According to the barcode reading standard, it's need the barcode image clear enough to recognize the bar and the space. But how is considered to the clear enough? It's hard to say. Many factors will impact the reading result, such as image size, image color and background color, image dpi, barcode reader software sensitivity and precision.
Plainly, we can make a judgment by our eyes. It may not need a too high dpi, usually the 72 dpi image can be very clear. If we find the barcode image with pixel picot edge or some blur, it can't be decoded in the most time. Please look at this barcode picture:
It's blurred obviously, and out .net barcode reader control can't scan the barcode in it.
So if you want to scan your barcode image 100% successfully, the picture need look like the follow one.
In the end, we still post some C# sample code for you.
Bitmap image = Bitmap.FromFile("barcode-image.jpg");
BarcodeResult results = BarCodeScanner.Scan(image);
Hope the C# code can be helpful.
---- pqScan Support Team