firefly-rk3399 开发记录8-NCNN检测

1.NCNN编译

NCNN就不描述了，这里采用NCNN最新的发布版ncnn-20200727，buildroot中的mk文件如下

NCNN_VERSION = 20200727
NCNN_SITE = $(call github,Tencent,ncnn,$(NCNN_VERSION))
NCNN_INSTALL_STAGING = YES
NCNN_LICENSE = BSD-2-Clause or GPL-2.0+
NCNN_LICENSE_FILES = LICENSE
NCNN_CONF_OPTS += -DNCNN_ARM82=OFF

$(eval $(cmake-package))

NCNN_ARM82这个要稍微注意下，这里用不到的，但是编译的时候再cmakelists中，检测到arm之后就默认开启了，这里会编译出错.

2.retinaface

这里就直接采用NCNN历程中的retinaface.cpp了，基本都可以直接使用，模型文件在另外的仓库上https://github.com/nihui/ncnn-assets/tree/master/models

QSmartNcnn::QSmartNcnn()
{
    retinaface.opt.use_vulkan_compute = true;
    retinaface.opt.num_threads        = 6;
    // model is converted from
    // https://github.com/deepinsight/insightface/tree/master/RetinaFace#retinaface-pretrained-models
    // https://github.com/deepinsight/insightface/issues/669
    // the ncnn model https://github.com/nihui/ncnn-assets/tree/master/models
    //     retinaface.load_param("retinaface-R50.param");
    //     retinaface.load_model("retinaface-R50.bin");
    int ret = retinaface.load_param("/root/ncnn-assets/models/mnet.25-opt.param");
    qDebug() << "load param " << ret;
    ret = retinaface.load_model("/root/ncnn-assets/models/mnet.25-opt.bin");
    qDebug() << "load bin " << ret;
}

QSmartNcnn::~QSmartNcnn()
{

}

int QSmartNcnn::detect_face(const cv::Mat &image, QVector &rect)
{
    std::vector faceobjects;
    qDebug() << "need do detect";
    if(detect_retinaface(image, faceobjects) < 0)
        return -1;
    qDebug() << faceobjects.size();
    for(auto &item : faceobjects)
    {
        rect.append(QRect(item.rect.x,item.rect.y,
                          item.rect.width,item.rect.height));
    }
    return rect.size();
}

int QSmartNcnn::extract_feature(const cv::Mat &image, const QRect &rect, QByteArray &feature)
{

}




void QSmartNcnn::qsort_descent_inplace(std::vector& faceobjects, int left, int right)
{
    int i = left;
    int j = right;
    float p = faceobjects[(left + right) / 2].prob;

    while (i <= j)
    {
        while (faceobjects[i].prob > p)
            i++;

        while (faceobjects[j].prob < p)
            j--;

        if (i <= j)
        {
            // swap
            std::swap(faceobjects[i], faceobjects[j]);

            i++;
            j--;
        }
    }

    #pragma omp parallel sections
    {
        #pragma omp section
        {
            if (left < j) qsort_descent_inplace(faceobjects, left, j);
        }
        #pragma omp section
        {
            if (i < right) qsort_descent_inplace(faceobjects, i, right);
        }
    }
}

void QSmartNcnn::qsort_descent_inplace(std::vector& faceobjects)
{
    if (faceobjects.empty())
        return;

    qsort_descent_inplace(faceobjects, 0, faceobjects.size() - 1);
}

void QSmartNcnn::nms_sorted_bboxes(const std::vector& faceobjects, std::vector& picked, float nms_threshold)
{
    picked.clear();

    const int n = faceobjects.size();

    std::vector areas(n);
    for (int i = 0; i < n; i++)
    {
        areas[i] = faceobjects[i].rect.area();
    }

    for (int i = 0; i < n; i++)
    {
        const FaceObject& a = faceobjects[i];

        int keep = 1;
        for (int j = 0; j < (int)picked.size(); j++)
        {
            const FaceObject& b = faceobjects[picked[j]];

            // intersection over union
            float inter_area = intersection_area(a, b);
            float union_area = areas[i] + areas[picked[j]] - inter_area;
            //             float IoU = inter_area / union_area
            if (inter_area / union_area > nms_threshold)
                keep = 0;
        }

        if (keep)
            picked.push_back(i);
    }
}

// copy from src/layer/proposal.cpp
ncnn::Mat QSmartNcnn::generate_anchors(int base_size, const ncnn::Mat& ratios, const ncnn::Mat& scales)
{
    int num_ratio = ratios.w;
    int num_scale = scales.w;

    ncnn::Mat anchors;
    anchors.create(4, num_ratio * num_scale);

    const float cx = base_size * 0.5f;
    const float cy = base_size * 0.5f;

    for (int i = 0; i < num_ratio; i++)
    {
        float ar = ratios[i];

        int r_w = round(base_size / sqrt(ar));
        int r_h = round(r_w * ar); //round(base_size * sqrt(ar));

        for (int j = 0; j < num_scale; j++)
        {
            float scale = scales[j];

            float rs_w = r_w * scale;
            float rs_h = r_h * scale;

            float* anchor = anchors.row(i * num_scale + j);

            anchor[0] = cx - rs_w * 0.5f;
            anchor[1] = cy - rs_h * 0.5f;
            anchor[2] = cx + rs_w * 0.5f;
            anchor[3] = cy + rs_h * 0.5f;
        }
    }

    return anchors;
}

void QSmartNcnn::generate_proposals(const ncnn::Mat& anchors, int feat_stride, const ncnn::Mat& score_blob, const ncnn::Mat& bbox_blob, const ncnn::Mat& landmark_blob, float prob_threshold, std::vector& faceobjects)
{
    int w = score_blob.w;
    int h = score_blob.h;

    // generate face proposal from bbox deltas and shifted anchors
    const int num_anchors = anchors.h;

    for (int q = 0; q < num_anchors; q++)
    {
        const float* anchor = anchors.row(q);

        const ncnn::Mat score = score_blob.channel(q + num_anchors);
        const ncnn::Mat bbox = bbox_blob.channel_range(q * 4, 4);
        const ncnn::Mat landmark = landmark_blob.channel_range(q * 10, 10);

        // shifted anchor
        float anchor_y = anchor[1];

        float anchor_w = anchor[2] - anchor[0];
        float anchor_h = anchor[3] - anchor[1];

        for (int i = 0; i < h; i++)
        {
            float anchor_x = anchor[0];

            for (int j = 0; j < w; j++)
            {
                int index = i * w + j;

                float prob = score[index];

                if (prob >= prob_threshold)
                {
                    // apply center size
                    float dx = bbox.channel(0)[index];
                    float dy = bbox.channel(1)[index];
                    float dw = bbox.channel(2)[index];
                    float dh = bbox.channel(3)[index];

                    float cx = anchor_x + anchor_w * 0.5f;
                    float cy = anchor_y + anchor_h * 0.5f;

                    float pb_cx = cx + anchor_w * dx;
                    float pb_cy = cy + anchor_h * dy;

                    float pb_w = anchor_w * exp(dw);
                    float pb_h = anchor_h * exp(dh);

                    float x0 = pb_cx - pb_w * 0.5f;
                    float y0 = pb_cy - pb_h * 0.5f;
                    float x1 = pb_cx + pb_w * 0.5f;
                    float y1 = pb_cy + pb_h * 0.5f;

                    FaceObject obj;
                    obj.rect.x = x0;
                    obj.rect.y = y0;
                    obj.rect.width = x1 - x0 + 1;
                    obj.rect.height = y1 - y0 + 1;
                    obj.landmark[0].x = cx + (anchor_w + 1) * landmark.channel(0)[index];
                    obj.landmark[0].y = cy + (anchor_h + 1) * landmark.channel(1)[index];
                    obj.landmark[1].x = cx + (anchor_w + 1) * landmark.channel(2)[index];
                    obj.landmark[1].y = cy + (anchor_h + 1) * landmark.channel(3)[index];
                    obj.landmark[2].x = cx + (anchor_w + 1) * landmark.channel(4)[index];
                    obj.landmark[2].y = cy + (anchor_h + 1) * landmark.channel(5)[index];
                    obj.landmark[3].x = cx + (anchor_w + 1) * landmark.channel(6)[index];
                    obj.landmark[3].y = cy + (anchor_h + 1) * landmark.channel(7)[index];
                    obj.landmark[4].x = cx + (anchor_w + 1) * landmark.channel(8)[index];
                    obj.landmark[4].y = cy + (anchor_h + 1) * landmark.channel(9)[index];
                    obj.prob = prob;

                    faceobjects.push_back(obj);
                }

                anchor_x += feat_stride;
            }

            anchor_y += feat_stride;
        }
    }
}

int QSmartNcnn::detect_retinaface(const cv::Mat& bgr, std::vector& faceobjects)
{


    const float prob_threshold = 0.8f;
    const float nms_threshold = 0.4f;

    int img_w = bgr.cols;
    int img_h = bgr.rows;

   
    ncnn::Mat in = ncnn::Mat::from_pixels(bgr.data, ncnn::Mat::PIXEL_BGR2RGB, img_w, img_h);
    
    ncnn::Extractor ex = retinaface.create_extractor();
    ex.set_num_threads(6);

    ex.input("data", in);

    std::vector faceproposals;

    // stride 32
    {
        ncnn::Mat score_blob, bbox_blob, landmark_blob;
        ex.extract("face_rpn_cls_prob_reshape_stride32", score_blob);
        ex.extract("face_rpn_bbox_pred_stride32", bbox_blob);
        ex.extract("face_rpn_landmark_pred_stride32", landmark_blob);

        const int base_size = 16;
        const int feat_stride = 32;
        ncnn::Mat ratios(1);
        ratios[0] = 1.f;
        ncnn::Mat scales(2);
        scales[0] = 32.f;
        scales[1] = 16.f;
        ncnn::Mat anchors = generate_anchors(base_size, ratios, scales);

        std::vector faceobjects32;
        generate_proposals(anchors, feat_stride, score_blob, bbox_blob, landmark_blob, prob_threshold, faceobjects32);

        faceproposals.insert(faceproposals.end(), faceobjects32.begin(), faceobjects32.end());
    }

    // stride 16
    {
        ncnn::Mat score_blob, bbox_blob, landmark_blob;
        ex.extract("face_rpn_cls_prob_reshape_stride16", score_blob);
        ex.extract("face_rpn_bbox_pred_stride16", bbox_blob);
        ex.extract("face_rpn_landmark_pred_stride16", landmark_blob);

        const int base_size = 16;
        const int feat_stride = 16;
        ncnn::Mat ratios(1);
        ratios[0] = 1.f;
        ncnn::Mat scales(2);
        scales[0] = 8.f;
        scales[1] = 4.f;
        ncnn::Mat anchors = generate_anchors(base_size, ratios, scales);

        std::vector faceobjects16;
        generate_proposals(anchors, feat_stride, score_blob, bbox_blob, landmark_blob, prob_threshold, faceobjects16);

        faceproposals.insert(faceproposals.end(), faceobjects16.begin(), faceobjects16.end());
    }

    // stride 8
    {
        ncnn::Mat score_blob, bbox_blob, landmark_blob;
        ex.extract("face_rpn_cls_prob_reshape_stride8", score_blob);
        ex.extract("face_rpn_bbox_pred_stride8", bbox_blob);
        ex.extract("face_rpn_landmark_pred_stride8", landmark_blob);

        const int base_size = 16;
        const int feat_stride = 8;
        ncnn::Mat ratios(1);
        ratios[0] = 1.f;
        ncnn::Mat scales(2);
        scales[0] = 2.f;
        scales[1] = 1.f;
        ncnn::Mat anchors = generate_anchors(base_size, ratios, scales);

        std::vector faceobjects8;
        generate_proposals(anchors, feat_stride, score_blob, bbox_blob, landmark_blob, prob_threshold, faceobjects8);

        faceproposals.insert(faceproposals.end(), faceobjects8.begin(), faceobjects8.end());
    }

    // sort all proposals by score from highest to lowest
    qsort_descent_inplace(faceproposals);

    // apply nms with nms_threshold
    std::vector picked;
    nms_sorted_bboxes(faceproposals, picked, nms_threshold);

    int face_count = picked.size();

    faceobjects.resize(face_count);
    for (int i = 0; i < face_count; i++)
    {
        faceobjects[i] = faceproposals[picked[i]];

        // clip to image size
        float x0 = faceobjects[i].rect.x;
        float y0 = faceobjects[i].rect.y;
        float x1 = x0 + faceobjects[i].rect.width;
        float y1 = y0 + faceobjects[i].rect.height;

        x0 = std::max(std::min(x0, (float)img_w - 1), 0.f);
        y0 = std::max(std::min(y0, (float)img_h - 1), 0.f);
        x1 = std::max(std::min(x1, (float)img_w - 1), 0.f);
        y1 = std::max(std::min(y1, (float)img_h - 1), 0.f);

        faceobjects[i].rect.x = x0;
        faceobjects[i].rect.y = y0;
        faceobjects[i].rect.width = x1 - x0;
        faceobjects[i].rect.height = y1 - y0;
    }

    return 0;
}

测试效果很慢，就算开了多线程也是，在720P的输入下，基本职能达到1.5FPS，每次检测都是600MS。这里目前只做了人脸检测，替换之前opencv的级联器。一般来说，这种还要做人脸特征值提取操作，用于和本地对比，做识别操作。

3.输入

输入这里就把前面method哪里修改一下。

cvtColor(img, mat,  cv::COLOR_YUV420p2BGR);
    
//    cascade.detectMultiScale( mat, faces,
//        1.1, 2, 0
//        //|CASCADE_FIND_BIGGEST_OBJECT
//        //|CASCADE_DO_ROUGH_SEARCH
//        |CASCADE_SCALE_IMAGE,
//        Size(30, 30) );
    method->detect_face(mat,rects);