JPH0782089B2 - Speed measuring instrument - Google Patents

Description

TECHNICAL FIELD The present invention relates to a velocity measuring device for detecting a moving velocity of an object to be measured based on distance information obtained from a light irradiation point on a moving object to be measured. Is.

[Conventional technology]

Conventionally, a velocity detection method using a spatial filter has been proposed for the optical movement velocity measurement of an object to be measured.

Figure 10 shows the principle. In the figure (1),
The surface pattern of the DUT 11 is imaged on the light receiving surface of the sensor 18 by the objective lens 19. The light-receiving surface of the sensor 18 has a structure in which a plurality of elongated light-receiving portions are arranged at intervals p, as indicated by circles in the figure. Here, the DUT 11
When the object moves at speed v, the objective lens 19
The surface pattern of the DUT 11 imaged on the light receiving surface of 18 also moves on the light receiving surface.

FIG. 2B shows a signal processing circuit of the speed detection system using the above-mentioned spatial filter. As shown on the left side of FIG. 2B, the signal extraction electrodes of the respective light receiving portions on the light receiving surface of the sensor 18 are alternately connected. Therefore, the two photocurrents obtained from the sensor 18 are current-voltage converted by the operational amplifiers U ₉ and U ₁₀ , and the difference between the two signals is output by the differential amplifier U ₂₀ .

As a result, the output of the differential amplifier U ₂₀ becomes a cross-correlation between the light receiving portion pattern of the sensor 18 and the imaged surface pattern, and the output waveform has a higher frequency component as the moving speed v becomes faster. By detecting this frequency component, the moving speed of the measured object can be obtained.

[Problems to be Solved by the Invention]

In the case of velocity measurement by the above-mentioned spatial filter method, the sensor
When the contrast of the surface pattern of the DUT 11 imaged on the light receiving surface of 18 is high and the spatial frequency thereof corresponds to the light receiving unit interval p, stable speed measurement is possible, but when the contrast is low, the measurement accuracy becomes low. If the frequency component of the light receiving unit interval p does not exist, measurement becomes impossible.

Therefore, when the speed measuring device based on the spatial filter method is mounted on an automobile and the speed of the automobile with respect to the ground is measured, the pattern condition of the road surface is different between the gravel road and the asphalt, and the contrast is low and the measurement accuracy is low. Furthermore, there is a problem that measurement is impossible when the road surface is wet, or when the road is a white line or a snowy road.

Further, there is a problem that it is impossible to determine the direction (positive or negative) of the velocity vector, and it is impossible to determine whether the vehicle is moving forward or backward.

The present invention has been made for the purpose of solving such problems.

[Means for Solving the Problems]

The speed measuring instrument according to the present invention comprises a pair of first and second distance detecting means, and speed detecting means for processing the outputs of the pair. Here, the first and second distance detecting means,
A light projecting means for projecting a light beam onto a moving object to be measured, a light receiving lens for receiving and condensing the light reflected from the object to be measured as detection light, and a light receiving surface are arranged at the light collecting position. And a light incident position detecting element that outputs a photocurrent according to the condensing position and the photocurrent obtained from the light incident position detecting element is processed to obtain the distance information to the irradiation point on the DUT. And a signal processing circuit for obtaining the signal, and a straight line connecting a pair of irradiation points of the light beam is installed in parallel with the moving direction of the object to be measured.

Further, the speed detecting means, based on the correlation of the distance information obtained by these distance detecting means, obtain the time difference of irradiating the same point on the DUT with a pair of light beams,
The moving speed of the object to be measured is detected from the time difference and the interval between the pair of irradiation points described above.

[Action]

According to the present invention, by using the distance detection means described above, it is possible to obtain distance information of a pair of irradiation points on the moving object to be measured, and the object to be measured based on the correlation of the distance information. The moving speed of the can be detected.

〔Example〕

Next, the principle of the measuring method of the speed measuring device according to the present invention will be described with reference to FIG.

In this speed detector, a pair of measurement positions (the straight line connecting them is used as a measurement reference line) at which distances should be measured by the first and second distance detectors are arranged in a direction parallel to the moving direction of the object to be measured. In addition, the pair of measurement positions are arranged at a predetermined distance l. Therefore, as a result of performing arithmetic processing using the distance information of two points on the DUT,
The moving speed of the measured object is detected.

In FIG. 1, a first distance detector includes a first light source 1, a first light projecting lens 2, a first light receiving lens 3, a first light incident position detecting element 4, and a first signal processing circuit. It is composed of 5. The luminous flux emitted from the first light source 1 is condensed on the DUT 11 by the first light projecting lens 2. The light reflected from the measurement surface is used as detection light, and the first projection lens 2
The first light receiving lens 3 arranged at a predetermined distance (hereinafter referred to as a base line length) from the optical axis of the light is focused on the light receiving surface of the first light incident position detection element 4.

Similarly, the second distance detector includes a second light source 6, a second light projecting lens 7, a second light receiving lens 8, a second light incident position detecting element 9, and a second signal processing circuit 10. It is configured. The luminous flux emitted from the second light source 6 is generated by the second light projecting lens 7
The light reflected by the measurement surface of the object 11 to be measured is reflected by the second light receiving lens 8 as the second light.
The light is condensed on the light receiving surface of the position detecting light receiving element 9.

Here, the baseline length direction of the first and second distance detectors is set to the same direction as the measurement reference line, but it is not necessarily limited to this direction.

The first light incident position detecting element 4 in the first distance detector
The values of the two photocurrents I _A1 and I _B1 obtained from are corresponding to the position of the center of gravity of the spot light focused on the light receiving surface.
Is amplified by the signal processing circuit 5 of I _A1 / I _B1 or (I _A1- I
The calculation of ( _B1 ) / (I _A1 + I _B1 ) is executed. The time-varying waveform of this calculated value is defined as f _{F (t)} . Similarly, the photocurrent output I of the second light incident position detection element 9 in the second distance detector
_{By processing A2} and I _B2 by the second signal processing circuit 10, the calculated value I _A2 / I _B2 or (I _A2 −I _B2 ) / (I _A2 + I _B2 )
And the time-varying waveform is defined as f _{R (t)} . And
When the fluctuation waveform f _{F (t) is shown} by a solid line and the fluctuation waveform f _{R (t)} is shown by a dotted line,
These have the relationship shown in FIG.

That is, as shown in FIG. 2, the above-mentioned two fluctuation waveforms are used.
Although f _{F (t)} and f _{R (t)} have the same shape, each fluctuation waveform is deviated by the time Δt as the DUT 11 moves. This time difference Δt is proportional to the reciprocal of the moving speed v of the object to be measured 11, and the relationship of the following equation (1) is established between the time difference Δt between the two spot lights irradiated on the object to be measured 11. It holds.

v = 1 / Δt (1) In the present invention, speed measurement is performed based on such a principle.

Here, the above-mentioned time difference Δt corresponds to the time difference from the time point when the first distance detector measures the distance to the time point when the second distance detector measures the distance to a certain point on the object to be measured. . Therefore, as described above, the two fluctuation waveforms f _{F (t)} and f _{R (t)}
It is natural that the time difference Δt can be obtained by investigating the correlation of the time difference Δt, but the time difference Δt can also be obtained by the following method.
It is possible to obtain t. The first is a method of examining the identity of the maximum value or the minimum value of the distance to the object to be measured. The second is a method of comparing the characteristic portion of the unevenness of the measured object between the distance information obtained by the first and second distance detectors. Therefore, the present invention, as shown in the following examples,
The method is not limited to the method of examining the correlation between two fluctuation waveforms.

Next, an embodiment according to the present invention will be described with reference to the drawings.

FIG. 3 is a perspective view showing the optical system of the first embodiment of the speed measuring instrument of the present invention.

The first distance detector has a first light source 1, a first light projecting lens 2, a first light receiving lens 3, and a first light incident position detecting element 4, and the direction of the baseline length C is It is set in the measurement reference line direction.

On the other hand, the second distance detector has three emission points ₀ ,
_A second light source 6 in which ₁ and ₂ are arranged in a direction orthogonal to the base line length C, and a second light incident position detection element 9 whose light receiving area is enlarged according to the arrangement width of these three light emitting points are provided. It also has a light projecting lens 7 and a light receiving lens 8. At this time, the emission point ₀ of the first light source 1 and the emission point of the second light source 6
_The straight line connecting ₀ is set parallel to the base length C direction. In addition, the three light emitting points ₀ , ₁ , _{2 of} the second light source 6
The pulse lights are time-divided, and the distance to each irradiation point on the DUT can be detected independently.

Next, a process for detecting the moving speed using the measuring instrument having this configuration will be described.

FIG. 4 is a diagram showing a relationship between the irradiation pattern of the irradiation light and the projections 12 when the object to be measured has only one hemispherical projection 12 on a flat surface thereof. In FIG. 6A, the irradiation pattern when the object to be measured moves in the measurement reference line direction is shown by diagonal lines. If the above-mentioned hemispherical projection 12 is located at the position indicated by the solid line at the time t = 0, the center point of the irradiation pattern F _{0 at} the light emission point ₀ coincides with the apex of the projection 12. In this case, the DUT is in the measurement reference line direction, that is, the irradiation pattern.
Since it moves on the straight line connecting the center points of F ₀ and R _0, the position of the hemispherical projection 12 at the time t = Δt is shown by the dotted circle. That is, the center point of the irradiation pattern R ₀ coincides with the apex of the protrusion 12.

On the other hand, the moving direction of the measured object is
When the angle θ deviates from the measurement reference line direction, the center point of the irradiation pattern R ₀ is displaced from the apex of the protrusion 12. That is, the position of the hemispherical projection 12 at the time point t = Δt / cos θ reaches the position of the circle shown by the dotted line below the measurement reference line.

Next, what kind of distance information can be obtained from such an irradiation pattern will be described.

FIG. 5 shows the irradiation patterns F ₀ , R ₀ , R ₁ shown in FIG.
The output waveform of the distance information measured at R ₂ is f _{F (t)} , f
_{R0 (t), f R1 (} t), and f _{R2 (t),} shows the output waveform when the respective cross-correlation process. FIG. 5 (1) corresponds to the state of FIG. 4 (a), and the waveform in a state where the moving speed v of the object to be measured is constant and the moving direction matches the measurement reference line direction. Indicates. Where f _F
() * F _{R0 ()} is the correlation waveform for irradiation pattern R ₀ , f _F
() * F _{R1 ()} is the correlation waveform for irradiation pattern R ₁ , f _F
() * F _{R2 ()} shows the correlation waveform for irradiation pattern R ₂ . Comparing these three cross-correlation waveforms, the peak value of the correlation waveform f _{F ()} * f _{R0 ()} becomes maximum,
Correlated waveforms f _{F ()} * f _{R1 ()} and f _{F ()} * f _{R2 () have} the same peak value. Therefore, the irradiation pattern F ₀
It can be seen that the center points of R and R ₀ both coincide with the apex of the protrusion 12.

On the other hand, in the case of FIG. 5 (2) corresponding to the state of FIG. 4 (b), the correlation waveforms f _{F ()} * f _{R1 ()} and f _F
() * F _{R2 ()} peak values are compared, f _{F ()}
* F The peak value of _{R1 ()} is larger. Therefore, it can be seen that the apexes of the protrusions 12 are displaced in the direction of the irradiation pattern R ₁ . Therefore, while comparing the two peak values, if the entire optical system shown in FIG. 3 is rotated in the direction in which the two peak values are equal, the correlation waveform f _F
When the peak values of ₍₎ * f _{R1 ()} and f _{F ()} * f _{R2 ()} become equal, the peak of the correlation waveform f _{F ()} * f _{R0 ()} becomes maximum. Therefore, when the deviation angle θ = 0,
The condition shown in FIG. 7A can be maintained, and the error due to the deviation angle θ does not occur. However, considering the practical aspect, executing the three cross-correlation calculations shown in FIG. 5 results in a larger processing circuit and longer processing time. In order to avoid such a problem, the shift angle θ may be set to zero.

Therefore, with reference to FIG. 6, a process for making the deviation angle θ zero will be described.

Similar to FIG. 4 (a) and FIG. 5 (1), FIG. 1 (1) shows the case where the moving speed v of the object to be measured is constant and the moving direction coincides with the measurement reference line direction. Shows the output waveform of. Of the waveforms shown in the figure, the horizontal axis of A _{1 to} A ₃ and A _{5 to} A ₈ is the time axis, and the vertical axis corresponds to the amplitude of the waveform.

Here, each waveform will be described. A ₁ is irradiation pattern F ₀
Is the output waveform f _{F (t)} of the distance information at, and the amplitude becomes maximum at time t = 0. A ₂ represents an output waveform f _{F (t)} the delay circuit output waveform was t = Delta] t delayed by f _{F (t- Δt).} In this case, the magnitude of the amplitude is the same as the output waveform of the irradiation pattern F ₀ shown by A ₁ , and the maximum value of the amplitude is t = Δt.
Come to. A ₃ shows the output waveform f _{R0 (t)} of the distance information in the irradiation pattern R ₀ . At this time, the moving direction of the measured object,
Since the measurement reference line direction matches, the output waveform in the irradiation pattern R ₀ shown by A ₃ is the output waveform f shown by A _2.
It agrees with _{F (t- Δt)} . A ₄ shows the output waveform when the cross-correlation of the output waveforms f _{F (t)} and f _{R0 (t)} is executed, and when it is displayed by using * as the calculation of the cross-correlation, it can be expressed by the following equation (2).

f _(t)* F_{R (t)} = ▲ ∫^{+ ∞} _-∞▼ f_{F (t)}f_{R0 (t-} dt: As is clear from the equation (2), the horizontal axis of the output waveform of the cross correlation
Is not a time axis but a correlation axis. This correlation waveform
The maximum value of is at = Δt. A_FiveAnd A₇Is the irradiation power
Turn R₁And R₂Output waveform f of distance information measured at_{R1 (t)}
And f_{R2 (t)}Indicates. A₆And A₈The shaded part of
A mentioned above_FiveAnd A₇Irradiation pattern R shown in₁And R₂In
Each output waveform and A₂Output waveform f_{F (t-
Δt)}Output wave when each difference calculation with
Represents a shape. Irradiation pattern R₀The center point of the projection 12
Passes the apex and therefore the irradiation pattern R₁, R₂Fluctuation waveform due to
Are the same, so in this figure A₆And A₈Indicated by the diagonal line
The integrated values are equal.

On the other hand, FIG. 6 (2) is similar to FIGS. 4 (b) and 5 (2) at each irradiation point when the moving direction of the measured object deviates from the measurement reference direction by the angle θ. 2 shows the output waveform of the. When the moving speed v of the object to be measured is constant, the output waveforms f _{F (t)} (shown in B ₁ ) and f _{R0 (t)} (B ₎ of the distance information measured in the irradiation patterns F ₀ and R ₀ , respectively. (Shown in Fig. ₃ ) is t = Δt / cos θ, and an error occurs due to the deviation of the angle θ. Further, in the irradiation pattern R ₀ , since the apex of the hemispherical projection 12 does not pass, the output waveform f _{R0 (t)} has a small amplitude like B ₃ , and the output waveform f _{F (t)} is t = Δt /. It does not match the output waveform f _{F (t- Δt / cos θ)} shown in B ₂ delayed by cos θ, so the maximum value of the cross-correlation calculation output with f _{F (t)} is also shown in B ₄ . Get smaller. Then, since the apex of the projection 12 is displaced in the direction from the irradiation pattern R ₀ to R ₁ , the fluctuation waveform f _{R1 (t)} is larger than f _{R2 (t)} . Here, when comparing the output waveforms shown by B ₂ and the output waveforms B ₆ and B ₈ showing the difference between the output waveforms shown by B ₅ and B ₇ , a clear difference appears as shown by the hatched line. , Comparing the integrated values, B ₈ is larger. Therefore, B ₆
By controlling the rotation of the entire optical system shown in FIG. 3 in the direction in which the integrated values indicated by B ₈ and B ₈ become equal, the moving direction of the DUT can be made coincident with the measurement reference line direction.

Next, the calculation processing of the output waveform of the distance information thus detected will be described.

FIG. 7 shows signal waveforms f _{F (t)} , f _{R0 (t)} , which correspond to the distances to the respective spot light positions irradiated on the object to be measured,
It is a block diagram for performing the signal processing of _{fR1 (t)} and _{fR2 (t)} . Irradiation pattern F ₀ on the DUT (not shown),
Output waveform of distance information measured at R ₀ , R ₁ , R ₂ f _{F (t)} , f
_{R0 (t)} , f _{R1 (t)} , f _{R2 (t)} are the output waveform f _{F (t) in the} correlator U _1.
Calculation of the cross-correlation of f _{R0 (t)} is performed. By this calculation, the time difference Δt between the output waveforms f _{F (t)} and f _{R0 (t)} is detected and sent to the delay circuit U ₂ . In the delay circuit U ₂ , the output waveform f _{F (t)}
Is delayed by a time difference Δt with respect to the waveform f after the delay.
_{F (t- Δt)} is sent to the differential circuits U ₃ and U ₄ , and the output waveform f
Difference calculation between _{R1 (t)} and f _(Rt) f _{F (t- Δt)} −f _{R1 (t)} and f
_{F (t- Δt)} −f _{R2 (t)} is executed. The two difference calculation values are sent to the integrating circuits U ₅ and U ₆ and predetermined integration is performed, and then the comparing circuit U ₇ determines the magnitude of the two integrated values. This determination signal is sent to a rotation drive circuit (not shown) for executing the direction control of the entire optical system in FIG. 3, and is rotated in the direction (deviation angle θ = 0) where the two integrated values become equal. Motion controlled.

From this, it is possible to make the moving direction of the measured object coincide with the measurement reference line direction. The time difference Δt is sent to the speed calculation circuit U ₈ and the moving speed (v = 1 / Δt) of the object to be measured can be calculated from the interval 1 between the irradiation points F ₀ and R ₀ .

Next, FIG. 8 shows an optical system of a second embodiment of the velocity measuring device according to the present invention.

A light source device 20 in the figure includes a light emitting point _{0, 1, 2} constituting the light source of the first distance detector, the light source ₀ of the second distance detector, _{1, 2} and has, in their respective They are arranged in a direction orthogonal to the base line length direction C. Further, the position detecting light receiving device 15 has two light incident position detecting elements 16 and 15, which respectively constitute light incident position detecting elements for the first and second distance detectors. Emission point ₀ , ₁ ,
The light fluxes from ₂ and ₀ , ₁ , and ₂ are irradiated to the object to be measured by the light projecting lens 13, and F ₀ , F ₁ , F ₂ and R ₀ , R ₁ and R ₂ are irradiated on the object to be measured as an irradiation pattern. Form. The reflected light from these irradiation patterns F ₀ , F ₁ , F ₂ is condensed by the light receiving lens 14 on the light receiving surface of the detection element 16 on the position detecting light receiving device 15, and the irradiation patterns R ₀ , R ₁ , R The reflected light from ₂ is condensed on the light receiving surface of the detection element 17. These irradiation patterns
The output waveforms of the distance information measured at F ₀ , F ₁ , F ₂ , R ₀ , R ₁ , and R ₂ are f _{F0 (t)} , f _{F1 (t)} , f _{F2 (t)} , and f _{R0 (t )} ,
As f _{R1 (t)} and f _{R2 (t)} , the following signal processing is executed in addition to the above equation (2).

f _{F0 (t- Δt)} -f _{R1 (t)} (3) f _{F0 (t- Δt)} -f _{R2 (t)} (4) f _{F1 (t- Δt)} -f _{R2 (t)} (5 ₎ ) F _{F2 (t- Δt)} −f _{R1 (t)} (6) Here, first, the expressions (3) and (4) are integrated for a predetermined time, and the two integrated values are compared, and (5) , (6)
The expression is integrated for a predetermined time, and the two integrated values are compared. By the two-step determination, the controllability of the deviation angle θ can be improved.

However, in the embodiment of FIG. 8, since the light beams emitted from the two light emitting points ₀ and ₀ are applied to the object to be measured by the light projecting lens 13, two irradiation patterns F on the object to be measured are provided. The distance l between the centers of ₀ and R ₀ changes in proportion to the distance to the object to be measured. Therefore, when calculating the speed,
As the distance l between the centers of the irradiation patterns F ₀ and R ₀ , the value of the distance between the centers of the two emission points ₀ and ₀ is the output waveform of the distance information.
It must be corrected and applied based on f _{F0 (t)} or f _{R0 (t)} .

Next, a third embodiment according to the present invention will be described.

FIG. 9 shows the optical system of the third embodiment. The light source device 20 is arranged on a circle with a predetermined radius centered around one light emitting point as a light source for the first distance detector and one light emitting point as a light source for the second distance detector, and arranged in sequence. And a plurality of light emitting points that are turned on. The luminous flux emitted from each of these light emitting points in a time division manner is reflected by the telecentric diaphragm mirror 21 and is projected and received by a mask (a shaded portion in the figure) so that the light can be condensed. Head to lens 22. In this figure, the light flux from the light source for the first distance detector at this time is indicated by a chain double-dashed line, and the light flux from a plurality of light emitting points which are the light sources for the second distance detector and are sequentially turned on is indicated by a one-dot chain line. Shows. At this time, if the telecentric diaphragm mirror 21 is arranged at the position of the focal length of the light projecting / receiving lens 22, the optical axes of the two light beams focused on the object to be measured 11 by the light projecting / receiving lens 22 become parallel, and the central irradiation point and its The intervals between the peripheral illumination points on the radius are constant. The detection light reflected from the object to be measured passes through the unmasked portion of the light projecting / receiving lens 22 and is focused on the position detecting light receiving device 15.

The position detecting light receiving device 15 is installed at a position optically conjugate with the light source device 20, and the light incident position detecting element 16 is provided.
And 17 are arranged respectively corresponding to the above-mentioned light projecting means. The light incident position detection element 16 has two electrodes T ₁ and T ₂
Is formed, the detection light from the central irradiation point on the DUT 11 is condensed, and the photocurrent value divided corresponding to the condensing position on the light receiving surface of the detection element 16 is obtained. . On the other hand, in the case of the light incident position detection element 17, the respective electrodes T ₃ and T ₄ are formed on a predetermined radius whose center of rotation is the center position of the detection element 16 described above, and The detection light from the irradiation point irradiated in a semicircular shape is condensed. The detection element 17 obtains a photocurrent value divided corresponding to the condensing position moving in the radial direction.

By using such an optical system, it is possible to detect the velocity vector in all moving directions of the measured object.

〔The invention's effect〕

According to the velocity measuring device of the present invention, by using the distance detecting means described above, it is possible to obtain the distance information of the pair of irradiation points on the moving object to be measured, and based on the correlation of the distance information. The moving speed of the object to be measured can be detected. Therefore, the moving speed of the object to be measured can be detected without being affected by the contrast level on the surface of the object to be measured and the spatial frequency band distribution of the pattern. For example, when it is mounted on an automobile and used as a ground speed detector, it is possible to enable measurement under a road surface condition such as a snow road or a white line, which was impossible with the conventional technology. Further, by detecting whether the time difference Δt is positive or negative, the direction (positive / negative) of the speed vector of the moving speed v can be obtained, so that the forward or backward speed of the vehicle can be determined. Furthermore, since the distance to the road surface is directly measured, it can be applied as a vehicle height detector, and vehicle height control is possible by one of the distance information or the average value of all the detected distance information. Becomes

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of a speed measuring instrument according to the present invention,
FIG. 2 is a diagram showing a time-varying waveform of a calculated value obtained by the present invention, FIG. 3 is a diagram showing an optical system of a first embodiment according to the present invention, and FIG. 4 is a first embodiment. Of the irradiation pattern on the DUT, FIG. 5 and FIG. 6 are diagrams showing the output waveforms of the respective irradiation parts of the first embodiment, and FIG. 7 is a block diagram showing the arithmetic processing system of the output waveforms. FIG. 8 is a diagram showing an optical system of a second embodiment according to the present invention, FIG. 9 is a diagram showing an optical system of a third embodiment according to the present invention, and FIG. 10 is a conventional technique. It is a figure which shows a speed detection system. DESCRIPTION OF SYMBOLS 1 ... 1st light source, 2 ... 1st light projection lens, 3 ... 1st light receiving lens, 4 ... 1st light incident position detection element, 5 ... 1st signal processing circuit, 6 ... 2nd light source , 7 ... Second light projecting lens, 8 ... Second light receiving lens, 9 ... Second light incident position detecting element, 10 ... Second signal processing circuit, 11 ... DUT, 12 ... Hemispherical projection , 13 ... Projecting lens, 14 ... Light receiving lens, 15 ... Position detecting light receiving device, 16 and 17 ... Light incident position detecting element, 20
… Light source device, 21… Telecentrit diaphragm mirror, 22… Projector / receiver lens.

Claims (6)

[Claims] 1. A light projecting means for projecting a light beam onto a moving object to be measured, a light receiving lens for receiving and condensing light reflected from the object to be measured as detection light, and a light receiving lens at the light collecting position. A light incident position detection element that outputs a current according to the condensing position of the surface and a distance to the irradiation point on the DUT by processing the photocurrent obtained from the light incident position detection element And a signal processing circuit for obtaining information,
First and second lines installed so that a straight line connecting a pair of irradiation points of the light beam is parallel to the moving direction of the object to be measured.
Of the same point on the object to be measured based on the correlation between the distance information of the pair of irradiation points on the object to be measured obtained by the first and second distance detecting means. The speed measuring device is characterized by further comprising: speed detection means for determining a time difference of irradiation with the light beam, and detecting a moving speed of the object to be measured from the time difference and the interval between the pair of irradiation points. 2. The first and second distance detecting means output the distance information as a time-varying waveform, and the speed detecting means calculates a correlation of a pair of the time-varying output waveforms. Characterized by having a correlator performing
The speed measuring instrument according to claim 1. 3. At least one of the first and second distance detecting means is, as the light projecting means, a light source in which a plurality of light emitting points are arranged in a direction orthogonal to a moving direction of the object to be measured. The light incident position detecting element corresponding to the light projecting means is configured to be capable of receiving the respective detection lights by the light beams projected from each of the plurality of light emitting points. The speed measuring instrument according to claim 1, wherein 4. The speed detecting means connects the pair of irradiation points on the object to be measured based on the correlation of distance information by light beams from a plurality of light emitting points of the light projecting means. Rotation means for correcting a direction connecting a pair of irradiation points by the first and second distance detection means is further provided to obtain a deviation between a reference line direction and a movement direction of the object to be measured. The speed measuring instrument according to claim 3, characterized in that. 5. One of the first and second distance detecting means includes a light source forming one light emitting point as the light projecting means, and the other distance detecting means as the light projecting means. The light incident position detecting element corresponding to the light projecting means includes a light source that forms a plurality of light emitting points which are arranged on a circumference of a predetermined radius around the one light emitting point and are sequentially turned on. The speed measuring instrument according to claim 1, wherein the reflected light from the light beams projected from each of the plurality of light emitting points can be received. 6. The vehicle height of the vehicle, wherein the first and second distance detecting means are installed in an automobile, and an average value of distance information obtained from one or both of the first and second distance detecting means. The speed measuring instrument according to claim 1, which is controlled.