outs, this->net.getUnconnectedOutLayersNames());
    
        int num_proposal = outs[0].size[0];
        int nout = outs[0].size[1];
        if (outs[0].dims > 2)
        {
            num_proposal = outs[0].size[1];
            nout = outs[0].size[2];
            outs[0] = outs[0].reshape(0, num_proposal);
        }
        /////generate proposals
        vector<float> confidences;
        vector<Rect> boxes;
        vector<int> classIds;
        float ratioh = (float)frame.rows / this->inpHeight, ratiow = (float)frame.cols / this->inpWidth;
        int n = 0, row_ind = 0; ///cx,cy,w,h,box_score,class_score
        float* pdata = (float*)outs[0].data;
        for (n = 0; n < num_proposal; n++)   ///ÌØÕ÷ͼ³ß¶È
        {
            float box_score = pdata[4];
            if (box_score > this->confThreshold)
            {
                Mat scores = outs[0].row(row_ind).colRange(5, nout);
                Point classIdPoint;
                double max_class_socre;
                // Get the value and location of the maximum score
                minMaxLoc(scores, 0, &max_class_socre, 0, &classIdPoint);
                max_class_socre *= box_score;
                if (max_class_socre > this->confThreshold)
                {
                    const int class_idx = classIdPoint.x;
                    float cx = pdata[0] * ratiow;  ///cx
                    float cy = pdata[1] * ratioh;   ///cy
                    float w = pdata[2] * ratiow;   ///w
                    float h = pdata[3] * ratioh;  ///h
    
                    int left = int(cx - 0.5 * w);
                    int top = int(cy - 0.5 * h);
    
                    confidences.push_back((float)max_class_socre);
                    boxes.push_back(Rect(left, top, (int)(w), (int)(h)));
                    classIds.push_back(class_idx);
                }
            }
            row_ind++;
            pdata += nout;
        }
    
        // Perform non maximum suppression to eliminate redundant overlapping boxes with
        // lower confidences
        vector<int> indices;
        dnn::NMSBoxes(boxes, confidences, this->confThreshold, this->nmsThreshold, indices);
        for (size_t i = 0; i < indices.size(); ++i)
        {
            int idx = indices[i];
            Rect box = boxes[idx];
            this->drawPred(confidences[idx], box.x, box.y,
                box.x + box.width, box.y + box.height, frame, classIds[idx]);
        }
    }
    
    int main()try
    {
        int img_index = 0;
        Net_config YOLOV7_nets = { 0.3, 0.5, "yolov7.onnx" };   ////choices=["models/yolov7_640x640.onnx", "models/yolov7-tiny_640x640.onnx", "models/yolov7_736x1280.onnx", "models/yolov7-tiny_384x640.onnx", "models/yolov7_480x640.onnx", "models/yolov7_384x640.onnx", "models/yolov7-tiny_256x480.onnx", "models/yolov7-tiny_256x320.onnx", "models/yolov7_256x320.onnx", "models/yolov7-tiny_256x640.onnx", "models/yolov7_256x640.onnx", "models/yolov7-tiny_480x640.onnx", "models/yolov7-tiny_736x1280.onnx", "models/yolov7_256x480.onnx"]
        YOLOV7 net(YOLOV7_nets);
        
        while (img_index <= 822)
        {
            string base_path = "D:/Post_Grad/STDF/Depth_estimation-master/workspace/test_vid/pngFrames/frame";
            //string imgpath = "frame1.png";
            string imgpath = base_path + to_string(img_index) + ".png";
            Mat srcimg = imread(imgpath);
            net.detect(srcimg);
    
            static const string kWinName = "Deep learning object detection in OpenCV";
            namedWindow(kWinName, WINDOW_NORMAL);
            imshow(kWinName, srcimg);
            waitKey(1);
            img_index++;
        }
        destroyAllWindows();
    }
    catch (const std::exception& e)
    {
        std::cerr << e.what() << std::endl;
        system("pause");
        return EXIT_FAILURE;
    }