JP2002042052A - Symbol information reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem of a symbol information reading device for a two-dimensional bar code that, in the state where no load or the like is carried in, if any pattern similar to a bar code is present in the imaging region of the symbol information reading device, every imaging operation necessarily involves detecting and decoding processing on the bar code symbol and resultantly produces a processing waiting time when a new load is carried in. SOLUTION: The symbol information reading device is characterized in that information in characteristic part of luminance value information from a two-dimensional image CCD 4 having a photoelectric transfer surface is extracted and is stored in a first storing device, characteristic part information obtained from the previous or order imaging through the characteristic extraction is stored in a second storing device, the variation in the two pieces of characteristic part information stored in both storing devices is evaluated, and according to the variation in the two pieces of characteristic part information thus obtained, it is determined whether the CCD 4 is actuated or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a symbol information reading apparatus having two-dimensional image pickup means such as a CCD (Charge Coupled Device) for reading symbol information, for example, bar codes and OCR characters.

[0002]

2. Description of the Related Art With the recent remarkable spread of POS (point-of-sale = point-of-sale information management system), various symbols represented by barcodes have been widely and generally used. Here, the symbol is an appropriate combination of bars and spaces printed for optical information recognition, or alphanumeric characters, characters, or symbols, or engraved uneven shapes, or the like, and This is for improving the efficiency of input.

At present, bar codes that are widely used for general consumer goods include JAN (Japanese Article).
Number) and EAN (European Article Number). In addition, there is a distribution symbol in which a one-digit or two-digit distribution identification code is added before the JAN symbol. Any of the above barcode symbols is called a one-dimensional barcode.

[0004] These symbol systems are more advantageous than conventional management methods in terms of simplicity, accuracy, high speed, cost, and the like in handling numerical and character information. In recent years, it has become very widespread.

In recent years, several symbol systems called two-dimensional barcodes have been announced as extensions of one-dimensional barcodes. Although these symbol systems are not as widely used as one-dimensional barcodes, by stacking one-dimensional barcodes and giving information in two-dimensional directions,
This has the advantage that more information can be processed collectively. Symbols of this type include, for example, P
There is a barcode symbology called DF-417. Also, postal barcodes that are being introduced in Europe and the United States and customer barcodes that have recently been introduced by the Ministry of Posts and Telecommunications of Japan have two-dimensional information, and are classified into two-dimensional barcode symbols. You.

Conventionally, as a symbol information reading device for such a two-dimensional bar code, for example, Japanese Patent Laid-Open No.
There was one disclosed in No. 7830. This apparatus continuously performs imaging and barcode symbol detection and decoding processing to determine the presence or absence of a barcode label in an imaging area, so that a user can operate a one-dimensional barcode without operating a reading switch or the like. When a luggage or the like to which a code label or a two-dimensional bar code label is attached is carried in, it can be automatically read.

[0007]

However, in such a two-dimensional bar code symbol information reading apparatus,
In the state where the luggage or the like with the barcode label attached is carried in and settled, it can be read. In such a case, the barcode symbol detection and decoding processing is always performed for each image pickup, and a problem occurs in that a processing waiting time is generated when a new package is carried in. Hereinafter, this problem will be described.

In general, a one-dimensional barcode, the above-described postal barcode, and the like are composed of simple patterns.
For example, in the above-mentioned JAN symbol, the start / stop pattern indicating the JAN symbol is composed of at most two parallel lines. In the normal use of the symbol information reading device, it is normal that there is a pattern composed of a diagram or a character on a desk or a wall portion serving as an imaging area of the device. Therefore, the symbol information reading device is continuously read. When the symbol information reading device is set on the desk or the like and set on a desk or the like, in many cases, the symbol information reading device is in a state of repeatedly detecting and decoding barcode symbols.

Further, the number of pixels of an image pickup element used in a commercially available two-dimensional bar code symbol information reading apparatus tends to increase over several hundred thousand, and one-dimensional bar code symbols and two-dimensional bar codes are used. Since the types of code symbols tend to be newly added in recent years, the time required for barcode symbol detection and decoding processing required for one imaging operation, that is, any position, orientation, and size from among all imaged image data. The time required to detect the presence and absence of barcode labels of any type and to decode the barcode pattern into barcode data tends to increase. For example, in a currently available symbol information reading device equipped with a CCD having about 300,000 pixels, a one-dimensional bar code having an information amount of about 10
It takes about 00 ms or more. In the case of a two-dimensional barcode such as PDF-417, a maximum of 10
Since character information of 00 characters or more can be encoded, it may take about 1000 ms to detect and decode the barcode symbol depending on the label to be read, the imaging conditions, and the like.

Therefore, when the apparatus is used for continuous reading, in many cases, the symbol information reading apparatus always takes about several hundreds to 1000 ms even though the bar code label is not actually imaged. The state is such that the detection and decoding of the barcode symbol is repeated.

In this state, if a baggage or the like to which a barcode label is newly attached is carried into the image pickup area, the barcode symbol detection and decoding processing is completed for the previous image in which the barcode label is not imaged. Later, since the barcode is imaged and the image is processed, a maximum of 1
A processing wait time of about 000 ms occurs.

Therefore, for example, when the baggage is continuously carried in by a belt conveyor or the like and automatic recognition is performed, there is a high possibility that the baggage will pass during the processing waiting time and fail to read the barcode. Become.

When the baggage passes, the pattern of the imaging region returns to the original state, and the barcode symbol detection and decoding process is repeated again.
Each time a new package is carried in, the processing waiting time repeatedly occurs. Therefore, the timing of imaging is repeatedly delayed, and the reading performance of the apparatus is significantly reduced.

Therefore, if the carrying speed of the belt conveyor is sufficiently reduced so that the barcode is reliably decoded within the processing waiting time, the probability of successful reading is improved. However, the essential problem of the occurrence of the processing waiting time has not been solved, and as a result, the reduction in the carrying speed of the belt conveyor significantly reduces the processing capacity of the entire belt conveyor facility.

Conventionally, for such a reason, a symbol information reading apparatus capable of continuously reading a two-dimensional bar code has been described.
A special position detector using infrared rays or the like is provided around the belt conveyor, and by detecting the passage of luggage in advance and adjusting the carrying speed of the belt conveyor and the timing of imaging, the barcode label that intermittently passes Although there was an apparatus that performs reading processing, such a configuration allows reading of one-dimensional and two-dimensional barcodes that pass at high speed, but requires the installation of a special position detector or the like, which makes the apparatus large. And resulted in higher prices. In addition, inconveniences such as limitations on the installation location and the intended use have occurred due to the size and configuration of the device.

Further, even in the symbol information reading apparatus for a two-dimensional bar code, instead of the continuous reading as described above, in the case of reading by a trigger in which a user reads a bar code by pulling a trigger, The user may point the device at the bar code portion and then pull the trigger, for example. At this time, the time interval for pulling the trigger is usually about several seconds. At the time when the trigger is pulled, the detection and decoding processing of the barcode symbol for the previously captured image has already been completed. It did not become.

On the other hand, in the case of a conventional one-dimensional bar code symbol information reading apparatus using a laser or a one-dimensional imaging device, the time required for one scan is about several tens of ms, Since the amount of information of the barcode itself is small, the processing waiting time as described above does not pose a problem even for continuous reading.

As described above, the symbol information reading device for two-dimensional barcodes has a practical use in which the waiting time occurs and the timing of image pickup is repeatedly delayed in the case of continuously and automatically processing luggage and the like. However, despite the advantage that more information can be processed collectively, the spread of the information has been delayed.

An object of the present invention is to transfer the luminance value information or the image-processed information at the time when a baggage or the like is carried in without providing a special position detector or the like even for continuous reading. It is an object of the present invention to provide a symbol information reading apparatus which is excellent in high-speed response, saves power, continuously captures images and is excellent in high-speed response.

[0020]

In order to achieve the above object, a symbol information reading apparatus according to the present invention comprises: an image pickup means for picking up an area having portions having different light reflectances as a two-dimensional image; Storage means for temporarily storing and holding the brightness value information, information processing means for performing image processing on the brightness value information according to a predetermined procedure, and information for transferring the brightness value information or the image-processed information. A symbol information reading device having a transfer unit;
A feature extracting unit that extracts information of a feature portion of the luminance value information; a first storage unit that stores information of a feature portion obtained by the feature extracting unit; A second storage unit for storing information of the obtained characteristic portion, the first storage unit, and the second storage unit.
Comparing and evaluating means for evaluating the amount of change in the information of the two characteristic parts stored in the storage means, and based on the amount of change in the information of the two characteristic parts obtained by the comparing and evaluating means, It is characterized in that it is determined whether or not to operate the imaging means.

[0021] Further, an image pickup means for picking up a region having different light reflectance portions as a two-dimensional image, a storage means for temporarily storing and holding luminance value information of the two-dimensional image, and In a symbol information reading device having information processing means for performing image processing according to a predetermined procedure and information transfer means for transferring the luminance value information or the information subjected to the image processing, information on a characteristic portion of the luminance value information , A first storage unit that stores information of a characteristic portion obtained by the feature extraction unit, and a storage unit that stores information of a characteristic portion obtained by one or more previous imaging by the feature extraction unit. A second storage unit, a comparison evaluation unit that evaluates a change amount of information of two characteristic portions stored in the first storage unit and the second storage unit, Illuminating means for illuminating an area having a portion having a light reflectance of, based on the amount of change in the information of the two characteristic portions obtained by the comparison and evaluation means, switching of illumination irradiation of the illuminating means It is characterized by performing.

Further, an image pickup means for picking up a region having different light reflectance portions as a two-dimensional image, a storage means for temporarily storing and holding luminance value information of the two-dimensional image, and In a symbol information reading apparatus having information processing means for performing image processing according to a predetermined procedure and information transfer means for transferring the luminance value information or the information subjected to the image processing, information of a characteristic portion of the luminance value information A feature extraction unit to be extracted, a first storage unit that stores information of a feature portion obtained by the feature extraction unit, and a feature unit that stores information of a feature portion obtained by one or more previous imaging by the feature extraction unit. A second storage unit, and a comparison evaluation unit that evaluates a change amount of information of two characteristic portions stored in the first storage unit and the second storage unit; 2 obtained by serial comparative evaluation means
The information transfer means determines whether to transfer the luminance value information or the image-processed information based on the amount of change in the information of the two characteristic portions.

According to the symbol information reading apparatus having the above-described configuration, a symbol information reading apparatus which is excellent in continuous image capturing and high-speed response without providing a special position detector or the like even for continuous reading. Can be provided.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. Drawings according to an embodiment of the present invention are shown in FIGS.

A first embodiment of the present invention will be described with reference to FIGS. First, FIG. 1 shows a mode in which the symbol information reading device according to the first embodiment of the present invention is used. The symbol information reading device 1 is connected to a host computer 6. First, a package 7 having a barcode label 8 affixed in a preset imaging area.
Is carried in by, for example, a belt conveyor 20. A light source (not shown) emits divergent light to the package 7 to which the barcode label 8 is attached. The symbol information reading device 1 includes a barcode label 8 as described in detail later.
Is imaged to detect a barcode, and the decoded information and the like are transferred to the host computer 6.

The host computer 6 includes, for example,
It is composed of a CPU (Central Processing Unit), a memory, and the like, and can communicate with the symbol information reading device 1. Based on the information decoded by the symbol information reading device 1, the peripheral device is automatically operated. And various processes such as temporarily stopping / starting the setting of continuous reading of the symbol information reading device 1.

The host computer 6 may be any computer, such as a personal computer or a mobile computer, as long as it can support the communication system of the symbol information reading device 1.

Next, the configuration of the symbol information reading device 1 will be described.

The symbol information reading device 1 comprises a light emitting diode 2, an imaging lens 3, an imaging device 4, and a main unit 5.

The light emitting diode 2 includes a main unit 5
Illuminates the imaging area of the imaging element 4 based on the input signal from the.

The imaging lens 3 has a bar code label 8
The light reflected from is formed on the photoelectric conversion surface (light receiving area) of the image sensor 4.

The image pickup device 4 is, for example, a two-dimensional CCD having 640 × 480 pixels having a photoelectric conversion surface, and has a function of converting information of an optical image formed on the photoelectric conversion surface into luminance value information. Having.

The main unit 5 comprises a CPU, a frame memory, an external interface and the like.
The image sensor 4 and the light emitting diode 2 are controlled, and the luminance value information of the two-dimensional image obtained from the image sensor 4 is temporarily stored and held in a frame memory. The direction, the size, and the type are estimated, and barcode symbol detection and decoding are performed. Also,
Various processes such as transferring the decoded barcode data and the captured image data to the host computer 6 are performed.

The various processes described above will be described in detail below.

FIG. 2 shows a block configuration of the control system according to the first embodiment of the present invention.

First, the information processing section 9, the feature extracting section 10 and the feature comparing section 11 are constituted by a CPU, a volatile memory, a non-volatile memory, an electric circuit and the like.

The information processing section 9 monitors the states of the information transfer section 15, the feature comparison section 11, the frame memory 12, and the like.
Further, it controls each unit such as the imaging control unit 14 and the information transfer unit 15 and controls the operation of the entire symbol information reading device 1 (see FIG. 1). When the barcode label is imaged, the barcode is detected and decoded for the luminance value information stored and held in the frame memory 12, and the information decoded via the information transfer unit 15 is output to, for example, a personal computer. Various processing such as transfer to a computer or the like is performed.

The image pickup control section 14 is composed of an electric circuit and the like, and sets an electric signal for controlling the exposure of the image pickup section 13 based on an input signal from the information processing section 9 to provide an illumination section. 16 and the imaging unit 13 are controlled and operated.

The illumination unit 16 includes the light emitting diode 2 (see FIG. 1), a mirror, and an electric circuit, and a two-dimensional image captured by the imaging unit 13 based on an input signal from the imaging control unit 14. Illuminate the area.

The image pickup section 13 has an image pickup lens 3, an image pickup device 4 (see FIG. 1), an electric circuit for exposure control, and the like.
Based on an input signal from the imaging control unit 14, parameters for exposure control of the imaging element 4 are set, and image information formed on the photoelectric conversion surface of the imaging element 4 is output as an analog image signal. The signal is A / D converted into 8-bit gray scale luminance value information and output.

The frame memory 12 temporarily stores and holds the luminance value information obtained from the image pickup unit 13.

The information transfer section 15 has, for example, an RS-232C communication circuit as an external interface, and transmits barcode data, image information, and the like decoded by the information processing section 9 to an external host computer 6. I do. The command data and the like received from the external host computer 6 are transferred to the information processing section 9.

The feature extracting unit 10 is provided with the frame memory 1
2 to obtain the luminance value information stored and held therein, extract the characteristic information of the luminance value and the characteristic information of the shape, and store the characteristic information already stored and held in the storage unit 17a by the previous imaging process. After being saved by the means 17b, the extracted feature information is transferred to the storage means 17a and stored.

The storage means 17a is composed of a memory, an electric circuit, or the like, and temporarily stores and retains the characteristic information of the luminance value and the characteristic information of the shape transferred by the characteristic extracting unit 10.

The storage means 17b is composed of a memory, an electric circuit, and the like. The characteristic information of the luminance value and the characteristic information of the shape obtained by the immediately preceding image pickup processing transferred by the characteristic extracting section 10 are provided. Is temporarily stored.

The characteristic comparing section 11 acquires the characteristic information of the luminance value and the characteristic information of the shape stored and held in the storage means 17a and 17b by a predetermined procedure, and calculates the difference between these values. It has a function of calculating and calculating a change amount of the feature information.

Next, the operation of the symbol information reading device 1 according to the first embodiment of the present invention will be described with reference to the flowchart of FIG.

The user of this device first turns on the power of the symbol information reading device 1 and the host computer 6 to activate the device. Then, initial setting of the symbol information reading device 1 is performed, and
After the PU, the electric circuit, and the like are reset, the contents of the nonvolatile memory are read, and various parameters such as thresholds used for detecting a characteristic portion described later are set in detail. Step S1) is performed.

Next, an imaging process (step S2) is performed. FIG. 4 shows an outline of the operation of this imaging processing. First, exposure control parameters are set (step S21). That is, the information processing unit 9 controls the frame memory 1
When the luminance value information stored and held in the memory 2 is acquired and the luminance value level is not at the appropriate level, the imaging time and the gain value of the amplifier for amplifying the image signal from the imaging element 4 are determined. The parameters for exposure control such as the presence or absence of illumination irradiation are changed. When the luminance value level is at an appropriate level, the exposure control parameters are not changed and are held. The parameters for the exposure control are input to the imaging control unit 14 as control signals, and are stored and held. Also, at the initial stage or immediately after the decoding process described later,
It is set not to irradiate illumination.

Next, an image capturing process (step S22) is performed by operating the image pickup device 4. The obtained image is transferred to the frame memory 12 as 8-bit gray scale luminance value information and stored and held (step S23). FIG. 5 is a conceptual diagram of luminance value information stored and held in the frame memory 12 when a background portion is imaged when a baggage or the like to which a barcode label is attached is not carried into the imaging region. (A). When the acquisition of the luminance value information from the frame memory is completed, the control is returned to the upper routine.

Next, the feature extraction process (step S3) in FIG. 3 is performed. FIG. 6 shows an outline of the operation. First,
As shown in the conceptual diagram of FIG.
The luminance values for two lines are obtained diagonally for the luminance value information in 2. These are the variables P1 (i) and
The value is stored in the volatile memory as P2 (i) (i = 1, 2, 3,..., 640) (step S31). By performing the diagonal feature extraction, it is possible to evaluate the amount of change in the information of the feature portion over the entire imaging region, as will be described later in detail. The values of the variables P1 (i) and P2 (i) are from 0 to 255
Take an integer value up to. After that, similarly, various variables are
The area is secured and stored in volatile memory by
Various calculations are performed.

Next, the variable P1
For (i) and P2 (i), according to (Equation 1), the average value P_a
ve is obtained (step S32). At this time, N1 corresponds to the number of pixels for one line of the region where the characteristic portion is extracted.

[0053]

(Equation 1)

Next, acquisition of shape characteristic information (step S)
33) is performed. FIG. 7 shows an outline of the operation. First, various parameters for acquiring shape characteristic information are set (step S331).

Next, the aforementioned P1 (i) (i = 1, 2, 3,...,
640), it is determined whether it exceeds the average value P_ave. If the average value exceeds P_ave, the corresponding variable B1
(i) 1 is substituted into (i = 1, 2, 3,..., 640) (step S333). If the average value P_ave is not exceeded, 0 is substituted for the corresponding variable B1 (i) (i = 1, 2, 3,..., 640) (step S334), and all i (i = 1, 2, 3) ,
…, 640). Equivalent operation
This is also performed for P2 (i) (i = 1, 2, 3,…, 640) to determine the value of the corresponding variable B2 (i) (i = 1, 2, 3,…, 640).

All P1 (i) and P2 (i) (i = 1, 2,
(3,…, 640) is completed (step S
335), B1 (i) and B2 (i) (i = 1, 2, 3,..., 64
Control is returned to the upper-level routine using the value of 0) as feature information of the shape. Next, in the feature extraction process (step S3) of FIG. 6, the average value P_ave is set to the feature information of the brightness value, the variable B1 (i),
Then, control is returned to the upper routine using B2 (i) (i = 1, 2, 3,..., 640) as the shape characteristic information.

Next, the process of storing the information of the characteristic portion in FIG. 3 (step S4) is performed. FIG. 8 shows an outline of the operation. First, before storing the information on the characteristic portion obtained in the feature extraction process (step S3) in the storage unit 17a, the information on the characteristic portion already stored and held in the previous imaging is stored in the storage unit 17a from the storage unit 17a. 17b
And save it. That is, the storage unit 17
The characteristic information Pa_ave of the luminance value stored and held in a
And shape feature information Ba_1 (i) and Ba_2 (i) (i =
, 640) are transferred to the storage means 17b, and the luminance value feature information Pb_ave and
Shape feature information Bb_1 (i) and Bb_2 (i) (i = 1, 2,
, 640) in the storage means 17b (step S41).

Next, the above-described feature extraction processing (step S
The characteristic information P_ave of the luminance value obtained in 3), and
Shape feature information B1 (i) and B2 (i) (i = 1, 2, 3,
, 640) are transferred to the storage means 17a, and the luminance value characteristic information Pa_ave and the shape characteristic information Ba_1 (i) and Ba_2 (i) (i = 1, 2, 3) ,…, 64
0) is newly stored in the storage means 17a (step S42). That is, according to this processing, 1
The storage unit 1 stores the feature information about the image taken last time.
7b, and characteristic information about the newly captured image is stored in the storage unit 17a. When the storing process of the information of the characteristic portion (step S4) is completed, the control is returned to the upper routine.

Next, the process of calculating the amount of change (step S5)
Is performed. First, P_div,
And two variables B_div are set. These correspond to the change amount of the characteristic portion of the luminance value and the change amount of the characteristic portion of the shape, respectively, and are calculated by (Equation 2) and (Equation 3) shown below, respectively.

[0060]

(Equation 2)

[0061]

(Equation 3)

Here, the symbols |... | Indicate that an absolute value is calculated for. N1 is equivalent to the number of pixels for one line in the region from which the characteristic portion is extracted, and is a constant of N1 = 640. After this calculation, the calculation of the amount of change (step S5) is terminated, and control is returned to the upper routine.

Next, referring to FIG. 3, the aforementioned change amount (P_di
(v, B_div) exceeds the threshold (step S6). Here, first, two thresholds P_thr, B_th
The value of r is read out at the time of the above-described initial setting (step S1), and is already stored and held in the nonvolatile memory as a set value.
thr = 10, B_thr = 200, and P_th
r = 10 and B_thr = 200 correspond to a threshold value for evaluating a change amount of a characteristic portion of a luminance value and a threshold value for evaluating a change amount of a characteristic portion of a shape portion.

These threshold values allow the user to arbitrarily change the set values in the nonvolatile memory by transferring command data from the host computer 6 to the information processing section 9. The detection sensitivity of luggage and the like can be arbitrarily changed according to the fluctuation of external light at the installation location, the color and type of the label, the size of luggage to be automatically recognized, and the like.

Next, P_div> P_thr or B_div>
It is determined whether two inequalities of B_thr hold. If either one or both inequalities hold, it is determined that the amount of change in the information of the characteristic portion has exceeded the threshold, and the flow proceeds to label reading processing (step S7). Otherwise, control is returned to the imaging process (step S2) routine.

Next, an outline of the operation of the label reading process (step S7) in FIG. 3 is shown in FIG. First, in the information processing section 9, the frame memory 12
It is determined from the luminance value information stored and held whether the luminance level of the captured image is appropriate (step S7).
1). If the luminance value level is not appropriate, switching of illumination irradiation, resetting of parameters for exposure control, and the like are performed, an image is captured by the imaging unit 13, and the luminance value information is stored in the frame memory 12. (Step S7
2) Next symbol detection / decoding processing (step S7)
Move to 3). On the other hand, if the luminance value level is appropriate, the detection / decoding processing of the next symbol is immediately performed (step S
73) is performed. That is, the frame memory 12
The presence / absence of a barcode pattern is detected with respect to the luminance value information stored in the barcode. If the barcode pattern is detected, the pattern is decoded into barcode data.
FIG. 5C is a conceptual diagram when the PDF-417 label is taken into the frame memory 12. The detection and decoding of these barcode symbols may be equivalent to the method disclosed in Japanese Patent Application Laid-Open No. 5-197830. Further, when a postal barcode or a one-dimensional barcode is imaged, the method may be equivalent to the method disclosed in Japanese Patent Application Laid-Open No. 11-3397. After this processing, control is returned to the upper routine (see FIG. 9).

Next, returning to FIG. 3, it is determined whether or not the barcode has been successfully decoded (step S8). If the barcode has not been successfully decoded, the control is returned to the imaging process (step S2). On the other hand, when the barcode is successfully decoded, data output processing (step S9) is performed. That is, it is determined whether or not there is a reading error, such as whether or not the same label is read twice, and if it is determined that there is no reading error and normal bar code label reading has succeeded, the decoded bar code label is read. The code data or the like is stored in the information
The data is output to the host computer 6 via the 32C interface (step S9). On the other hand, if there is a reading error or the like, the process proceeds to the next step without outputting the barcode data. If the decoded barcode is a barcode for a special command for a predetermined device setting, the setting of the main body of the symbol information reading device 1 is changed. When the decoded barcode is a barcode for outputting a special image determined in advance, the captured image data is output to the host computer 6 instead of outputting the decoded barcode data. . Thereafter, decoding end processing such as resetting various parameters is performed.

Further, after this, the image pickup processing (step S
The control is returned to 2), and the above operation is repeated.

As described above, the symbol information reading apparatus according to the first embodiment of the present invention evaluates the change amounts of the luminance value characteristic information and the shape characteristic information for continuously captured images. As a result, the imaging process (step S2) can be performed continuously without performing the label reading process (step S7). Further, according to the first embodiment of the present invention, even if the processing capability of the CPU or the like is about the same as that of the currently marketed two-dimensional symbol information reading device, the processing from step S3 to step S6 in FIG. The time required is about several tens ms or less, and the device can be used without stress. In addition, the imaging process (step S
The time required for 2) depends on the specifications of the mounted image sensor 4 and the like, but is about several tens of ms. Therefore, the imaging process (step S2) can be repeated at a high speed.

Further, when a load to which a barcode label has been attached is carried in, the luminance value information stored in the storage means 17a and 17b changes, and the label reading process (step S7) is executed.
Further, when a load to which the barcode label is attached is carried in, the information of the shape portion stored in the storage means 17a and 17b changes, and the pattern of the load or the background moves by a predetermined amount or more. At this point, a label reading process (step S7) is executed. Therefore, the label reading process (step S7) is performed at the time when the baggage is carried in, without depending on the shape of the baggage or the label, etc., for the baggage etc. which are continuously carried in. Also,
At this time, the illuminance is insufficient at the time when the baggage is carried in, and the illumination irradiation is switched to change the gain value and the exposure time of the amplifier for amplifying the image signal from the image sensor 4 to perform the next imaging process. Is carried out in about several tens of ms, there is no particular problem.

Further, even if the baggage to which the barcode label is attached is imaged, even if it is determined that the image is the background, the baggage can be stored in a predetermined procedure. Since the label reading process (step S7) is performed at the time when the label is moved beyond the threshold value obtained by the above, there is no particular problem. In addition, in a state where the change of the characteristic portion of the image is reduced to a certain amount or less after the label decoding process or the like is completed, the state is reset to a state where illumination is not performed, so that power saving is excellent.

In the first embodiment of the present invention, the feature extracting unit 10 and the feature comparing unit 11 are processed by software on a memory by a CPU. It may be configured in hardware as in the embodiment.

Next, a second embodiment of the present invention will be described.
This will be described with reference to FIG.

FIG. 10 shows a block configuration of the symbol information reading apparatus according to the second embodiment of the present invention.

The configurations of the illumination unit 16, the imaging unit 13, the imaging control unit 14, the information processing unit 9, and the information transfer unit 15 having the configuration shown in FIG. 2 according to the first embodiment of the present invention are the same. In addition, as conceptually shown in FIG.
An IC chip 18 having the feature comparison unit 11, the storage unit 17a, and the storage unit 17b is configured to be incorporated on a substrate on which the CPU of the information processing unit 9 is mounted. Then, the IC chip 18 is incorporated at a position where the luminance value information having the configuration of FIG. 2 is transferred from the imaging unit 13 to the frame memory 12. That is, when the luminance value information is transferred to the frame memory, the feature extraction is performed by the IC chip 18, the amount of change is evaluated by the feature comparison unit 11, and the result is output as an output signal from the IC chip 18. . Then, the output signal is directly input to the imaging control unit 14 to operate the imaging unit 13 continuously.

Here, the parameters for the exposure control are sent to the imaging control unit 14 as input signals from the information processing unit 9 and stored when the initialization at the time of startup and the detection and decoding of the barcode symbol are performed. Is held.

The acquisition of the luminance value information in the feature extracting unit 10 is performed in the same manner as in FIG.
Instead of the diagonal shape shown in (b), the order in which the luminance value information is transferred from the imaging unit 13 to the frame memory 12, that is, the horizontal direction in the frame memory 12 (the main scanning direction of the imaging device 4). Orientation). Further, as information on the characteristic portion, an average value of the transferred luminance value information is calculated, and these are used as information on the characteristic portion. And the I
The information in the storage unit 17a in the C chip 18 is stored in the storage unit 17
After that, the information of these characteristic portions is stored in the storage unit 17a. Then, the difference between the average values of the luminance values stored in the storage unit 17a and the storage unit 17b is calculated by an electric circuit to determine whether the change amount exceeds a threshold value. As an output signal to the imaging control unit 14. This imaging control unit 14
Operates the imaging unit 13 and the illumination unit 16 repeatedly based on a preset exposure control signal and an input signal from the feature comparison unit 11 in the IC chip 18.

As described above, according to the second embodiment of the present invention, C
The PU only needs to perform barcode symbol detection and decoding processing, change parameters for exposure control, and the like when there is a change in the captured image, and eliminate the delay in the imaging timing to improve the reading performance. Is greatly improved.

With the hardware configuration as described above, a symbol information reading device with further excellent high-speed response can be configured.

In the acquisition of the feature information of the shape according to the first embodiment of the present invention (step S33), an edge may be extracted. That is, when acquiring the luminance value information, a difference between the luminance values of adjacent pixels is calculated, and when the difference value exceeds a threshold obtained by a predetermined procedure, 1 is set, and in other cases, 0 is set. The contour shape of the image information is obtained as the shape feature information. This allows
It is possible to provide a symbol information reading device that is not easily affected by unevenness in illumination of external light.

In the first embodiment of the present invention,
Although the threshold values P_thr and B_thr are fixed values, the threshold values may be calculated and varied according to a predetermined procedure based on the image quality of a captured image or the like. For example, the amount of noise is evaluated with respect to the above-described luminance value information, and the amount of change in the characteristic information when the label is successfully decoded is evaluated.
The values may be repeatedly changed so that P_thr and B_thr sufficiently exceed the noise amount and are equal to or less than the change amount of the feature information when the label is successfully decoded. This allows
Less susceptible to image noise generated during imaging, and
It is possible to provide a symbol information reading device excellent in baggage detection accuracy.

Further, in the first embodiment of the present invention, the feature information stored in the storage means 17b stores and holds the feature information obtained in the immediately preceding imaging process. The information of the characteristic portion obtained in the above-described imaging processing may be numerically processed.
For example, in the process of transferring the information of the characteristic portion in step S41, the average value of the value of the characteristic information already stored in the storage unit 17b and the value of the characteristic information stored in the storage unit 17a is calculated. The result may be newly stored in the storage unit 17b. According to this method, it is possible to evaluate the information of a large number of characteristic parts obtained in the one or more previous imaging with a certain weight, and thus to reduce the influence of the temporary fluctuation of the imaging condition, It is possible to improve the stability of the device and the accuracy of detecting the load. In the process of transferring the information of the characteristic portion in step S41, a process of removing image noise caused by the image sensor 4 may be performed. According to these, it is possible to provide a symbol information reading device that is excellent in high-speed response and excellent in detection accuracy and stability.

In the label reading process (step S7) according to the first embodiment of the present invention, instead of outputting the decoded barcode data, the output of the picked-up image data may be performed. That is, the image data of the package may be transferred to the host computer 6 when the package is detected. At this time, the information processing unit 9 may compress the image data in a format such as JPEG, GIF, or TIFF according to a predetermined procedure, and transfer the image-processed information. According to this, the transfer time in the information transfer unit 15 can be reduced according to the compression ratio of the image-processed information due to the compression. BITMAP,
It may be output in a format such as PICT. At this time, if a database for temporarily storing the image data is configured on the host computer 6 side, there is an inquiry or the like from the transport destination regarding the carried-out luggage or the like by using the symbol information reading device of the present invention. It is possible to easily configure a system that can refer to or confirm the luggage that has been carried out or the inside of the luggage with image data.

In the process of acquiring the characteristic information of the shape (step S33) in the symbol information reading apparatus 1 according to the first embodiment of the present invention, the coordinate area where the characteristic information of the shape has changed is obtained in advance. In the label reading process (Step S7) performed thereafter, the symbol detection process may be preferentially performed in this coordinate area. According to this configuration, the label reading process (step S7) can be further speeded up.

In the symbol information reading apparatus 1 according to the first embodiment of the present invention, continuous reading is set when the apparatus is set on a stand or the like, and when the apparatus is removed from the stand or the like. The reading may be set by the trigger described above. In this case, for example, a magnet is incorporated in the stand, and a sensor and an electric circuit of the magnet are incorporated in the device side, and an output signal of the sensor is subjected to an imaging process (step S
Monitoring is performed immediately before step 2) to determine whether the apparatus is placed on a stand. Thus, it is possible to provide a symbol information reading device that supports both continuous reading and reading using a trigger.

In the first embodiment of the present invention, the baggage conveyed by the belt conveyor 20 is automatically recognized. However, the present invention is not necessarily limited to the above-mentioned use form. For example, the symbol information reading apparatus of the present invention is configured as a slot-type POS terminal, and a product or the like on which a one-dimensional barcode label or a two-dimensional barcode label is printed is carried into the imaging area by hand and automatically recognized. May be used.

For example, as an outdoor camera,
The symbol information reader of the present invention may be used to automatically recognize intermittently passing cargo trucks.

Further, for example, when the symbol information reader of the present invention is incorporated in a mobile computer and a card on which a bar code is printed is read, information in a database created in advance in the mobile computer is obtained. May be displayed. In this case, as already used in several states in the United States as a driver's license, the card has a PDF-41.
If seven symbols are printed and the card is read, a system that can refer to a database of personal information or the like can be easily configured.

In the feature extraction process (step S3) according to the second embodiment of the present invention, similar to the feature extraction according to the first embodiment of the present invention, a binary And may be stored in the storage unit 17a as feature information of the shape. Then, in the feature comparison unit 11, the storage unit 17a and the storage unit 17b
A configuration in which exclusive OR is calculated by an electric circuit for the feature information of the corresponding shape stored in, the total value is counted, and a label reading process is executed when the total value exceeds a threshold obtained by a predetermined procedure. It may be. According to this, the feature extraction unit 10, the feature comparison unit 11, the storage unit 17a, the storage unit 17b, and the like can be configured in hardware, and a symbol information reading device excellent in high-speed response can be configured. .

Further, according to the present invention, the above-mentioned comparison and evaluation means evaluates the amount of change in the information of the characteristic portion and does not depend on the barcode pattern. Regardless of the code, a symbol information reading device excellent in high-speed response can be configured.

Further, as examples of barcode labels, for example, PDF-417 and postal barcodes have been mentioned. However, a two-dimensional barcode symbol information reader can read one-dimensional barcodes. However, the bar code label is not necessarily limited to the two-dimensional bar code. Therefore, the bar code label is used, for example, to read only the one-dimensional bar code using the symbol information reader according to the present invention. You may. Also,
A usage form in which only a two-dimensional barcode is read may be used. Further, a one-dimensional barcode and a two-dimensional barcode may coexist, and the barcode may be read.

Furthermore, PDF-417 and postal barcodes have been described as examples of the barcode symbol system to be read, but are not necessarily limited to these symbol systems. That is, PDF-417, Maxi
Code, Data Matrix, QR Code, V
A two-dimensional barcode symbol system such as eriCode, Aztec Code, etc., JAN, Int
errored 2of 5, Code39, Code
128, UCC / EAN128, Codabar, Bo
okland EAN, MSI Pressey, Cod
A one-dimensional barcode symbol system such as e93 may be used. Also, UCC / EAN Composite Sym
The symbol system may be a symbol system in which a one-dimensional barcode and a two-dimensional barcode are combined, such as bol.

The present invention can be summarized as follows.

[Supplementary Note] Supplementary Note 1 An image pickup means for picking up a region having a portion having a different light reflectance as a two-dimensional image, a storage means for temporarily storing and holding luminance value information of the two-dimensional image, A symbol information reading device having information processing means for performing image processing according to a predetermined procedure for information and information transfer means for transferring the luminance value information or the image-processed information; Feature extraction means for extracting information of a portion, first storage means for storing information of a feature portion obtained by the feature extraction means,
A second storage unit for storing information of a characteristic portion obtained in the one or more previous imaging by the characteristic extraction unit, and a second storage unit for storing information in the first storage unit and the second storage unit.
Comparing and evaluating means for evaluating the amount of change in the information of the two characteristic parts, and determining whether to operate the imaging means based on the amount of change in the information of the two characteristic parts obtained by the comparative evaluation means A symbol information reading device (corresponding to claim 1).

With this configuration, it is possible to provide a symbol information reading apparatus which is excellent in power saving, continuous image capturing and high-speed response.

Supplementary Note 2 Image pickup means for picking up a region having different light reflectance portions as a two-dimensional image, storage means for temporarily storing and holding luminance value information of the two-dimensional image, and In a symbol information reading apparatus having information processing means for performing image processing according to a predetermined procedure and information transfer means for transferring the luminance value information or the information subjected to the image processing, information of a characteristic portion of the luminance value information A feature extraction unit to be extracted, a first storage unit that stores information of a feature portion obtained by the feature extraction unit, and a feature unit that stores information of a feature portion obtained by one or more previous imaging by the feature extraction unit. A second storage unit; a comparative evaluation unit that evaluates a change amount of information of two characteristic portions stored in the first storage unit and the second storage unit; Illuminating means for illuminating an area having a portion with a light reflectance of, based on the amount of change in the information of the two characteristic parts obtained by the comparing and evaluating means, switching the illumination of the illuminating means A symbol information reading device (corresponding to claim 2).

Supplementary Note 3 Image pickup means for picking up a region having different light reflectance portions as a two-dimensional image, storage means for temporarily storing and holding luminance value information of the two-dimensional image, and In a symbol information reading apparatus having information processing means for performing image processing according to a predetermined procedure and information transfer means for transferring the luminance value information or the information subjected to the image processing, information of a characteristic portion of the luminance value information A feature extraction unit to be extracted, a first storage unit that stores information of a feature portion obtained by the feature extraction unit, and a feature unit that stores information of a feature portion obtained by one or more previous imaging by the feature extraction unit. A second storage unit, and a comparison evaluation unit that evaluates a change amount of information of two characteristic portions stored in the first storage unit and the second storage unit; 2 obtained by the comparative evaluation means
A symbol information reading device that determines whether the information transfer unit transfers the luminance value information or the image-processed information based on a change amount of information of the two characteristic portions. Correspondence).

Supplementary Note 4 When the amount of change in the information of the two characteristic portions obtained by the comparison and evaluation means is equal to or less than a threshold value obtained by a predetermined procedure, the image pickup means is repeatedly operated. Supplementary notes 1 to 3
The symbol information reading device described in the above.

Supplementary Note 5 When the amount of change in the information of the two characteristic portions obtained by the comparison and evaluation means exceeds a threshold value obtained by a predetermined procedure, the information processing means changes the predetermined symbol information. 5. The symbol information reading device according to any one of claims 1 to 4, wherein the symbol information reading device detects and performs a decoding process.

(Supplementary Note 6) The feature extracting means obtains luminance value information of a predetermined area from the luminance value information, and the comparing and evaluating means obtains the first storage means and the second storage means.
The symbol information reading device according to any one of supplementary notes 1 to 5, wherein a difference between two pieces of luminance value information stored in the storage unit is calculated.

Supplementary Note 7 The feature extracting means obtains shape feature information from the luminance value information, and the comparison and evaluation means calculates the two shape data stored in the first storage means and the second storage means. 7. The symbol information reading device according to any one of supplementary notes 1 to 6, wherein the difference of the feature information is calculated.

[0102]

As described above, according to the symbol information reading apparatus of the present invention, the symbol information reading device obtained by the comparing and evaluating means is used.
By determining whether or not to operate the imaging unit based on the amount of change in the information of the three characteristic portions, luggage or the like is carried in without providing a special position detector or the like even for continuous reading. At the time when the luminance value information or the image-processed information is transferred, it is possible to provide a symbol information reading device which is excellent in high-speed response, is excellent in power saving, continuously captures images, and is excellent in high-speed response. .

[Brief description of the drawings]

FIG. 1 is a diagram showing a mode in which a symbol information reading device according to a first embodiment and a second embodiment of the present invention is used.

FIG. 2 is a diagram showing a block configuration of a symbol information reading device according to the first embodiment of the present invention.

FIG. 3 is a flowchart schematically showing an operation of the symbol information reading device according to the first and second embodiments of the present invention.

FIG. 4 is a flowchart illustrating an outline of an operation in an imaging process in the symbol information reading device according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a luminance value of a background portion stored and held in a frame memory in a state where a baggage or the like to which a barcode label is attached is not carried in the symbol information reading apparatus according to the first embodiment of the present invention. A conceptual diagram of information and a conceptual diagram showing a mode of obtaining a luminance value in a frame memory.
The DF-417 label shows a conceptual diagram of the luminance value information stored and held in the frame memory.

FIG. 6 is a flowchart illustrating an outline of an operation in a feature extraction process in the symbol information reading device according to the first embodiment of the present invention.

FIG. 7 is a flowchart showing an outline of an operation in a process of acquiring shape characteristic information in the symbol information reading apparatus according to the first embodiment of the present invention.

FIG. 8 is a flowchart showing an outline of an operation in a process of storing information of a characteristic portion in the symbol information reading apparatus according to the first embodiment of the present invention.

FIG. 9 is a flowchart schematically showing an operation in a label reading process in the symbol information reading device according to the first embodiment of the present invention.

FIG. 10 is a diagram showing a block configuration of a symbol information reading device according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Symbol information reading device, 2 ... Light emitting diode, 3 ... Imaging lens, 4 ... Imaging element, 5 ...
Main unit, 6 ... host computer, 7 ...
Baggage, 8: Barcode label, 9: Information processing unit, 10: Feature extraction unit, 11: Feature comparison unit, 1
2 ... frame memory, 13 ... imaging unit, 14 ...
An imaging control unit, 15 information transfer unit, 16 illumination unit, 17a, 17b storage unit, 18 IC chip, 20 belt conveyor

Claims (3)

[Claims] 1. An area having portions having different light reflectivities is defined as 2
Imaging means for imaging as a two-dimensional image; storage means for temporarily storing and holding luminance value information of the two-dimensional image; information processing means for performing image processing according to a predetermined procedure for the luminance value information; A symbol information reading device having: value information or information transfer means for transferring the image-processed information; a feature extraction means for extracting information of a characteristic portion of the luminance value information; A first storage unit configured to store information of a characteristic portion; a second storage unit configured to store information of a characteristic portion obtained by the feature extraction unit in one or more previous images; Comparing and evaluating means for evaluating an amount of change in information of two characteristic parts stored in the second storage means, wherein the two characteristic parts obtained by the comparative evaluating means Based on the amount of change in information, symbol information reading apparatus and determines whether to operate the imaging means. 2. An area having portions having different light reflectances is defined as 2
Imaging means for imaging as a two-dimensional image; storage means for temporarily storing and holding luminance value information of the two-dimensional image; information processing means for performing image processing according to a predetermined procedure for the luminance value information; A symbol information reading device having: value information or information transfer means for transferring the image-processed information; a feature extraction means for extracting information of a characteristic portion of the luminance value information; A first storage unit configured to store information of a characteristic portion; a second storage unit configured to store information of a characteristic portion obtained by the feature extraction unit in one or more previous images; Comparison and evaluation means for evaluating the amount of change in the information of the two characteristic portions stored in the second storage means; and illumination means for illuminating an area having the different light reflectance portions A symbol information reading device, comprising: switching illumination irradiation of the illumination unit based on a change amount of information of two characteristic portions obtained by the comparison evaluation unit. 3. A region having portions having different light reflectivities is defined as two regions.
Imaging means for imaging as a two-dimensional image; storage means for temporarily storing and holding luminance value information of the two-dimensional image; information processing means for performing image processing according to a predetermined procedure for the luminance value information; A symbol information reading device having: value information or information transfer means for transferring the image-processed information; a feature extraction means for extracting information of a characteristic portion of the luminance value information; A first storage unit configured to store information of a characteristic portion; a second storage unit configured to store information of a characteristic portion obtained by the feature extraction unit in one or more previous images; Comparing and evaluating means for evaluating an amount of change in information of two characteristic parts stored in the second storage means, wherein the two characteristic parts obtained by the comparative evaluating means Based on the amount of change in information, the information transfer means symbol information reading apparatus characterized by determining whether to forward the luminance value information or the image processing information.