Higher read rates than laser scanners
Cognex DataMan and MX series of industrial, image-based barcode readers decode 1-D and 2-D codes, from printed labels to the hardest to read direct part mark (DPM) codes, and deliver industry-leading read rates.
John Keating, 06-27-2013There is a major technology difference between laser scanners and image-based barcode readers:
- Laser scanners: Use a moving pinpoint of light to illuminate the barcode and a single photocell receives the reflected light. Most laser scanners sweep the laser beam horizontally using an electronically controlled mirror. Two-dimensional laser scanners sweep the beam horizontally and vertically at the same time, creating a raster pattern. A laser scanner uses a photosensor to convert the barcode into an electrical signal as it moves across a barcode. The scanner then measures the relative widths of the bars and spaces, translates the different patterns back into regular characters, and sends them on to a computer or portable terminal.
- Image-based readers: Work like cameras. It is a self-contained product that contains the imager and processor with either internal or external lighting. The imager’s job is to acquire a picture of a scene, digitize that picture, and transfer it to a microprocessor. That processor or DSP then analyzes that digital image using software algorithms in order to locate and decode a barcode.
When a product goes by the laser scanner, it has one opportunity to scan it with one laser. Not so with an image-based reader. Image-based readers take multiple images of the product as it passes by the field-of-view of the reader, enabling more chances to catch an image that will enable a successful read of the barcode. This is especially important for applications that have low lighting or have challenging barcodes.
Additionally, the powerful software algorithms that DataMan image-based readers have for finding and decoding the barcodes are able to produce much higher read rates than laser scanners.
What do higher read rates give you? Less rejected products, which means less costs associated with labor having to handle those rejects and higher throughput.
In the next blog, we’ll talk about another DataMan technology difference that provides benefits to customers: performance feedback.