1D vs 2D Scanners: What Actually Changes

The physical difference

A 1D laser scanner sweeps a line across a barcode and measures reflected light. A 2D area imager takes a picture and decodes it in software. Everything else follows from that: an imager can read a code at any rotation, can read stacked and matrix codes, and can read a code off a phone screen, because a screen emits light rather than reflecting it.

Symbologies you cannot read with a laser

QR, Data Matrix, Aztec, MaxiCode, PDF417 and MicroPDF417 are all two-dimensional. PDF417 in particular matters because it is the format on North American driver licences. Every 2D scanner in this range also reads the mainstream 1D families — UPC, EAN, Code 39, Code 93, Code 128, Interleaved 2 of 5 and the GS1 DataBar group — so choosing 2D does not cost you 1D coverage.

Motion tolerance and shutter type

A rolling shutter reads the sensor line by line, so anything moving across the window is captured skewed. A global shutter exposes the whole frame at once. If codes arrive in motion — on a conveyor, swept past a till, or held out by a customer — global shutter is what makes the read reliable. Motion tolerance figures of 2m/s and decoding speeds quoted in cm/s describe the same capability from different directions.

Reading precision

Precision is quoted in mils: the width of the narrowest bar the scanner can resolve. A 4 mil rating reads denser codes than a 5 mil rating. Small packs — medication, cigarettes, electronic components — are where this decides whether a scanner works at all.

What to specify

For a general counter, a 640x480 imager at 4 mil precision is sufficient. For payment QR on phone screens, step up to a megapixel sensor. For documents and MRZ, a 1.3 megapixel global shutter is the practical floor.

More guides

• ICAO 9303, MRZ and What a Document Reader Actually Captures
• IP Ratings and Drop Resistance, Read Properly
• Bluetooth, 2.4G or Wired: Choosing a Connection Mode
• Choosing a Wearable Scanner
• How OEM and ODM Works Here