I use the following code to read QR code; I tried passing in higher resolution too and also tried various other options extracting as a jpeg file and using PDF extractor. None of them seems to work. I have a small mobile app and other software that i am using to test and it seems to work there.
string codeText = null;
//Aspose.Pdf.Devices.Resolution resolution = new Aspose.Pdf.Devices.Resolution(300);
//Get page in memory
PngDevice pngDevice = new PngDevice();
//using (BarCodeReader barcodeReader = new BarCodeReader(imageStream))
using (BarCodeReader barcodeReader = new BarCodeReader(imageStream, DecodeType.QR))
codeText = barcodeReader.GetCodeText();