虹軟人臉識別SDK在網絡攝像頭中的實際應用

時間 2019-11-06

標籤識別 sdk 網絡攝像頭中實際應用欄目系統網絡简体版

原文原文鏈接

目前在人臉識別領域中，網絡攝像頭的使用很廣泛，但接入網絡攝像頭和人臉識別SDK有必定門檻，在此文章中有介紹過虹軟人臉識別SDK的接入流程，本文着重介紹網絡攝像頭獲取視頻流並處理的流程(紅色框內)，如下內容僅供參考。html

門禁系統.png

市面上目前有不少款網絡攝像頭，以海康攝像頭爲例。海康SDK包含不少接口，接入有必定難度，這裏只介紹獲取視頻幀相關的接口。windows

1.海康SDK接入基本流程

a.初始化並登陸驗證

NET_DVR_Init();
        NET_DVR_DEVICEINFO_V30 struDeviceInfo = { 0 };
        long lUserID = NET_DVR_Login_V30(m_cameraIp, m_cameraPort,
            m_cameraUser, m_cameraPwd, &struDeviceInfo);
        if (lUserID < 0)
        {
            NET_DVR_Cleanup();
            return false;
        }

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b.建立線程並註冊回調函數

thread videoThread(&HCNetCamera::getCameraPreview, this);
        videoThread.detach();
        
        bool HCNetCamera::getCameraPreview()
        {
            NET_DVR_CLIENTINFO ClientInfo;
            ClientInfo.lChannel = 1; //Channel number 設備通道號
            ClientInfo.hPlayWnd = NULL;  //窗口爲空，設備SDK不解碼只取流
            ClientInfo.lLinkMode = 0;    //Main Stream
            ClientInfo.sMultiCastIP = NULL;
            //預覽取流 
            g_realHandle = NET_DVR_RealPlay_V30(g_cameraUserId, &ClientInfo, fRealDataCallBack, NULL, TRUE);
            if (g_realHandle < 0)
            {
                qDebug() << "NET_DVR_RealPlay_V30 failed! Error number: " << NET_DVR_GetLastError();
                return false;
            }
            return true;
        }   
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c.使用回調接口，獲取實時的視頻幀數據

void CALLBACK fRealDataCallBack(LONG lRealHandle, DWORD dwDataType, BYTE *pBuffer, DWORD dwBufSize, void *pUser)
        {
            UNREFERENCED_PARAMETER(lRealHandle);
            UNREFERENCED_PARAMETER(pUser);

            DWORD dRet = 0;
            BOOL inData = FALSE;

            switch (dwDataType)
            {
            case NET_DVR_SYSHEAD:
                if (g_cameraPort >= 0)
                {
                    break; //同一路碼流不須要屢次調用開流接口
                }
                if (!PlayM4_GetPort(&g_cameraPort))
                {
                    break;
                }
                if (!PlayM4_OpenStream(g_cameraPort, pBuffer, dwBufSize, 1024 * 1024))
                {
                    dRet = PlayM4_GetLastError(g_cameraPort);
                    break;
                }
                //設置解碼回調函數 
                if (!PlayM4_SetDecCallBack(g_cameraPort, DecCBFun))
                {
                    dRet = PlayM4_GetLastError(g_cameraPort);
                    break;
                }
                //打開視頻解碼
                if (!PlayM4_Play(g_cameraPort, NULL))
                {
                    dRet = PlayM4_GetLastError(g_cameraPort);
                    break;
                }
                dRet = PlayM4_GetLastError(g_cameraPort);
                break;

            case NET_DVR_STREAMDATA:       //視頻流數據
            default:
                inData = PlayM4_InputData(g_cameraPort, pBuffer, dwBufSize);
                while (!inData)
                {
                    Sleep(10);
                    inData = PlayM4_InputData(g_cameraPort, pBuffer, dwBufSize);
                    dRet = PlayM4_GetLastError(g_cameraPort);
                    OutputDebugString(L"PlayM4_InputData failed \n");
                }
                break;
            }
        }
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//解碼回調 視頻爲YUV數據(YV12)
        void CALLBACK DecCBFun(long port, char * pBuf, long nSize, FRAME_INFO * pFrameInfo, long nReserved1, long nReserved2) {
            UNREFERENCED_PARAMETER(nReserved1);
            UNREFERENCED_PARAMETER(nReserved2);
            UNREFERENCED_PARAMETER(nSize);
            UNREFERENCED_PARAMETER(port);

            //圖像格式轉換 
            if (pFrameInfo->nType == T_YV12)
            {
                {
                    lock_guard<mutex> locker(g_CameraMutex);

                    Utils_ns::ImageUtils_ns::YV12ToBGR24_FFMPEG((unsigned char*)pBuf, (unsigned char*)g_curRGBImage->imageData,
                        pFrameInfo->nWidth, pFrameInfo->nHeight);//獲得所有RGB圖像 
                }
            }
        }
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d.應用層獲取視頻幀，這裏爲了簡化操做，只獲取了當前幀；你們也可使用線程安全隊列來處理

int HCNetCamera::getFrame(Mat& image)
        {
            lock_guard<mutex> locker(g_CameraMutex);
            if (g_curRGBImage && g_curRGBImage->imageData)
            {
                image = g_curRGBImage;
                return 0;
            }
            return -1;
        }
        
        //如下是線程函數的一部分，主要是取幀，而後進行人臉檢測
        {
            lock_guard<std::mutex> locker(g_CameraMutex);
            int ret = m_camera->getFrame(curFrame);
            if (ret == -1)
            {
                continue;
            }
        }
        
        ftProcessor->faceDetect(curFrame);
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2.基本圖像格式轉換

目前虹軟SDK支持如下幾種圖像數據格式：安全

虹軟SDK說明文檔.png

在實際開發過程當中通常使用opencv，opencv默認的圖像數據格式是BGR24，而我使用的海康攝像頭視頻編碼格式是H264，視頻幀數據格式是YV12，所以須要將YV12轉換爲BGR24 ，同時也會說明下怎麼轉換爲虹軟SDK支持的其它格式，主要參考了[2]，如下的代碼僅供參考。性能優化

a.YV12 To BGR24

void yv12ToBGR24(unsigned char* yv12, unsigned char* bgr24, int width, int height) {
    unsigned char* y_yv12 = yv12;
    unsigned char* v_yv12 = yv12 + width*height;
    unsigned char* u_yv12 = yv12 + width*height + width*height / 4;

    unsigned char* b = bgr24;
    unsigned char* g = bgr24 + 1;
    unsigned char* r = bgr24 + 2;

    int yIndex, uIndex, vIndex;
    for (int i = 0; i < height; ++i)
    {
        for (int j = 0; j < width; ++j)
        {
            yIndex = i * width + j;
            vIndex = (i / 2) * (width / 2) + (j / 2);
            uIndex = vIndex;

            *b = (unsigned char)(y_yv12[yIndex] + 1.732446 * (u_yv12[vIndex] - 128));
            *g = (unsigned char)(y_yv12[yIndex] - 0.698001 * (u_yv12[uIndex] - 128) - 0.703125 * (v_yv12[vIndex] - 128));
            *r = (unsigned char)(y_yv12[yIndex] + 1.370705 * (v_yv12[uIndex] - 128));

            b += 3;
            g += 3;
            r += 3;
        }
    }
}

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b.YV12 To I420

void yv12ToI420(unsigned char* yv12, unsigned char* i420, int width, int height) {
    unsigned char* y_yv12 = yv12;
    unsigned char* v_yv12 = yv12 + width*height;
    unsigned char* u_yv12 = yv12 + width*height + width*height / 4;

    unsigned char* y_i420 = i420;
    unsigned char* u_i420 = i420 + width*height;
    unsigned char* v_i420 = i420 + width*height + width*height / 4;

    memcpy(i420, yv12, width*height);
    memcpy(v_i420, v_yv12, width*height / 4);
    memcpy(u_i420, u_yv12, width*height / 4);

}
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c.YV12 To NV21

void yv12ToNV21(unsigned char* yv12, unsigned char* nv21, int width, int height) {
    unsigned char* y_yv12 = yv12;
    unsigned char* v_yv12 = yv12 + width*height;
    unsigned char* u_yv12 = yv12 + width*height + width*height / 4;

    unsigned char* y_nv21 = nv21;
    unsigned char* v_nv21 = nv21 + width*height;
    unsigned char* u_nv21 = nv21 + width*height + 1;

    memcpy(nv21, yv12, width*height);

    for (int i = 0; i < width*height / 4; ++i)
    {
        *v_nv21 = *v_yv12;
        *u_nv21 = *u_yv12;

        v_nv21 += 2;
        u_nv21 += 2;

        ++v_yv12;
        ++u_yv12;
    }
}

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d.YV12 To NV12

void yv12ToNV12(unsigned char* yv12, unsigned char* nv12, int width, int height) {
    unsigned char* y_yv12 = yv12;
    unsigned char* v_yv12 = yv12 + width*height;
    unsigned char* u_yv12 = yv12 + width*height + width*height / 4;

    unsigned char* y_nv12 = nv12;
    unsigned char* u_nv12 = nv12 + width*height;
    unsigned char* v_nv12 = nv12 + width*height + 1;

    memcpy(nv12, yv12, width*height);

    for (int i = 0; i < width*height / 4; ++i)
    {
        *v_nv12 = *v_yv12;
        *u_nv12 = *u_yv12;

        v_nv12 += 2;
        u_nv12 += 2;

        ++v_yv12;
        ++u_yv12;
    }
}
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e.YV12 To YUYV

void yv12ToYUYV(unsigned char* yv12, unsigned char* yuyv, int width, int height) {
    unsigned char* y_yv12 = yv12;
    unsigned char* v_yv12 = yv12 + width*height;
    unsigned char* u_yv12 = yv12 + width*height + width*height / 4;

    unsigned char* y_yuyv = yuyv;
    unsigned char* u_yuyv = yuyv + 1;
    unsigned char* v_yuyv = yuyv + 3;

    for (int i = 0; i < width; ++i)
    {
        for (int j = 0; j < height; ++j)
        {
            *y_yuyv = *y_yv12;

            y_yuyv += 2;
            ++y_yv12;
        }
    }

    for (int j = 0; j < height / 2; ++j)
    {
        for (int i = 0; i < width / 2; ++i)
        {
            *u_yuyv = *u_yv12;
            *(u_yuyv + width * 2) = *u_yv12;
            u_yuyv += 4;
            ++u_yv12;

            *v_yuyv = *v_yv12;
            *(v_yuyv + width * 2) = *v_yv12;
            v_yuyv += 4;
            ++v_yv12;
        }
        u_yuyv += width * 2;
        v_yuyv += width * 2;
    }
} 複製代碼