OpenCV compile

1. download OpenCV windows Source code

2. install CMake( belt GUI Of )

3. download MinGW

4. Add environment variables （MinGW Of bin Contents and CMake Of bin Catalog ）

5. stay OpenCV Source code build The same as creating in the directory build-mginw Folder

6. To configure CMake

For details, please refer to ：Windows10+CLion+OpenCV4.5.2 Development environment construction - podesta ...... - Blog Garden

If appear opencv_videoio For module error reporting, please refer to the following link

OPENCV compile Videoio Module problem solving _fengxueniu The blog of -CSDN Blog

CLion Environment building

Create a new project ;Cmakelist Import OpenCV

Cmakelist Add code ：

cmake_minimum_required(VERSION 3.17)
project(IDdect)

set(CMAKE_CXX_STANDARD 14)

add_executable(IDdect main.cpp)

# Add code 
set(OpenCV_DIR F:/opencvWin/opencv/build-mginw)
find_package(OpenCV REQUIRED)
include_directories(${OpenCV_INCLUDE_DIRS})

target_link_libraries(IDdect ${OpenCV_LIBS})

#include <iostream>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;
#define DEFAULT_CARD_WIDTH 640
#define DEFAULT_CARD_HEIGHT 400
#define  FIX_IDCARD_SIZE Size(DEFAULT_CARD_WIDTH,DEFAULT_CARD_HEIGHT)

int main() {
    Mat dts;
    Mat source_image;
    Mat dst_img;
    Mat src = imread("C:\\Users\\As10906\\Desktop\\pjl.jpg");
    if(src.empty())
    {
        fprintf(stderr, "Can not load image\n");
        return -1;
    }

    imshow("src",src);
    // Compressed format 
    resize(src,src,FIX_IDCARD_SIZE);
//    resize(src,src,Size(640,400),0,0,INTER_LINEAR);
    imshow("resize",src);
    source_image = src;
    // grayscale 

    cvtColor(src,dts,COLOR_BGR2GRAY);
    imshow("gray",dts);

    // Two valued 
    threshold(dts,dts,100,255,CV_THRESH_BINARY);
    imshow("threshold",dts);

    // corrosion +  inflation 
    Mat erodeElement = getStructuringElement(MORPH_RECT,Size(20,10));
    erode(dts, dts, erodeElement);
    imshow("erode",dts);

    vector< vector<Point> > contours;
    vector<Rect> rects;
    findContours(dts, contours, rects,RETR_LIST, CHAIN_APPROX_SIMPLE, Point(0, 0));

    for (int i = 0; i < contours.size(); i++)
    {
        Rect rect = boundingRect(contours.at(i));
        rectangle(dts, rect, Scalar(0, 0, 255));  //  stay dst  The picture shows  rect  rectangular 
        imshow("rectangle",dts);
        if (rect.width > rect.height * 11) {// Defined by aspect ratio  18 position  13:1
            rects.push_back(rect);
//            rectangle(source_image, rect, Scalar(0,255,255));//rect Is the coordinate that satisfies the scale    Draw the coordinates that meet the conditions on the original drawing 
//            dst_img = source_image(rect);
            // The reason for taking pictures may lead to the identification of the address or other row of the address as ID number. 
        }
    }
    // Robustness judgment --- Get the set coordinate points exceeding the scale rects, Then traverse and take out y The most valuable   That is, closest to the bottom of the ID card 
    if(rects.size() ==1 ){
        Rect rect = rects.at(0);
        dst_img = source_image(rect);
    }else{
        int lowPoint = 0;
        Rect finalRect;
        for (int i = 0; i < rects.size(); ++i) {
            Rect rect = rects.at(i);
//            Point p = rect.tl();
            if(rect.tl().y > lowPoint){
                lowPoint = rect.tl().y;
                finalRect = rect;
            }
            rectangle(source_image,finalRect,Scalar(255,255,0));
        }
        dst_img = source_image(finalRect);
    }

    imshow("aim",dst_img);

    waitKey();// amount to VS  Medium inputkey   Blocking wait operation , Otherwise, all the picture effects will flash by 
    return 0;
}

Original picture ：

effect ：

At this point, I got the key picture of the ID number. , Next, import Android Studio Just identify the number in the picture

Rendering view path ：https://download.csdn.net/download/xxwbwm/29939726