JP5605627B2 - Pattern or image reading apparatus, control method thereof, and program - Google Patents

Description

The present invention, pattern or image reading apparatus, a control method thereof and a program, in particular, Rupa turns or the image reading apparatus can read a location or Lapa turns or image away, a control method and program .

The pattern or image as the information display tag representing information such as black and white pattern arrangement, there is one to tables in such as, white and black lattice pattern sequence represented by the thickness of the striped pattern of the line, representative of the former Is a barcode, and the latter is a matrix type two-dimensional code (registered trademark). Note that the two-dimensional pattern in a broad sense includes photographs and pictures represented by pixel patterns. This is because it is possible to identify a person, an article, a landscape (location), etc. by recognizing these photographs and pictures, and it can be said that the identification result is “information” displayed in a pattern. In this specification, the two-dimensional pattern is described as a barcode for the sake of simplicity, but this is merely an example for convenience. It may be another code pattern such as a matrix type two-dimensional code, or may be a photograph or a picture represented by a pixel pattern.

  The two-dimensional pattern is read by a reading device (referred to as a two-dimensional pattern reading device) that is dedicated or incorporated in another device. However, in recent years, with the improvement of the performance of the two-dimensional pattern reading device, for example, the two-dimensional pattern has moved away. What can be read from a place is also put into practical use (see, for example, Patent Document 1).

  There are two types of two-dimensional pattern reading devices: one that reads a pattern using a laser beam (hereinafter referred to as a laser method) and one that reads as an image using a two-dimensional imaging device such as a CCD or CMOS (hereinafter referred to as an image reading method). Can be divided into The former laser method reproduces pattern information from reflected light of a laser beam emitted toward a two-dimensional pattern, and the latter image reading method reproduces pattern information by processing an image taken by a two-dimensional imaging device. .

  By the way, in the latter image reading system, an illumination light source for photographing is indispensable particularly when used in a dark place. This is because the two-dimensional imaging device cannot obtain good imaging quality, that is, good image quality that can reproduce the pattern information without any trouble unless the brightness is higher than the predetermined brightness. For this reason, many two-dimensional pattern reading apparatuses adopting an image reading method are provided with an illumination light source so that the pattern information can be read after the two-dimensional pattern is illuminated brightly.

JP 2009-193447 A

However, simply illuminating the two-dimensional pattern with light from the illumination light source and reading the pattern information has the following disadvantages.
(A) A two-dimensional pattern located far away cannot be illuminated with an appropriate amount of light.
This is because the brightness of the target point is inversely proportional to the square of the distance from the light source. For example, when the distance from the light source to the two-dimensional pattern is n times, the brightness of the two-dimensional pattern located at the target point is This is because it decreases to approximately 1 / n.
(B) Increase in power consumption In order to cope with the above (A), the light quantity of the light source may be increased. For example, when the distance becomes n times, the light quantity may be increased by n times. In particular, since the power consumption increases and the battery consumption becomes severe, the convenience of the portable two-dimensional pattern reading device is impaired.

An object of the present invention, while achieving power saving, distance regardless, Rupa turns or the image reading apparatus can illuminate the pattern or image of the target at a proper brightness, its control method and program Is to provide.

The invention according to claim 1, an image reading means for reading a subject der Rupa turn by images recognition, illuminating means for illuminating the object, and measures a distance to the subject, the distance measuring means An irradiation width changing means for changing an irradiation width of light emitted from the illumination means based on the distance measurement result; and a luminance of the light emitted from the illumination means based on the distance measurement result of the distance measurement means. Brightness changing means and detection means for detecting the size of the subject from the reading result of the image reading means, and the irradiation width changing means narrows the irradiation width as the distance to the subject increases. after performing front changes, to fine-tune the pre-stage change result on the basis of the detection result of said detecting means, it is pattern reading apparatus according to claim.

According to the present invention, while achieving power saving, distance regardless, it is possible to illuminate the pattern or image of the target at a proper brightness.

1 is a schematic configuration diagram of a two-dimensional pattern reading device according to an embodiment. It is a use condition figure of the two-dimensional pattern reading device concerning an embodiment. It is a figure which shows the variable characteristic of irradiation width. It is a figure which shows the variable characteristic of a brightness | luminance. It is a figure which shows the operation | movement flow of the two-dimensional pattern reading apparatus which concerns on embodiment. It is a figure which shows the operation | movement flow of a decoding process (step S5). It is a figure which shows the other example of an irradiation width variable aspect.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a two-dimensional pattern reading apparatus according to an embodiment. In this figure, the two-dimensional pattern reading device 1 includes an illumination unit 2, an imaging unit 3, an operation unit 4, a control unit 5, a display unit 6, a storage unit 7, a communication unit 8, and a power supply unit 9.

  The illumination unit 2 includes a light emitting unit 10, an irradiation width variable optical unit 11, and an irradiation width driving unit 12. The light emitting unit 10 includes a light source such as an LED, an incandescent lamp, or a halogen lamp, and emits illumination light having a predetermined light amount and a predetermined irradiation width in the direction of the optical axis La in response to a control signal from the control unit 5. The irradiation width variable optical unit 11 includes, for example, an optical lens 11a that can move back and forth along the optical axis La, and the irradiation width of illumination light emitted from the light emitting unit 10 by changing the position of the optical lens 11a. The irradiation width driving unit 12 changes the position of the optical lens 11a in response to a control signal from the control unit 5.

  The imaging unit 3 includes a two-dimensional imaging device 13, a variable focus optical unit 14, a focus driving unit 15, and a distance measuring unit 16. The two-dimensional imaging device 13 is composed of an imaging device such as a CCD or a CMOS, and converts the subject image captured via the variable focus optical unit 14 into an electrical image signal and outputs it. The variable focus optical unit 14 includes a photographic lens 14a and a focus lens 14b arranged along the optical axis Lb, and moves the focus lens 14b back and forth along the optical axis Lb to thereby change the two-dimensional imaging device 13. The subject image is formed (focused) on the imaging surface of the lens, and the focus driving unit 15 changes the position of the focus lens 14 b in response to a control signal from the control unit 5.

  Here, the optical axis La of the illuminating unit 2 and the optical axis Lb of the imaging unit 3 need to be approximately parallel and laid out as close as possible. This is because the imaging range (imaging field angle) by the imaging unit 3 is uniformly illuminated by the illumination light of the illumination unit 2 regardless of the distance.

  The imaging unit 3 also has an autofocus function. In short, the autofocus function is to measure the distance to the subject by the distance measuring unit 16 and control the position of the focus lens 14b based on the distance, and is divided into several types depending on the distance measurement method. A typical one is an optical distance measuring method. In the optical ranging method, spot light such as LED light is emitted toward a subject, and the reflected spot light is detected by a semiconductor position detection element called PSD (Position Sensitive Detector). The semiconductor position detection element is a sensor that can detect the position of the spot light, and measures the distance from the detection position to the subject by the principle of triangulation. The optical distance measuring method may be adopted for the distance measuring unit 16 in the embodiment, but is not limited thereto. In short, any method may be used as long as the distance to the subject can be measured and the position of the focus lens 14b can be controlled based on the distance.

  The operation unit 4 is a so-called input user interface unit that includes various operation buttons and operation keys necessary for the operation of the two-dimensional pattern reading device 1. The operation unit 4 may include a touch panel. Here, for simplification of explanation, only one operation button (trigger key 4a) is illustrated. The trigger key 4a is operated by a user when reading a two-dimensional pattern. When the trigger key 4a is operated, the two-dimensional pattern reading device 1 performs a series of two-dimensional pattern reading processes (see FIG. 5). The number of trigger keys 4a may be one, but may be plural. For example, if the two-dimensional pattern reading device 1 is appropriately provided at an easy-to-operate position in each part of the body, such as one on the front of the body and one on each side, the degree of freedom of operation increases. preferable.

The control unit 5 includes, for example, a CPU (Central Processing Unit) 5a, a ROM (Read Only Member) 5b, and a RAM (Random
Access Memory) 5c and a microcomputer composed of necessary peripheral circuits. The control program stored in the ROM 5b is expanded on the RAM 5c, and the control program is executed by the CPU 5a. 1 overall control (operation related to the two-dimensional pattern reading process, etc.). Here, the control unit 5 using a microcomputer, that is, two-dimensional pattern reading is performed by organic coupling of software resources such as a control program and hardware resources such as CPU 5a, ROM 5b and RAM 5c, and necessary peripheral circuits. Although the control unit 5 is a so-called program control type that performs overall control of the overall operation of the apparatus 1, the present invention is not limited to this. For example, a part or all of the control may be realized by hard logic.

  The display unit 6 is a so-called output user interface unit configured by a display device such as a liquid crystal display, and various information appropriately output from the control unit 5, for example, a raw image during two-dimensional pattern reading, The two-dimensional pattern reading result or other information is visualized and displayed. The display unit 6 may have a touch panel.

  The storage unit 7 is configured by a non-volatile storage device such as a flash memory, and appropriately stores and saves a two-dimensional pattern reading result and the like. In addition, the communication unit 8 exchanges data with an external device such as a personal computer via a communication medium such as a wireless LAN, and externally stores data stored in the storage unit 7 as necessary. The data can be transmitted to a device, or required data can be taken from an external device. Furthermore, the power supply unit 9 includes a battery such as a primary battery or a rechargeable secondary battery, and generates power necessary for the operation of the two-dimensional pattern reading device 1 from the power of the battery.

  FIG. 2 is a use state diagram of the two-dimensional pattern reading apparatus according to the embodiment. (A) shows a state when reading a near two-dimensional pattern, and (b) shows a state when reading a far two-dimensional pattern. Further, (c) is a view of the main part of the two-dimensional pattern reading device viewed from the back side.

  In these drawings, the two-dimensional pattern reading device 1 includes a vertically long thin plate rectangular body 17 suitable for hand-holding, and a trigger key 4 a provided at an arbitrary position of the body 17. In the illustrated example, one trigger key 4a is provided on the front surface and one on each side surface. However, the present invention is not limited to this. For example, only one on the front surface may be provided. The reason why a plurality of trigger keys 4a are provided is that the purpose is to improve the degree of freedom of operation. In other words, the trigger key 4a at a position that is easy to operate can be selectively used depending on how the user 18 is hand-held. Incidentally, in the illustrated example, since the trigger key 4a on the front surface is located near the thumb of the user 18, the state where the trigger key 4a is operated with the thumb is illustrated. The trigger key 4a may be operated, or the left side trigger key 4a may be operated with an index finger or the like.

  The two-dimensional pattern reading device 1 includes the trigger key 4 a and the other operation buttons 19 on the front surface of the body 17. Although the explanation of the operation buttons 19 is omitted, in short, it is an input interface other than the trigger key 4a described above, and various operations other than the activation use of the two-dimensional pattern reading process among the operations of the two-dimensional pattern reading device 1 are described. Operation buttons and operation keys related to processing execution.

  Further, the two-dimensional pattern reading device 1 arranges the display unit 6 at an easily viewable position on the front surface of the body 17. As described above, the display unit 6 visualizes and displays a raw image during reading a two-dimensional pattern, a reading result of a two-dimensional pattern, or other information. It comes with a touch panel.

  Furthermore, the two-dimensional pattern reading device 1 has an illumination unit 2 and a storage unit 20 for the imaging unit 3 at the upper end of the body 17. As shown in FIG. 5C, the housing 20 exposes the light source window 21 (protective window of the optical lens 11a) of the illumination unit 2 and the imaging window 22 (protective window of the photographing lens 14a) of the imaging unit 3. A surface 23 is provided, and when the user 18 naturally holds the body 17, the vertical direction of the opening surface 23 of the housing portion 20 is oriented in the direction of the two-dimensional pattern 24 to be read.

  In short, the technical problem of the two-dimensional pattern reading device 1 according to the present embodiment is “to illuminate a target two-dimensional pattern with appropriate brightness regardless of the distance while saving power”.

  In order to achieve this task, in this embodiment, the distance from the two-dimensional pattern reading device 1 to the two-dimensional pattern 24 is measured, and the irradiation width of the illumination light of the illumination unit 2 is linearly or stepwise according to the distance. The gist is that a configuration for changing to is provided.

  That is, the root cause of the above technical problem is that the brightness of the two-dimensional pattern is inversely proportional to the square of the distance from the light source, so that the two-dimensional pattern located far away cannot be illuminated with an appropriate amount of light. In addition, in order to illuminate a two-dimensional pattern located far away with an appropriate amount of light, it is necessary to increase the amount of light according to the distance. Yes, depending on the distance, “change the irradiation width of the illumination light linearly or step by step” to avoid these causes, and “Proper brightness regardless of distance while saving power” It is possible to illuminate the target two-dimensional pattern.

  This will be described with reference to the drawings. As shown in FIG. 2A, when reading a nearby two-dimensional pattern 24, the “illumination light irradiation width” is sufficient so that the entire two-dimensional pattern 24 can be illuminated uniformly. The irradiation width at this time is assumed to be Wa for convenience. On the other hand, as shown in FIG. 2B, when reading a distant two-dimensional pattern 24, the brightness of the distant two-dimensional pattern 24 is considerably reduced unless the irradiation width is changed as Wa. This is because the illumination luminance decreases in inverse proportion to the square of the distance from the light source. In the present embodiment, when reading such a distant two-dimensional pattern 24, the irradiation width is changed from Wa to Wb. Here, Wa> Wb, and the difference between Wa and Wb corresponds to the difference between the distance to the two-dimensional pattern 24 in FIG. 2A and the distance to the two-dimensional pattern 24 in FIG. That is, the difference between Wa and Wb increases as the distance to the two-dimensional pattern increases.

  In this way, Wa and Wb only need to change appropriately according to the distance of the two-dimensional pattern. Ideally, the entire two-dimensional pattern 24 is displayed at both the perspective and the intermediate position. It is necessary to have a variable characteristic of an appropriate irradiation width that can be illuminated evenly.

  In addition, a dedicated distance measuring unit may be provided for measuring the distance to the two-dimensional pattern. However, the imaging unit 3 of the present embodiment has an autofocus function, and the autofocus function is used to measure a subject. Considering that the distance means (ranging section 16) is essential, it can be said that the use of the distance measuring means (ranging section 16) having the autofocus function is preferable from the viewpoint of cost. Then, the distance measuring unit (ranging unit 16) of the autofocus function of the imaging unit 3 is also used as a unit for measuring the distance to the two-dimensional pattern.

  FIG. 3 is a diagram showing a variable characteristic of the irradiation width. This variable characteristic is stored in advance in the form of a data table (hereinafter referred to as an irradiation width data table) in the ROM 5b of the control unit 5. The irradiation width data table 25 has a two-dimensional map structure in which the vertical axis represents distance and the horizontal axis represents irradiation width, and an irradiation width control characteristic line 26 is set between both axes. Here, the distance on the vertical axis is “far” on the upper end side, “near” on the lower end side, the irradiation width on the horizontal axis is “narrow” on the right end side, and “wide” on the left end side, and the irradiation width control characteristics between both axes Since the line 26 is a straight line that rises to the right, according to the irradiation width control characteristic line 26, it is possible to obtain a variable characteristic of the irradiation width that the irradiation width becomes narrower as the distance increases. As the distance increases, the difference between Wa and Wb increases.

  In addition, although it was set as the linear, ie, linear irradiation width control characteristic line 26 here, it is not limited to this. It may be a curve or a free line. A straight line, a curve, or a free line is a line that exhibits a linear change. Or it is good also as the irradiation width control characteristic line 27 which changes in steps as shown with the broken line in a figure. The linear irradiation width control characteristic line 26 is preferable in terms of control precision, but the stepwise irradiation width control characteristic line 27 is preferable in terms of prevention of battery consumption. This is because the consumption of the battery can be avoided by intermittently moving the irradiation width variable optical unit 11. Whether to use a linear line (irradiation width control characteristic line 26 or the like) or a stepwise irradiation width control characteristic line 27 can be selected as appropriate depending on which one is important, control precision or battery consumption prevention. Good.

  In the above description, the luminance of the light emitting unit 10 of the illumination unit 2 is set to a predetermined value (fixed value). However, the luminance is not limited to this and may be variable according to the distance of the two-dimensional pattern.

  FIG. 4 is a diagram illustrating the variable characteristics of luminance. This variable characteristic is also stored in advance in the form of a data table (hereinafter referred to as a luminance data table) in the ROM 5b of the control unit 5. The luminance data table 28 has a two-dimensional map structure with the vertical axis representing distance and the horizontal axis representing luminance, and a luminance control characteristic line 29 is set between the two axes. Here, the distance on the vertical axis is “far” on the upper end side, “near” on the lower end side, the luminance on the horizontal axis is “high luminance” on the right end side, and “low luminance” on the left end side. The line 29 is a straight line that rises to the right (may be a curved line or a free line). According to the luminance control characteristic line 29, it is possible to obtain a variable luminance characteristic that the luminance of the light emitting unit 10 increases as the distance increases. Accordingly, the two-dimensional pattern becomes brighter as the distance to the two-dimensional pattern increases. Since the action of illuminating is obtained, the effect of “illuminating the target two-dimensional pattern with an appropriate brightness regardless of the distance” by complementing the action of the irradiation width control characteristic line 26 (or 27). Can be further enhanced.

  The luminance control characteristic line 29 may also be changed stepwise instead of linearly. That is, a luminance control characteristic line 30 as indicated by a broken line in the figure may be used.

  FIG. 5 is a diagram illustrating an operation flow of the two-dimensional pattern reading apparatus according to the embodiment. This operation flow is stored in advance in the form of a control program in the ROM 5b of the control unit 5, loaded into the RAM 5c of the control unit 5 as necessary, and executed by the CPU 5a.

  In this operation flow, first, a predetermined specified value (default value) is set in the illumination brightness control value of the light emitting unit 10 and the irradiation width control value of the irradiation width driving unit 12 (step S1). The specified values are, for example, a luminance of 50% and an irradiation width of 40 degrees. Here, 50% means substantially half of the full light emission luminance of the light emitting unit 10, and the irradiation width of 40 degrees means the absolute value of the spread angle of the light emitted from the light emitting unit 10. These specified values are examples, and other values may be used. For example, the illumination brightness and the irradiation width corresponding to the most frequently used distance may be used.

  Next, it waits until the trigger key 4a is operated by the user (step S2). When the trigger key 4a is operated, the illumination unit 2 is driven to emit light having the set illumination brightness and irradiation width. (Step S3).

  Next, the imaging unit 3 is driven to measure the distance to the subject (two-dimensional pattern), focus the subject, and shoot the subject, and the distance measurement result (measurement result of the distance measurement unit 16) is controlled by the control unit. 5 is temporarily stored in the RAM 5b (step S4), and then a two-dimensional pattern decoding process is executed (step S5).

  FIG. 6 is a diagram showing an operation flow of the decoding process (step S5). In this operation flow, first, a two-dimensional pattern is extracted from a bright part of a captured image (that is, a part that is exposed to light emitted from the illumination unit 2) (step S21). Next, the number of two-dimensional patterns extracted is determined (step S22). This determination corresponds to checking whether or not only one two-dimensional pattern is included in the captured image. That is, when the number of extractions is 0, it indicates that no two-dimensional pattern is included in the photographed image, and when the number of extractions is 2 or more, two or more two-dimensional patterns are present in the photographed image. This is a determination for eliminating these cases as errors because the information of the two-dimensional pattern cannot be correctly reproduced in any case.

  When the number of extractions = 1 (step S23), since the number of extractions of the two-dimensional pattern is one, the printing interval of the two-dimensional pattern is set to 0 (step S26), and the extracted two-dimensional pattern is analyzed (decoded). (Step S27), it is determined whether or not the decoding is successful (Step S28). If the decoding is successful, the decoding success flag is set to 1 (Step S29) and then the flow is exited, but the decoding is not successful. Sets 0 to the decoding success flag (step S30), and then exits the flow.

  When the number of extractions is 0 (step S24), since the number of extractions of the two-dimensional pattern is 0, the printing interval is set to 0 (step S31), and the decoding success flag is set to 0 (step S30). Exit.

  When the number of extractions ≧ 2 (step S25), since the number of extractions of the two-dimensional pattern is 2 or more, the printing interval is acquired (step S32), and a required error message is output to the display unit 6 (step S33). After the decoding success flag is set to 0 (step S30), the flow is exited.

  Here, the printing interval refers to a printing (or display) interval at the time of printing or outputting a captured raw image of a two-dimensional pattern. When the number of extractions is 0 or 1, the number of extractions is naturally 0, and when the number of extractions is 2 or more, the interval is appropriate according to the number of extractions (the value acquired in step S32).

  Returning to FIG. 5 again, it is next determined whether or not the decoding is successful (decoding success flag = 1) (step S6). If the decoding is successful, the decoding result is output to the display unit 6 (step S7), and then the illumination brightness and irradiation width of the next scan are determined (step S8). If the decoding is not successful, step S7 is passed. Immediately after that, the illumination brightness and irradiation width of the next scan are determined (step S8).

  Here, the determination of “the illumination brightness and the irradiation width of the next scan” is performed based on the distance measurement result temporarily stored in the RAM 5b of the control unit 5 (in step S4). That is, since the distance measurement result is the distance to the two-dimensional pattern, in short, the illumination brightness and the irradiation width of the next scan are determined based on the distance to the two-dimensional pattern. More specifically, in accordance with the irradiation width variable characteristic diagram of FIG. 3 and the luminance variable characteristic diagram of FIG. 4, the next scan is performed so that the irradiation width becomes narrower and the luminance becomes higher as the distance to the two-dimensional pattern increases. Determine the illumination brightness and irradiation width.

  Next, the operation of the trigger key 4a is determined (step S9), and if it is operated, the process returns to step S3, and if it is not operated, it is determined whether the reading is finished (step S10). The determination of “end of reading” can be performed by determining a pressing operation of a dedicated reading end button included in the other operation buttons 19, but is not limited thereto. For example, a special operation such as a long press of the trigger key 4a may be determined and performed.

  If the reading is finished, the flow is finished as it is. If the reading is not finished, step S2 and the subsequent steps are repeated.

  Since the two-dimensional pattern reading apparatus 1 of the present embodiment is configured as described above, the following specific effects can be obtained.

(A) Regardless of the distance to the two-dimensional pattern, it is possible to illuminate the two-dimensional pattern with sufficient brightness.
This is because the irradiation width of the light of the illumination unit 2 is made variable according to the distance to the two-dimensional pattern. Specifically, as the distance is further away, the irradiation width is narrowed, thereby eliminating the cause that “the illumination brightness decreases in inverse proportion to the square of the distance from the light source”, regardless of the distance, This is because the entire two-dimensional pattern could be illuminated with sufficient brightness. In addition, the luminance of the light of the illumination unit 2 is also changed according to the distance to the two-dimensional pattern, that is, the luminance is increased as the distance increases.

  Note that variable brightness is not essential. This is because, in principle, the proposition “illuminate a target two-dimensional pattern with appropriate brightness regardless of distance” can be achieved by reducing the irradiation width as the distance increases. However, this measure (to narrow the irradiation width as the distance increases) may cause a practical problem. This is because if the distance is too long, even if the irradiation width is narrowed to the limit, it may not be possible to obtain a brightness sufficiently higher than the imaging sensitivity of the imaging unit 3. The combined use is practical. This is because by increasing the luminance of the illuminating unit 2, brightness suitable for the imaging sensitivity of the imaging unit 3 can be obtained.

(B) Avoid battery consumption.
The main technical idea of the embodiment is “to illuminate the target two-dimensional pattern with appropriate brightness regardless of the distance”, “to increase the irradiation width of the light of the illumination unit 2 as the distance to the two-dimensional pattern increases. The mechanism is to “narrow”. In this respect, since it is not simply a matter of compensating for the insufficient brightness by increasing the light amount of the illumination unit 2, there is an advantage that it is possible to prevent excessive battery consumption accompanying the increase in the light amount. However, as described above, the embodiment employs a mechanism of “decreasing the irradiation width as the distance increases” and “increasing the luminance as the distance increases”, and thus avoids battery consumption associated with this variable luminance. There is also a view that there is no. However, this variable brightness is a subordinate mechanism added from a practical point of view to achieve the task of illuminating a target two-dimensional pattern with appropriate brightness regardless of distance. It is not essential. Therefore, the mechanism of “increasing the brightness as the distance increases” does not need to be added especially when importance is attached to avoiding battery consumption. Can also be avoided.

  In the above embodiment, a mechanism of “decreasing the irradiation width as the distance increases” is adopted, but this mechanism may be improved as follows. That is, when “determining the irradiation width of the next scan based on the distance measurement result” in step S8 of FIG. 5, not only based on the distance measurement result but also the actual size of the two-dimensional pattern is taken into account. Then, the irradiation width may be determined. This is because the role of the illumination unit 2 is to brightly illuminate the target object to be read, that is, the two-dimensional pattern, and ideally, only the two-dimensional pattern “only” needs to be illuminated. In this regard, as in the embodiment, just by “determining the irradiation width of the next scan based on the distance measurement result”, the possibility of extra illumination around the two-dimensional pattern cannot be denied. It causes waste of light. In order to eliminate such waste, the actual size of the two-dimensional pattern is measured after “determining the irradiation width of the next scan based on the distance measurement result” and according to the measurement result. The irradiation width may be finely adjusted. This is preferable because it is possible to illuminate the two-dimensional pattern and not to perform extra illumination around the two-dimensional pattern, thereby eliminating waste of illumination light.

  The variation mode of the irradiation width of the illumination light in the above embodiment is an example. That is, the irradiation width of the illumination light is changed by changing the position of the optical lens 11a, but other modes may be adopted.

  FIG. 7 is a diagram illustrating another example of the irradiation width variable mode. In this aspect, as shown in (a), a plurality of rows arranged concentrically around the shooting window 22 of the imaging unit 3 (three rows in the figure, but may be three or more rows). ) Light emitting element groups 31-33. Each of the light emitting element groups 31 to 33 includes a different number of light emitting elements (here, LED elements). Here, when the number of the light emitting element groups 31 in the innermost row is A, the number of the light emitting element groups 32 in the intermediate row is B, and the number of the light emitting element groups 33 in the outermost row is C, each number is “A <B <C ”. Further, as shown in the cross-sectional arrangement of FIG. 5B, when the optical axes of the light emitting element groups 31 to 33 are La1, La2, and La3, the optical axis La3 of the innermost light emitting element group 31 is a short distance. , And the optical axis La2 of the light emitting element group 32 in the middle row is set to illuminate farther than the optical axis La3. Further, the light of the light emitting element group 33 in the outermost row is set. The axis La1 is set to illuminate farther than the optical axis La2.

  Therefore, according to such an aspect, it is possible to illuminate a short distance when only the innermost light emitting element group 31 is lit, and it is possible to illuminate a middle distance when only the intermediate light emitting element group 32 is lit. Since only the outermost light emitting element group 33 can be turned on to illuminate a long distance, the light irradiation width of the illumination unit 2 can be varied according to the distance to the two-dimensional pattern, as in the above-described embodiment. The following characteristics can be given.

  In addition, each of the light emitting element groups 31 to 33 in this embodiment includes a different number (A, B, C) of light emitting elements, and the number is “small” in the innermost row, “medium” in the middle row, Since the outermost row has a “many” relationship (A <B <C), if the light amount of each light emitting element is constant, the total light amount of the intermediate row is made higher than the total light amount of the innermost row, and Since the total amount of light in the outermost row can be further increased, it is possible to provide characteristics equivalent to “variable brightness” in the above embodiment.

La1 to La3 Optical axis 1 Two-dimensional pattern reading device 2 Illumination unit (illumination means)
3 Imaging unit (image reading means)
5 Control unit (irradiation width changing means, detecting means, brightness changing means)
11 Irradiation width variable optical part (irradiation width changing means)
11a Optical lens 12 Irradiation width driving unit (irradiation width changing means)
14a Shooting lens 16 Distance measuring unit (ranging means)
24 Two-dimensional pattern 31-33 Light emitting element group

Claims (9)

An image reading means for reading a subject der Rupa turn by images recognition,
Illumination means for illuminating the subject;
Ranging means for measuring the distance to the subject;
An irradiation width changing means for changing an irradiation width of light emitted from the illumination means based on a distance measurement result of the distance measuring means;
Brightness changing means for changing the brightness of light emitted from the illumination means based on the distance measurement result of the distance measuring means;
Detecting means for detecting the size of the subject from the reading result of the image reading means;
With
The irradiation width changing means performs the previous stage change to narrow the irradiation width as the distance to the subject increases, and finely adjusts the previous stage change result based on the detection result of the detection means,
Pattern reading apparatus characterized by. The luminance changing unit pattern reading apparatus according to claim 1, characterized in that to increase the light intensity enough distance to the subject becomes distant. The irradiation width changing unit includes an optical lens arranged on an optical axis of the illumination unit, and the irradiation width is changed by moving the optical lens along the optical axis. pattern reading device according to 1 or 2. The irradiation width changing means comprises a plurality of rows of light emitting element groups arranged concentrically around the photographing lens of the image reading means, and the optical axes of the plurality of light emitting elements constituting each light emitting element group pattern reading apparatus according to claim 1 or 2, characterized in that different for each light emitting element group. Group of light emitting elements of the plurality of rows is made from the light emitting elements of different numbers for each group, and its number is, in claim 4, characterized in that it is set to be larger as on the outside of the concentric circle pattern reading device according. Image reading means for reading the target image from a position separated from the target image;
Illuminating means for illuminating the target image;
Ranging means for measuring the distance to the target image,
Detecting means for detecting a size of the target image from a reading result of the image reading means;
A fine change is made to finely adjust the previous change result based on the detection result of the detection means, after changing the previous change to change the irradiation condition of the light emitted from the illumination means based on the distance measurement result of the distance measurement means. Adjusting means;
An image reading apparatus comprising: An image reading step of reading the subject der Rupa turn by images recognition,
An illumination process for illuminating the subject;
A distance measuring step for measuring a distance to the subject;
An irradiation width changing step for changing the irradiation width of the light emitted in the illumination step based on the distance measurement result of the distance measuring step,
A luminance changing step for changing the luminance of the light emitted by the illumination step based on the distance measurement result of the distance measuring step;
A detection step of detecting the size of the subject from the reading result of the image reading step;
Including
In the irradiation width changing step, after performing the previous stage change to narrow the irradiation width as the distance to the subject increases, finely adjust the previous stage change result based on the detection result of the detection step,
Pattern reading wherein the. An image reading means for reading a subject der Rupa turn by images recognized, the computer Rupa turn reader an illumination means for illuminating the subject,
Ranging means for measuring the distance to the subject,
Irradiation width changing means for narrowly changing the irradiation width of the light emitted from the illumination means based on the distance measurement result of the distance measuring means;
Luminance changing means for changing the luminance of light emitted from the illumination means based on the distance measurement result of the distance measuring means;
Detecting means for detecting the size of the subject from the reading result of the image reading means;
Function as
Further, the irradiation width changing means performs a previous stage change to narrow the irradiation width as the distance to the subject increases, and finely adjusts the previous stage change result based on the detection result of the detection means.
Program to make it function like . An image reading step of reading the target image from a position separated from the target image;
An illumination process for illuminating the target image;
A distance measuring step for measuring a distance to the target image;
A detection step of detecting a size of the target image from a reading result of the image reading step;
A fine change is made to finely adjust the previous change result based on the detection result of the detection step after changing the previous change to change the irradiation condition of the light emitted from the illumination step based on the distance measurement result of the distance measurement step. Adjustment process;
An image reading method comprising:

Images