...
services.AddQRCodeFixer();
...

var fixer = serviceProvider.GetRequiredService<QRCodeFixer>();

var data = fixer.FixAndSaveAsPng("qrcode-damaged.png", "qrcode-fixed.png");

...
services.AddQRCodeEncoder();
...

var encoder = serviceProvider.GetRequiredService<QRCodeEncoder>();

var stringData = "test";
encoder.Encode(stringData);
encoder.SaveQRCodeToPngFile("qrcode.png");

...
services.AddQRCodeDecoder();
...

var decoder = _serviceProvider.GetRequiredService<QRDecoder>();
byte[][] data = decoder.ImageDecoder(sourceBitmap);

var data = QRDecoder.ByteArrayToString(data[0]);