JPH07168907A - Bar code decoder - Google Patents

Abstract

PURPOSE:To obtain a wide dynamic range with the addition of less hardware or processing by detecting the count value of a data counting means in a data control means and deciding data stored in a data storage means by means of a data conversion means based on the result. CONSTITUTION:When the number of bits of the count value in the data counting means 2 is larger than the number of data processing bits of a decoding processing means 7 when analog data from the data storage means 6 is counted by a reference clock in the data counting means 2, the data control means 5 compares the number of the bits which can be processed in the decoding means 7 with the number of the counting bits of the data counting means 2. The data conversion means 3 rounds down the lower bits of counting data of the data counting means 2 since influence on a decoding processing is small in the lower bits of data, and data is outputted to the decoding processing means 7 of a poststage. Data stored in the data storage means 6 is decided according to the output of the data control means 5 by the data conversion means 3 in such a way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code decoding device for reading bar code labels.

[0002]

2. Description of the Related Art In a scanner, such as a pen scanner, in which a person manually scans, the scanning speed varies depending on the person handling the situation and the situation. It is conceivable that overflow of the count value data will occur in the counting means or the data storage means when the scanning is performed with.

Further, if the reference clock is slowed down in accordance with the low speed scan, it is possible that a sufficient count value cannot be obtained when the high speed scan is performed and the accuracy in the decoding process is deteriorated. The same problem can be considered when data from scanners having different scanning speeds is decoded by one decoding device.

In the bar code decoder device,
In the technique of setting the bit width of the counter and the processing circuit to have the same bit width, or the counting means,
A technique for counting analog data by varying a reference clock when counting data is disclosed in Japanese Patent Laid-Open No. 2-76086.
Japanese Patent Application Laid-Open No. 4-216184, Japanese Patent Application Laid-Open No. 5-35902, and the like.

[0005]

By expanding the readable width (dynamic range), a wider scanning speed can be accommodated. However, the counting means and the data storing (storing) means for counting the width of the bar space. In the conventional decoder in which the memory bit width of is the same bit width, when trying to widen the dynamic range of read data, the bit width of not only the counting means but also the data storage means must be widened. However, there is a problem that the amount of hardware of the data storage means increases.

It is an object of the present invention to provide a bar code decoding device which can obtain a wide dynamic range by adding a small amount of hardware or processing.

[0007]

In order to achieve the above object, a bar code decoding device according to the present invention comprises a data reading means, a margin detecting means, a data storing means for storing data, and a data storing means of the data storing means. A data counting means having a bit width wider than the memory bus width and counting analog data from the data reading means by a reference clock; and a control amount output for detecting the count value of the data counting means and performing data conversion. Data control means for performing, decoding processing means for performing decoding processing, and data conversion means for converting the data output from the data counting means and determining the data to be stored in the data storage means by the output of the data control means. It is characterized by having and.

Further, the data reading means, the margin detecting means, the data storing means for storing the data, the data counting means having a bit width wider than the memory bus width of the data storing means, and the data control means for performing the decoding process. When,
The data output from the data counting means is converted, and data is stored in the remaining bits by using several bits of the data stored in the data storage means as digit number data, and data is read again when the data is read from the data storage means. And a data conversion means for converting.

[0009]

According to the barcode decoding device having the above structure,
When performing the decoding process, the count value of the data counting means is detected by the data control means, and based on the result, the data conversion means determines the data to be stored in the data storage means.

Further, the data output from the data counting means is converted by the data converting means, and several bits of the data stored in the data storing means are used as digit number data to store the data in the remaining bits. Data is converted again when is read.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a first embodiment of the bar code decoding apparatus of the present invention, FIG. 2 is a timing chart, and FIG. 3 is an operation flowchart. In the bar code decoding apparatus shown in FIG. Is data reading means, 2 is data counting means, 3 is data converting means, 4 is margin detecting means, 5 is data controlling means, 6 is data storing means, and 7 is decoding processing means.

In such a configuration, when the analog data from the data storage means 6 is counted by the data counting means 2 by the reference clock and the count value is obtained, the data counting means 2 is calculated from the number of data processing bits of the decoding processing means 7.
2 has a large number of bits (when the number of bits of the decoding processing means 7 and the data storage means 6 is set to 4 in FIG. 2, the count value of the data counting means 2 is the third count value of FIG. When the number of bits is 5 bits or more), the data control means 5 compares the number of bits processable by the decoding processing means 7 with the number of counting bits of the data counting means 2,
As a result, since the lower bits of the data by the data converting means 3 have less influence on the decoding process, the lower bits of the count data of the data counting means 2 are discarded.
It outputs to the decoding processing means 7 in the subsequent stage. By this operation, it is possible to widen the data processable bit width of the barcode decoding device itself without changing the decoding processing means 7 in the subsequent stage.

That is, the margin of the analog data read by the data reading means 1 is detected by the margin detecting means 4. Then, based on the count value of the data counting means 2, the data control means 5 detects the bit width of the count data and derives the conversion amount of the data converting means 3. The data conversion means 3 receives the information from the data control means 5 and outputs the data to the decoding processing means 7 in accordance with the information.

The operation of the first embodiment will be described below with reference to the flowchart of FIG.

From the analog signal read by the data reading means 1, the margin detection means 4 detects the margin (S1, S2), and after the margin detection (YES in S2),
Data counting means 2 of Y-bit width using a reference clock
The data is counted by (S3). When the number of bits of the count value of the first count data after the margin detection is C bits and the bit width of the decoding processing means 7 and the data storage means 6 is X bits, the data control means 5 causes the data conversion means 3 to operate. On the other hand, when C ≦ X-3, 0 is output, and when C> X-3, the value C−X + 3 is output as control data (S
4, S5).

In the data conversion means 3 which has received the data from the data control means 5, since the data of the lower bits has little influence on the processing result of the decoder, the count value is right-shifted by the number of data, that is, the lower bits are truncated. The data is converted (S6, S7) and output to the data storage means 6 (S8). By this operation, the data input to the decoding processing means 7 is always X bits or less regardless of the count value of the data counting means 2, and decoding can be performed without changing the data storage means 6 and the decoding processing means 7 (S
9).

When the data control means 5 has once determined the data control amount and the data counting means 2 must further change the control amount (NO in S4), that is, the bit width of the count value data is set to R. At this time, if R> C + 3, the count value data after margin detection is eight times or more of the data, so that it is judged that it is a margin and the import processing is ended (S10, S11). In this case, Y
Let ≧ X.

FIG. 4 is a block diagram showing the configuration of the second embodiment of the bar code decoding apparatus of the present invention. The difference between the second embodiment and the first embodiment is that the data storage means 6 is interposed. The point is that the two data conversion means 3a and 3b are provided separately.

In such a configuration, when the number of bits of the counter in the data counting means 2 is 12 bits and the data width of the data storing means 6 is 8 bits, the highest rank where the data counting means 2 has 1 bit. When the bit is the fifth bit or more (see FIG. 5), the data of 5 bits from the most significant bit and the remaining 3 bits of the lower bit number are stored in the data storage means 6. When the most significant bit whose bit is 1 in the data counting means 2 is the fifth bit or less (see FIG. 6),
Data of 5 bits from the least significant bit and 0 data of 3 bits are stored in the data storage means 6.

When data is read, the reverse conversion is performed to obtain data with 5 significant digits. By performing such conversion before the data storage and before the data read, the decoding process can be performed without changing the bit width of the data storage means 6, and the read data range can be expanded. When actually performing the decoding process,
The accuracy does not increase even if the number of significant digits is large, and decoding is possible if a certain number of digits is obtained.

[0022]

As described above, according to the invention of claim 1, the bar code decoding device of the present invention detects the count value of the data counting means by the data control means when performing the decoding process, Since the data conversion unit determines the data to be stored in the data storage unit based on the result, the dynamic range of data reading can be expanded without changing the decoding function and increasing the memory amount of the data storage unit.

According to the second aspect of the present invention, the data converting means converts the data output from the data counting means, and at the same time, several bits of the data stored in the data storing means are used as the digit number data and the remaining bits are filled with the data. Since the data is stored and the data is converted again when the data is read from the data storage unit, the count value in the data counting unit is stored with a small memory amount, and the dynamic range of data reading can be expanded without increasing the memory amount. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of a bar code decoding device of the present invention.

FIG. 2 is a timing chart of the first embodiment.

FIG. 3 is an operation flowchart of the first embodiment.

FIG. 4 is a block diagram showing the configuration of a second embodiment of the barcode decoding device of the present invention.

FIG. 5 is an explanatory diagram showing an example of a relationship among count data, stored data, and processed data.

FIG. 6 is an explanatory diagram showing another example of the relationship between count data, stored data, and processed data.

[Explanation of symbols]

1 ... Data reading means, 2 ... Data counting means, 3 ... Data converting means, 4 ... Margin detecting means, 5 ... Data controlling means, 6 ... Data storing means, 7 ... Decoding processing means.

Claims (2)

[Claims] 1. A data reading means, a margin detecting means, a data storing means for storing data, and a bit width wider than a memory bus width of the data storing means, wherein analog data from the data reading means is used as a reference. A data counting means for counting by a clock, a data control means for detecting a count value of the data counting means and outputting a control amount for data conversion, a decoding processing means for performing a decoding process, and a data counting means from the data counting means. A bar code decoding device, comprising: a data conversion means for converting a data output and determining the data to be stored in the data storage means by the output of the data control means. 2. A data reading means, a margin detecting means, a data storing means for storing data, a data counting means having a bit width wider than a memory bus width of the data storing means, and a data control means for performing a decoding process. And converting the data output from the data counting means,
Data conversion means for storing data in the remaining bits by using several bits of data stored in the data storage means as digit number data and performing data conversion again when reading data from the data storage means And barcode decoding device.