Watch this video to learn how automated in-line vision inspection systems verify alphanumeric, 1D and 2D barcodes on packaging surfaces and labels. Watch the video to learn how it works
Optical Character Recognition (or OCR) is a method for identifying printed characters on a package surface. OCR is ideal for variable text fields, where it may not be possible to know what text string will be on the production line. The system compares a given character image against all the characters in a pre-defined font to find the closest match. Optical Character Verification, on the other hand, is looking for a pre-defined value – it is used to check for the accuracy of a code rather than determine what a code is. More information on the way that OCR and OCV work can be found in our white paper Making Codes Readable.
Cameras read barcodes in the same way that any barcode reader functions: the software analyses the contrast between filled and empty spaces in order to understand the shape of the code, and then decodes the pattern into an alphanumeric string. Depending on the code type, this either means analysing a simple horizontal line (as in a 1D barcode) or analysing a square (in the case of a 2D barcode). Either way, the basic principle of reading in a pattern of light and dark is the same. The advantage of using a camera instead of a more traditional barcode reader is that camera systems are better-suited to gauging barcode quality – a more traditional barcode reader can only really return a readable or undreadable result.
Smart Cameras are completely self-contained systems which perform all the image processing and analysis work using an on-board CPU. Smart Cameras often feature integrated lighting as well, making them ideal for simple applications such as code reading. Unfortunately, this simplicity is not without its drawbacks – on-board memory is naturally limited, meaning that a comprehensive record of all products inspected may not be feasible. A PC-controlled system uses cameras which transmit images to a control PC which coordinates image capturing and processing. PC-controlled systems generally deliver faster processing times – which can be important for more complex applications – and carry the advantage of having far more memory to store different inspection profiles and inspection images.