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基于OpenCV与深度神经网络——实现证件识别扫描并1比1还原证件到A4纸上

知来者逆 2023-06-06 04:00:02
简介基于OpenCV与深度神经网络——实现证件识别扫描并1比1还原证件到A4纸上

前言

1.用拍照的证件照片正反面,实现用证件去复印到A4纸上的效果,还有证件的格式化识别。

 图1:把拍照的证件1比1还原证件到A4纸上

 图2:证件OCR格式化识别

2.使用Yolo做目标识别,Enet做边缘检测,Paddle OCR做文字识别,OpenCV做处理图像,当前的开发环境为开发环境是win10,显卡RTX3080,cuda11.2,cudnn8.1,OpenCV4.5,ncnn,IDE 是Vs2019,界面是Qt 写的。

一、目标识别

1.要识别的证卡有身份证正反面、银行卡正反面、社保卡正反面、港澳通行证正反面、护照、驾驶证、居住证等,这些数据都涉及到个人数据安全,所以很难找到可以使用的数据集,但训练模型又不能没有数据集,解决的办法是从网上获取一些公开的证件样本数据集,然后使用生成对抗(GAN)生成可以训练的数据集。

2.使用yolov5训练目标识别模型,关于yolov5的如果训练模型,可以看我之前的博客《深度学习目标检测(YoloV5)项目——完整记录从数据处理开始到项目落地部署》https://blog.csdn.net/matt45m/article/details/118598706?spm=1001.2014.3001.5501

3.身份证的正面和社保卡、居住证特征很像,目标识别时往往会错检,为了更好的区分,在标注的时候,把头像,国徽这些统一的特征也标注出来,做目标识别时,再做逻辑判断。比如当前识别到身份证的背面时,要去判断有没有同时识别到国徽,国徽是否在背面识别框内。

static void mergeFrameRect(std::vector<cv::Rect> r1, std::vector<cv::Rect> r2, std::vector<cv::Rect>& r_m)
{
    for (int i = 0; i < r1.size(); i++)
    {
        for (int j = 0; j < r2.size(); j++)
        {
            if (computRectJoinUnion(r1.at(i), r2.at(j)))
            {
                r_m.push_back(r1.at(i));
            }
        }
    }
}

int filterTarget(std::vector<ObjectFlag>& objects, std::map<int, std::vector<cv::Rect>>& rect_frame)
{
    std::vector<cv::Rect> IDF_Frame, IDB_Frame, SSCB_Frame, SSCF_Frame, BCF_Frame, BCB_Frame, CNPF_Frame, RPF_Frame, DLF_Frame, OWPF_Frame, OWPB_Frame;

    std::vector<cv::Rect> AC, BD, CNPF, DLF, OWPB, OWPF, RPF, SSCB, SSCF, UPAY, BCF, BCB, IDF, IDB, CNM, PTT;
    //"AC标识", "书本", "护照", "驾驶证", "港澳通行证背面", "港澳通行证正面", "居住证", 
    //"社保卡背面", "社保卡正面", "银联标示", "银行卡正面", "银行卡背面", "身体证正面", "身体证背面", "国徽", "头像"
    ///目标识别返回标志位///
    //AC芯片			0		AC
    //书本				1		BD
    //护照正面			2		CNPF
    //驾驶证			3       DLF
    //港澳通行证背面    4       OWPB
    //港澳通行证正面	5	    OWPF
    //居住证			6		RPF
    //社保卡反面		7		SSCB
    //社保卡正面		8		SSCF
    //银联标志			9		UPAY
    //银行卡正面		10		BCF
    //银行卡反面		11		BCB
    //身份证正面		12		IDF
    //身份证反面		13		IDB
    //国徽				14		CNM
    //头像				15		PTT
    for (int i = 0; i < objects.size(); i++)
    {
        const ObjectFlag obj = objects[i];
        if (obj.prob >= 0.4)
        {
            switch (obj.label)
            {
            case 0:
                AC.push_back(obj.rect);
                break;
            case 1:
                BD.push_back(obj.rect);
                break;
            case 2:
                CNPF.push_back(obj.rect);
                break;
            case 3:
                DLF.push_back(obj.rect);
                break;
            case 4:
                OWPB.push_back(obj.rect);
                break;
            case 5:
                OWPF.push_back(obj.rect);
                break;
            case 6:
                RPF.push_back(obj.rect);
                break;
            case 7:
                SSCB.push_back(obj.rect);
                break;
            case 8:
                SSCF.push_back(obj.rect);
                break;
            case 9:
                UPAY.push_back(obj.rect);
                break;
            case 10:
                BCF.push_back(obj.rect);
                break;
            case 11:
                BCB.push_back(obj.rect);
                break;
            case 12:
                IDF.push_back(obj.rect);
                break;
            case 13:
                IDB.push_back(obj.rect);
                break;
            case 14:
                CNM.push_back(obj.rect);
                break;
            case 15:
                PTT.push_back(obj.rect);
                break;
            default:
                break;
            }
        }
    }
    if (BD.size() > 0)//书本
    {
        rect_frame.insert(std::pair<int, std::vector<cv::Rect>>(10, BD));
    }
    if (IDF.size() > 0 && PTT.size() > 0)//身份证正面
    {
        mergeFrameRect(IDF, PTT, IDF_Frame);
        if (IDF_Frame.size() > 0)
        {
            rect_frame.insert(std::pair<int, std::vector<cv::Rect>>(20, IDF_Frame));
        }
        else
        {
            return -2;
        }
    }
    if (IDB.size() > 0 && CNM.size() > 0)//身份证反面
    {
        mergeFrameRect(IDB, CNM, IDB_Frame);
        if (IDB_Frame.size() > 0)
        {
            rect_frame.insert(std::pair<int, std::vector<cv::Rect>>(21, IDB_Frame));
        }
        else
        {
            return -2;
        }
    }
    if (SSCF.size() > 0 && AC.size() > 0 && PTT.size() > 0) //社保卡正面
    {
        std::vector<cv::Rect> RECT;
        mergeFrameRect(SSCF, AC, RECT);
        if (RECT.size() > 0)
        {
            mergeFrameRect(RECT, PTT, SSCF_Frame);
        }
        if (SSCF_Frame.size() > 0)
        {
            rect_frame.insert(std::pair<int, std::vector<cv::Rect>>(30, SSCF_Frame));
        }
        else
        {
            return -2;
        }
    }
    if (SSCB.size() > 0 && CNM.size() > 0)//社保卡反面
    {
        mergeFrameRect(SSCB, CNM, SSCB_Frame);
        if (SSCB_Frame.size() > 0)
        {
            rect_frame.insert(std::pair<int, std::vector<cv::Rect>>(31, SSCB_Frame));
        }
        else
        {
            return -2;
        }
    }
    if (CNPF.size() > 0 && PTT.size() > 0)//护照正面
    {
        mergeFrameRect(CNPF, PTT, CNPF_Frame);
        rect_frame.insert(std::pair<int, std::vector<cv::Rect>>(40, CNPF_Frame));
    }
    if (BCF.size() > 0 && UPAY.size()>0)//银行卡正面
    {
        mergeFrameRect(BCF, UPAY, BCF_Frame);
        if (BCF_Frame.size() > 0)
        {
            rect_frame.insert(std::pair<int, std::vector<cv::Rect>>(50, BCF_Frame));
        }
        else
        {
            return -2;
        }
    }
    if (BCB.size() > 0 && UPAY.size()>0)//银行卡反面
    {
        mergeFrameRect(BCB, UPAY, BCB_Frame);
        if (BCB_Frame.size() > 0)
        {
            rect_frame.insert(std::pair<int, std::vector<cv::Rect>>(51, BCB_Frame));
        }
        else
        {
            return -2;
        }
    }
    if (RPF.size() > 0 && PTT.size()>0)//居住证
    {
        mergeFrameRect(RPF, PTT, RPF_Frame);
        if (RPF_Frame.size())
        {
            rect_frame.insert(std::pair<int, std::vector<cv::Rect>>(60, RPF_Frame));
        }
        else
        {
            return -2;
        }
    }
    if (OWPF.size() > 0 && PTT.size()>0)//港澳通行证正面
    {
        mergeFrameRect(OWPF, PTT, OWPF_Frame);
        if (OWPF_Frame.size())
        {
            rect_frame.insert(std::pair<int, std::vector<cv::Rect>>(70, OWPF_Frame));
        }
        else
        {
            return -2;
        }
    }
    if (OWPB.size())//港澳通行证背面
    {
        rect_frame.insert(std::pair<int, std::vector<cv::Rect>>(71, OWPB));
    }
    if (DLF.size() > 0 && PTT.size()>0)//驾驶证
    {
        mergeFrameRect(DLF, PTT, DLF_Frame);
        if (DLF_Frame.size() > 0)
        {
            rect_frame.insert(std::pair<int, std::vector<cv::Rect>>(80, DLF_Frame));
        }
        else
        {
            return -2;
        }
    }
    return 0;
}
int screeningTarget(cv::Rect& rect_out, std::map<int, std::vector<cv::Rect>>& rect_frame)
{
    std::vector<cv::Rect> IDF_Frame, IDB_Frame, SSCB_Frame, SSCF_Frame, BCF_Frame, BCB_Frame, CNPF_Frame, BD_Frame, RPF_Frame, DLF_Frame, OWPF_Frame, OWPB_Frame;
    std::vector<int> indes;
    for (auto i = rect_frame.begin(); i != rect_frame.end(); i++)
    {
        int index = i->first;

        //std::cout << index << std::endl;
        switch (index)
        {
        case 10:
            BD_Frame = i->second;
            indes.push_back(atoi((std::to_string(i->first) + std::to_string(BD_Frame.size())).c_str()));
            break;
        case 20:
            IDF_Frame = i->second;
            indes.push_back(atoi((std::to_string(i->first) + std::to_string(IDF_Frame.size())).c_str()));
            break;
        case 21:
            IDB_Frame = i->second;
            indes.push_back(atoi((std::to_string(i->first) + std::to_string(IDB_Frame.size())).c_str()));
            break;
        case 30:
            SSCF_Frame = i->second;
            indes.push_back(atoi((std::to_string(i->first) + std::to_string(SSCF_Frame.size())).c_str()));
            break;
        case 31:
            SSCB_Frame = i->second;
            indes.push_back(atoi((std::to_string(i->first) + std::to_string(SSCB_Frame.size())).c_str()));
            break;
        case 40:
            CNPF_Frame = i->second;
            indes.push_back(atoi((std::to_string(i->first) + std::to_string(CNPF_Frame.size())).c_str()));
            break;
        case 50:
            BCF_Frame = i->second;
            indes.push_back(atoi((std::to_string(i->first) + std::to_string(BCF_Frame.size())).c_str()));
            break;
        case 51:
            BCB_Frame = i->second;
            indes.push_back(atoi((std::to_string(i->first) + std::to_string(BCB_Frame.size())).c_str()));
            break;
        case 60:
            RPF_Frame = i->second;
            indes.push_back(atoi((std::to_string(i->first) + std::to_string(RPF_Frame.size())).c_str()));
            break;
        case 70:
          
            OWPF_Frame = i->second;
            indes.push_back(atoi((std::to_string(i->first) + std::to_string(OWPF_Frame.size())).c_str()));
            break;
        case 71:
            OWPB_Frame = i->second;
            indes.push_back(atoi((std::to_string(i->first) + std::to_string(OWPB_Frame.size())).c_str()));
            break;
        case 80:
            DLF_Frame = i->second;
            indes.push_back(atoi((std::to_string(i->first) + std::to_string(DLF_Frame.size())).c_str()));
            break;
        default:
            break;
        }
    }
    if (indes.size() > 0)
    {
        for (int i = 0; i < indes.size(); i++)
        {

            int index = std::stoi(std::to_string(indes.at(i)).substr(0, 2));
            switch (index)
            {
            case 10:
            {
                rect_out = BD_Frame.at(0);
                return indes.at(i);
            }
            break;
            case 20:
            {
                rect_out = IDF_Frame.at(0);
                return indes.at(i);
            }
            break;
            case 21:
            {
                rect_out = IDB_Frame.at(0);
                return indes.at(i);
            }
            break;
            case 30:
            {
                rect_out = SSCF_Frame.at(0);
                return indes.at(i);
            }
            break;
            case 31:
            {
                rect_out = SSCB_Frame.at(0);
                return indes.at(i);
            }
            break;
            case 40:
            {
                rect_out = CNPF_Frame.at(0);
                return indes.at(i);
            }
            break;
            case 50:
            {
                rect_out = BCF_Frame.at(0);
                return indes.at(i);
            }
            break;
            case 51:
            {
                rect_out = BCB_Frame.at(0);
                return indes.at(i);
            }
            break;
            case 60:
            {
                rect_out = RPF_Frame.at(0);
                return indes.at(i);
            }
            break;
            case 70:
            {
                rect_out = OWPF_Frame.at(0);
                return indes.at(i);
            }
            break;
            case 71:
            {
                rect_out = OWPB_Frame.at(0);
                return indes.at(i);
            }
            break;
            case 80:
            {
                rect_out = DLF_Frame.at(0);
                return indes.at(i);
            }
            break;
            default:
                break;
            }
        }
    }
    return 0;
}


识别效果如下:

  

二、边缘提取与校正

1.获取当前目标之后,要对当前目标进行语义分割,为了分割速度,这里先择了Enet做目标分割,关于Enet网络的训练步骤可以参考我之前的博客《轻量化实时语义分割LiteSeg——从算法原理到模型训练与部署https://blog.csdn.net/matt45m/article/details/124539667?spm=1001.2014.3001.5502》,ENet的训练框架是Pytorch,可以使用git上的这个源码进行训练:GitHub - davidtvs/PyTorch-ENet: PyTorch implementation of ENetPyTorch implementation of ENet. Contribute to davidtvs/PyTorch-ENet development by creating an account on GitHub.https://github.com/davidtvs/PyTorch-ENet 。

2.训练好模型之后,把模型量化成FP16以提升速度,用NCNN实现模型推理

/// <summary>
/// 语义分割
/// </summary>
/// <param name="ncnn_net">分割模型</param>
/// <param name="cv_src">输入图像</param>
/// <param name="cv_enet">输出分割后的图像</param>
/// <param name="threadsm">阈值</param>
/// <param name="image_size">推理尺寸大小</param>
/// <returns></returns>
static int enetSegmentation(cv::Mat& cv_src, cv::Mat& cv_enet, ncnn::Net& ncnn_net, int threadsm, int image_size)
{

    if (cv_src.empty())
    {
        return -20;
    }
    ncnn::Mat in = ncnn::Mat::from_pixels_resize(cv_src.data, ncnn::Mat::PIXEL_BGR, cv_src.cols, cv_src.rows, image_size, image_size);

    const float norm_vals[3] = { 1 / 255.f, 1 / 255.f, 1 / 255.f };
    in.substract_mean_normalize(0, norm_vals);
    ncnn::Extractor ex = ncnn_net.create_extractor();
    ex.set_num_threads(threadsm);

    ncnn::Mat out;


    ex.input("input.1", in);
    ex.extract("887", out);

    cv::Mat cv_seg = cv::Mat::zeros(cv::Size(out.w, out.h), CV_8UC1);
    for (int i = 0; i < out.h; ++i)
    {
        for (int j = 0; j < out.w; ++j)
        {
            const float* bg = out.channel(0);
            const float* fg = out.channel(1);
            if (bg[i * out.w + j] < fg[i * out.w + j])
            {
                cv_seg.data[i * out.w + j] = 255;
            }
        }
    }

    cv::resize(cv_seg, cv_enet, cv::Size(cv_src.cols, cv_src.rows), cv::INTER_LINEAR);
    return 0;
}

分割效果:

 

 3.获取目标的分割位置之后要对目标的连边缘进行提取,要进行直线检测,直线可以用传统算法,OpenCV的霍夫曼直接检测,也可以用基于深度学习的M-LSD,如果用M-LSD也可以直接省掉语义分割的这一步,直线检测效果的对比可以看我之前的博客《直线检测——对比M-LSD直线检测(基于深度学习)与霍夫曼直线检测https://blog.csdn.net/matt45m/article/details/124362068?spm=1001.2014.3001.5502》。

直线检测与拟合边缘点:

static int getCorrectionPoint(cv::Mat cv_edge, cv::Mat& cv_enet, std::vector<cv::Point>& points_out,
    double theta = 50, int threshold = 30, double minLineLength = 10)
{
    std::vector<cv::Vec4f> lines;
    HoughLinesP(cv_edge, lines, 1, CV_PI * 1 / 180, theta, threshold, minLineLength);

    if (lines.size() <= 3)
    {
        int mask = enetLinesToPoint(cv_enet, points_out);

        return std::stoi(std::to_string(42) + std::to_string(mask));
    }

    std::vector<Line> horizontals, verticals;

    linesDichotomy(lines, horizontals, verticals, cv_edge);

    if (horizontals.size() < 2 || verticals.size() < 2)
    {
        int mask = enetLinesToPoint(cv_enet, points_out);

        return std::stoi(std::to_string(43) + std::to_string(mask));
    }
    std::vector<Line> lines_out;
    screenLines(horizontals, verticals, lines_out, 40);

    if (lines_out.size() < 4)
    {
        int mask = enetLinesToPoint(cv_enet, points_out);

        return std::stoi(std::to_string(44) + std::to_string(mask));
    }

    if (decideAngle(lines_out))
    {
        int mask = enetLinesToPoint(cv_enet, points_out);

        return std::stoi(std::to_string(45) + std::to_string(mask));
    }

    std::vector<cv::Point> points;
    points.push_back(computeIntersect(lines_out.at(0), lines_out.at(2)));
    points.push_back(computeIntersect(lines_out.at(0), lines_out.at(3)));
    points.push_back(computeIntersect(lines_out.at(2), lines_out.at(1)));
    points.push_back(computeIntersect(lines_out.at(1), lines_out.at(3)));

    if (decodeArea(cv_enet, points, 4))
    {
        int mask = enetLinesToPoint(cv_enet, points_out);

        return std::stoi(std::to_string(46) + std::to_string(mask));
    }
    if (((points.at(1).x - points.at(0).x) < 60) || ((points.at(3).x - points.at(2).x) < 60) || 
        ((points.at(2).y - points.at(0).y) < 60) || ((points.at(3).y - points.at(1).y) < 60))
    {
        int mask = enetLinesToPoint(cv_enet, points_out);

        return std::stoi(std::to_string(47) + std::to_string(mask));
    }

    points_out = points;

    return 400;
}

 4.获取边缘之后,要对边缘进行校正,校正就是把边缘的四个点重新映射到平面上,为了更智能化的处理,在这里加上了文字检测与文字角度检测,为了达到,不管用户拍照的证件照不管是什么方向,最终得到的校正后图像文字都是正过来的,避免用户过多的参与操作。

int reviseImage(cv::Mat& cv_src, cv::Mat& cv_dst, ncnn::Net& db_net, 
    ncnn::Net& angle_net, std::vector<cv::Point>& in_points)
{
    int val = verify();
    if (val != 0)
    {
        return val;
    }

    if (cv_src.empty())
    {
        return -20;
    }
    cv::Mat cv_warp = cv_src.clone();
    if (in_points.size() != 4)
    {
        return -444;
    }

    cv::Point point_f, point_b;

    point_f.x = (in_points.at(0).x < in_points.at(2).x) ? in_points.at(0).x : in_points.at(2).x;
    point_f.y = (in_points.at(0).y < in_points.at(1).y) ? in_points.at(0).y : in_points.at(1).y;
    point_b.x = (in_points.at(3).x > in_points.at(1).x) ? in_points.at(3).x : in_points.at(1).x;
    point_b.y = (in_points.at(3).y > in_points.at(2).y) ? in_points.at(3).y : in_points.at(2).y;

    //2020.8.24更新了比例不对的问题,加了点到点之间的距离运算,最终取水平与垂直线最长线
    float l_1 = getDistance(in_points.at(0), in_points.at(1));
    float l_2 = getDistance(in_points.at(2), in_points.at(3));
    float l_3 = getDistance(in_points.at(1), in_points.at(3));
    float l_4 = getDistance(in_points.at(0), in_points.at(2));

    int width = l_1 >= l_2 ? l_1 : l_2;
    int height = l_3 >= l_4 ? l_3 : l_4;

    //旧代码取目标的最小外接矩形,但倾斜45度时会出现比例变形的现象
    //cv::Rect rect(point_f, point_b);
    cv_dst = cv::Mat::zeros(height, width, CV_8UC3);

    std::vector<cv::Point2f> dst_pts;
    dst_pts.push_back(cv::Point2f(0, 0));
    dst_pts.push_back(cv::Point2f(width - 1, 0));
    dst_pts.push_back(cv::Point2f(0, height - 1));
    dst_pts.push_back(cv::Point2f(width - 1, height - 1));

    std::vector<cv::Point2f> tr_points;
    tr_points.push_back(in_points.at(0));
    tr_points.push_back(in_points.at(1));
    tr_points.push_back(in_points.at(2));
    tr_points.push_back(in_points.at(3));

    cv::Mat transmtx = getPerspectiveTransform(tr_points, dst_pts);

    cv::Mat cv_revise;
    cv::warpPerspective(cv_warp, cv_revise, transmtx, cv_dst.size());


    std::vector<cv::Mat> cv_dsts;
    int vh = cutTextLines(cv_revise, db_net, cv_dsts);

    int angle = directionTextLines(cv_dsts, angle_net);

    //std::cout << angle << std::endl;

    int rotate_angle = 0;

    if (vh == 7 && angle == 1)//横排文字竖放从上到下
    {
        rotate_angle = 90;
    }
    if (vh == 7 && angle == 0)//横排文字竖放从下到上
    {
        rotate_angle = 270;
    }
    if (vh == 4 && angle == 0)//横排文字颠倒
    {
        rotate_angle = 180;
    }
    if (vh == 7 && angle == 3)//竖排文字正常
    {
        rotate_angle = 0;
    }
    if (vh == 4 && angle == 2)//竖排文字横放从下到上
    {
        rotate_angle = 90;
    }
    if (vh == 4 && angle == 3)//竖排文字横放从上到下
    {
        rotate_angle = 270;
    }
    if (vh == 7 && angle == 2)//竖排文字颠倒
    {
        rotate_angle = 180;
    }
    if (vh == 4 && angle == 1)//横排文字正常
    {
        rotate_angle = 0;
    }
    if (vh == 7 && angle < 0)//横排文字检测不到多于3行的文字
    {
        rotate_angle = 0;
    }
    if (vh == 4 && angle < 0)//竖排文字检测不到多于3行的文字
    {
        rotate_angle = 90;
    }

    switch (rotate_angle)
    {
    case 0:
        cv_dst = cv_revise;
        break;
    case 90:
        cv_dst = rotateMat(cv_revise, 0);
        break;
    case 180:
        cv_dst = rotateMat(cv_revise, -1);
        //flip(cv_revise, cv_dst, -1);
        break;
    case 270:
        cv_dst = rotateMat(cv_revise, 1);
        break;
    default:
        break;
    }
   
    return std::stoi(std::to_string(vh) + std::to_string(angle));
}

 

三、正反面合并

1、按正常扫描逻辑,合并扫描时,正面的那张一般都是放在最上边,这里做了判断,如果合并的时同一类型的证件,比如只合并身份证,不混着合并身份证和银行卡,那么身份证的下面照片就放在上面。

void KL_SmartOffice::merge_imgae()
{
    ui.label_r->setMaximumWidth(0);
    ui.widget_d->setMaximumHeight(0);
    
    if (btnGroup->checkedId() == 1)
    {
        if (!cv_dis_1.empty() && !cv_dis_2.empty())
        {
            if (od_index_1 == 20 && od_index_2 == 21)
            {
                scan.merge_a4(cv_dis_1, cv_dis_2, cv_merge);
            }
            else if (od_index_1 == 21 && od_index_2 == 20)
            {
                scan.merge_a4(cv_dis_2, cv_dis_1, cv_merge);
            }
            else if (od_index_1 ==30 && od_index_2 == 31)
            {
                scan.merge_a4(cv_dis_1, cv_dis_2, cv_merge);
            }
            else if (od_index_1 == 31 && od_index_2 == 30)
            {
                scan.merge_a4(cv_dis_2, cv_dis_1, cv_merge);
            }
            else if (od_index_1 == 50 && od_index_2 == 51)
            {
                scan.merge_a4(cv_dis_1, cv_dis_2, cv_merge);
            }
            else if (od_index_1 == 51 && od_index_2 == 50)
            {
                scan.merge_a4(cv_dis_2, cv_dis_1, cv_merge);
            }
            else
            {
                scan.merge_a4(cv_dis_1, cv_dis_2, cv_merge);
            }
        }
       
        ui.pushButton_save->setEnabled(true);
        ui.pushButton_style->setEnabled(false);
        ui.pushButton_rotate->setEnabled(false);
        ui.pushButton_merge->setEnabled(false);
        ui.pushButton_ocr->setEnabled(false);
    }
}

2.合并到A4纸上,300dpi,如果太低了,合并出来的照片就是很模糊。

void ScanJia::merge_a4(const cv::Mat& cv_src_1, const cv::Mat& cv_src_2, cv::Mat& cv_dst)
{
    cv::Mat cv_1, cv_2;
    cv::resize(cv_src_1, cv_1, cv::Size(1031, 658));
    cv::resize(cv_src_2, cv_2, cv::Size(1031, 658));
    cv_dst = cv::Mat(3508, 2479, CV_8UC3, cv::Scalar(255, 255, 255));
    cv::Mat cv_one = cv_dst(cv::Rect(724, 700,cv_1.cols, cv_1.rows));
    cv_1.copyTo(cv_one);
    cv::Mat cv_two = cv_dst(cv::Rect(724, 2058,cv_2.cols, cv_2.rows));
    cv_2.copyTo(cv_two);
}

合并的效果如下,社保卡正反面合并:

身份证正反面合并:

四、OCR文字识别

1.证件的识别相对于场景简单一引起,使用的是paddle离线版本,为了库的统一,关于paddle模型转ncnn模型可以参考:

https://github.com/FeiGeChuanShu/ncnn_paddleocr ​​​​​​icon-default.png?t=N3I4https://github.com/FeiGeChuanShu/ncnn_paddleocr

2.NCNN推理代码 

 OcrResult OcrLite::detect(const cv::Mat& mat, int padding, int maxSideLen,
        float boxScoreThresh, float boxThresh, float unClipRatio, bool doAngle, bool mostAngle)
    {
        cv::Mat originSrc = mat;
        int originMaxSide = (std::max)(originSrc.cols, originSrc.rows);
        int resize;
        if (maxSideLen <= 0 || maxSideLen > originMaxSide) {
            resize = originMaxSide;
        }
        else {
            resize = maxSideLen;
        }
        resize += 2 * padding;
        cv::Rect paddingRect(padding, padding, originSrc.cols, originSrc.rows);
        cv::Mat paddingSrc = makePadding(originSrc, padding);
        ScaleParam scale = getScaleParam(paddingSrc, resize);
        OcrResult result;
        result = detect(NULL, NULL, paddingSrc, paddingRect, scale,
            boxScoreThresh, boxThresh, unClipRatio, doAngle, mostAngle);
        return result;
    }

    std::vector<cv::Mat> OcrLite::getPartImages(cv::Mat& src, std::vector<TextBox>& textBoxes)
    {
        std::vector<cv::Mat> partImages;
        for (int i = 0; i < textBoxes.size(); ++i)
        {
            cv::Mat partImg = getRotateCropImage(src, textBoxes[i].boxPoint);
            partImages.emplace_back(partImg);
        }
        return partImages;
    }

    OcrResult OcrLite::detect(const char*, const char*,
        cv::Mat& src, cv::Rect& originRect, ScaleParam& scale,
        float boxScoreThresh, float boxThresh, float unClipRatio, bool doAngle, bool mostAngle) {

        cv::Mat textBoxPaddingImg = src.clone();
        int thickness = getThickness(src);

        double startTime = getCurrentTime();
        std::vector<TextBox> textBoxes = dbNet.getTextBoxes(src, scale, boxScoreThresh, boxThresh, unClipRatio);
        double endDbNetTime = getCurrentTime();
        double dbNetTime = endDbNetTime - startTime;

        drawTextBoxes(textBoxPaddingImg, textBoxes, thickness);

        //---------- getPartImages ----------
        std::vector<cv::Mat> partImages = getPartImages(src, textBoxes);

        std::vector<Angle> angles;
        angles = angleNet.getAngles(partImages, doAngle, mostAngle);


        //Rotate partImgs
        for (int i = 0; i < partImages.size(); ++i) {
            if (angles[i].index == 1) {
                partImages.at(i) = matRotateClockWise180(partImages[i]);
            }
        }
        std::vector<TextLine> textLines = crnnNet.getTextLines(partImages);

        std::vector<TextBlock> textBlocks;
        for (int i = 0; i < textLines.size(); ++i) {
            std::vector<cv::Point> boxPoint = std::vector<cv::Point>(4);
            int padding = originRect.x;//padding conversion
            boxPoint[0] = cv::Point(textBoxes[i].boxPoint[0].x - padding, textBoxes[i].boxPoint[0].y - padding);
            boxPoint[1] = cv::Point(textBoxes[i].boxPoint[1].x - padding, textBoxes[i].boxPoint[1].y - padding);
            boxPoint[2] = cv::Point(textBoxes[i].boxPoint[2].x - padding, textBoxes[i].boxPoint[2].y - padding);
            boxPoint[3] = cv::Point(textBoxes[i].boxPoint[3].x - padding, textBoxes[i].boxPoint[3].y - padding);
            TextBlock textBlock{ boxPoint, textBoxes[i].score, angles[i].index, angles[i].score,
                                angles[i].time, textLines[i].text, textLines[i].charScores, textLines[i].time,
                                angles[i].time + textLines[i].time };
            textBlocks.emplace_back(textBlock);
        }

        double endTime = getCurrentTime();
        double fullTime = endTime - startTime;

        //cropped to original size
        cv::Mat textBoxImg;

        if (originRect.x > 0 && originRect.y > 0) {
            textBoxPaddingImg(originRect).copyTo(textBoxImg);
        }
        else {
            textBoxImg = textBoxPaddingImg;
        }

        std::string strRes;
        for (int i = 0; i < textBlocks.size(); ++i) {
            strRes.append(textBlocks[i].text);
            strRes.append("
");
        }

        return OcrResult{ dbNetTime, textBlocks, textBoxImg, fullTime, strRes };
    }
}

 3.识别的效果

 

 

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