Price checker scan engine: 640×480, 40°×29°, and three things that decide if it is enough
The price checker uses an area imager with a 640×480 sensor and a field of view of 40° horizontal, 29° vertical and 49.4° diagonal. It reads common linear barcodes and matrix codes, on paper or on phone screens. Whether it is enough depends on code density, scan distance and media, not on the pixel count.
Engine specifications
| Scan method | Two-dimensional area imager |
|---|---|
| Sensor resolution | 640 × 480 CMOS |
| Field of view | 40° horizontal / 29° vertical / 49.4° diagonal |
| Light source | White illumination (per model) |
| Linear symbologies | Code128 / EAN128 / UPC / EAN / ISSN / ISBN / Codabar / Code 39 / Code 93 / Code 11 / ITF series / MSI-Plessey / GS1 DataBar and others |
| Matrix symbologies | QR / Micro QR / Data Matrix / PDF417 / Micro PDF / Aztec / MaxiCode / Han Xin Code |
| Media | Paper labels, plastic packaging, phone and monitor screens |
Measured depth of field
Depth of field from the datasheet, as an example (lens and light source vary slightly by model):
| Symbology and density | Read distance |
|---|---|
| EAN-13（5mil） | 30–60mm |
| EAN-13（13mil） | 20–130mm |
| QR Code（15mil） | 15–110mm |
| QR Code（30mil） | 15–200mm |
Depth of field is the range where a code can be read, not the range where it reads well. In practice customers hold a code 5–15cm from the scan window, and reading is most stable in that band.
When 640×480 is enough and when to change approach
| Case | Is 640×480 enough | Notes |
|---|---|---|
| Product barcode (EAN-13, UPC) | Yes | Standard retail codes at 5–13mil read without difficulty |
| Product matrix codes (QR, Data Matrix) | Yes | Commonly 15–30mil; screen codes also read |
| Phone payment code / member code | Yes | Calibrate exposure to screen brightness and avoid screen glare |
| Worn, creased or partly covered labels | Mostly | Usually reads when under 1/3 of the code is damaged; beyond that a higher resolution engine is needed |
| Very small codes (under 3mil) and high density PDF417 | No | Move to a higher resolution model in the industrial scanner line |
| Scanning at long range (over 50cm) | No | Use a long-range model or change the mounting position rather than relying on digital zoom |
Four on-site actions
Avoid direct light
When the scan window faces a spotlight or shop window, glare washes out the barcode. Turning the unit 10–15° or adding a light shield works better than changing parameters.
Control the scan distance
Put a guide frame around the scan window and ask customers to hold the code 5–15cm inside it; the read rate improves noticeably.
Set exposure for screen codes
Phone screens vary a lot in brightness. Test on site with phones at different brightness levels, then set exposure and gain to a middle value that reads all of them.
Do not patch labels with clear tape
Tape glare brightens the code surface and lowers the read rate. If a label is damaged, reprint it; that costs less than repeated tuning.
Scan engine FAQ
Is 640×480 too low?
It is enough for retail product codes. Retail codes are low density and read close up, and 640×480 engines are widely used in price checkers and at checkout counters. Higher resolution matters only for small codes, long distance or industrial DPM codes.
Does it read PDF417?
Yes, PDF417 and Micro PDF are supported. PDF417 carries a lot of data, so aim at the whole code and keep the distance at 10–20cm.
Do screen codes and paper codes need separate settings?
One parameter set usually covers both. If screen codes dominate, such as member or payment codes, optimize exposure for screens and keep the default for paper labels.
Can it read colored codes or inverse codes?
Standard black-on-white codes are fine. Inverse codes (light code on a dark background) need engine support; some models can enable it, confirmed at project start.
Can it read codes on curved surfaces such as bottles and tubes?
Labels on gently curved bottles read fine if you face the code to the scan window and avoid strong glare. Thin tubes with tight curvature need rotating to find an angle, or a surround scan setup.
Send us your barcode to test
Testing with your actual labels and screens and reporting a read rate and recommended distance is more reliable than reading a spec sheet.