ZXing.Net cannot decode QR code captured by camera

Question

Last information:

After reminding @Michael I to successfully capture and decode the QR code using

zxingnet-88246 \ trunk \ Clients \ WindowsFormsDemo

EmguCVDemo (successful decoding of a QR code in a camera frame today)

I will try to compare the difference between the demo code and my code. Thanks, Michael, so happy to successfully decode it.

p / s: these example codes work with net4.0 zxing.dll but not net4.5 zxing.dll

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Old questions:

Using Zxing.Net, I can decode the original image of the QR code encoded by ZXing.Net.

But when I get the image from Emgu.CV capture , it cannot be decoded by ZXing.Net even I | try cropping, resizing and adding canvas size.

But the magic is the Android QR code scanner . Scan the QR code even directly from the camera. I tried to parse the Android source code, but I did not find anything special. I wonder if the Android version uses one autofocus function of the camera?

Below is my code:

DecoderResult decoderResult;
Bitmap bitmap = new Bitmap(@"C:\testfunny678.bmp");
LuminanceSource source = new BitmapLuminanceSource(bitmap);
//
BinaryBitmap binBitmap = new BinaryBitmap(new GlobalHistogramBinarizer(source));

try
{
    //null Hashable Hints
    DetectorResult detectorResult = new Detector(binBitmap.BlackMatrix).detect(null);

    Result result = decoder.decode(binBitmap);

    //decoderResult = decoder.decode(detectorResult.Bits,null);
    //points = detectorResult.Points;
    //Result result = new Result(decoderResult.Text, decoderResult.RawBytes, points, BarcodeFormat.QR_CODE);

    if (result.Text != null)
    {
        //QR_CODE
        //MessageBox.Show("format is: " + result.BarcodeFormat);
        MessageBox.Show("result is: " + result.Text);
    }
    else
    {
        MessageBox.Show("bitmap is null");
    }
}
//com.google.zxing.ReaderException: Exception of type 'com.google.zxing.ReaderException' was thrown.
//   at com.google.zxing.qrcode.detector.FinderPatternFinder.selectBestPatterns() in d:\Temp\zxing-2.1\csharp\qrcode\detector\FinderPatternFinder.cs:line 602
//   at com.google.zxing.qrcode.detector.FinderPatternFinder.find(Hashtable hints) in d:\Temp\zxing-2.1\csharp\qrcode\detector\FinderPatternFinder.cs:line 238
//   at com.google.zxing.qrcode.detector.Detector.detect(Hashtable hints) in d:\Temp\zxing-2.1\csharp\qrcode\detector\Detector.cs:line 90
//   at qrcode.Form1.Decode3() in c:\Users\User\Documents\Visual Studio 2013\Projects\qrcode\qrcode\Form1.cs:line 139
catch (Exception e)
{
    //MessageBox.Show(e.ToString());
}

My code can decode this

Camera capture like this

After cropping, resizing and adding the canvas, it will look like this (testfunny678.bmp)

canvas QR-, QR- , , Android- QR-.

HybridBinarizer QR-.

        LuminanceSource source = new RGBLuminanceSource(GetRGBValues(bitmap), bitmap.Width, bitmap.Height);
        BinaryBitmap binBitmap = new BinaryBitmap(new HybridBinarizer(source));

- QR- ( QR-), QR-, . sharpen , ZXing QR-.

, QR- ( (23.5, 76.5), (23.5, 23.5), (75, 24.5))   THIRD QR

    public string Detect(Bitmap bitmap)
    {
        try
        {
            ZXing.LuminanceSource source = new RGBLuminanceSource(GetRGBValues(bitmap), bitmap.Width, bitmap.Height);
            var binarizer = new HybridBinarizer(source);
            var binBitmap = new BinaryBitmap(binarizer);
            BitMatrix bm = binBitmap.BlackMatrix;
            Detector detector = new Detector(bm);
            DetectorResult result = detector.detect();

            string retStr = "Found at points ";
            foreach (ResultPoint point in result.Points)
            {
                retStr += point.ToString() + ", ";
            }

            return retStr;
        }
        catch
        {
            return "Failed to detect QR code.";
        }
    }

    private byte[] GetRGBValues(Bitmap bmp)
    {
        // Lock the bitmap bits. 
        System.Drawing.Rectangle rect = new System.Drawing.Rectangle(0, 0, bmp.Width, bmp.Height);
        System.Drawing.Imaging.BitmapData bmpData = bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadOnly, bmp.PixelFormat);

        // Get the address of the first line.
        IntPtr ptr = bmpData.Scan0;

        // Declare an array to hold the bytes of the bitmap.
        int bytes = bmpData.Stride * bmp.Height;
        byte[] rgbValues = new byte[bytes];
        // Copy the RGB values into the array.
        System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes);
        bmp.UnlockBits(bmpData);

        return rgbValues;
    }

DetectorResult.Points Detect() Detect() DetectorResult , fail , Result.

    public DetectorResult Detect(Bitmap bitmap)
    //public string Detect(Bitmap bitmap)
    {
        try
        {
            ZXing.LuminanceSource source = new RGBLuminanceSource(GetRGBValues(bitmap), bitmap.Width, bitmap.Height);
            var binarizer = new HybridBinarizer(source);
            var binBitmap = new BinaryBitmap(binarizer);
            BitMatrix bm = binBitmap.BlackMatrix;
            Detector detector = new Detector(bm);
            DetectorResult result = detector.detect();
            return result;
            //string retStr = "Found at points ";
            //foreach (ResultPoint point in result.Points)
            //{
            //    retStr += point.ToString() + ", ";
            //}

            //return retStr;
        }
        catch
        {
            //return "Failed to detect QR code.";
            return null;
        }
    }

    void Decode3()
    {
        //System.Collections.Hashtable hints = null;
        DecoderResult decoderResult;
        Bitmap bitmap = new Bitmap(@"C:\testfunny678.bmp");
        LuminanceSource source = new BitmapLuminanceSource(bitmap);
        BinaryBitmap binBitmap = new BinaryBitmap(new GlobalHistogramBinarizer(source));
        ResultPoint[] points;

        ZXing.QrCode.Internal.Decoder decoder = new ZXing.QrCode.Internal.Decoder();
        //ZXing.MultiFormatReader decoder = new ZXing.MultiFormatReader();

        try
        {
            DetectorResult detectorResult = new Detector(binBitmap.BlackMatrix).detect(null);
            //DetectorResult detectorResult = Detect(bitmap);
            //Result result = decoder.decode(binBitmap);
            //null decoderResult here
            decoderResult = decoder.decode(detectorResult.Bits,null);
            points = detectorResult.Points;
            Result result = new Result(decoderResult.Text, decoderResult.RawBytes, points, BarcodeFormat.QR_CODE);

            if (result.Text != null)
            {
                MessageBox.Show("result is: " + result.Text);
            }
            else
            {
                MessageBox.Show("bitmap is null");
            }
        }
        catch (Exception e)
        {
            //MessageBox.Show(e.ToString());
        }

    }

2- QR QR ZXing.NET QR- , .

Answer 1

-, QR- ZXing.Net WinFormsDemo. : ​​ ?

- EmguCV. EmguCV ZXing.Net, . , EmguCV ZXing.Net.