JP2008298741A - Distance measuring apparatus and distance measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a distance measuring apparatus and a distance measuring method that provide wider measuring ranges and higher measuring accuracy. <P>SOLUTION: A distance computing section 26 computes a distance from a given point on the surface of a floor in accordance with reflected light received by a light-receiving device 20. An attitude detecting section 28 detects an attitude angle θ in accordance with the distance from the point as computed by the distance computing section 26. A light source control section 24 controls the intensity of light from a light source 18 in accordance with the attitude angle θ and the distance from the point so that the intensity of irradiation at the point is an intensity of irradiation obtained as a function of distance from the point. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a distance measuring device and a distance measuring method, and more particularly to a distance measuring device and a distance measuring method for measuring a distance based on reflected light received by a light receiving means.

Conventionally, equipped with a time-of-flight distance image sensor that measures the distance to the object based on the time from when the light is emitted to the object until the reflected light from the object is received by the light receiving unit And the obstacle detection apparatus which measures the distance to a floor surface using this distance image sensor is known (for example, refer patent document 1).
JP 2006-262009 A

  However, in the obstacle detection device described in Patent Document 1, the intensity of reflected light from the floor surface portion far from the distance image sensor is weaker than the intensity of reflected light from the near floor surface portion. This is because the intensity of each reflected light received is inversely proportional to the square of the moving distance from when the light is projected until it is received. As a result, a difference occurs in the intensity of the plurality of reflected lights received. Therefore, the distance image sensor in the obstacle detection apparatus described in Patent Document 1 has a problem that the measurement range becomes narrow and the measurement accuracy deteriorates.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a distance measuring device and a distance measuring method in which a measurement range is widened and measurement accuracy is good.

  In order to achieve the above object, a distance measuring device according to a first aspect of the present invention includes a light source that emits modulated light on a floor surface, and a plurality of light receiving elements that receive reflected light of light emitted from the light source. Based on the reflected light received by the light receiving means and the measuring means provided at a predetermined height from the floor so as to have a predetermined posture angle with respect to the floor. A distance calculating means for calculating a distance to an arbitrary point on the floor, an attitude angle detecting means for detecting the attitude angle, an attitude angle detected by the attitude angle detecting means, and the distance calculating means. The light emitted from the light source so that the irradiation intensity at the arbitrary point becomes the irradiation intensity obtained by the function of the distance to the arbitrary point based on the distance to the arbitrary point calculated by Light source control means for controlling the intensity of There.

  According to the distance measuring device according to the first invention, the distance calculating means calculates the distance to an arbitrary point on the floor surface based on the reflected light received by the light receiving means. The posture angle detection means detects the posture angle. Based on the detected attitude angle and the calculated distance to the arbitrary point, the light source control means causes the irradiation intensity at the arbitrary point to be the irradiation intensity obtained as a function of the distance to the arbitrary point. In addition, the intensity of light emitted from the light source is controlled. As a result, the intensity of the reflected light from the far floor surface portion becomes smaller in difference from the intensity of the reflected light from the near floor surface portion. Therefore, the distance measuring device according to the first aspect of the invention has a wider measurement range and better measurement accuracy than the case where this configuration is not provided.

  Moreover, according to the distance measuring device according to the first aspect of the present invention, even when the posture angle varies, the posture angle can be detected, and the light source is appropriately irradiated based on the detected posture angle. The intensity of light can be controlled.

  In the distance measuring device according to the first invention, the light source control means further includes an attitude angle detected by the attitude angle detection means and a distance to an arbitrary point calculated by the distance calculation means. On the basis of the predetermined posture before controlling the intensity of light emitted from the light source so that the irradiation intensity at the arbitrary point becomes an irradiation intensity obtained by a function of the distance to the arbitrary point. Based on the distance to an arbitrary point to the floor surface at a corner, the light source is irradiated so that the irradiation intensity at the arbitrary point becomes an irradiation intensity obtained by a function of the distance to the arbitrary point. It is possible to control the intensity of light.

  Further, in the distance measuring device according to the first invention, the posture angle detection unit is configured to measure the distance in each case calculated from the output of each light receiving element of the light receiving unit and a plurality of candidate posture angles. The posture angle can be detected based on each theoretical distance from the means to the floor surface.

  The distance measuring method according to the second invention includes a light source that irradiates modulated light on the floor, and a light receiving means in which a plurality of light receiving elements that receive reflected light of the light emitted from the light source are arranged. The light receiving means of the measuring means provided at a predetermined height position with respect to the floor surface from the floor surface receives the reflected light and the reflection received by the light receiving means. A distance to an arbitrary point on the floor surface is calculated based on light, the posture angle is detected, and the arbitrary angle is determined based on the detected posture angle and the calculated distance to the arbitrary point. The intensity of light emitted from the light source is controlled so that the irradiation intensity at the point becomes the irradiation intensity obtained by the function of the distance to the arbitrary point.

  In the distance measuring method according to the second invention, the distance to an arbitrary point on the floor surface is calculated based on the reflected light received by the light receiving means. In this distance measurement method, the posture angle is detected based on the calculated distance to an arbitrary point. And this distance measurement method is based on the detected attitude angle and the calculated distance to the arbitrary point, and the irradiation intensity obtained from the irradiation intensity at the arbitrary point as a function of the distance to the arbitrary point. Thus, the intensity of light emitted from the light source is controlled. As a result, the intensity of the reflected light from the far floor surface portion becomes smaller in difference from the intensity of the reflected light from the near floor surface portion. Therefore, the distance measurement method according to the second invention has a wide measurement range and good measurement accuracy.

  In addition, according to the distance measurement method according to the second aspect of the present invention, even when the posture angle fluctuates, the posture angle can be detected, and the light source is appropriately irradiated based on the detected posture angle. The intensity of light can be controlled.

  As described above, according to the distance measuring device and the distance measuring method of the present invention, it is possible to obtain the effects that the measurement range is widened and the measurement accuracy is good.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, a distance measuring device 10 according to an embodiment of the present invention is mounted on a traveling body 16 that travels on a floor surface.

  As shown in FIG. 2, the distance measuring device 10 is arranged in a horizontal direction with the optical axis 70 of light emitted from the light source 18 at a predetermined height H from the floor surface, for example, at a height of 0.5 m from the floor surface. Is set at a predetermined posture angle θ, for example, a posture angle of 30 °.

  As shown in FIG. 3, the distance measuring device 10 includes a control device 14, a light source 18, and a light receiving device 20.

  As illustrated in FIG. 4, the light source 18 includes a plurality of, for example, 50 to 60 LEDs that irradiate light arranged in a matrix. Each LED emits light whose intensity is modulated with a sine wave having a predetermined frequency, for example, 20 MHz, under the control of the light source control unit 24 described in detail below. In addition, the intensity of light emitted from each LED is controlled by the light source control unit 24.

  The light receiving device 20 includes a plurality of light receiving elements. For example, the light receiving device 20 includes a CMOS sensor including a plurality of pixels. The light receiving device 20 receives reflected light from the object 22 or the floor surface.

  The control device 14 stores a ROM (not shown) as a storage medium storing a program for executing the reflected light equalization processing routine, a program for executing the attitude detection processing routine, a program for executing various processing routines, and the like. It consists of a microcomputer (not shown) that reads and executes from the ROM, a RAM (not shown) that temporarily stores data, and a microcomputer that includes an I / O (input / output) port (not shown). Yes. The control device 14 includes a light source control unit 24, a distance calculation unit 26, an attitude detection unit 28, an installation condition storage unit 30, and a theoretical distance calculation unit 32.

  The light source controller 24 determines the intensity of light emitted from each LED of the light source 18 based on the attitude angle detected by the attitude detector 28 and the distance to an arbitrary point calculated by the distance calculator 26. Control.

  The distance calculation unit 26 determines the distance to the object for each light receiving element of the light receiving device 20 based on the time from when the light source 18 irradiates light until the reflected light from the object is received by the light receiving device 20. Calculate.

  The installation condition storage unit 30 stores a plurality of candidate posture angles θ ′. This candidate posture angle θ ′ is determined from the predetermined posture angle θ (in this embodiment, for example, θ = 30 °) due to vibration applied to the distance measuring device 10 when the traveling body 16 travels. It represents the attitude angle θ of the distance measuring device 10 that is expected when it deviates. For example, in this embodiment, when the posture angle of the distance measuring device 10 is set to 30 ° in advance, it is assumed that the posture angle is expected to be shifted by ± 5 ° at the maximum when the traveling body 16 travels. At this time, the installation condition storage unit 30 stores the candidate posture angle θ ′ from 25 ° to 35 °, for example, every 1 °. Further, the installation condition storage unit 30 stores a height H (for example, 0.5 m) from the floor surface to the distance measuring device 10.

  The theoretical distance calculation unit 32 uses the height H and the candidate posture angle θ ′ stored in the installation condition storage unit 30, and the distance when the posture angle θ of the distance measuring device 10 is each candidate posture angle θ ′. A theoretical distance (theoretical distance) on the optical axis 70 of the light source 18 from the measuring device 10 to the floor surface is calculated.

  The posture detection unit 28 calculates the distance corresponding to each of the N light receiving elements among the distances of the plurality of light receiving elements of the light receiving device 20 calculated by the distance calculation unit 26 and the theoretical distance calculation unit 32. The posture angle θ of the distance measuring device 10 is detected based on the theoretical distance for each candidate posture angle θ ′.

  The traveling body 16 includes a traveling body control unit 34 that controls traveling.

  The traveling body control unit 34 detects the floor using the distance for each light receiving element calculated by the distance calculation unit 26, the posture angle θ detected by the posture detection unit 28, and the like. And the traveling body control part 34 detects the obstruction with respect to the detected floor surface. And the traveling body control part 34 controls the driving | running | working (for example, moving speed and moving direction) of the traveling body 16 so that it may correspond to the detected obstruction.

  Next, the reflected light equalization processing routine performed by the CPU of the control device 14 will be described with reference to FIG. In the present embodiment, the reflected light equalization processing routine is executed every time the traveling body 16 travels a predetermined distance based on a signal from the traveling body control unit 34.

  First, in step 100, posture detection processing is executed.

The routine of the posture detection process will be described with reference to FIG. 6. First, in step 200, the distance calculation unit 26 receives the reflected light of the light emitted from the light source 18, as shown in FIG. The distance Lm _(i) (i = 1, 2,... _{) From} each of the N light receiving elements to the floor m _(i) (i = 1, 2,..., N). .., N) is calculated. Here, the N light receiving elements may be selected by any method, and among the plurality of light receiving elements of the light receiving device 20, N light receiving elements may be selected so as to be equally spaced. It should be noted that θm _(i) (i = 1, 2,..., N) illustrated in the figure is the light reflected from each of the floor surfaces m _(i) and reaching the light receiving device 20 (P). Represents the angle formed with the floor surface.

In the next step 202, the theoretical distance calculation unit 32, as shown in FIG. 8, uses the posture angle θ of the distance measuring device 10 from each candidate posture θ ′ and the height H stored in the installation condition storage unit 30. Is a theoretical distance Lr _{(θ ′)} (θ ′ = 25, 26,..., 35) on the optical axis 70 of the light source 18 from the distance measuring device 10 to the floor surface when each is a candidate posture angle θ ′. Calculation is performed according to the following equation (1).

Lr _{(θ ′)} = H / sin θ ′ (1)
In FIG. 8, for example, when the candidate posture angle θ ′ is 25 ° (A), the candidate posture angle θ ′ is 26 ° (B), and the candidate posture angle θ ′ is 35 ° (C The theoretical distances Lr ₍₂₅₎ , Lr ₍₂₆₎ , and Lr _{(35) in} FIG.

As a result, the theoretical distance Lr _{(θ ′)} is calculated for each of the plurality of candidate posture angles θ ′.

In the next step 204, the posture angle detection unit 28 calculates the theoretical distance Lr _{(θ ′)} (θ ′ = 25, 26,..., 35) calculated in step 202 and the distance Lm _(i) calculated in step 200. Each of (i = 1, 2,..., N) is compared to create a histogram based on the comparison result. Specifically, the posture angle detection unit 28, for each candidate posture angle θ ′, N differences indicating a difference in absolute value between the theoretical distance Lr _{(θ ′)} and each of the plurality of distances Lm _(i). Is calculated. Then, the posture angle detection unit 28 calculates a score of θ ′ = 25 to 35, with the number of calculated N differences equal to or less than the predetermined threshold Q as the score of the candidate posture angle θ ′. (That is, the number of θ ′ = 25 to 35 is calculated by setting the number satisfying | Lm _(i) −Lr _(θ) | ≦ Q as the number of candidate posture angles θ ′.)

  A histogram as shown in FIG. 9 is created by the processing in steps 200 to 204 described above. This histogram indicates that the candidate posture angle θ ′ is more likely to be the actual posture angle θ as the number of candidate posture angles θ ′ increases.

  In the next step 206, the posture angle detector 28 detects the candidate posture angle θ ′ having the maximum score as the current posture angle θ of the distance measuring device 10.

  When the histogram as shown in FIG. 9 is created, the candidate posture angle θ ′ having the maximum score is 29 °, so the posture angle detection unit 28 sets 29 ° to the current distance measuring device 10. Is detected as the posture angle θ of the.

  Through the above attitude angle detection process, the actual attitude angle θ of the distance measuring device 10 is detected.

In the next step 102, the light source control unit 24 determines the projection light intensity ratio of each LED of the light source 18. Specifically, in step 102, the light source control unit 24, as shown in FIG. 7, the maximum irradiation angle (θ + α) of the angle formed by the light irradiated from the light source 18 and the floor surface, and the distance from the floor surface. Using the height H to the measuring device 10, the shortest moving distance PA of the light until the light receiving device 20 of the distance measuring device 10 receives the reflected light reflected from the floor surface in the irradiation range of the light source 18. It calculates by the following formula (2).
PA = H / sin (θ + α) (2)

Then, the light source control unit 24 uses the minimum irradiation angle (θ−α) of the angle formed between the light emitted from the light source 18 and the floor and the height H from the floor to the distance measuring device 10. In the irradiation range of the light source 18, the longest moving distance PB of the light until the light receiving device 20 of the distance measuring device 10 receives the reflected light reflected from the floor surface is calculated by the following equation (3).
PB = H / sin (θ−α) (3)

Further, the light source control unit 24 moves the light travel distance Lm until the light receiving device 20 of the distance measuring device 10 receives the reflected light reflected from each of the floor surfaces m ₍₁₎ ,..., M _{(n). (1)} ,..., Lm _(n) is calculated by the following equation (4).
Lm _(k) = H / sin (θm _(k) ) (k = 1, 2,..., N) Expression (4)

In the next step 104, the light source control unit 24, in order to make difference in the intensity distribution of the reflected light below the predetermined value, _A from P, m (1), ··· , m (n), each of B The ratio of the irradiation intensity of the light irradiated toward is determined. For example, the light source control unit 24 sets the movement distances PA, PB, Lm _{(1) to} Lm _(n) calculated in Step 102 based on the phenomenon that the light intensity is inversely proportional to the square of the movement distance of the light. The following formula (6) obtained by squaring each value in the following formula (5) representing the relationship of the ratio is determined as the ratio of the light irradiation intensity.

PA: Lm ₍₁₎ : ...: Lm _(n) : PB
= {Sin (θ−α) × sin (θm ₍₁₎ ) ×... × sin (θm _(n) )}: {sin (θ−α) × sin (θm ₍₂₎ ) ×. sin (θm _(n) ) × sin (θ + α)}:... {sin (θ−α) × sin (θm ₍₁₎ ) ×... × sin (θm _(n−1) ) × sin ( θ + α)}: {sin (θm ₍₁₎ ) ×... × sin (θm _(n) ) × sin (θ + α)}... Equation (5)
(PA) ² : (Lm ₍₁₎ ) ² :...: (Lm _(n) ) ² : (PB) ²
= {Sin (θ−α) × sin (θm ₍₁₎ ) ×... × sin (θm _(n) )} ² : {sin (θ−α) × sin (θm ₍₂₎ ) ×. * Sin ((theta ₎ m _(n) ) * sin ((theta) + (alpha))} ² : ...: {sin ((theta)-(alpha)) * sin ((theta) m ₍₁₎ )) * ... * sin ((theta) m _(n-1) ) * sin (θ + α)} ² : {sin (θm ₍₁₎ ) ×... sin (θm _(n) ) × sin (θ + α)} ² ... Equation (6)

In the next step 106, the light source control unit 24 determines that the ratio of the irradiation intensity of light emitted from P toward each of A, m ₍₁₎ ,..., M _(n) , B is a function of distance. For example, the light emitted from the light source 18 is controlled so as to have the ratio indicated by the above equation (6) so that the irradiation intensity obtained by the above equation (6) is obtained. That is, the light source control unit 24 irradiates an arbitrary point on the floor surface so that the irradiation intensity at an arbitrary point on the floor surface becomes an irradiation intensity obtained by a function of the distance to the arbitrary point, for example. The intensity of light emitted from the light source 18 is controlled so that the intensity is proportional to the square of the distance to this arbitrary point.

According to the above reflected light intensity equalization processing, as shown in FIG. 10 (B), the light source control unit 24 uses each of P to A, m ₍₁₎ ,..., M _(n) , B. The intensity of the light irradiated from the light source 18 is controlled so that the ratio of the irradiation intensity of the light irradiated toward is similar to that in the above formula (6). As a result, the intensity of the reflected light is not uniform as shown in FIG. 10A, and the intensity of the reflected light that becomes smaller as the distance is longer is the intensity of the reflected light as shown in FIG. 10C. The difference in distribution is below a predetermined value. Therefore, the intensity of the reflected light from the floor surface received by the light receiving device 20 of the distance measuring device 10 is made uniform.

As described above, according to the distance measurement device 10 of the present embodiment, the posture angle θ detected by the posture detection unit 28 and m _{(1) to} m _(n) that are arbitrary points on the floor surface. based on the distance _{Lm (1) ~Lm (n)} up to an arbitrary point _{m (1) ~m (n)} irradiation intensity given point _m (1) of the distance to _{~m (n)} Lm _{( 1)} so that the illumination intensity obtained by the function _{to L m (n),} for example, the distance _Lm (1) to be proportional to the square of each _{to L m (n),} the light emitted from the light source 18 To control the intensity. As a result, the difference in the intensity distribution of the reflected light received by the light receiving device 20 becomes a predetermined value or less, that is, the intensity of the reflected light received by the light receiving device 20 is made uniform. As a result, the distance measuring device 10 of the present embodiment has a wide measurement range and good measurement accuracy.

  In addition, since the distance measurement device 10 of the present embodiment can detect the posture angle θ even when the posture angle θ varies, the distance measurement device 10 appropriately irradiates from the light source 18 based on the detected posture angle θ. The intensity of light can be controlled.

Note that the posture detection processing routine described above is not limited to step 204 and step 206 described above. For example, in step 204 and step 206, the posture detection unit 28 determines the sum of absolute values of differences between the theoretical distance Lr _{(θ ′)} and the plurality of distances Lm _(i) (Σ | Lr _{(θ ′) −} Lm _(i) The candidate posture angle θ ′ with the smallest |) may be detected as the current posture angle θ of the distance measuring device 10.

  In the present embodiment, the example in which the attitude angle θ of the distance measuring device 10 is an angle formed by the optical axis 70 of the light emitted from the light source 18 and the horizontal direction has been described. It may be an angle formed by the optical axis 70 of light and the vertical direction. At this time, sin θ used in the above description can be used as sin (90−θ).

In addition, the light emitted from the light source 18 in step 200 of the posture detection processing routine described above may be as follows. That is, as shown in FIG. 11, when the attitude angle θ is a predetermined value at the time of design (30 ° in the present embodiment), the distance of the reflected light reflected from the floor surface in the irradiation range of the light source 18 is measured. Reflection reflected from each of the shortest moving distance PA of light until the light receiving device 20 of the apparatus 10 receives light, the longest moving distance PB of light, and the floor surfaces m ₍₁₎ ,..., M _(n). The light moving distances Lm ₍₁₎ ,..., Lm _(n) until light is received by the light receiving device 20 of the distance measuring device 10 are calculated in the same manner as the processing described above, and the calculated moving distance PA, The following formula (8) obtained by squaring each value in the following formula (7) representing the relationship of the ratio of PB, Lm _{(1) to} Lm _{( n)} is determined as the ratio of the light irradiation intensity.

PA: Lm ₍₁₎ : ...: Lm _(n) : PB
= {Sin (30 ° -α) × sin (θm ₍₁₎ ) ×... × sin (θm _(n) )}: {sin (30 ° -α) × sin (θm ₍₂₎ ) × * Sin ([theta] m _(n) ) * sin (30 [deg.] + [Alpha])}: ...: {sin (30 [deg.]-[Alpha]) * sin ([theta] m ₍₁₎ ) * ... * sin ([theta] m _{(n-1) )} ) × sin (30 ° + α)}: {sin (θm ₍₁₎ ) ×... × sin (θm _(n) ) × sin (30 ° + α)} (7)
(PA) ² : (Lm ₍₁₎ ) ² :...: (Lm _(n) ) ² : (PB) ²
= {Sin (30 ° -α) × sin (θm ₍₁₎ ) ×... × sin (θm _(n) )} ² : {sin (30 ° -α) × sin (θm ₍₂₎ ) ×. .. * sin ([theta] m _(n) ) * sin (30 [deg.] + [Alpha])} ² : ...: {sin (30 [deg.]-[Alpha]) * sin ([theta] m ₍₁₎ ) * ... * sin ([theta] m _{(n) −1)} ) × sin (30 ° + α)} ² : {sin (θm ₍₁₎ ) ×... × sin (θm _(n) ) × sin (30 ° + α)} ^2. )

Then, the light source control unit 24, _A from P, m (1), shows · · _{·, m (n),} the ratio of the irradiation intensity of light emitted to the respective B is, the above equation (8) You may make it control the intensity | strength of the light irradiated from the light source 18 so that it may become ratio. That is, in step 106, the light source control unit 24 determines the posture angle θ detected in step 206 of the posture detection process and the distance Lm ₍ m ₎ from m _{(1) to} m _(n) that is an arbitrary point on the floor surface. ₁₎ based on the _{to L m (n),} an arbitrary point _m (1) _{~m (n)} illumination intensity arbitrary point _m (1 in) _{~m (n)} distance _Lm (1 up) to L m ₍ Before controlling the intensity of light emitted from the light source 18 so as to be proportional to the square of each of _n) , in step 200, on the floor surface at a predetermined posture angle θ (30 ° in the present embodiment). any in which on the basis of _m (1) _~m distance to _{(n) Lm} (1) _{to L m (n)} point, an arbitrary point _m (1) _~m irradiation intensity of any _(n) point m _{(1) ~m (n)} distance to _Lm (1) to be proportional to the square of the _{to L m (n),} or the light source 18 It may be to control the intensity of the irradiated light.

It is a figure which shows the arrangement position of the distance measuring device in this Embodiment. It is a figure which shows the arrangement position of the distance measuring device in this Embodiment. It is the schematic which shows this Embodiment. It is a figure for demonstrating the light source in this Embodiment. It is a figure which shows the flowchart of the reflected light equalization processing routine which CPU of the control apparatus in this Embodiment performs. It is a figure which shows the flowchart of the attitude | position detection process routine which CPU of the control apparatus in this Embodiment performs. It is a figure which shows the irradiation range of the light from the light source in this Embodiment. It is a figure for demonstrating the theoretical distance in this Embodiment. It is a figure which shows the histogram of the candidate attitude | position angle in this Embodiment. It is a figure which shows the effect of this invention. It is a figure which shows an example of the light irradiated from the light source in this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Distance measuring device 14 Control device 18 Light source 20 Light receiving device 24 Light source control unit 26 Distance calculation unit 28 Attitude detection unit 30 Installation condition storage unit 32 Theoretical distance calculation unit

Claims (4)

A light source that emits modulated light on the floor surface, and a light receiving unit in which a plurality of light receiving elements that receive reflected light of the light emitted from the light source are arranged, and the light source is arranged at a predetermined height from the floor surface. A measuring means provided to have a predetermined posture angle with respect to the floor surface;
Based on the reflected light received by the light receiving means, distance calculating means for calculating a distance to an arbitrary point on the floor surface;
Posture angle detection means for detecting the posture angle;
Based on the posture angle detected by the posture angle detecting means and the distance to the arbitrary point calculated by the distance calculating means, the irradiation intensity at the arbitrary point is a function of the distance to the arbitrary point. A light source control means for controlling the intensity of light emitted from the light source so as to obtain the obtained irradiation intensity;
Distance measuring device including   The light source control means further has the irradiation intensity at the arbitrary point based on the attitude angle detected by the attitude angle detection means and the distance to the arbitrary point calculated by the distance calculation means. Before controlling the intensity of light emitted from the light source so as to obtain an irradiation intensity obtained by a function of the distance to the point, the distance to an arbitrary point to the floor surface at the predetermined posture angle 2. The distance according to claim 1, wherein the intensity of light emitted from the light source is controlled so that the irradiation intensity at the arbitrary point becomes an irradiation intensity obtained by a function of the distance to the arbitrary point. Measuring device.   The posture angle detection means includes a distance calculated from each light receiving element of the light receiving means and a theoretical distance from the measurement means to the floor in each case of a plurality of candidate posture angles. The distance measuring device according to claim 1, wherein the posture angle is detected based on A light source that emits modulated light on the floor surface, and a light receiving unit in which a plurality of light receiving elements that receive reflected light of the light emitted from the light source are arranged, and the light source is arranged at a predetermined height from the floor surface. The light receiving means of the measuring means provided to have a predetermined posture angle with respect to the floor surface receives the reflected light,
Based on the reflected light received by the light receiving means, calculate the distance to an arbitrary point on the floor surface,
Detecting the posture angle;
Based on the detected attitude angle and the calculated distance to an arbitrary point, the irradiation intensity at the arbitrary point becomes an irradiation intensity obtained by a function of the distance to the arbitrary point, A distance measurement method that controls the intensity of light emitted from a light source.

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