Ciao,
prova con una cosa di questo tipo, se ho capito bene quello che ti necessita:
using System;
using System.Drawing;
using ZXing;
using ZXing.Common;
// create new obj
Bitmap qrImage = new Bitmap("YourQR.png");
LuminanceSource source = new BitmapLuminanceSource(qrImage);
BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
Result result = new MultiFormatReader().decode(bitmap);
// retrieve point QR Code
ResultPoint[] qrCodeCoordinates = result.ResultPoints;
// result...
foreach (ResultPoint point in qrCodeCoordinates)
{ Console.WriteLine("QR Code Coordinates: {0}, {1}", point.X, point.Y); }