bitmap image decode

    public string Barcode(System.Drawing.Image img)
        {
            MemoryStream memoryStream = new MemoryStream();


            byte[] byteArray = memoryStream.GetBuffer();

            ZXing.LuminanceSource source = new RGBLuminanceSource(byteArray, img.Width, img.Height);
            var binarizer = new HybridBinarizer(source);
            var binBitmap = new BinaryBitmap(binarizer);
            QRCodeReader qrCodeReader = new QRCodeReader();

            Result str = qrCodeReader.decode(binBitmap);

            return str.ToString();

        }