BAR-CODE READER, METHOD OF READING A BAR CODE, AND COMPUTER PRODUCT

In an optical scanner, an optical scanner optically scans a bar code to obtain signal strength of light reflected from black bars and white bars of the bar code, an extracting unit extracts edge data, which includes a plurality of edges and the signal strength of which changes corresponding to a change from a black bar to a white bar and vice versa, an edge-emphasizing unit that emphasizes edge data of an edge that satisfies a predetermined condition, a ternary judgment unit that makes a ternary judgment of each edge based on the edge emphasized to obtain a ternarizing result, and a decoder that decodes bar-code characters from the ternarizing result.