JP2008292308A - Optical radar device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical radar device, improving resolving power while restraining deterioration of follow-up performance to a moving body even when an object to be measured is the moving body. <P>SOLUTION: A control circuit of this optical radar device sets the irradiation frequency f of a pulse beam emitted from a laser light source so that the irradiation pulse number per scanning period is not a natural number. Therefore, at the emit timing of a pulse beam in each scanning cycle T during the consecutive scanning cycles T, shift for a time ▵t (▵t=t×1/2) shorter than the irradiation period t of the pulse beam is caused. Thus, between the irradiation positions pO-p6 of the adjacent pulse beams in the preceding scanning, the irradiation positions pO'-p6' of the pulse beams in the next scanning connected to the above scanning are set to thereby improve the resolving power in pseudo. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical radar device.

  2. Description of the Related Art Conventionally, an optical radar device that irradiates a target with pulsed light, determines the presence or absence of the target, and measures the distance to the target is disclosed in, for example, Patent Document 1. The optical radar device includes a light source that emits pulsed light, a rotating mirror that scans the light emitted from the light source into a predetermined scanning range, a light receiving element that receives light reflected by the measurement object, and the rotation And a detection element for detecting a rotation angle (scan position) of the mirror. The pulsed light emitted from the light source is reflected by the reflecting surface of the rotating mirror and emitted outward. The light emitted toward the outside is reflected by the target if there is a target at the irradiation position, and is received by the light receiving element. The pulsed light emitted from the light source is scanned on the measurement object at a scanning speed corresponding to the rotational speed of the rotating mirror, and the irradiation pitch angle of the pulsed light depends on the scanning speed of the pulsed light and the irradiation period of the same pulsed light. (Azimuth resolution) is determined. Then, based on the time required for the light to travel back and forth between the objects and the phase difference of the reflected light, the presence / absence of the object in the scanning range and the distance to the object existing in the scanning range are measured.

By the way, the azimuth resolution of the measurement of such an optical radar apparatus is determined by the irradiation period of the pulsed light, that is, the irradiation frequency and the scanning speed as described above. For example, when the rotation speed of the rotating mirror (the number of rotations per second) is 10 [sec ⁻¹ ] and the irradiation frequency of the pulsed light is 10 kHz, the number of irradiation pulses per rotation of the rotating mirror is 1000 pulses, and the direction The resolution is 0.36 deg. If the object is located 10 m away and is stationary, the distance to the object is measured at intervals of 6.3 cm along the scanning direction. The measurement resolution is improved in proportion to the number of irradiation pulses per one scanning cycle (one rotation of the rotating mirror), that is, the irradiation frequency of the pulsed light, and finer measurement is possible.
JP-A-6-137867

  However, in such an optical radar device, if the irradiation frequency of the pulsed light is set high in order to improve the resolution, a high-performance processing circuit that can cope with the irradiation frequency is required. Moreover, there is a limit to the irradiation frequency that can be handled no matter how high-performance processing circuits are used. Therefore, there is a limit to setting the irradiation frequency to 2 times, 3 times, etc. to make the resolution 2 times, 3 times, etc. in this way. Therefore, as a method for further improving the resolution in an apparatus having such a limit, it is conceivable to set the scanning speed of the pulsed light low so that the number of irradiation pulses per scanning period increases. However, in this case, as the resolution is doubled, tripled, etc., the scanning period is doubled, tripled, etc., and as the resolution is improved, the number of measurements per unit time is significantly reduced. Therefore, when the measurement object is a moving object, the followability to the moving object is significantly reduced.

  The present invention has been made in view of such circumstances, and its purpose is to improve the resolution while suppressing a decrease in the followability to the moving object even when the object to be measured is a moving object. An object of the present invention is to provide an optical radar apparatus capable of

  The invention according to claim 1 is a light emitting means for emitting pulsed light, an optical scanning means for repeatedly scanning the pulsed light emitted from the light emitting means within a predetermined scanning range with a predetermined scanning period, and An optical radar apparatus comprising: a light receiving unit configured to receive light reflected by a measurement target existing within a scanning range; and measuring a distance to the measurement target based on outputs of the light emitting unit and the light receiving unit. The gist of the invention is that it includes control means for controlling the light emitting means and the light scanning means so that the number of irradiation pulses per scanning period does not become a natural number.

  According to the present invention, the light emitting means and the optical scanning means are controlled by the control means so that the number of irradiation pulses per scanning period does not become a natural number. For this reason, every time scanning is repeated, the pulse light emission timing in each scanning period is shifted by a time shorter than the irradiation period of the pulsed light between successive scanning periods. Therefore, the irradiation position of the pulsed light in the next scanning subsequent to the scanning is set between the irradiation positions of the adjacent pulsed light in the previous scanning, and the resolution is improved in a pseudo manner. Therefore, even when the measurement object is a moving object, the resolution can be improved while suppressing a decrease in the followability to the moving object. As a result, a stationary measurement object can be measured more precisely, and followability can be ensured for a moving measurement object.

The gist of the invention described in claim 2 is that the control means sets the irradiation frequency of the pulsed light so that the scanning period does not become a natural number multiple of the irradiation period of the pulsed light.
According to the present invention, the irradiation frequency of the pulsed light is set so that the scanning period is not a natural number multiple of the irradiation period of the pulsed light, in other words, the scanning period of the pulsed light is T, and the irradiation period of the pulsed light is t. T = t (N + 1 / n) (where N is a natural number and n is a natural number of 2 or more). For this reason, the number of irradiation pulses per scanning cycle becomes N + 1 / n, and a deviation of t · 1 / n occurs in the emission timing of the pulsed light in the continuous scanning cycle. Therefore, every time the number of scans is repeated, the irradiation position of the pulsed light is shifted by 1 / n times the irradiation pitch (the interval between the irradiation positions of adjacent pulsed light in one scan), and the resolution is improved in a pseudo manner. Therefore, unlike the case where the resolution is ensured by slowing the scanning speed, the resolution can be improved without reducing the followability to the moving body.

  According to a third aspect of the present invention, there is provided a natural number input means capable of inputting an arbitrary natural number by an operator, and the control means has a scanning period of the pulsed light by the optical scanning means as T, and an irradiation period of the pulsed light. T and the arbitrary natural number n, and the gist of setting the irradiation frequency so as to satisfy T = t (N + 1 / n) (where N is a natural number and n is a natural number of 2 or more). To do.

  According to the present invention, an arbitrary natural number of the operator is input via the natural number input means. The pulsed light irradiation frequency satisfies T = t (N + 1 / n), where T is the scanning period of the pulsed light by the optical scanning unit, t is the irradiation period of the pulsed light, and n is any natural number of the operator. Is set as follows. For this reason, every time the number of scans is repeated, the irradiation position of the pulse light is shifted by an amount corresponding to an arbitrary natural number input by the operator (by 1 / n times the irradiation pitch). Therefore, it can be set to an arbitrary resolution of the operator.

  According to a fourth aspect of the present invention, the control means has T = t (N + 1/2) (where N is the scanning period of the pulsed light by the optical scanning means, and t is the irradiation period of the pulsed light. The gist is to set the irradiation frequency so as to satisfy a natural number.

  According to the present invention, the irradiation frequency of the pulsed light satisfies T = t (N + 1/2), where T is the scanning period of the pulsed light and t is the irradiation period of the pulsed light, that is, irradiation per scanning period. The number of pulses is set to be N + 1/2. For this reason, a deviation of t · 1/2, that is, a half of the irradiation period occurs in the emission timing of the pulsed light in the continuous scanning period. Therefore, the irradiation position of the pulsed light in the next scanning following the scanning is set at a position shifted from the irradiation position of the pulsed light in the previous scanning by ½ times the irradiation pitch of the pulsed light, and the resolution is simulated. Will be doubled. Therefore, unlike the case where the resolution is ensured by slowing the scanning speed, the resolution can be improved without reducing the followability to the moving body. Further, since the irradiation position of the pulsed light is shifted by ½ times the irradiation pitch of the pulsed light, it is changed alternately every time the number of scans is repeated. Therefore, it is possible to irradiate the pulsed light at equal intervals in a relatively short time.

The gist of the invention described in claim 5 is provided with a scanning cycle input means capable of inputting an arbitrary scanning cycle by an operator.
According to the present invention, an arbitrary scanning cycle is input via the scanning cycle input means. Therefore, it is possible to improve the resolution while ensuring the followability with an arbitrary scanning cycle of the operator.

The gist of the invention described in claim 6 is that the control means sets the scanning period so that the scanning period does not become a natural number multiple of the irradiation period of the pulsed light.
According to the present invention, the scanning period of the pulsed light is set so that the scanning period is not a natural number multiple of the irradiation period of the pulsed light, in other words, the scanning period of the pulsed light is T, and the irradiation period of the pulsed light is t. T = t (N + 1 / n) (where N is a natural number and n is a natural number of 2 or more). For this reason, the number of irradiation pulses per scanning cycle becomes N + 1 / n, and a deviation of t · 1 / n occurs in the emission timing of the pulsed light in the continuous scanning cycle. Therefore, every time the number of scans is repeated, the irradiation position of the pulsed light is shifted by 1 / n times the irradiation pitch (the interval between the irradiation positions of adjacent pulsed light in one scan), and the resolution is improved in a pseudo manner. Therefore, as compared with the case where the number of irradiation pulses per scanning period is set to be a natural number, the resolution can be improved while suppressing a decrease in followability to the moving body.

  According to a seventh aspect of the present invention, the optical scanning unit includes a rotary reflecting member that rotates at a predetermined rotational speed, and the pulsed light from the light emitting unit is emitted in a direction according to the rotation angle of the rotary reflecting member. The gist is that the pulse light is reflected and scanned.

  According to the present invention, the pulsed light from the light emitting means is reflected in the direction according to the rotation angle of the rotary reflecting member by the rotary reflecting member of the optical scanning means. As described above, this pulsed light is emitted so that the number of irradiation pulses per scanning period does not become a natural number. Therefore, the irradiation angle of the pulse light by the next scanning that follows the scanning is set between the irradiation angles of the pulse light by the previous scanning, and the azimuth resolution is improved. Therefore, the azimuth | direction resolution can be improved, suppressing the fall of the followable | trackability to a moving body.

  According to the present invention, it is possible to provide an optical radar device capable of improving the resolution while suppressing a decrease in the followability to the moving object even when the measurement object is a moving object.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. In this embodiment, the optical radar device of the present invention measures the distance to an obstacle as a detection object around the vehicle, determines the presence or absence of the obstacle based on the change in the measured value, The present invention is applied to a collision prevention system for informing.

  As shown in FIG. 1, a laser light source 2 as a light emitting means provided in a radar head unit 1 a of an optical radar apparatus 1 is connected to a light projecting circuit 3, which projects the optical radar apparatus 1. It is connected to a control circuit 4 as a control means for overall control. The light projecting circuit 3 supplies a drive pulse signal to the laser light source 2 based on the control signal output from the control circuit 4. The laser light source 2 is a laser diode or the like, and emits (projects) pulsed light having a predetermined irradiation frequency f (see FIG. 2) based on the drive pulse signal supplied from the light projecting circuit 3. In the optical radar apparatus 1, a light projecting lens 2 a and a half mirror 5 are disposed in order on the optical path of the pulsed light emitted from the laser light source 2, and the light emitted from the laser light source 2 is emitted from the light projecting lens 2 a. And is transmitted through the half mirror 5 and emitted toward the outside. Further, the light projecting circuit 3 outputs a start pulse signal S1 to the control circuit 4 at the timing when the pulsed light L is emitted.

  An actuator 6 as an optical scanning unit of the optical radar device 1 is connected to the radar head unit 1a. The actuator 6 is connected to the control circuit 4. The actuator 6 rotates the radar head unit 1 a 360 ° based on the control signal output from the control circuit 4, and repeats the emission direction of the pulsed light L emitted from the laser light source 2 at a predetermined rotation speed (scanning speed). change. Therefore, the pulsed light L emitted from the laser light source 2 has a predetermined scanning range A (in the present embodiment, a range of 360 °) around the optical radar device 1, as shown in FIGS. Are scanned at the scanning cycle T. Further, the actuator 6 outputs an angle detection signal of the projection lens 2 a corresponding to the emission direction of the pulsed light L to the control circuit 4.

  A light receiving element 7 as a light receiving means provided in the radar head unit 1 a is connected to a light receiving circuit 8, and the light receiving circuit 8 is connected to a control circuit 4. The light receiving element 7 is a photodiode or the like, and can receive light (pulse light L) reflected by the obstacle W existing at the irradiation position of the pulse light L via the half mirror 5 in the radar head unit 1a. Placed in position. In the radar head unit 1 a, a light receiving lens 7 a is disposed on the optical path of the pulsed light reflected by the half mirror 5 and directed toward the light receiving element 7, and reflected by the obstacle W present at the irradiation position of the pulsed light L. The light (pulsed light L) is focused on the light receiving element 7 through the light receiving lens 7a. The light receiving circuit 8 outputs to the control circuit 4 a light receiving signal S2 corresponding to the time when the reflected light from the obstacle W is received based on the amount of light received by the light receiving element 7.

  An input device 9 as a natural number input means and a scanning cycle input means is connected to the control circuit 4, and an arbitrary scanning speed (rotational speed) can be input by the operator via the input device 9. . The control circuit 4 outputs to the actuator 6 a control signal indicating that the pulsed light L is scanned at the scanning period T corresponding to the inputted arbitrary scanning speed of the operator. The irradiation frequency setting unit 4a of the control circuit 4 also applies the irradiation frequency f of the pulsed light L so that the number of irradiation pulses per scanning period (the number of times the pulsed light L is emitted per scanning period) does not become a natural number. And a control signal for emitting the pulsed light L at the irradiation frequency f is output to the light projecting circuit 3. An arbitrary natural number can be input to the control circuit 4 as a parameter that affects the irradiation frequency f by the operator via the input device 9. The irradiation frequency setting unit 4a sets T = t (N + 1 / n) (where N is a natural number, where T is the scanning period of the pulsed light by the actuator 6, t is the irradiation period of the pulsed light, and n is the arbitrary number). And n is a natural number of 2 or more), and the irradiation frequency f is set. That is, when an arbitrary natural number n of the operator is input, the irradiation frequency setting unit 4a sets the irradiation frequency f (1 / t) so that the scanning period T is not a natural number times the irradiation period t of the pulsed light L. Set.

  The time-of-flight measuring unit 4b of the control circuit 4 is used until the light receiving element 7 receives light (pulse light) emitted from the laser light source 2 based on the start pulse signal S1 and the light receiving signal S2 output to the control circuit 4. The time, that is, the time required for the light emitted from the laser light source 2 to reciprocate between the obstacles W is measured, and the measurement result is output to the distance calculation unit 4 c of the control circuit 4. The distance calculation unit 4c of the control circuit 4 calculates the distance to the obstacle W based on the measurement result of the flight time measurement unit 4b. Further, the distance calculation unit 4 c determines the emission direction of the pulsed light L based on the angle detection signal output from the actuator 6. Then, the distance calculation unit 4c displays the measurement result including the calculated distance data and the emission direction of the pulsed light L corresponding to the data (irradiation positions p0 to p6 and p0 ′ to p6 ′ of the pulsed light) as a collision prevention system. To the main computer M. Based on the measurement result, the main computer M outputs a sound, a warning sound, or the like to notify the passenger of the presence of the obstacle W.

Next, the operation of the optical radar device 1 according to the present embodiment will be described.
When “2” is input as a parameter that affects the irradiation frequency f by the operator via the input device 9, the irradiation frequency setting unit 4 a of the control circuit 4 sets the irradiation frequency f of the pulsed light L to the pulsed light. Assuming that the scanning period is T and the irradiation period of the pulsed light is t, T = t (N + 1/2) is satisfied, that is, the number of irradiation pulses per scanning period (one rotation) is set to N + 1/2. . For this reason, as shown in FIG. 2, a deviation of t · 1/2 occurs in the emission timing of the pulsed light in the continuous scanning cycle. Therefore, every time the number of scans is repeated, the irradiation positions p0 to p6 and p0 ′ to p6 ′ of the pulsed light are ½ times the irradiation pitch (the interval d between adjacent irradiation positions of the pulsed light in one scan (see FIG. 3)). It will be shifted one by one. Therefore, as shown in FIG. 3A, when the obstacle W is moving in the scanning range A of the pulsed light L along the scanning direction of the pulsed light L, the light receiving element 7 is scanned by the time T1. The light emitted to the irradiation positions p1 to p5 and reflected by the object is received. Further, the light receiving element 7 receives the light emitted to the irradiation positions p1 ′ to p4 ′ and reflected by the object by scanning at time T2. Therefore, the presence / absence of an object can be determined by an interval that is half (1/2 · d) the interval d of the irradiation positions of the adjacent pulsed light L in one scan by two successive scans at times T1 and T2. For this reason, the measurement resolution (azimuth resolution) by scanning at times T1 and T2 is approximately twice the measurement resolution by a single scan.

  On the other hand, in the conventional optical radar apparatus in which the irradiation frequency f of the pulsed light L is set so that the number of irradiation pulses per scanning period becomes a natural number, as shown in FIG. In each scan, the pulsed light L is irradiated to the irradiation positions p0 to p6. Therefore, the measurement resolution at the times T1 and T2 is approximately the same as the measurement resolution by a single scan. In such a conventional optical radar apparatus, in order to obtain a resolution equivalent to the resolution obtained by scanning the times T1 and T2 by the optical radar apparatus 1 of the present embodiment, the irradiation cycle is about ½ times (irradiation The frequency f must be approximately doubled). That is, according to the optical radar device 1 of the present embodiment, unlike the conventional case where the irradiation frequency f of the pulsed light L is set so that the number of irradiation pulses per scanning period becomes a natural number, A resolution approximately twice as high can be obtained without doubling the irradiation frequency f.

  Further, as shown in FIG. 3A, in the optical radar device 1 of the present embodiment, the position of the obstacle W at each point in time T1, T2, and T3 is measured. Here, it is conceivable that the scanning speed is halved (scanning cycle is doubled) and the resolution is doubled. However, in this case, since the scanning cycle is doubled as shown in FIG. 3C, the position of the obstacle W at the time T2 is not measured. According to the present embodiment, as described above, the displacement of the obstacle W at each point in time T1, T2, and T3 can be captured, so that the followability to the moving obstacle W is maintained.

Next, the operational effects of the above embodiment will be described below.
(1) The laser light source 2 and the actuator 6 are controlled by the control circuit 4 of the optical radar device 1 so that the number of irradiation pulses per scanning period does not become a natural number. Therefore, every time scanning is repeated, the emission timing of the pulsed light L in each scanning period T between successive scanning periods T is shorter than the irradiation period t of the pulsed light L Δt (in this embodiment, Δt = A deviation of t · 1/2) occurs. Therefore, between the irradiation positions p0 to p6 of the adjacent pulsed light L in the previous scan, the irradiation positions p0 ′ to p6 ′ of the pulsed light L in the next scanning subsequent to the scanning are set, and the resolution is simulated. improves. Therefore, even when the measurement object is a moving object, the resolution can be improved while suppressing a decrease in the followability to the moving object. As a result, the stationary obstacle W can be measured more precisely, and the followability can be secured for the moving obstacle W.

  (2) The control circuit 4 of the optical radar apparatus 1 sets the scanning cycle of the pulsed light L by the actuator 6 to T and the pulsed light so that the scanning cycle T does not become a natural number multiple of the irradiation cycle t of the pulsed light L. The irradiation frequency f is set so as to satisfy T = t (N + 1 / n) (where N is a natural number and n is a natural number of 2 or more) where L is an irradiation period. For this reason, the number of irradiation pulses per scanning cycle becomes N + 1 / n, and a deviation of t · 1 / n occurs in the emission timing of the pulsed light L in the continuous scanning cycle T. Accordingly, each time the number of scans is repeated, the irradiation positions p0 to p6 and p0 ′ to p6 ′ of the pulse light L are shifted by 1 / n times the irradiation pitch (the interval d between the irradiation positions of the adjacent pulsed light L in one scan). Thus, the resolution is improved in a pseudo manner. Therefore, unlike the case where the resolution is ensured by slowing the scanning speed, the resolution can be improved without reducing the followability to the moving body.

  (3) The control circuit 4 of the optical radar device 1 is connected to the input device 9, and an arbitrary natural number is input via the input device 9 as a parameter that affects the irradiation frequency f. Then, the control circuit 4 (irradiation frequency setting unit 4a) sets the irradiation frequency f of the pulsed light L, T the scanning period of the pulsed light L by the optical scanning means, t the irradiation period of the pulsed light L, and the input device 9 Is set so that T = t (N + 1 / n) is satisfied, where n is an arbitrary natural number of the operator input via. Therefore, each time the number of scans is repeated, the irradiation positions p0 to p6 and p0 ′ to p6 ′ of the pulsed light L are shifted by an amount corresponding to an arbitrary natural number input by the operator (by 1 / n times the irradiation pitch). It will be. Therefore, it can be set to an arbitrary resolution of the operator.

  (4) The control circuit 4 of the optical radar device 1 receives an arbitrary scanning speed (rotational speed) via the input device 9. Therefore, it is possible to improve the resolution while ensuring followability in the scanning cycle T corresponding to an arbitrary scanning speed of the operator.

The embodiment of the present invention may be modified as follows.
In the above embodiment, when the natural number n is input as a parameter that affects the irradiation frequency f by the operator via the input device 9, the scanning period T does not become a natural number times the irradiation period t of the pulsed light L. However, the present invention is not limited to this mode. For example, the input device 9 is omitted, and an irradiation frequency and a scanning cycle set in advance so that the number of irradiation pulses per scanning cycle does not become a natural number are stored in the control circuit 4 in advance, and based on the irradiation frequency and the scanning cycle. Then, the laser light source 2 and the actuator 6 may be controlled. In this case, when the irradiation frequency f is set so as to satisfy T = t (N + 1/2) (where N is a natural number) where T is the scanning period of the pulsed light L and t is the irradiation period of the pulsed light L, The number of irradiation pulses per scanning period is N + 1/2. For this reason, a deviation of t · 1/2, that is, a half of the irradiation period occurs in the emission timing of the pulsed light L in the continuous scanning period. Therefore, the irradiation position of the pulsed light L in the next scanning subsequent to the scanning is set at a position shifted from the irradiation position of the pulsed light L in the previous scanning by ½ times the irradiation pitch of the pulsed light L, and the resolution. Becomes pseudo double. Therefore, unlike the case where the resolution is ensured by slowing the scanning speed, the resolution can be improved without reducing the followability to the moving body. Further, since the irradiation position of the pulsed light L is shifted by ½ times the irradiation pitch of the pulsed light L, it is changed alternately every time the number of scans is repeated. Therefore, the pulsed light L can be irradiated at equal intervals in a relatively short time.

  In the above embodiment, an arbitrary scanning speed (rotational speed) of the operator is input via the input device 9 and the scanning cycle T is set. However, the scanning speed is always set to a constant value. It may be.

  In the above embodiment, the control circuit 4 sets the irradiation frequency f of the pulsed light so that the scanning period T does not become a natural number multiple of the irradiation period t of the pulsed light, but is not limited to such an aspect. For example, an arbitrary irradiation period t (irradiation frequency f) of the operator can be input, and the scanning period T is set so that the scanning period T is not a natural number multiple of the irradiation period t of the pulsed light. Good.

  In the above embodiment, the distance to the obstacle W is calculated based on the start pulse signal S1 and the light reception signal S2 output from the light projecting circuit 3, but the present invention is not limited to such a mode. For example, as shown in FIG. 4, a half mirror 10 is provided on the optical path of the pulsed light L in the optical radar device 11, and the light transmitted through the half mirror 10 is reflected by the light receiving element 7 and reflected by the half mirror 10. The distance to the obstacle W may be calculated based on the light reception signal S3 corresponding to the time when the light receiving element 7 receives the light reciprocating between the obstacle W. In this case, light is scanned by rotating or swinging the half mirror 10 by an actuator (not shown).

  In the above embodiment, the radar head unit 1a is rotated to scan the pulsed light L. However, for example, only the light projection lens 2a may be driven to scan the pulsed light L. Further, the pulsed light L is scanned by rotating or swinging a half mirror 10 (see FIG. 4) or a polygon mirror as a rotary reflecting member that reflects light from the laser light source 2 in a predetermined direction. May be.

  In the above embodiment, the light emitted from the laser light source 2 based on the light reception signal S2 corresponding to the reception time point of the reflected light from the obstacle W based on the amount of light received by the light receiving element 7 is between the obstacle W Is applied to the optical radar device 1 that measures the time required to reciprocate and calculates the distance to the obstacle W, but is not limited to such an embodiment. For example, the time required for the light emitted from the laser light source 2 to reciprocate between the obstacle W based on the phase difference between the light emitted from the laser light source 2 and the light incident on the light receiving element 7 is measured. The present invention can also be applied to a distance measuring device that calculates the distance to an object.

  In the above embodiment, the radar head unit 1a is rotated 360 ° to obtain a scanning range A of 360 °. However, the scanning range may not be 360 °.

1 is a schematic configuration diagram of an optical radar apparatus according to an embodiment. Explanatory drawing for demonstrating the effect | action of an optical radar apparatus. (A)-(c) Explanatory drawing for demonstrating the effect | action of an optical radar apparatus. The schematic block diagram of the optical radar apparatus of other embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,11 ... Optical radar apparatus, 2 ... Laser light source as light emission means, 4a ... Irradiation frequency setting part as control means, 6 ... Actuator as light scanning means, 7 ... Light receiving element as light receiving means, 9 ... Natural number Input device as input means and scanning period input means, 10... Half mirror as rotating reflecting member, A... Scanning range, f .. irradiation frequency, L .. pulsed light, T ... scanning period, t ... irradiation period, W ... detection Obstacles as objects.

Claims (7)

Light emitting means for emitting pulsed light;
Optical scanning means for repeatedly scanning the pulsed light emitted from the light emitting means within a predetermined scanning range with a predetermined scanning period;
An optical radar apparatus comprising: a light receiving unit configured to receive light reflected by a measurement target existing within the scanning range; and measuring a distance to the measurement target based on outputs of the light emitting unit and the light receiving unit. Because
An optical radar apparatus comprising: a control unit that controls the light emitting unit and the optical scanning unit so that the number of irradiation pulses per scanning period does not become a natural number. The optical radar device according to claim 1,
The optical radar apparatus, wherein the control means sets the irradiation frequency of the pulsed light so that the scanning period does not become a natural number multiple of the irradiation period of the pulsed light. The optical radar device according to claim 2,
Provided with natural number input means that allows an operator to input an arbitrary natural number,
The control means has a scanning period of the pulsed light by the optical scanning means as T, an irradiation period of the pulsed light as t, and the arbitrary natural number as n.
T = t (N + 1 / n) (where N is a natural number and n is a natural number of 2 or more)
An optical radar apparatus, wherein the irradiation frequency is set so as to satisfy The optical radar device according to claim 2,
The control means has a scanning period of the pulsed light by the optical scanning means as T and an irradiation period of the pulsed light as t.
T = t (N + 1/2) (N is a natural number)
An optical radar apparatus, wherein the irradiation frequency is set so as to satisfy In the optical radar device according to any one of claims 1 to 4,
An optical radar apparatus comprising scanning period input means capable of inputting an arbitrary scanning period by an operator. The optical radar device according to claim 1,
The optical radar device characterized in that the control means sets the scanning period so that the scanning period does not become a natural number multiple of the irradiation period of the pulsed light. In the optical radar device according to any one of claims 1 to 6,
The light scanning unit includes a rotary reflection member that rotates at a predetermined rotation speed, and scans the pulsed light by reflecting the pulsed light from the light emitting unit in a direction according to the rotation angle of the rotary reflection member. An optical radar device characterized by that.

Images