초록 ▼

A method and apparatus scans or images a machine-readable symbol to produce several reflectance profiles therefrom. The profiles are averaged to produce an averaged profile. Weighted coefficients for each profile are then computed based on the averaged profile. Using the weighted coefficients, a wei

A method and apparatus scans or images a machine-readable symbol to produce several reflectance profiles therefrom. The profiles are averaged to produce an averaged profile. Weighted coefficients for each profile are then computed based on the averaged profile. Using the weighted coefficients, a weighted profile from each of the profiles is then produced. Low pass filtering is applied to the weighted profile to filter noisy or gray level signals therefrom. The resulting filtered profile is transformed using a non-linear technique to enhance high amplitude signals, but suppress low amplitude signals. The resulting transform signal is stretched over the range of reflectance values. The resulting stretched signal is then decoded using, for example, techniques for decoding profiles that fail to resolve narrow (1-wide) elements in the machine-readable symbol.

대표청구항 ▼

[ We claim:] [1.] A method of decoding a machine-readable symbol representing encoded information, the symbol including a plurality of selectively spaced bars, the bars and spaces between the bars having at least a narrow and a wide width in at least one dimension, the method comprising the steps of

[ We claim:] [1.] A method of decoding a machine-readable symbol representing encoded information, the symbol including a plurality of selectively spaced bars, the bars and spaces between the bars having at least a narrow and a wide width in at least one dimension, the method comprising the steps of:producing a plurality of reflectance signals based on light reflected from the symbol, the plurality of reflectance signals having valleys and peaks that represent the reflectance of the bars and spaces having the wide width, but failing to resolve at least some of the bars and spaces having the narrow width;averaging the plurality of reflectance signals to produce an average profile;computing weighting coefficients for at least one of the plurality of reflectance signals based on the averaged profile;producing a weighted profile for at least one of the plurality of reflectance signals based on the weighting coefficients;filtering the weighted profile to produce a filtered profile;transforming the filtered profile to enhance the peaks and valleys that represent the bars and spaces having the wide width, to produce a transformed profile; anddecoding the information encoded in the symbol based on the transformed profile.