文章目录
依赖库
opencv4.7
及以上
导入onnx
python
yolo export model=./runs/detect/train2/weights/best.pt imgsz=640 format=onnx opset=12
cpp推理代码
cpp
/*
yolov8目标检测推理
*/
#include<opencv.hpp>
#include<iostream>
#include<fstream>
#include<filesystem>
#include<random>
cv::Mat modify_image_size(const cv::Mat& img);
int main()
{
namespace fs = std::filesystem;
const char* onnx_file{ "./best.onnx" };
constexpr int input_size[2]{ 640, 640 };
double confidence_threshold = 0.5;
double iou_threshold = 0.7;
constexpr bool cuda_enabled{ false };
std::vector<std::string> classesNames{ "back" };
const std::string testPath("./027.png");
// 分离出文件名
std::string filename;
if (std::filesystem::exists(std::filesystem::path(testPath)) == false)
{
std::cout << testPath << " is not exists." << std::endl;
return -1;
}
else
{
filename = std::filesystem::path(testPath).filename().string();
std::cout << "filename = " << filename << std::endl;
}
const std::string result_dir{ "./predictResult" };
auto net = cv::dnn::readNetFromONNX(onnx_file);
if (net.empty())
{
std::cerr << "Error: there are no layers in the network: " << onnx_file << std::endl;
return -1;
}
if (cuda_enabled) {
net.setPreferableBackend(cv::dnn::DNN_BACKEND_CUDA);
net.setPreferableTarget(cv::dnn::DNN_TARGET_CUDA);
}
else {
net.setPreferableBackend(cv::dnn::DNN_BACKEND_OPENCV);
net.setPreferableTarget(cv::dnn::DNN_TARGET_CPU);
}
std::cout << "read model complete." << std::endl;
if (!fs::exists(result_dir))
{
fs::create_directories(result_dir);
}
#pragma region 预测
cv::Mat frame = cv::imread(testPath, cv::IMREAD_COLOR);
if (frame.empty())
{
std::cerr << "Warning: unable to load image: " << testPath << std::endl;
return -1;
}
auto tstart = std::chrono::high_resolution_clock::now();
cv::Mat bgr = modify_image_size(frame);
std::cout << "bgr.size=" << bgr.size << std::endl;
#if 0
cv::imshow("w", bgr);
cv::waitKey();
#endif
cv::Mat blob;
cv::dnn::blobFromImage(bgr, blob, 1.0 / 255.0, cv::Size(input_size[1], input_size[0]), cv::Scalar(), true, false);
net.setInput(blob);
std::vector<cv::Mat> outputs;
net.forward(outputs, net.getUnconnectedOutLayersNames());
std::cout << "outputs.size = " << outputs.size() << std::endl;
cv::Mat result = outputs[0];
std::cout << "out0.size=" << result.size << std::endl;
#pragma endregion
cv::Mat output0 = cv::Mat(outputs[0].size[1], outputs[0].size[2], CV_32FC1, outputs[0].data).t();
std::cout << "output0.size=" << output0.size << std::endl;
#pragma region 后处理
std::vector<int> class_ids;
std::vector<float> confidences;
std::vector<cv::Rect> boxes;
float scalex = frame.cols * 1.f / input_size[1]; // note: image_preprocess function
float scaley = frame.rows * 1.f / input_size[0];
auto scale = (scalex > scaley) ? scalex : scaley;
const float* data = (float*)output0.data;
for (auto i = 0; i < output0.rows; ++i)
{
// 第5位是概率
cv::Mat scores(1, classesNames.size(), CV_32FC1, (float*)data + 4);
cv::Point class_id;
double max_class_score;
//std::cout << scores << std::endl;
cv::minMaxLoc(scores, 0, &max_class_score, 0, &class_id);
//std::cout << max_class_score << ", " << class_id << std::endl;
if (max_class_score > confidence_threshold) {
confidences.emplace_back(max_class_score);
class_ids.emplace_back(class_id.x);
float x = data[0];
float y = data[1];
float w = data[2];
float h = data[3];
int left = std::max(0, std::min(int((x - 0.5 * w) * scale), frame.cols));
int top = std::max(0, std::min(int((y - 0.5 * h) * scale), frame.rows));
int width = std::max(0, std::min(int(w * scale), frame.cols - left));
int height = std::max(0, std::min(int(h * scale), frame.rows - top));
boxes.emplace_back(cv::Rect(left, top, width, height));
}
data += output0.cols;
}
std::vector<int> nms_result;
cv::dnn::NMSBoxes(boxes, confidences, confidence_threshold, iou_threshold, nms_result);
std::cout << nms_result.size() << std::endl;
#pragma endregion
std::vector<int> ids;
std::vector<float> confs;
std::vector<cv::Rect> rects;
for (size_t i = 0; i < nms_result.size(); ++i)
{
auto index = nms_result[i];
ids.emplace_back(class_ids[index]);
confs.emplace_back(confidences[index]);
boxes[index] = boxes[index] & cv::Rect(0, 0, frame.cols, frame.rows);
rects.emplace_back(boxes[index]);
}
#pragma region 画图
std::random_device rd;
std::mt19937 gen(rd());
std::uniform_int_distribution<int> dis(100, 255);
std::vector<cv::Scalar> colors;
for (auto i = 0; i < classesNames.size(); ++i)
{
colors.emplace_back(cv::Scalar(dis(gen), dis(gen), dis(gen)));
}
for (auto i = 0; i < ids.size(); ++i)
{
cv::rectangle(frame, boxes[i], colors[ids[i]], 2);
//cv::Rect rect = boxes[i]; // xywh
std::string class_string = classesNames[ids[i]] + ' ' + std::to_string(confidences[i]).substr(0, 4);
cv::Size text_size = cv::getTextSize(class_string, cv::FONT_HERSHEY_DUPLEX, 1, 2, 0);
cv::Rect text_box(boxes[i].x, boxes[i].y - 40, text_size.width + 10, text_size.height + 20);
cv::rectangle(frame, text_box, colors[ids[i]], cv::FILLED);
cv::putText(frame, class_string, cv::Point(boxes[i].x + 5, boxes[i].y - 10), cv::FONT_HERSHEY_DUPLEX, 1, cv::Scalar(0, 0, 0), 2, 0);
}
#if 1
cv::imshow("Inference", frame);
cv::waitKey(-1);
#endif
#pragma endregion
return 0;
}
cv::Mat modify_image_size(const cv::Mat& img)
{
auto max = std::max(img.rows, img.cols);
cv::Mat ret = cv::Mat::zeros(max, max, CV_8UC3);
img.copyTo(ret(cv::Rect(0, 0, img.cols, img.rows)));
return ret;
}