JP2008040584A - Information reader and its method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information reader for reading information attached to an article, in a wider range. <P>SOLUTION: In a distance measuring unit 21, scanning in a two-dimensional direction is performed with a laser 25 for distance measurement, so as to acquire the distance information of an article within a predetermined range. A focal position decision unit 22 calculates a distance to an article 7 from the distance information acquired by the distance measuring unit 21, and determines the focal position corresponding to a distance to the article. A focal position varying unit 23 adjusts the focal point at the determined focal position. A decoding part 5 reads optical information attached to the article at the adjusted focal point. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an information reading device that reads information attached to an article, and more particularly to an optical information reading device that reads information by irradiating the article with a laser beam and receiving reflected light.

  Information readers that read article information such as barcode labels and image images on articles are used in a wide range of applications such as POS (Point Of Sales). FIG. 6 is a block diagram showing a configuration of a general information reading device 13. The information reading device 13 includes an image information input unit 4, a decoding unit 5, a decoding result output unit 6, and a reading window 11. The image information input unit 4 includes a laser beam light output device 1, a scanner 2, and a light receiver 3. The image information input unit 4 irradiates the article with scanning light 9 of a laser beam from the reading window 11 and receives reflected light 10 from the article from the reading window 11.

  The laser beam light output unit 1 fixes the focal position of the laser beam and outputs the laser beam to the scanner 2. The scanner 2 is composed of an optical member such as a mirror. For example, the scanner 2 scans the laser beam from the laser beam light output device 1 by rotating the mirror, and the barcode of the article 7 as a laser scanning beam 9 from the reading window 11. The label 8 is irradiated. The light receiver 3 receives the reflected light 10 of the laser scanning beam 9 from the reading window 11 and converts it into an electrical signal. The decoding unit 5 decodes the content of the bar code label 8 converted into an electric signal by the light receiver 3. The decoding result output unit 6 outputs the contents of the barcode label 8 decoded by the decoding unit 5 to an external device (not shown).

  FIG. 7 is a flowchart showing the operation of the information reading device 13 shown in FIG. The laser beam light output device 1 outputs a laser beam with a fixed focal position to the scanner 2 (step 701). The scanner 2 scans the laser beam from the laser beam light output device 1 and irradiates the barcode label 8 of the article 7 as the laser scanning beam 9 from the reading window 11 (step 702).

  The bar code label 8 of the article 7 reflects the laser scanning beam 9 emitted from the scanner 2 (step 703). The light receiver 3 receives the reflected light 10 of the laser scanning beam 9 through the reading window 11 and converts it into an electrical signal (step 704). The decoding unit 5 decodes the contents of the bar code label 8 converted into an electric signal by the light receiving unit 3 (step 705). The decryption result output unit 6 outputs the contents of the barcode label 8 decrypted by the decryption unit 5 to an external device (step 706).

  Normally, the information reading device 13 as shown in FIG. 6 has a range in which information can be read (hereinafter referred to as “reading range”). The reading range is a range in which the information reading device 13 can read the barcode label 8 and is generally located in front of the reading window 11. The article enters this reading range from various directions.

  FIG. 8 is a diagram illustrating an example of how the article 7 is moved within the reading range 14. In FIG. 8, the article 7 is moved so as to approach the reading window 11. FIG. 9 is a diagram illustrating another example of how the article 7 is moved within the reading range 14. In FIG. 9, the reading window 11 of the information reading device 13 and the surface of the barcode label 8 of the article 7 are parallel to each other, and the article 7 is moved to the side while maintaining the state. It is preferable that the information reader 13 can read the barcode label 8 of the article 7 entering the reading range from various directions as described above.

  As another example of the information reading apparatus, Patent Document 1 discloses a technique for measuring a distance from an article and setting a focus according to the measured distance. In Patent Document 1, the distance to an article is measured in advance using a distance meter before the article enters the reading range. Then, the information reading device sets a focus according to the distance measured by the distance meter, and reads the barcode label of the article when the article passes through the reading range.

  In addition, an information reading apparatus may be used for sorting goods in the physical distribution field. FIG. 10 is a diagram showing a barcode label reading method in the physical distribution system. The physical distribution system includes an information reading device 13, a two-dimensional sensor 50, and a belt conveyor 54.

  The two-dimensional sensor 50 includes a light projecting side and a light receiving side, and receives a plurality of two-dimensional sensor light beams 51 irradiated from the light projecting side on the light receiving side. The two-dimensional sensor detection area 52 is an area between the light projecting side and the light receiving side of the two-dimensional sensor 50. The article 7 is moved by the belt conveyor 54 and enters the two-dimensional sensor detection area 52. When the article 7 enters the two-dimensional sensor detection area 52, the two-dimensional sensor 50 measures the height of the article 7 by detecting the light shielding state of the two-dimensional sensor light beam 51. The information reading device 13 sets the focal point of the laser beam according to the height of the article 7 measured by the two-dimensional sensor 50. Meanwhile, the article 7 is moved from the two-dimensional sensor detection area 52 to the reading range by the belt conveyor, and when the article 7 passes through the reading range, the information reading device 13 applies the laser beam whose focal length is adjusted to the article 7. Irradiate and read the bar code label 8.

In this type of distribution sorting system, the barcode label 8 of the article 7 is read using the information reading device 13 as one method for confirming that the article 7 has been loaded on the truck. At that time, the article 7 is moved by placing the article 7 upstream of the belt conveyor 54 and rotating the belt conveyor. Then, the information reader 13 reads the barcode label 8 attached to the article 7 when the article 7 passes just below the information reader 13.
Japanese Patent Laid-Open No. 5-67227

  In the method of irradiating the laser beam scanning light as shown in FIG. 6, the beam diameter of the laser beam scanning light output from the laser beam light output device 1 once converges with increasing distance from the laser beam light output device 1, and then again. Spread and diverge. In general, the resolution of information reading is highest at the waist position where the beam diameter is most converged. The waist position becomes the focal position. The information reading device 13 can acquire the clearest article information at the focal position. However, since the focal position is fixed, when the article deviates from the focal position, the resolution is lowered, the width of the bar constituting the barcode cannot be accurately detected, and correct article information cannot be acquired. There was a thing. If the width of the bar constituting the bar code label cannot be accurately detected, the reading performance of the information reading device 13 is degraded.

  Moreover, in the reading method of patent document 1, the distance to an article | item is previously measured and a focus is set. In this method, after the distance to the article is measured, if the distance between the article and the information reader changes, the focus is shifted. Therefore, the information reader may not be able to accurately read the barcode label of the article. there were.

  FIG. 11 is a diagram illustrating an example of the article 7 moving outside the reading range 14. Since the reading range is determined depending on the focal length and the resolution, the actual shape of the reading range is a curved disk shape within a predetermined distance range from the laser beam irradiation position as shown in FIG. In general, the thickness of the disk is about 15 centimeters. In order to read the bar code label 8, it is necessary to make the article 7 enter the reading range in the shape of a curved disk having a thickness of about 15 centimeters. However, since the reading range is invisible, it is difficult to recognize the shape, and the user may not be able to successfully pass the article through the reading range. In the example of FIG. 11, the article 7 has moved from the position of the article 7A to the position of the article 7C via the position of the article 7B. When the article 7 moves outside the reading range 14 as shown in FIG. 11, the information reading device 12 cannot read the barcode label 8 of the article 7.

In FIG. 10, when the article 7 passes through the two-dimensional sensor detection area 52 and enters the reading range of the information reading device 13, the information reading device 13 reads the barcode label 8 of the article 7. For this reason, the article 7 must pass through the two-dimensional sensor detection area 52 and the reading range, and the movement of the article is limited. The object of the present invention is to read information attached to the article in a wider range. An object of the present invention is to provide an information reading apparatus capable of performing the above.

In order to achieve the above object, an information reading apparatus of the present invention provides:
An information reader for reading optical information attached to an article,
A distance measuring device that scans a distance measuring laser in a two-dimensional direction and acquires distance information in the two-dimensional direction from reflected light of the distance measuring laser;
A focal position determiner that calculates a distance to the article from the distance information acquired by the distance measuring instrument and determines a focal position according to the distance to the article;
A reader capable of adjusting a focus for reading the optical information, and reading the optical information at the adjusted focus;
An information reading apparatus comprising: a focus position variable unit that adjusts the focus of the reader so as to follow the focus position determined by the focus position determiner.

  According to the present invention, the distance measuring device scans the distance measuring laser in a two-dimensional direction, and acquires distance information of an article within a predetermined range. The focal position determiner calculates the distance to the article from the distance information acquired by the distance measuring device, and determines the focal position according to the distance to the article. The focal position varying device adjusts the focal point to the determined focal position. The decoding unit reads the optical information attached to the article with the adjusted focus. Thereby, the optical information attached to the article can be read in a wider range.

  Further, a range of the same distance may be extracted as a block from a plurality of points included in the distance information, the block having the shortest distance may be determined as the article, and the focus position may be adjusted to the block.

  According to this, when the distance to the article is short, the optical information attached to the article can be focused efficiently.

  Further, a range of the same distance is extracted as a block from the distances of a plurality of points included in the distance information, a change in the position of the block is detected, a block whose position is changed is determined as the article, and the block is The focal position may be adjusted.

  According to this, regardless of the distance to the article, it is possible to focus on the optical information attached to the article efficiently.

  Further, an average value of distances of each part of the article may be obtained from the distance information, and the focal position may be obtained from the average value.

  According to this, it is possible to efficiently focus on the optical information attached to a small article that falls within the reading range.

  In addition, the information processing apparatus further includes a storage unit that stores in advance information on the shape of the article and information on a position to which the optical information is attached, and the focal position determiner is a distance between a plurality of points in the two-dimensional direction. And the information on the shape of the article stored in the storage unit, the position of the article is recognized, and the recognized article and the position information to which the optical information is stored stored in the storage unit. The position of the optical information may be detected, and the distance to the position of the optical information may be acquired as the distance information.

  According to this, regardless of the size of the article, it is possible to efficiently focus on the optical information attached to the article.

  According to the present invention, information attached to an article can be read in a wider range.

  Embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an information reading device 12 according to an embodiment of the present invention. The information reading device 12 includes an image information input unit 4, a decoding unit 5, a decoding result output unit 6, and a reading window 11. The image information input unit 4 includes a laser beam light output device 1, a scanner 2, a light receiver 3, a distance measurement device 21, a focus position determination device 22, and a laser beam focus position variable device 23.

  The information reader 12 irradiates the barcode label 8 of the article 7 from the reading window 11 with the laser scanning beam 9 scanned by the scanner 2, and the reflected light 10 of the laser scanning beam 9 from the reading window 11 is received by the light receiver 3. The bar code label 8 is read by receiving light.

  The distance measuring device 21 measures the distance from the reading window 11 to all objects existing within a predetermined range in the two-dimensional direction, and outputs the distance information to the focal position determining device 22 as distance information. Since the distance information includes the distances of a plurality of points in the two-dimensional direction, the distance from the reading window 11 to the article with the barcode label and the distance from the reading window 11 to the article without the barcode label. Will be included.

  The distance measuring device 21 irradiates the laser beam 25 for distance measurement, which is pulsed light, while scanning in a two-dimensional direction that can be expressed by X and Y coordinates. The distance measuring device 21 receives the reflected light from the article as a distance measuring laser reflected light 24, and measures the delay time of the pulsed light from irradiation to light reception. Then, the distance measuring device 21 calculates the distance between the irradiated article and the information reading device 12 based on the measured delay time of the pulsed light. For example, since the speed of light is 300,000 km per second, if the delay time of pulse light is 1 nanosecond, the distance of the optical path is 30 cm. Since the time from receiving the pulsed light to receiving it is a reciprocal time, the distance between the information reader 12 and the article is half, 15 cm. Thereby, the distance in each point of the predetermined range of XY plane is calculated.

  When receiving the distance information from the distance measuring device 21, the focal position determining unit 22 extracts the article 7 from the distance information, and determines the position of the article as the focal position.

  The laser beam focal position varying unit 23 sets the focal point of the laser beam at the focal position determined by the focal position determining unit 22.

  The information reading device 12 changes the reading range in accordance with the movement of the article 7 by continuously executing the series of operations from the above-described distance measurement at a plurality of points in the two-dimensional direction to the focus setting of the laser beam. FIG. 2 is a diagram illustrating how the reading range changes in accordance with the movement of the article 7. In FIG. 2, the article 7 has moved from the position of the article 7A to the position of the article 7C via the position of the article 7B. The information reading device 12 recognizes the article 7 from the distance information and focuses the laser beam on the position of the article 7. The readable range is determined by the focal position of the laser beam. Further, the information reading device 12 changes the focal position of the laser beam as the article 7 moves. The readable range changes as the focal position changes. A reading range 36 indicates a readable range at the point of the article 7A. A reading range 37 indicates a readable range at the point of the article 7B. A reading range 38 indicates a readable range at the point of the article 7C.

  The distance measuring device 21 measures the distance between the article present in front of the reading window 11 and the reading window 11 every moment. For example, when the article 7 reaches the position of the article 7A, the distance measuring device 21 measures the distance between the reading window 11 and the position of the article 7A, and outputs the distance information to the focal position determining unit 22. When receiving the distance information from the distance measuring device 21, the focal position determining unit 22 determines the focal position of the article 7 from the received distance information. The laser beam focal position varying unit 23 sets the focal point of the laser beam at the focal position determined by the focal position determining unit 22. Similarly, when the article 7 comes to the position of the article 7B, the focal position of the laser beam is set to the position of the article 7B. Furthermore, when the article 7 comes to the position of the article 7C, the focal position of the laser beam is set to the position of the article 7C. In this way, the focal position of the laser beam changes every moment following the movement of the article 7, and the barcode label 8 can be read satisfactorily.

  FIG. 3 is a flowchart showing an example of the operation of the information reading apparatus 12 of the present embodiment. The distance measuring device 21 measures the distance between the reading window 11 and an object existing within a predetermined range in front of the reading window 11 (step 301). The focal position determiner 22 determines whether or not the article 7 is detected within a predetermined range (step 302). If the article 7 is not detected within the predetermined range, the process returns to step 301 and the distance measuring device 21 repeats the distance measurement. When the article 7 is detected within a predetermined range, the focal position determining unit 22 determines the focal position from the detected distance to the article 7 and sets the focal point at the position (step 303).

  The light receiver 3 receives the reflected light of the focused laser beam and converts it into an electrical signal (step 304). The decoding unit 5 determines whether or not the information converted into the electrical signal by the image information input unit 3 can be decoded (step 305). If decryption is possible, the decryption result output unit 6 decrypts the content of the information and outputs it to the external device (not shown) as the decryption result of the bar code label 8 (step 306). If the decoding is impossible, the information reading device 12 continues the reading operation.

  As described above, according to the present embodiment, the distance measuring device 21 scans the distance measuring laser irradiation light 25 in a two-dimensional direction and measures the distance information of the article within a predetermined range every moment. . The focal position determiner 22 calculates the distance to the barcode label 8 attached to the article 7 from the measured distance information, and determines the focal position according to the distance to the barcode label 8. The focus position variable unit 23 adjusts the focus to the determined focus position. The decoding unit 5 reads the contents of the barcode label 8 with the adjusted focus. Thereby, the information reader 12 can read the barcode label 8 attached to the article in a wider range.

  In the present embodiment, an information reading apparatus using a laser beam is exemplified, but the present invention is not limited to this. As another example, an image pickup tube or a CCD may be used for the image information unit 4. In that case, the information reading device 12 may measure the distance to the article 7 and adjust the focus of the imaging tube or the CCD with respect to the distance.

  FIG. 4 is a schematic diagram for explaining a specific example of the reading method for reading the barcode label 8 attached to the article 7. In this example, it is assumed that the article 7 is moved so that the surface to which the barcode label 8 is attached is parallel to the reading window 11.

  In FIG. 4, the operator moves the article 7 so as to cross the information reading device 12. The distance measuring device 21 irradiates the distance measuring laser irradiation light 25 while scanning in a two-dimensional direction, and receives the distance measuring laser reflected light 24 which is the reflected light. Since the surface of the article 7 to which the barcode label 8 is attached is parallel to the surface of the reading window 11, the time from irradiation to light reception is substantially the same in the surface of the article 7 to which the barcode label 8 is attached. . When the time is converted into a distance, almost the same distance can be obtained. In this specific example, a range having the same distance in the result of distance measurement in the two-dimensional direction is defined as one block. A block 43 is formed by the surface to which the barcode label 8 of the article 7 is attached.

  If the operator holds the article 7 over the reading window 11 by hand, the distance measuring device 21 measures the distance to the arm of the operator moving the article 7 in addition to the distance to the article 7. Become. Here, it is assumed that the distance between the reading window 11 and each part of the operator's arm is substantially the same. Therefore, the time from irradiation to light reception is almost the same within the range of the operator's arm. When the time is converted into distance, almost the same distance can be obtained. A block 44 is formed by the arm of the operator.

  Furthermore, if there is another object in the reading range, the information reading device 12 also measures the distance to that object. These measurement results become three-dimensional distance information that can obtain an image equivalent to a moire pattern by plotting points at the same distance. In this specific example, it is assumed that only the article 7 and the arm exist. Therefore, the distance information output from the distance measuring device 21 to the focal position determining device 22 includes the distance to the block 43 and the distance to the block 44.

  When receiving the distance information from the distance measuring device 21, the focal position determining unit 22 recognizes the article 7 from the received distance information by a predetermined method, and adjusts the focal position there.

  Usually, the operator holds the surface of the barcode label 8 over the reading window 11. Therefore, when a plurality of blocks are formed, there is a high possibility that the barcode label 8 is attached to the block with the shortest distance. Therefore, as an example of a method for determining the focal position, the focal position determining unit 22 determines that the block having the shortest distance among the distance information received from the distance measuring device 21 is the article 7 with the barcode label 8 attached thereto. The focal position is determined based on the block distance.

  In addition, it is assumed that there are various items other than the article 7 with the barcode label 8 attached, such as the operator himself, in front of the reading window 11. If the operator moves the article 7 so that the surface of the barcode label 8 passes in front of the reading window 11, the moving block is considered to be the article 7 with the barcode label. As the article 7 moves, the position and distance of the block corresponding to the article 7 changes. The distance measuring device 21 measures the difference between the position of the previous block and the position of the current block, and includes the difference in the distance information and sends it to the focal position determining device 22. In that case, when receiving the distance information from the distance measuring device 21, the focal position determining unit 22 compares the difference included in the distance information with a predetermined threshold value. If the difference exceeds a predetermined threshold, the focal position determination unit 22 regards the block as the article 7 with the barcode label 8 and determines the focal position based on the distance of the block.

  According to this reading method, the distance measuring device 21 irradiates the distance measuring laser irradiation light 25 while scanning in the two-dimensional direction, and receives the distance measuring laser reflected light 24 that is the reflected light. If the surface of the article 7 on which the barcode label 8 is affixed and the surface of the reading window 11 are parallel, the distance measuring device 21 converts the time from irradiation to light reception into distance and obtains substantially the same distance. Then, the distance measuring device 21 captures a set of portions having the same distance as one block and sends it to the focal position determining device 22 as distance information. When receiving the distance information from the distance measuring device 21, the focal position determining unit 22 recognizes the article 7 from the received distance information and adjusts the focal position there.

  According to this, it is possible to focus on the barcode label attached to the article.

  In the example of FIG. 4, the operator sets the range of the same distance of the article 7 on the assumption that the article 7 is held over the information reader 12 so that the surface with the barcode label 8 is parallel to the reading window 11. The candidate block. However, you may extract the block used as the candidate of the articles | goods 7 with the barcode label 8 by another method. For example, assuming that the surface of the article 7 to which the barcode label 8 is attached is a plane, the range of the plane may be extracted as a block from the distances of a plurality of points measured by the distance measuring device 21. When a plurality of blocks are extracted, the block having the shortest distance or the moving block may be determined as the article 7 as described above. According to this, the article 7 can be identified even if the barcode label 8 is not parallel to the reading window 11.

  In the example of FIG. 4, an example in which the information reading device 12 reads one barcode label 8 attached to the article 7 is shown, but the present invention is not limited to this. As another example, there is a case where the information reader 12 reads a plurality of barcode labels attached to an article.

  FIG. 5 is a schematic diagram for explaining another specific example of the reading method by the distance measuring device 21. In this specific example, three bar code labels 65, 66, and 67 are attached to the article 7, and the information reading device 12 reads the bar code labels 65, 66, and 67, respectively. When the article 7 is moving, the surface to which the barcode labels 65, 66, and 67 are attached and the surface of the reading window 11 may not be parallel. In that case, the distances 70, 71, 72 are different from each other.

  In this specific example, as an example of a method for reading three bar code labels 65, 66, and 67 having different distances from each other, the focal position is determined from the average value of the distances of the points on the surface to which the bar code labels 65, 66, and 67 are attached. There is a way to determine. If the article 7 has such a size that all the barcode labels 65, 66, and 67 are within the reading range, the information reader 12 can read all the barcode labels 65, 66, and 67 at the same focal position. .

  The distance measuring device 21 irradiates the distance measuring laser irradiation light 25, receives the distance measuring laser reflected light 24 from each point in the two-dimensional direction including the article 7, and measures the delay time. Here, since the surface of the article 7 to which the barcode labels 65, 66, and 67 are attached is not parallel to the reading window 11, the distance between the points of the article 7 is not the same. When receiving the distance information from the distance measuring device 21, the focal position determining unit 22 extracts the article 7 by the above-described method, calculates an average value of the distances at each point of the article 7 included in the distance information, The focal position is determined from the average value. The laser beam focus position variable unit 23 sets the focus of the laser beam at the determined focus position. By setting the focal position of the laser beam in this way, all bar code labels 65, 66, and 67 enter the reading range. The information reading device 12 receives the reflected light of the laser beam and reads the bar code labels 65, 66 and 67 attached to the article 7.

  According to this reading method, the distance measuring device 21 irradiates the distance measuring laser irradiation light 25 and receives the distance measuring laser reflected light 24 from each point in the two-dimensional direction including the article 7 to reduce the delay time. taking measurement. The distance measuring device 21 sends distance information including the distance of each point of the article 7 to the focal position determining device 22. When receiving the distance information from the distance measuring device 21, the focal position determining unit 22 calculates the average value of the distances at each point of the article 7 included in the distance information, and determines the focal position from the average value. The laser beam focus position variable unit 23 sets the focus of the laser beam at the determined focus position.

  Accordingly, it is possible to efficiently focus on a bar code label attached to a small article that falls within the reading range.

  In this specific example, as another example of a method of reading three bar code labels 65, 66, 67 having different distances from each other, the information reader 12 is an article that focuses a laser beam as the article 7 moves. There is a method of changing the point on 7.

  When the article is at the central position 7B of the information reading device 12, the information reading device 12 sets the focus at the center of the article 7 (bar code label 66). Further, when the article passes through the positions 7A and 7C that are not near the center of the information reading device 12, the information reading device 12 sets the focus at both ends (the barcode label 66 or the barcode label 67) of the article. . At that time, depending on the position of the article 7, it is arbitrary which focus is set at both ends, and may be set in advance. Thus, by changing the focal position of the laser beam as the article 7 moves, the information reading device 12 can sequentially read the bar code labels 65, 66, and 67 attached to the article.

  For example, when the article 7 passes the position of the article 7 </ b> A, the information reading device 12 focuses on the barcode label 65 and reads the barcode label 65. When the article 7 passes the position of the article 7B, the information reading device 12 reads the barcode label 66 while focusing on the barcode label 66 attached to the center of the article 7. When the article 7 passes the position of the article 7 </ b> C, the information reader 12 focuses on the barcode label 67 and reads the barcode label 67.

  According to this reading method, the distance measuring device 21 sends distance information measured within the reading range to the focus position determining device 22. Upon receiving the distance information from the distance measuring device 21, the focal position determining unit 22 extracts the article 7 by the above-described method, calculates the distance to each part of the article 7 from the distance information, and the article 7 moves along with the movement of the article 7. 7 The focal position is determined so as to move on. The laser beam focus position variable unit 23 sets the focus of the laser beam at the determined focus position.

  Thereby, it is possible to efficiently focus on a bar code label attached to a large article that does not fall within the reading range.

  In this specific example, there is a method of recognizing the position where the barcode label is attached from the shape of the article 7 as still another example of the method of reading the three barcode labels 65, 66, 67 having different distances.

  The information reading device 12 in this example further includes a storage unit in addition to the configuration shown in FIG. The storage unit stores in advance the relationship between the shape of the article 7 and the positions of the three barcode labels of the article 7. When the article enters the reading range, the focal position determiner 22 of the information reading device 12 recognizes the shape of the article 7 from the distances of a plurality of points included in the distance information from the distance measuring device 21, and recognizes the recognized article. It is determined whether or not the shape of 7 matches the shape of the stored article.

  If the shapes match, the focus position determiner 22 determines three focus positions from the shape of the bar code label 8 of the article 7. The laser beam focus position variable device 23 sequentially sets the focus of the laser beam at the three focus positions determined by the focus position determination unit 22. Thereby, the information reader 12 can sequentially read the bar code labels 65, 66, and 67.

  In this example, the case where there are three barcode labels 65, 66, and 67 is illustrated, but the present invention is not limited to this. As long as the position where the barcode label is attached can be recognized from the shape of the article 7, the number of barcode labels may be one or plural.

  According to this method, when the article enters the reading range, the focal position determining unit 22 of the information reading device 12 recognizes the shape of the article 7 and the shape of the recognized article 7 and the stored shape of the article. It is determined whether or not. If the shapes match, the focus position determiner 22 detects the position of the barcode label of the article and determines three focus positions from the distance information. The laser beam focus position variable device 23 sequentially sets the focus of the laser beam at the three focus positions determined by the focus position determination unit 22.

  Thereby, it is possible to efficiently focus on the barcode label attached to the article regardless of the size of the article.

2 is a block diagram showing a configuration of an information reading device 12. FIG. It is a figure which shows a mode that a reading range changes according to the movement of the articles | goods. It is a flowchart which shows operation | movement of the information reader 12 of this embodiment. It is a schematic diagram for demonstrating the specific example of the reading method which reads the barcode label 8 attached | subjected to the articles | goods 7. FIG. It is a figure which shows an example of the mode of the change of the focal distance accompanying the movement of articles | goods. 2 is a block diagram illustrating a configuration of a general information reading device 13. FIG. 5 is a flowchart showing an operation of a general information reading device 13. 6 is a diagram illustrating an example of a state in which an article 7 is moved within a reading range 14. FIG. It is a figure which shows another example of a mode that the articles | goods 7 are moved within the reading range. It is a figure which shows the reading method of the bar code label 8 in a physical distribution system. It is a figure which shows an example of the articles | goods 7 which are moving out of the reading range.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser beam light output device 2 Scanner 3 Light receiver 4 Image information input part 5 Decoding part 6 Decoding result output part 7 Article 8 Bar code label 11 Reading window 12 Information reading device 13 Conventional information reading devices 301-306, 701 706 steps

Claims (11)

An information reader for reading optical information attached to an article,
A distance measuring device that scans a distance measuring laser in a two-dimensional direction and acquires distance information in the two-dimensional direction from reflected light of the distance measuring laser;
A focal position determiner that calculates a distance to the article from the distance information acquired by the distance measuring instrument and determines a focal position according to the distance to the article;
A reader capable of adjusting a focus for reading the optical information, and reading the optical information at the adjusted focus;
An information reading apparatus comprising: a focus position variable unit that adjusts the focus of the reader so as to follow the focus position determined by the focus position determiner.   The focal position determining unit extracts a range of the same distance from a plurality of points included in the distance information as a block, determines a block having the shortest distance as the article, and matches the focal position to the block. Item 2. The information reading device according to Item 1.   The focus position determiner extracts a range of the same distance as a block from a plurality of points included in the distance information, detects a change in the position of the block, and determines a block whose position is changed as the article. The information reading apparatus according to claim 2, wherein the focal position is adjusted to the block.   The information reading apparatus according to claim 1, wherein the focal position determining unit obtains an average value of distances of each part of the article from the distance information, and obtains the focal position from the average value. The information reading device further includes a storage unit that stores in advance information on the shape of the article and information on a position to which the optical information is attached,
The focus position determiner recognizes the position of the article from the distances of the plurality of points in the two-dimensional direction and the shape information of the article stored in the storage unit, and stores the recognized article and the storage unit. The information reading apparatus according to claim 1, wherein a position of the optical information is detected from the position information to which the optical information is added, and a distance to the position of the optical information is acquired as the distance information. .   The reader receives a reflected light of the laser beam scanned by the scanner, and scans the laser beam whose focus is adjusted by the focal position changer, and converts the reflected light into an electrical signal. The information reader according to any one of claims 1 to 5, further comprising: a light receiver configured to perform decoding; and a decoding unit configured to decode the optical information attached to the article from the electrical signal. An information reading method for reading optical information attached to an article,
The distance measurement laser is scanned in a two-dimensional direction, and the distance information in the two-dimensional direction is obtained from the reflected light of the distance measurement laser,
Calculate the distance to the article from the acquired distance information, determine the focal position according to the distance to the article,
An information reading method in which the optical information is read by adjusting the focal point for reading the optical information to follow the determined focal position.   The information reading according to claim 7, wherein a range of the same distance is extracted as a block from a plurality of points included in the distance information, the block having the shortest distance is determined as the article, and the focal position is adjusted to the block. Method.   A range of the same distance is extracted as a block from a plurality of points included in the distance information, a change in the position of the block is detected, a block whose position is changed is determined as the article, and the focus is set on the block. The information reading method according to claim 7, wherein the positions are adjusted.   The information reading method according to any one of claims 7 to 9, wherein an average value of distances of respective parts of the article is obtained, and the focal position is obtained from the average value. Information on the shape of the article and information on the position to which the optical information is attached are stored in advance.
Recognizing the position of the article from the distances of the plurality of points in the two-dimensional direction and the stored information on the shape of the article, and the information on the recognized article and the position with the optical information stored therein; The information reading method according to claim 7, wherein a position of the optical information is detected from a distance and a distance to the position of the optical information is acquired as the distance information.

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