Bar-code reader, method of reading a bar code, and computer product

A method of reading a bar code comprising:

• optically scanning a bar code to obtain signal strength of light reflected from black and white bars of the bar code;
• extracting 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;
• emphasizing an edge from the edge data;
• making a ternary judgment for each edge based on the edge emphasized to obtain a ternarizing result;
• and
• decoding bar-code characters from the ternarizing result.

A computer program for reading a bar-code that makes the computer execute:

• optically scanning a bar code to obtain signal strength of light reflected from black and white bars of the bar code;
• extracting 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;
• emphasizing an edge from the edge data;
• making a ternary judgment of each edge based on the edge emphasized to obtain a ternarizing result;
• and
• decoding bar-code characters from the ternarizing result.