60、在Visual Studio 2019 环境下，使用C#调用C++生成的dll实现yolov5的图片检测

基本思想：写了一个简单的c#调用c++的dll库图形化界面程序，完成yolov5检测图片的分类

一、创建一个c++工程，详细的构建和配置环境就不详细累述了，贴代码吧，导入opencv和ncnn库即可，因为需要考虑使用C#调用，所以改的代码尽量迎合C#调用的风格

main.cpp

#include "connect.h"
 
int main(int argc, char** argv)
{
     

   
    cv::Mat image = cv::imread("F:\\sxj\\predictions.jpg");
    unsigned char* src = image.data;
    cv::Mat result = cv::Mat(image.rows, image.cols, CV_8UC3, src);
    unsigned char* dest = result.data;
    const char* model_param = "F:\\sxj\\20211201\\yolov5s_6.0.param";
    const char* model_bin = "F:\\sxj\\20211201\\yolov5s_6.0.bin";
    ConnectCppWrapper::init_model(model_param, model_bin);
    ConnectCppWrapper::detect_image(src, dest, image.rows, image.cols);
     cv::imshow("demo", result);
     cv::waitKey(0);
    

    return 0;
}

connect.h

#pragma once

#include "yolov5.h"

namespace  ConnectCppWrapper
{
    extern "C" __declspec(dllexport) int __stdcall init_model(const char* model_param, const char* bin_param);
    extern "C" __declspec(dllexport) int __stdcall detect_image(unsigned char* ImageBuffer, unsigned char* ImageResult, int imageWidth, int imageHeight);
     
}

connect.cpp

#include "connect.h"

namespace ConnectCppWrapper
{
    Yolov5* yolov5Item = new Yolov5();

    int __stdcall init_model(const char* model_param, const char* bin_param)
    {
        return yolov5Item->init_model(model_param, bin_param);
    }

    int __stdcall detect_image(unsigned char* ImageBuffer, unsigned char* ImageResult, int imageWidth, int imageHeight)
    {
        cv::Mat result;
        cv::Mat image = cv::Mat(imageHeight, imageWidth, CV_8UC3, ImageBuffer);
        yolov5Item->detect_yolov5(image);
        int length = (int)(result.total() * result.elemSize());
        unsigned char* buffer = new unsigned char[length];
        memcpy(ImageResult, result.data, length * sizeof(unsigned char));
        return 0;
    }
}

yolov5.h  这部分代码和模型来自ncnn的example

#pragma once

#include "layer.h"
#include "net.h"

#if defined(USE_NCNN_SIMPLEOCV)
#include "simpleocv.h"
#else
#include 
#include 
#include 
#endif
#include 
#include 
#include 

#define YOLOV5_V60 1 //YOLOv5 v6.0
using namespace std;
using namespace ncnn;
struct Object
{
	cv::Rect_ rect;
	int label;
	float prob;
};
class Yolov5 {
public:
	Yolov5();
	~Yolov5();
private:
	float  intersection_area(const Object& a, const Object& b);
    void qsort_descent_inplace(std::vector