Bar code void and spot discrimination
AssigneePSC Inc.
InventorChay La
Life of this patent
Estimating the term…
Abstract
A void and spot discrimination apparatus and method for successfully decoding bar code symbols having imperfections therein. A first and a second scan are performed, and a signal return is obtained, in which information is obtained related to a smallest size black bar and white space, as well as a largest size black bar and white space. The signal returns from the first and second scans is sent to a decoder, and third and fourth scans are performed. The signal returns from the third and fourth scans are altered based on the smallest/largest sizes obtained from the two previous scans, in order to eliminate potential ink spreads and print voids. The process is alternated in this manner until a successful bar code decoding is made.
Claims22
A method of scanning a bar code symbol, comprising the steps of:
- a) scanning a bar code symbol and obtaining a first signal return as a result thereof;
- b) attempting to decode the first signal return in order to obtain a decoded bar code symbol;
- c) determining a size of a minimum width bar within the bar code symbol based on the first signal return;
- d) scanning the bar code symbol and obtaining a second signal return as a result thereof;
- e) altering the second signal return as an altered second signal return to eliminate bars in the second signal return that have a width less than or equal to the minimum width bar;
- and
- f) attempting to decode the altered second signal return in order to obtain a decoded bar code symbol if the decoding attempt of the first signal return was unsuccessful.
An apparatus for scanning a bar code symbol, the apparatus being housed within a bar code scanner which receives signal returns of the bar code symbol via a light detector, the bar code scanner also having a trigger signal indicative of a desired scanning operation by an operator, and a start-of-scan signal indicative of an actual scanning operation being performed by the bar code scanner, the bar code scanner further having a decoder for decoding an input signal in order to obtain a digital representation of the bar code symbol, the apparatus comprising:
- a void and spot discrimination circuit connected to receive the signal returns of the bar code symbol and to output a discriminated signal to the decoder based on a number of scans as determined by the start-of-scan signal input to the void and spot discrimination circuit at a first input port,
- wherein the void and spot discrimination circuit eliminates bars that are less than a predetermined size in one of the signal returns corresponding to one of the scans, and
- wherein the predetermined size is determined based on a minimum width bar determined from another of the signal returns corresponding to a previous one of the scans.
A method of recognizing a set of characters having dark-colored regions and light-colored regions, the method comprising the steps of:
- a) scanning the set of characters and obtaining a first signal return as a result thereof;
- b) attempting to decode the first signal return in order to obtain a decoded set of characters;
- c) determining a size of a minimum width region within the character set based on the first signal return, the minimum width region being one of the light-colored regions and the dark-colored regions;
- d) scanning the set of characters and obtaining a second signal return as a result thereof;
- e) altering the second signal return as an altered second signal return to eliminate regions in the second signal return that have a same color as the minimum width region and that have a width less than or equal to the minimum width region;
- and
- f) attempting to decode the altered second signal return in order to obtain the decoded set of characters if the decoding attempt of the first signal return was unsuccessful.
An apparatus for scanning a set of characters, the set of characters having light-colored regions and dark-colored regions, the apparatus being housed within a scanner which receives signal returns of the set of characters via a light detector, the scanner also having a trigger signal indicative of a desired scanning operation by an operator, and a start-of-scan signal indicative of an actual scanning operation being performed by the scanner, the scanner further having a decoder for decoding an input signal in order to obtain a digital representation of the set of characters, the apparatus comprising:
- a void and spot discrimination circuit connected to receive the signal returns of the set of characters and to output a discriminated signal to the decoder based on a number of scans as determined by the start-of-scan signal input to the void and spot discrimination circuit at a first input port,
- wherein the void and spot discrimination circuit eliminates all of the light-colored regions and dark-colored regions that are less than a predetermined size in one of the signal returns corresponding to one of the scans, and
- wherein the predetermined size is determined based on a minimum width of one of the dark-colored regions and light-colored regions determined from another of the signal returns corresponding to a previous one of the scans.
Dependencies are inferred from the claim text.