Qt Picture Correction (2)

Qt Picture Correction (2)


In the previous section, the principle of picture correction is briefly described.This explains the code section.

PDF to Picture Code

PDF to Picture Code <----- Download PDF to Picture Code, click here

//In the PDF to Picture section, I applied a third-party library.Then I encapsulated it myself
//WcharPdfFile: PDF file path;
//imageName: Outgoing Picture Path
//PageNum:PDFThe number of pages
bool CPdf2PngDll::PdfToPng(const wchar_t* wcharPdfFile, const char* imageName, int &pageNum)
    CMuPDFConvert pdfConvert;
    return pdfConvert.Pdf2Png(wcharPdfFile, imageName, pageNum);

//Note here that imageName: The output path is a dead png format picture, and passing in parameters to the path of all folders is sufficient, such as output asTest.pngPicture imageName = D:\OfficeWare\test; that's it
bool CMuPDFConvert::Pdf2Png(const wchar_t* wcharPdfFile,const char* imageName, int &pageNum)
    char tempPath[1024];
    strcpy_s(tempPath, imageName);
    strcat_s(tempPath, "%d.png");
. . . . . . . . . . . Later, check the source I uploaded, which is omitted.The main purpose is to illustrate the parameter problem.

Opencv Picture Correction

Loading the opencv library, which I won't describe here.Here I paste out my correction code.

#include "opencv2/opencv.hpp"

using namespace std;
std::vector<std::vector<cv::Point>> contours;

void CImageRotationDll::ImageRotationStart(const std::string& inputPath, const std::string& outputPath)
    auto FNsearchQR = [&](cv::Mat image)
        cv::Mat imageGray, imageROI, imageGuussian, imageSobelX, imageSobelY, imageSobelOut;
        //2. Convert to Grayscale  
        cvtColor(image, imageGray, CV_RGB2GRAY);
        imageROI = imageGray(cv::Range(image.rows - 80, image.rows), cv::Range(image.cols - 450, image.cols));
        //3. Gauss Smoothing Filter  
        GaussianBlur(imageROI, imageGuussian, cv::Size(3, 3), 0);

        //4. Find the gradient difference between horizontal and vertical gray-scale images using Sobel operator  
        cv::Mat imageX16S, imageY16S;
        Sobel(imageGuussian, imageX16S, CV_16S, 1, 0, 3, 1, 0, 4);
        Sobel(imageGuussian, imageY16S, CV_16S, 0, 1, 3, 1, 0, 4);
        convertScaleAbs(imageX16S, imageSobelX, 1, 0);//Convert intermediate results to CV_8U
        convertScaleAbs(imageY16S, imageSobelY, 1, 0);
        imageSobelOut = imageSobelX - imageSobelY;

        //5. Mean filter to eliminate high frequency noise  
        blur(imageSobelOut, imageSobelOut, cv::Size(3, 3));

        //6. Binarization  
        cv::Mat imageSobleOutThreshold;
        threshold(imageSobelOut, imageSobleOutThreshold, 180, 255, CV_THRESH_BINARY);

        //7. Close operation, fill bar code gap  
        cv::Mat  element = cv::getStructuringElement(0, cv::Size(7, 7));
        morphologyEx(imageSobleOutThreshold, imageSobleOutThreshold, cv::MORPH_CLOSE, element);

        //8. Corrosion, removing isolated points  
        erode(imageSobleOutThreshold, imageSobleOutThreshold, element);

        //9. Expansion, filling gaps between barcodes, depending on the size of the core, may require 2-3 expansion operations  
        dilate(imageSobleOutThreshold, imageSobleOutThreshold, element);
        dilate(imageSobleOutThreshold, imageSobleOutThreshold, element);
        dilate(imageSobleOutThreshold, imageSobleOutThreshold, element);

        //10. Find the rectangular boundary of the barcode area with findContours
        vector<cv::Vec4i> hiera;
        findContours(imageSobleOutThreshold, contours, hiera, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_NONE);

    cv::Mat image;
    cv::Mat imagetrans;
    image = cv::imread(inputPath);
    //Search Barcode
    int index = 0;
    //Determine if barcode is detected or if not rotate 90 degrees clockwise
    while (contours.size() != 1)
        transpose(image, imagetrans);
        flip(imagetrans, image, 1);
        if (index == 3)
    cv::imwrite(outputPath, image);

Picture to PDF

#include <QPrinter>
#include <QPainter>
#include <QPageSize>

//Picture to PDF encapsulated library for my QT
void ImageToPdf::startImageToPdf(const QString& imgPath, const QString& pdfpath)
    QPrinter printer_pixmap(QPrinter::HighResolution);
    QPixmap pixmap(imgPath);
    printer_pixmap.setOutputFormat(QPrinter::PdfFormat);  //Set output format to pdf
    printer_pixmap.setOutputFileName(pdfpath);   //Set Output Path
    printer_pixmap.setPageSize(QPageSize(QSize(pixmap.width(), pixmap.height())));  //Set paper size to A4

    QPainter painter_pixmap;
    QRect rect = painter_pixmap.viewport();
    int mutipleW = rect.width() / pixmap.width();
    int mutipleH = rect.height() / pixmap.height();
    painter_pixmap.scale(mutipleW, mutipleH);

    painter_pixmap.drawPixmap(0, 0, pixmap);  //Drawing


My idea for picture correction is to turn the PDF into a picture, then use opencv to process the picture, and finally, turn the picture into a PDF.Finally, the result I want is that if there are great gods with better ideas and algorithms, don't forget to mention them.Thank you here.

Just for recording, just for sharing! May what you write help you.


Qt Picture Correction (1)

Keywords: OpenCV Qt

Added by healthnut on Sun, 24 May 2020 19:08:56 +0300