samples/dnn/classification.cpp

Check the corresponding tutorial for more details

#include <fstream>
#include <sstream>
#include <iostream>
 
#include <opencv2/dnn.hpp>
#include <opencv2/imgproc.hpp>
#include <opencv2/highgui.hpp>
 
#include "common.hpp"
 
using namespace cv;
using namespace std;
using namespace dnn;
 
const string about =
        "Use this script to run a classification model on a camera stream, video, image or image list (i.e. .xml or .yaml containing image lists)\n\n"
        "Firstly, download required models using `download_models.py` (if not already done). Set environment variable OPENCV_DOWNLOAD_CACHE_DIR to specify where models should be downloaded. Also, point OPENCV_SAMPLES_DATA_PATH to opencv/samples/data.\n"
        "To run:\n"
        "\t ./example_dnn_classification model_name --input=path/to/your/input/image/or/video (don't give --input flag if want to use device camera)\n"
        "Sample command:\n"
        "\t ./example_dnn_classification resnet --input=$OPENCV_SAMPLES_DATA_PATH/baboon.jpg\n"
        "\t ./example_dnn_classification squeezenet\n"
        "Model path can also be specified using --model argument. "
        "Use imagelist_creator to create the xml or yaml list\n";
 
const string param_keys =
    "{ help  h         |                   | Print help message. }"
    "{ @alias          |                   | An alias name of model to extract preprocessing parameters from models.yml file. }"
    "{ zoo             | ../dnn/models.yml | An optional path to file with preprocessing parameters }"
    "{ input i         |                   | Path to input image or video file. Skip this argument to capture frames from a camera.}"
    "{ imglist         |                   | Pass this flag if image list (i.e. .xml or .yaml) file is passed}"
    "{ crop            |       false       | Preprocess input image by center cropping.}"
    //"{ labels          |                   | Path to the text file with labels for detected objects.}"
    "{ model           |                   | Path to the model file.}";
 
const string backend_keys = format(
    "{ backend          | default | Choose one of computation backends: "
                              "default: automatically (by default), "
                              "openvino: Intel's Deep Learning Inference Engine (https://software.intel.com/openvino-toolkit), "
                              "opencv: OpenCV implementation, "
                              "vkcom: VKCOM, "
                              "cuda: CUDA, "
                              "webnn: WebNN }");
 
const string target_keys = format(
    "{ target           | cpu | Choose one of target computation devices: "
                              "cpu: CPU target (by default), "
                              "opencl: OpenCL, "
                              "opencl_fp16: OpenCL fp16 (half-float precision), "
                              "vpu: VPU, "
                              "vulkan: Vulkan, "
                              "cuda: CUDA, "
                              "cuda_fp16: CUDA fp16 (half-float preprocess) }");
 
string keys = param_keys + backend_keys + target_keys;
 
vector<string> classes;
static bool readStringList( const string& filename, vector<string>& l )
{
    l.resize(0);
    FileStorage fs(filename, FileStorage::READ);
    if( !fs.isOpened() )
        return false;
    size_t dir_pos = filename.rfind('/');
    if (dir_pos == string::npos)
        dir_pos = filename.rfind('\\');
    FileNode n = fs.getFirstTopLevelNode();
    if( n.type() != FileNode::SEQ )
        return false;
    FileNodeIterator it = n.begin(), it_end = n.end();
    for( ; it != it_end; ++it )
    {
        string fname = (string)*it;
        if (dir_pos != string::npos)
        {
            string fpath = samples::findFile(filename.substr(0, dir_pos + 1) + fname, false);
            if (fpath.empty())
            {
                fpath = samples::findFile(fname);
            }
            fname = fpath;
        }
        else
        {
            fname = samples::findFile(fname);
        }
        l.push_back(fname);
    }
    return true;
}
 
int main(int argc, char** argv)
{
    CommandLineParser parser(argc, argv, keys);
 
    if (!parser.has("@alias") || parser.has("help"))
    {
        cout << about << endl;
        parser.printMessage();
        return -1;
    }
    const string modelName = parser.get<String>("@alias");
    const string zooFile = findFile(parser.get<String>("zoo"));
 
    keys += genPreprocArguments(modelName, zooFile);
    parser = CommandLineParser(argc, argv, keys);
    parser.about(about);
    if (argc == 1 || parser.has("help"))
    {
        parser.printMessage();
        return 0;
    }
    String sha1 = parser.get<String>("sha1");
    float scale = parser.get<float>("scale");
    Scalar mean = parser.get<Scalar>("mean");
    Scalar std = parser.get<Scalar>("std");
    bool swapRB = parser.get<bool>("rgb");
    bool crop = parser.get<bool>("crop");
    int inpWidth = parser.get<int>("width");
    int inpHeight = parser.get<int>("height");
    String model = findModel(parser.get<String>("model"), sha1);
    String backend = parser.get<String>("backend");
    String target = parser.get<String>("target");
    bool isImgList = parser.has("imglist");
 
    // Open file with labels.
    string labels_filename = parser.get<String>("labels");
    string file = findFile(labels_filename);
    ifstream ifs(file.c_str());
    if (!ifs.is_open()){
        cout<<"File " << file << " not found";
        exit(1);
    }
    string line;
    while (getline(ifs, line))
    {
        classes.push_back(line);
    }
    if (!parser.check())
    {
        parser.printErrors();
        return 1;
    }
    CV_Assert(!model.empty());
    EngineType engine = ENGINE_AUTO;
    if (backend != "default" || target != "cpu"){
        engine = ENGINE_CLASSIC;
    }
    Net net = readNetFromONNX(model, engine);
    net.setPreferableBackend(getBackendID(backend));
    net.setPreferableTarget(getTargetID(target));
 
    // Create a window
    static const std::string kWinName = "Deep learning image classification in OpenCV";
    namedWindow(kWinName, WINDOW_NORMAL);
 
    //Create FontFace for putText
    FontFace sans("sans");
 
    VideoCapture cap;
    vector<string> imageList;
    size_t currentImageIndex = 0;
 
    if (parser.has("input")) {
        string input = findFile(parser.get<String>("input"));
 
        if (isImgList) {
            bool check = readStringList(samples::findFile(input), imageList);
            if (imageList.empty() || !check) {
                cout << "Error: No images found or the provided file is not a valid .yaml or .xml file." << endl;
                return -1;
            }
        } else {
            // Input is not a directory, try to open as video or image
            cap.open(input);
            if (!cap.isOpened()) {
                cout << "Failed to open the input." << endl;
                return -1;
            }
        }
    } else {
        cap.open(0); // Open default camera
    }
 
    Mat frame, blob;
    for(;;)
    {
        if (!imageList.empty()) {
            // Handling directory of images
            if (currentImageIndex >= imageList.size()) {
                waitKey();
                break; // Exit if all images are processed
            }
            frame = imread(imageList[currentImageIndex++]);
            if(frame.empty()){
                cout<<"Cannot open file"<<endl;
                continue;
            }
        } else {
            // Handling video or single image
            cap >> frame;
        }
        if (frame.empty())
        {
            break;
        }
        blobFromImage(frame, blob, scale, Size(inpWidth, inpHeight), mean, swapRB, crop);
        // Check std values.
        if (std.val[0] != 0.0 && std.val[1] != 0.0 && std.val[2] != 0.0)
        {
            // Divide blob by std.
            divide(blob, std, blob);
        }
        net.setInput(blob);
 
        TickMeter timeRecorder;
        timeRecorder.reset();
        Mat prob = net.forward();
        double t1;
        timeRecorder.start();
        prob = net.forward();
        timeRecorder.stop();
 
        int N = (int)prob.total(), K = std::min(5, N);
        std::vector<std::pair<float, int> > prob_vec;
        for (int i = 0; i < N; i++) {
            prob_vec.push_back(std::make_pair(-prob.at<float>(i), i));
        }
        std::sort(prob_vec.begin(), prob_vec.end());
 
        t1 = timeRecorder.getTimeMilli();
        timeRecorder.reset();
        string label = format("Inference time: %.1f ms", t1);
        Mat subframe = frame(Rect(0, 0, std::min(1000, frame.cols), std::min(300, frame.rows)));
        subframe *= 0.3f;
        putText(frame, label, Point(20, 50), Scalar(0, 255, 0), sans, 25, 800);
 
        // Print predicted class.
        for (int i = 0; i < K; i++) {
            int classId = prob_vec[i].second;
            float confidence = -prob_vec[i].first;
            label = format("%d. %s: %.2f", i+1, (classes.empty() ? format("Class #%d", classId).c_str() :
                                        classes[classId].c_str()), confidence);
            putText(frame, label, Point(20, 110 + i*35), Scalar(0, 255, 0), sans, 25, 500);
        }
        imshow(kWinName, frame);
        int key = waitKey(isImgList ? 1000 : 100);
        if (key == ' ')
            key = waitKey();
        if (key == 'q' || key == 27) // Check if 'q' or 'ESC' is pressed
            return 0;
    }
    waitKey();
    return 0;
}