Decoding Code128 at various angles

Hi, We have been using XZing in .net to decode QR codes from image files flawlessly for more than 8 years. Now we have a new requirement to decode Code128 barcodes that are manually placed on physical documents which are scanned and converted to TIF. Because the barcodes are stickers that are manually placed on documents, they may appear at an angle. To simulate this scenario, I generated images with a Code128 barcode at an angle from 0 degrees to 359 and tried to decode the barcode on each image and I noticed that the decoding worked only at certain angles, namely from 0 to 6, 87 to 93, 176 to 184, 268 to 272, 356 to 359.

The images can be found here.

Here is part of the code:

private void btnScan360_Click(object sender, EventArgs e)
{
    int i;
    Image img;
    string filename;
    string filepath;
    BarcodeReader reader;

    reader = createNewReader();

    filepath = "E:\\Barcodes\\Tilted\\";

    for (i=0; i<360; i++)
    {
        filename = filepath + i.ToString() + ".tif";
        img = Image.FromFile(filename);
        decode((Bitmap)img, i, reader);

        img.Dispose();              
    }

}

private BarcodeReader createNewReader()
{
    BarcodeReader reader = new BarcodeReader();
    reader.AutoRotate = true;
    reader.TryInverted = true;

    reader.Options.PossibleFormats = new List<BarcodeFormat>();
    reader.Options.PossibleFormats.Add(BarcodeFormat.CODE_128);
    reader.Options.PureBarcode = true;
    reader.Options.TryHarder = true;

    return reader;
}

public void decode(Bitmap bitmap, int angle, BarcodeReader reader)
{
    int i;

    //LuminanceSource source;
    //source = new BitmapLuminanceSource(bitmap);

    Result[] result = reader.DecodeMultiple(bitmap);    //Without LuminanceSource

    if (result != null)
    {
        textBox1.Text = "";
        for (i = 0; i < result.Length; i++)
        {
                Console.WriteLine("Angle={0} {1}", angle, result[i].ToString().Trim());
        }
    }
    else
    {
        Console.WriteLine("{0} {1}", angle, "Nothing!");        
    }   
}

Is there anything I can do to improve the accuracy of the decoder so that we decode at a wider range of angles?

Your help is greatly appreciated Ioannis Demetriades

micjahn / ZXing.Net

Decoding Code128 at various angles #365