Registers – Coded record sensors – Particular sensor structure
Reexamination Certificate
2001-01-23
2003-05-20
Lee, Michael G. (Department: 2876)
Registers
Coded record sensors
Particular sensor structure
C235S462170, C235S462240, C235S462110
Reexamination Certificate
active
06565004
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to an optical reading apparatus having an optical scanner for scanning information on objects, and more particularly to a bar code scanner that collectively reads bar codes existing in a scanning field of a laser beam by scanning a laser beam in a plurality of directions.
2. Description of the Related Art
There are roughly two types of bar code scanners. One is a bar code scanner that reads bar code symbol by bringing its reading part in contact with a bar code label or bringing the reading part very close to the bar code label. For example, a CCD touch scanner and pen scanner, etc., that are frequently used in small-sized retail stores belong to this type.
On the other hand, the fixed laser scanner and hand laser scanner can read bar code labels in a scanning field having a predetermined spatial spread by scanning a laser beam in various directions.
The CCD touch scanner and pen scanner described above have limits to the positional relationship between the reading part thereof and a bar code label of an object to be read. Therefore, only a single bar code can be read by one reading operation.
On the other hand, although a fixed laser scanner and a hand-held laser scanner have, respectively, predetermined reading depths, only a single bar code can be read by a single scanning operation in prior arts.
The reason resides in that a strict limitation is implied in terms of the time required for a reading process in major uses of this type of bar code scanner. Fixed laser scanners are mainly installed in a cash register in large-scaled retail stores. In such a use, a bar code symbol must be read at the instant when the bar code label crosses the reading field of a bar code scanner as the operator moves an article across it.
FIG. 19
shows a configurational example of a prior art fixed laser scanner. Also,
FIG. 20
is a view explaining a reading action made by a prior art fixed laser scanner.
A laser beam is scanned in various directions by an optical system
401
. When a bar code label is scanned by the laser beam, light diffused by the bar code label is incident into a photo acceptance unit
403
, and is converted to electric signals corresponding to the intensity thereof, where the electric signals are inputted to a signal processing part
404
. As shown in FIG.
20
(
a
), the signal processing part
404
removes noise by binarizing the inputted electric signals in compliance with a predetermined slicing level. Also, a demodulating part
405
shown in
FIG. 19
analyzes the pulse width and pulse interval of binarized signals obtained by the signal processing part
404
, and generates reading data corresponding to the bar code symbol recorded in the bar code label described above on the basis of the results of analysis. Then, the demodulating part
405
outputs the reading data to the host computer
407
via an interface part
406
.
In order to read bar code symbols at a high efficiency by effectively utilizing the binarized signals obtained in a limited time, the demodulating part
405
employs a block data composite process and a label stitching method, etc.
The block data composite process is a technique for generating binarized signals corresponding to the entire bar code symbol by combining, as shown in FIG.
20
(
b
), binarized signals obtained by scanning a range including half a block from a guard bar to a center bar and binarized signals obtained by scanning a range including the other half of the block from the center bar to the other guard bar.
Also, the label stitching method is a technique for generating binarized signals corresponding to the entire bar code symbol by detecting the respective binarized signals obtained in further detailed ranges, and the overlapped portion of these binarized signals and by combining these.
By employing these techniques, then, regardless of the alignment of articles when an operator moves the articles in the reading field of a bar code scanner, the bar code symbol can be read at high accuracy on the basis of the binarized signals obtained in a short period of time during which the articles cross the reading field of the bar code scanner.
The above-described block data composite process and label stitching method are based on the assumption that, in any case thereof, binarized signals inputted within the time corresponding to one reading operation is generated by diffusely reflected light from a single bar code label.
In uses in which these techniques are requisite and indispensable, this is the basis that the number of bar codes read by one reading operation by a fixed laser scanner is limited to a single bar code symbol.
However, recently, laser scanners are being developed and downsized to hand-held laser scanners. In line therewith, there is a possibility that the above-described hand-held laser scanners can be utilized in uses where a touch scanner and a pen scanner have conventionally been used.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an optical reading apparatus capable of collectively reading a plurality of optically readable codes resting in a field scanned by a laser beam.
It is a further object of the invention to greatly reduce the work load applied to an operator of an optical reading apparatus represented by a scanning apparatus, by collectively reading a plurality of different bar code labels indicating various symbols resting in a limited field on, for example, a checkout counter.
The above-described objects are achieved by a first scanning apparatus comprising: a discriminating part that discriminates and extracts a set of consecutive data which meet predetermined conditions among candidates obtained by a signal converting part; a choosing part for choosing a set of consecutive data different from each other from a group of the sets of consecutive data; and an outputting part for outputting reading result in response to the input of chosen set of consecutive data.
The first scanning apparatus like this is capable of extracting a set of consecutive data that consecutively expresses all modules constituting bar code symbols, by inputting candidates obtained by converting electric signals, which are obtained by a photoelectric converting part, into the discriminating part by a signal converting part.
Only sets of consecutive data that are different from each other are chosen from a group of the sets of extracted consecutive data by the choosing part, and the sets of consecutive data overlapped due to the same bar code symbols having been scanned two or more times are excluded, wherein by outputting the remaining sets of consecutive data via an outputting part, the plurality of bar code labels described above can be collectively read, and the reading result corresponding thereto can be outputted.
Also, the above-described objects can be achieved by a first optical reading apparatus that is provided with: a scanning part that generates a scanning laser beam capable of scanning optically readable symbols by scanning a laser beam; a transducer that receives light reflected from the symbol and generates electric signals corresponding to the amount of the received light; a demodulating part that demodulates the electric signals outputted from the transducer and reproduces data recorded as the symbol; a discriminating part for extracting sets of data that are different from each other among the data demodulated by the demodulating part; a numeric inputting part that receives numeric data; and a comparing part for comparing the numeric data inputted from the numeric inputting part with the number of sets of data extracted by the discriminating part.
The first optical reading apparatus as described above is capable of collectively reading these symbols according to the electric signals obtained when scanning a plurality of symbols by a scanning laser beam.
By an optical reading apparatus as such, which can discriminate demodulated data that are different from each other among the demodulated data ob
Aoki Toshitaka
Ishii Mitsuharu
Armstrong Westerman & Hattori, LLP
Fujitsu Limited
Lee Michael G.
Walsh Daniel
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