A barcode is built using a sequence of white and black bars, coding the data using theyr size and position. The encoded data are numbers, alphanumeric characters, special characters and symbols. The barcode was created to be recognized by machines, so usually are the most accurate method to capture data from images.
The search and the decodification of a barecode in an images can be done on a specific image zone or in the full image: smaller is the search area, greater is the recognition speed and smaller the error rate.
In the recognition process are examinated all the possible barcode in the specified zone: if is found a probable barcode, it is examined to check if it fits minimal requirements. Is checked the barcode type, the size, the number of encoded characters, the check digit if present, and all this informations are compared with the predifined settings to decide if decode it or not.