JP2009058497A - Electronic measuring tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic measuring tape capable of accurately deriving the pull-out quantity of a measuring tape at low cost. <P>SOLUTION: The electronic measuring tape 1 includes a measuring tape 4; a winding means R winding the measuring tape 4 inside a case 2; a laser irradiation means 8 irradiating the measuring tape 4 with laser output from a semiconductor laser element; an imaging means 9 imaging the laser irradiated part of the measuring tape 4; a displacement information deriving means 11 comparing the patterns of a plurality of taken images imaged by the imaging means 9 every set time with each other to derive the displacement quantity and displacement direction of the measuring tape 4 in the taken images; a storage means 14 storing the correlation between the displacement quantity of the measuring tape 4 in the taken images and the actual moving quantity of the measuring tape 4; a pull-out quantity determining means 12 deriving the actual moving quantity of the measuring tape 4 based on the displacement quantity and displacement direction of the measuring tape 4 and the correlation stored in the storage means 14 to determine the pull-out quantity of the measuring tape 4 from the case 2; and a display means 15 displaying the pull-out quantity of the measuring tape 4 from the case 2 toward the outside of the case 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic tape measure that reads and displays the amount of tape measure drawn by an electronic method.

  In order to prevent erroneous reading of numerical values, an electronic tape measure that electronically reads and displays the amount of tape tape drawn from the housing has been proposed. For example, Patent Document 1 describes an electronic tape measure provided with an optical reading mechanism. FIG. 7 is a schematic diagram for explaining the operating principle of the electronic tape measure described in Patent Document 1. FIG. As shown in the figure, black and white stripes are drawn on the surface of the tape measure 104 at equal intervals (for example, 1 mm intervals). The light emitted from the light emitting diode (LED) 102 is reflected by a minute region on the surface of the tape measure and received by the light receiving element 103. At this time, when the light radiated from the light emitting diode 102 is reflected by the minute region of the white portion of the tape measure, the light intensity received by the light receiving element 103 increases. On the other hand, when the light radiated from the light emitting diode 102 is reflected by the micro area of the black portion, the light intensity received by the light receiving element 103 is reduced. Therefore, the arithmetic processing unit 101 can derive the amount of the tape measure drawn according to the interval of the striped pattern by counting the increase / decrease of the light intensity received by the light receiving element 103 (that is, the number of times of white or the number of times of black).

JP-A-6-58701

  In the electronic tape measure described in Patent Document 1, unless the black and white striped pattern is accurately drawn on the surface of the tape measure, the amount of the tape measure drawn out cannot be accurately derived. Further, in order to detect the drawing direction of the tape measure, two reading units each including a light emitting diode and a light receiving element are provided, and two minute readings on the surface of the tape measure along the drawing direction are provided using the two reading units. It is necessary to detect an increase or decrease in light intensity in the region. Here, the two minute regions need to be located at a shorter interval than the interval of the stripe pattern drawn on the surface of the tape measure.

  As described above, with a conventional electronic tape measure, it is necessary to print a striped pattern on the surface of the tape measure with high accuracy, and further, contamination on the surface of the tape measure, blurring of printing, etc. are not allowed. In addition, since a plurality of reading units composed of light emitting diodes and light receiving elements are required, there are problems of an increase in the number of parts and a problem that high mounting accuracy is required for the plurality of reading units.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an electronic tape measure that can accurately derive the amount by which the tape measure is pulled out.

In order to achieve the above object, the characteristic configuration of the electronic tape measure according to the present invention includes a tape measure that can be pulled out of the housing,
Winding means for winding the tape measure inside the housing;
Laser irradiation means for irradiating the tape measure with laser output from a semiconductor laser element;
Imaging means for imaging the laser irradiated portion of the tape measure;
Displacement information deriving means for deriving a displacement amount and a displacement direction of the tape measure in the captured image by comparing patterns of a plurality of captured images captured at set times by the imaging unit,
Storage means for storing a correlation between a displacement amount of the tape measure in the captured image and an actual movement amount of the tape measure;
Based on the displacement amount and the displacement direction of the tape measure derived by the displacement information deriving unit and the correlation stored in the storage unit, an actual movement amount of the tape measure is derived from the housing. A drawer amount determining means for determining a drawer amount of the tape measure;
And a display means for displaying the amount of the tape measure drawn from the housing toward the outside of the housing.

According to the above characteristic configuration, the displacement information deriving means compares the patterns of a plurality of captured images with each other by utilizing the inherent presence of fine patterns (including uneven patterns and color patterns) on the surface of the tape measure. Then, a displacement amount and a displacement direction of the tape measure in the captured image are derived. That is, it is not necessary to draw a striped pattern or the like on the surface of the tape measure as in the prior art. In addition, since there is no need to provide two reading units composed of a light emitting element such as a light emitting diode and a light receiving element as in the prior art, there has been a problem of an increase in the number of parts, which has been a problem, and a plurality of reading units. The problem that high mounting accuracy is required can be avoided.
Furthermore, since the laser output from the semiconductor laser element is irradiated to the tape measure, even if the tape measure has a glossy surface and less unevenness than the case where the tape measure is irradiated using another light source such as an LED. Thus, the imaging means can accurately obtain the pattern on the surface of the tape measure. As a result, the drawing amount determination means can accurately determine the amount of drawing of the tape measure from the housing.
Therefore, it is possible to provide an electronic tape measure capable of accurately deriving the amount of tape tape drawn.

  Another characteristic configuration of the electronic tape measure according to the present invention includes reference position detection means for detecting a reference position display attached to the tape measure from an image captured by the imaging means, and the withdrawal amount determination means includes the reference amount determination means. When the position detection means detects the reference position display, the amount of the tape measure drawn from the housing is determined to be a predetermined reference amount.

According to the above characteristic configuration, when the reference position detecting means detects the reference position display attached to the tape measure from the image taken by the image pickup means, that is, when the drawing amount of the tape measure is in the reference state, the drawing amount determining means. Automatically determines the amount of tape measure drawn from the housing to a predetermined reference amount. That is, since the amount of drawing of the tape measure is automatically calibrated regularly to the reference amount, the accuracy of the amount of drawing of the tape measure can be continuously maintained.
The reference display is not particularly limited as long as it can be detected by the reference position detection means. For example, a predetermined pattern indicating the reference position or a hole indicating the reference position can be applied.

Another characteristic configuration of the electronic tape measure according to the present invention includes a reference state receiving means for receiving an input that the state where the tape measure is pulled out from the housing is a reference state,
The withdrawal amount determining means is such that the withdrawal amount of the tape measure from the housing when the reference state receiving means receives an input indicating that it is in the reference state is determined as a predetermined reference amount.

  According to the above characteristic configuration, when the reference state accepting unit accepts an input indicating that the tape measure is in the reference state, the drawer amount determining unit automatically sets the tape measure withdrawal amount from the housing to a predetermined reference amount. To decide. That is, it is possible to manually calibrate the drawing amount of the tape measure to the reference amount.

  Another characteristic configuration of the electronic tape measure according to the present invention is that a correction display attached to the tape measure to correct the pull-out amount of the tape measure determined by the pull-out amount determination means, and a correction display that detects the correction display And a drawing means determining means for correcting the determined drawing amount of the tape measure when the correction display detecting means detects a correction display.

  According to the above characteristic configuration, when the correction display detection unit detects the correction display attached to the tape measure from the image captured by the imaging unit, the extraction amount determination unit corrects the determined extraction amount of the tape measure. For this reason, since the withdrawal amount is periodically corrected, it is possible to prevent errors from accumulating in the determined withdrawal amount, and to maintain the accuracy of the withdrawal amount of the tape measure continuously.

<First Embodiment>
The electronic tape measure 1 according to the first embodiment will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing the configuration of the electronic tape measure 1 of the first embodiment. As shown in the figure, a tape measure 4 is accommodated inside the housing 2 so as to be pulled out of the housing 2. The tape measure 4 is connected to a mainspring spring 6 wound around a mainspring shaft 5 inside the housing 2. Therefore, the mainspring shaft 5 and the mainspring spring 6 function as winding means R for winding the tape measure 4 inside the housing 2. The tape measure 4 can be pulled out of the housing 2 through the outlet 3 formed in the housing 2, but a force for pulling into the housing 2 by the mainspring spring 6 is always applied to the tape measure 4. ing. However, a stopper 7 is attached to the tip of the tape measure 4, and the stopper 7 prevents all the tape measure 4 from being drawn into the housing 2. A state in which the tape measure 4 is pulled into the inside of the housing 2 as much as possible until the stopper 7 contacts the housing 2 is a reference state, that is, a state in which the amount of the tape measure 4 drawn from the housing 2 is zero.

The electronic tape measure 1 includes a laser irradiation means 8, an imaging means 9, an arithmetic processing unit 10, a storage means 14, and a display means 15 in addition to the tape measure 4 and the winding means R. The arithmetic processing unit 10 includes at least a displacement information deriving unit 11 and an extraction amount determining unit 12, and further includes a reference position detecting unit 13.
The laser irradiation means 8 is configured using a semiconductor laser element, and irradiates the tape measure 4 with a laser output from the semiconductor laser. The imaging means 9 images the portion of the tape measure 4 irradiated with the laser. The laser irradiation means 8 guides the laser output from the semiconductor laser element to a range including at least the imaging area A on the surface of the tape measure 4 using an optical element (not shown) such as a lens or a prism. Then, the imaging unit 9 captures a reflection image of the imaging area A of the tape measure 4 irradiated with the laser by the laser irradiation unit 8.

  The displacement information deriving unit 11 compares the patterns of the plurality of captured images captured at the set time by the imaging unit 9 to derive the displacement amount and the displacement direction of the tape measure 4 in the captured image. For example, the displacement information deriving unit 11 compares the pattern of the captured image of the imaging area A of the tape measure 4 at a certain time with the pattern of the captured image of the imaging area A of the tape measure 4 at another time. At this time, the displacement information deriving unit 11 may compare three or more captured images. Then, the displacement information deriving unit 11 derives the displacement amount (which may be expressed as “count” in this embodiment) and the displacement direction of the pattern that exists in common in the captured image.

  The drawing amount determination unit 12 derives the actual movement amount of the tape measure 4 based on the displacement amount and the displacement direction of the tape measure 4 derived by the displacement information deriving unit 11, and determines the drawing amount of the tape measure 4 from the housing 2. To do. In the present embodiment, the storage means 14 configured using a nonvolatile memory such as an EEPROM correlates the displacement amount (count) of the tape measure 4 in the captured image as described above with the actual movement amount of the tape measure 4. Remember the relationship. FIG. 2 is a graph showing the correlation between the amount of displacement (count) of the tape measure 4 and the actual amount of movement (mm). The storage means 14 stores the slope value of this graph: K (mm / count). Therefore, the actual movement amount of the tape measure 4 can be derived by multiplying the displacement amount (count) of the tape measure 4 derived by the displacement information deriving means 11 and the inclination value K. Then, the drawing amount determination means 12 determines the new drawing amount of the tape measure 4 based on the drawing amount of the previous tape measure 4 stored in the storage means 14 and the newly derived movement amount of the tape measure 4. . As described above, the drawing amount determination means 12 is based on the displacement amount and displacement direction of the tape measure 4 derived by the displacement information deriving means 11 and the correlation (slope value: K) stored in the storage means 14. The actual amount of movement of the tape measure 4 is derived, and the amount of the tape measure 4 pulled out from the housing 2 is determined.

  When the drawing amount determination means 12 determines the drawing amount of the tape measure 4 from the housing 2, the arithmetic processing unit 10 sends information on the drawing amount to the display means 15. The display means 15 can be realized using various display devices such as a liquid crystal display device and a self-luminous EL (electroluminescence) element. Then, the display unit 15 displays the value of the amount of the tape measure 4 drawn from the housing 2 that is received toward the outside of the housing 2.

  As described above, the arithmetic processing unit 10 always derives the displacement amount and the displacement direction of the tape measure 4 using the displacement information deriving unit 11 and determines the tape measure 4 from the casing 2 determined using the drawing amount determining unit 12. It is always reflected in the amount of withdrawal. Therefore, while the tape measure 4 is being pulled out from the casing 2, the value of the tape measure 4 displayed on the display means 15 gradually increases. When the tape measure 4 is stopped, the display means 15 displays the value. The value of the withdrawal amount to be stopped is also stopped. When the tape measure 4 is taken up by the take-up means R, the value of the withdrawal amount of the tape measure 4 displayed on the display means 15 is also reduced.

  Hereinafter, a specific configuration and operation of the electronic tape measure 1 will be described. In FIG. 1, the displacement information deriving unit 11, the extraction amount determining unit 12, and the reference position detecting unit 13 are illustrated in a form that is realized by one arithmetic processing unit 10. The functions of the irradiating means 8, the imaging means 9, the displacement information deriving means 11 and the reference position detecting means 13 can be realized by an optical sensor module, and the function of the extraction amount determining means 12 can be realized by a microcomputer or the like. The storage unit 14 can be realized by a nonvolatile memory such as an EEPROM.

In the optical sensor module, the reflected image of the tape measure 4 irradiated by the laser irradiation unit 8 is captured by the imaging unit 9 at a predetermined frame rate. The displacement information deriving means 11 performs signal processing on the obtained captured image, and the displacement amount (count) and the displacement direction of the tape measure 4 are derived.
In the microcomputer, the drawing amount determining means 12 requests the derived information about the displacement amount (count) and the displacement direction of the tape measure 4 every predetermined time (for example, every 1 msec) from the optical sensor module. Then, the withdrawal amount determination means 12 sends the displacement amount and displacement direction of the tape measure 4 during the predetermined time sent from the optical sensor module in response to the request, and the correlation stored in the storage means 14. Based on (inclination value: K), an actual movement amount of the tape measure 4 during the predetermined time is derived, and an amount of the tape measure 4 drawn out from the housing 2 is determined.
In addition, the microcomputer has a function of setting the frame rate of the reflected image for the imaging unit 9 of the optical sensor module, a function of setting the laser output intensity for the laser irradiation unit 8 of the optical sensor module, and the like. Have.

  As described above, in the electronic tape measure 1 of the present embodiment, the amount of withdrawal of the tape measure 4 is accumulated and displayed on the basis of when the amount of withdrawal of the tape measure 4 is zero. Therefore, it is necessary that the display on the display means 15 when the drawing amount of the tape measure 4 is zero is surely zero. Therefore, in the electronic tape measure 1 of the present embodiment, the arithmetic processing unit 10 is configured so as to have a function of a reference position detection unit 13 described later.

Specifically, the electronic tape measure 1 of the present embodiment is attached to the tape measure 4 with a pattern m1 of the reference position indication M, and the amount of the tape measure 4 drawn is zero (that is, attached to the tip of the tape measure 4). The pattern m1 (black line pattern in the present embodiment) of the reference position display M is imaged while the tape measure 4 is wound around the winding means R) until the stopper 7 comes into contact with the drawing port 3 of the housing 2. It is located in area A.
The reference position detection unit 13 has a function of calculating the lightness and darkness of the imaging area A imaged by the imaging unit 9 with numerical values. Specifically, the reference position detection unit 13 outputs a small numerical value when the imaging region A increases in black color, and outputs a large numerical value when the white color increases. Therefore, as described above, when the pattern m1 of the reference position display M is present in the imaging region A, the imaging region A is all black, so the reference position detection unit 13 calculates “0 (zero)”. . That is, the reference position detection unit 13 detects the pattern m1 of the reference position display M attached to the tape measure 4 from the captured image obtained by the imaging unit 9 by quantifying it.
The drawing amount determination means 12 receives the numerical value of the image area A output from the reference position detection means 13, and if the value is “0” (that is, the reference position detection means 13 indicates the pattern m1 of the reference position display M). Is detected), the amount by which the tape measure 4 is pulled out from the housing 2 is determined to be a predetermined reference amount (“0 (zero)” in the present embodiment).

  Note that the optical sensor module has the function of the reference position detecting means 13. In the microcomputer, the drawing amount determination means 12 requests the optical sensor module for the density value of the imaging region A detected by the reference position detection means 13 every predetermined time (for example, every 1 msec). . Then, the amount of drawing of the tape measure 4 from the housing 2 is “0” based on the shade value of the imaging area A sent from the optical sensor module by the drawing amount determination means 12. It is determined whether or not there is.

  As described above, the electronic tape measure 1 of the present embodiment derives the displacement amount and the displacement direction of the tape measure by utilizing the fact that a fine pattern is inherently present on the surface of the tape measure 4. There is no need to draw a striped pattern on the surface of the tape measure. In addition, since there is no need to provide two reading units composed of a light emitting element such as a light emitting diode and a light receiving element as in the past, an increase in the number of parts, which has been a problem, and high mounting for a plurality of reading units. Problems such as accuracy required can be avoided. Further, since the laser output from the semiconductor laser element (laser irradiation means 8) is irradiated onto the tape measure 4, even if the tape measure has a glossy surface and little unevenness, another light source such as an LED is used. Compared to the case where the tape measure is irradiated, the imaging means 9 can accurately obtain the pattern on the surface of the tape measure 4. As a result, the amount by which the tape measure 4 is pulled out from the housing 2 can be accurately determined.

Second Embodiment
The electronic tape measure 30 according to the second embodiment is different from the electronic tape measure 1 according to the first embodiment in that the electronic tape measure 30 includes the reference state receiving means 16. Although the electronic tape measure 30 of 2nd Embodiment is demonstrated below, description is abbreviate | omitted about the structure similar to 1st Embodiment.

  FIG. 3 is a schematic diagram showing the configuration of the electronic tape measure 30 of the second embodiment. As shown in the drawing, the electronic tape measure 30 of the present embodiment includes a reference state receiving unit 16 that receives an input from the operator that the state in which the tape measure 4 is pulled out from the housing 2 is the reference state. And the reference position detection means 13 with which the electronic tape measure 1 of 1st Embodiment was provided is not provided. Further, the tape measure 4 is not provided with the pattern m1 of the reference position display M as in the first embodiment. For example, the reference state receiving unit 16 is a so-called zero correction switch for receiving an instruction that the amount of the tape measure 4 drawn from the housing 2 is zero (an example of a reference amount).

  The withdrawal amount determination unit 12 determines the withdrawal amount of the tape measure 4 from the housing 2 when the reference state reception unit 16 receives an input indicating that it is in the reference state as a predetermined reference amount. In this case, when the operation input of the reference state receiving means 16 is performed, the withdrawal amount determination means 12 determines the withdrawal amount of the tape measure 4 from the housing 2 at that time to be zero and is displayed on the display means 15. Make the value of the withdrawal amount to be zero.

<Third Embodiment>
Next, the electronic tape measure 50 of 3rd Embodiment is demonstrated with reference to drawings. FIG. 4 is a schematic view showing the configuration of the electronic tape measure 50 of the third embodiment. In the electronic tape measure 50 of the third embodiment, a hole m2 is formed in the tape measure 4 in place of the pattern m1 described in the first embodiment as a reference position display M. The tape measure 4 is provided with a correction display C, and is different from the electronic tape measure 1 of the first embodiment described above in that the arithmetic processing unit 10 is provided with the reference position detection means 18. Although the electronic tape measure 50 of 3rd Embodiment is demonstrated below, description is abbreviate | omitted about the structure similar to 1st Embodiment.

  In the present embodiment, the hole m2 of the reference position display M is in a state in which the amount of drawing of the tape measure 4 is zero, that is, the stopper 7 attached to the tip of the tape measure 4 abuts on the outlet 3 of the housing 2. The hole m2 of the reference position display M is formed so as to be positioned in the imaging region A in a state where the tape measure 4 is wound up by the winding means R. When the hole m2 of the reference position display M exists in the imaging area A, the laser output from the laser irradiation means 8 passes through the hole m2 and is not reflected on the surface of the tape measure 4. For this reason, the reflected image of the imaging area A of the tape measure 4 irradiated with the laser is not captured. The reference position detection unit 13 detects a state where the reflected image of the imaging area A is not captured.

Further, a correction display C is attached to the tape measure 4, and the drawing amount determination means 12 corrects the determined drawing amount of the tape measure 4 when the correction display detection means 18 detects the correction display C.
The correction display C is, for example, a predetermined pattern, and a plurality of patterns are arranged at a known interval (pitch). In this embodiment, the correction display C is a black line, and a plurality of black lines are attached to the tape measure 4 at a constant interval (pitch). The correction display detection unit 18 has a function of calculating the density of the imaging area A imaged by the imaging unit 9 with a numerical value. Specifically, the correction display detection means 18 outputs a small numerical value when the imaging region A has a large black color, and outputs a large numerical value when the white color increases. When the correction display C exists in the imaging area A, the imaging area A is all black, and the correction display detection means 18 calculates “0 (zero)”. That is, the correction display detection unit 18 detects the black line of the correction display C attached to the tape measure 4 from the image captured by the imaging unit 9 by quantifying it. The withdrawal amount determination unit 12 receives the numerical value of the image area A output from the reference position detection unit 13, and when the value is “0” (that is, when the correction display detection unit 18 detects the correction display C). The amount of the tape measure 4 pulled out from the housing 2 is corrected.

  Specifically, as shown in FIG. 4, when the area between the adjacent correction displays C1 and C2 is located in the imaging area A (that is, when the correction display detection means 18 has not detected the correction display C). The amount-of-drawing determination means 12 is based on the displacement amount and direction of the tape measure 4 derived by the displacement information deriving means 11, and the movement amount Δd of the tape measure 4 in the region between the correction indications C1 and C2 (that is, correction) The amount of movement of the tape measure 4 with respect to the display C1 is derived. Then, the drawing amount of the tape measure 4 is determined by adding the movement amount Δd to the drawing amount of the tape measure 4 after the correction when the correction display C1 is positioned in the imaging region A. When the correction display C2 reaches the imaging area A, that is, when the correction display detection unit 18 detects the correction display C2, the correction display C1 is replaced with the adjacent correction display C1, instead of the displacement amount Δd based on the result derived by the displacement information deriving unit 11 described above. The drawing amount of the tape measure 4 is determined by adding the pitch between C2 to the drawing amount of the tape measure 4 after the correction when the correction display C1 is positioned in the imaging region A. When the tape measure 4 is further pulled out and the area between the correction display C2 and the correction display C3 reaches the imaging area A, the movement amount Δd based on the correction display C2 based on the result derived by the displacement information deriving means 11 as described above. Is calculated and the withdrawal amount is determined. When the correction display C3 reaches the imaging area A, the amount of withdrawal is determined by integrating the pitch between the correction displays C2 and C3 as described above. In this way, the withdrawal amount determination unit 12 corrects the withdrawal amount every time the correction display C reaches the imaging area A.

  In the present embodiment, the storage means 14 configured using a non-volatile memory such as an EEPROM has the displacement amount (count) of the tape measure 4 in the captured image and the actual tape measure 4 as described in the first embodiment. The correlation K (mm / count) with the amount of movement is stored. Further, an interval (pitch) between adjacent correction displays C is stored. Therefore, by multiplying the displacement amount (count) of the tape measure 4 derived by the displacement information deriving means 11 and K, the movement amount Δd between the adjacent correction displays C of the tape measure 4 can be derived. Then, the drawing amount determination unit 12 determines a new drawing amount of the tape measure 4 based on the previous corrected drawing amount stored in the storage unit 14 and the derived movement amount Δd of the tape measure 4. The storage means 14 is configured to store the number of correction displays C detected by the correction display detection means 18 and moves to a value obtained by multiplying the number of detected correction displays C and the pitch between the correction displays C. The amount of withdrawal may be determined by integrating the amount Δd.

<Another embodiment>
<1>
The electronic tape measure 40 of another embodiment is configured to be able to calibrate the correlation between the displacement amount (count) of the tape measure 4 in the captured image as illustrated in FIG. 2 and the actual movement amount of the tape measure 4. This is different from the embodiment described above. Although the electronic tape measure 40 of another embodiment obtained by modifying the electronic tape measure 4 of the first embodiment will be described below, the electronic tape measure 4 of the second embodiment can be modified.

  FIG. 5 is a schematic view showing a configuration of an electronic tape measure 40 of another embodiment. As shown in the figure, the electronic tape measure 40 of this embodiment includes a communication unit 17 that enables the arithmetic processing unit 10 to communicate with an external device. The communication unit 17 is configured using an antenna for performing wireless communication with an external device, a communication terminal for performing wired communication with the external device, or the like.

  FIG. 6 is a diagram showing a state in which the electronic tape measure 40 and the information processing apparatus 20 such as a computer as the external apparatus are connected by wire via the communication means 17. FIG. 7 is a display screen example of the information processing apparatus 20. First, in order to calibrate the correlation between the displacement amount (count) of the tape measure 4 and the actual movement amount of the tape measure 4 as illustrated in FIG. 2, as shown in FIG. 6, the electronic tape measure 40 and the information processing device 20 are used. And connect to each other. Next, the operator of the information processing apparatus 20 activates calibration software installed in the information processing apparatus 20. FIG. 7 is a display screen example of the information processing apparatus 20 when the calibration software is activated. When the operator pulls out the tape measure 4 from the casing 2 of the electronic tape measure 40, the displacement amount (count) of the tape measure 4 derived by the displacement information deriving means 11 of the electronic tape measure 40 is transmitted via the communication means 17 to the information processing apparatus. 20 and displayed on the display screen. In addition, an input box 21 in which the operator inputs the amount of withdrawal of the tape measure 4 is also displayed. In the example shown in FIG. 7, a count value (4735 counts) when the operator pulls out the tape measure 4 from the housing 2 by 30 cm using a certain electronic tape measure 40 is displayed. In this state, when the operator inputs “30” cm into the input box 21 and selects and inputs the OK button 22, information on the count value (4735 counts) and the actual withdrawal amount (30 cm) is obtained. To the electronic tape measure 40. Then, the arithmetic processing unit 10 of the electronic tape measure 40 derives a value (0.0634 mm / count) obtained by dividing the actual withdrawal amount received from the information processing apparatus 20 by the count value. Alternatively, the information processing device 20 may be configured such that a value obtained by dividing the actual withdrawal amount by the count value is sent from the information processing device 20 to the electronic tape measure 40.

  A value obtained by dividing the actual withdrawal amount by the count value corresponds to the slope value K illustrated in FIG. Therefore, the arithmetic processing unit 10 of the electronic tape measure 40 can be used to store the value K obtained by this calibration work in the storage means 14 and derive the actual movement amount of the tape measure 4.

  Note that the method of calibrating the slope value K is not limited to that described above. For example, the count value when the operator pulls out the tape measure 10 cm: C10 and the count value when the operator pulls out 30 cm: C30 are acquired, and K (mm / count) = (300 mm-100 mm) / (C30-C10 It is also possible to derive the slope value K from the calculation of).

  Also, in the electronic tape measure of the third embodiment shown in FIG. 4 described above, the correlation between the amount of displacement (count) of the tape measure 4 and the actual amount of movement of the tape measure 4 can be calibrated. Also in this case, similarly to the above-described electronic tape measure (see FIG. 5), the communication processing unit 17 that enables the arithmetic processing unit 10 to communicate with an external device is provided. Also in this embodiment, the method of calibrating the slope value K is the same as that in the above-described embodiment. In this embodiment, a hole m2 is formed in the tape measure 4 as the reference position display M. When the imaging region A is located in the hole m2, there is no reflected image by the laser irradiation unit 8, and the displacement information deriving unit 11 cannot derive the displacement of the tape measure 4. For this reason, it is necessary to obtain the diameter a of the hole m2 at the time of calibration. The tape measure 4 is pulled out to a known withdrawal amount (for example, 20 mm), and the difference between the known withdrawal amount (for example, 20 mm) and the detection result (for example, 17 mm) of the displacement information deriving means 11 is defined as the diameter a of the hole m2. In the case of this example, the diameter a of the hole m2 is 3 mm. The obtained diameter a of the hole m2 is stored in the storage means 14.

<2>
In the first embodiment, the example has been described in which the reference position detection unit 13 detects the pattern m1 of the reference position display M by calculating the lightness and darkness of the imaging region A captured by the imaging unit 9 numerically. It may be modified to detect the pattern m1 of the reference position display M in the form of. For example, the storage unit 14 stores an image (reference image) of the imaging region A including the pattern m1 of the reference position display M captured by the imaging unit 9 in a state where the amount of the tape measure 4 is zero. The reference position detection unit 13 detects the pattern m1 of the reference position display M attached to the tape measure 4 when the pattern of the image captured by the imaging unit 9 is the same as the pattern of the reference image stored in the storage unit 14. You may comprise so that it may determine with having carried out.

<3>
In the second embodiment described above, the correction display detection unit 18 detects the correction display C by calculating the density of the imaging area A captured by the imaging unit 9 using numerical values. However, the correction display detection unit 18 performs correction in other forms. The display C may be modified so as to be detected. For example, the pattern of the correction display C is stored in the storage unit 14, and the correction display detection unit 18 has the same pattern as the correction display C stored in the storage unit 14. In some cases, it may be configured to determine that the correction display C attached to the tape measure 4 has been detected.

<4>
In the said embodiment, although the numerical structure was illustrated and the characteristic structure of the electronic type tape measure concerning this invention was demonstrated, this invention is not limited by those numerical examples, and various changes are possible. In addition, an example in which the laser irradiation unit, the imaging unit, the reference position detection unit, the arithmetic processing unit, and the like are configured by two modules of the optical sensor module and the microcomputer has been described. However, the laser irradiation unit, the imaging unit, and the reference position detection unit are described. The arithmetic processing unit and the like may be configured by one module.

  The electronic tape measure according to the present invention can be used as a tape measure for reading the drawing amount of the tape measure by an electronic method and displaying it so that the operator can easily read it. If a self-luminous display device is used as the display means, it is possible to accurately know the amount by which the tape measure is pulled out even in a dark place.

Schematic which shows the structure of the electronic tape measure of 1st Embodiment. A graph showing the correlation between the amount of tape measure displacement (count) and the actual amount of movement Schematic which shows the structure of the electronic tape measure of 2nd Embodiment. Schematic which shows the structure of the electronic tape measure of 3rd Embodiment. Schematic which shows the structure of the electronic tape measure of another embodiment. The figure which shows the state which wired and connected information processing apparatuses, such as an electronic tape measure, and a computer Display screen example of information processing device Schematic diagram for explaining the operating principle of a conventional electronic tape measure

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic type tape measure 2 Housing | casing 4 Tape measure 5 Spring main shaft (winding means R)
6 Spring spring (winding means R)
8 Laser irradiation means 9 Imaging means 11 Displacement information derivation means 12 Extraction amount determination means 14 Storage means 15 Display means

Claims (6)

A tape measure that can be pulled out of the housing,
Winding means for winding the tape measure inside the housing;
Laser irradiation means for irradiating the tape measure with laser output from a semiconductor laser element;
Imaging means for imaging the laser irradiated portion of the tape measure;
Displacement information deriving means for deriving a displacement amount and a displacement direction of the tape measure in the captured image by comparing patterns of a plurality of captured images captured at set times by the imaging unit,
Storage means for storing a correlation between a displacement amount of the tape measure in the captured image and an actual movement amount of the tape measure;
Based on the displacement amount and the displacement direction of the tape measure derived by the displacement information deriving unit and the correlation stored in the storage unit, an actual movement amount of the tape measure is derived from the housing. A drawer amount determining means for determining a drawer amount of the tape measure;
An electronic tape measure comprising: display means for displaying the amount of the tape measure drawn from the housing toward the outside of the housing. Reference position detection means for detecting a reference position display attached to the tape measure from an image captured by the imaging means,
2. The electronic tape measure according to claim 1, wherein when the reference position detection unit detects a reference position display, the pull-out amount determination unit determines a pull-out amount of the tape measure from the housing as a predetermined reference amount.   The electronic tape measure according to claim 2, wherein the reference position display is a predetermined pattern indicating the reference position.   The electronic tape measure according to claim 2, wherein the reference position display is a hole indicating the reference position. Comprising a reference state receiving means for receiving an input that the state in which the tape measure is pulled out of the housing is a reference state;
2. The electronic device according to claim 1, wherein the drawing amount determining unit determines a drawing amount of the tape measure from the housing when the reference state receiving unit receives an input indicating that the reference state is set to a predetermined reference amount. Expression tape measure. A correction display attached to the tape measure to correct the drawing amount of the tape measure determined by the pull-out amount determination means, and a correction display detection means for detecting the correction display.
The electronic tape measure according to any one of claims 1 to 5, wherein the drawing amount determination means corrects the determined drawing amount of the tape measure when the correction display detection means detects a correction display.

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