WO2019021887A1 - Optical radar device - Google Patents

Abstract

The present invention enables the position of an object to be accurately recognized with a small amount of data processing. This optical radar device (100) includes: a pulsed-light illumination system (110) that projects pulsed light onto an object; a light reception system (150) that detects the light reflected from the object and thereby measures the distance to the object; and a horizontal sensor (140) that detects an inclination angle with respect to a horizontal plane of the light axis of the light reception system (150). The light reception system (150) corrects the inclination, with respect to the horizontal plane, of the light axis of the light reception system (150) by the inclination angle amount detected by the horizontal sensor (140).

Description

Optical radar device

The present invention relates to an optical radar device, and more particularly to an optical radar device for acquiring a three-dimensional image mainly composed of a two-dimensional image of an object and distance information on the object.

The three-dimensional image is a concept that includes distance information to the object in the field of view in addition to two-dimensional images like ordinary photographs, and in recent years, three-dimensional image sensors have been used for peripheral recognition of automobiles and robots. It is extremely important. As sensors for two-dimensional images, charge coupled devices (CCDs) and complementary metal oxide semiconductors (CMOSs) imagers are in widespread use, and light intensity is converted into an electrical signal by a photodiode made of silicon for imaging. As for the measurement of distance information with high accuracy, a method of irradiating a laser beam and measuring a time-of-flight until the laser beam is reflected and returned from an object is spreading.

As a method of irradiating the entire field of view with laser light, a scanning type in which a laser beam focused in a point shape (see Non-Patent Document 1) or a band (see Patent Document 1) is scanned by a mirror etc. There is a batch irradiation type in which a laser beam is spread and irradiated, and many scan types in which a strong beam intensity can be easily obtained on an object have been developed. The scan type is expensive and bulky because it requires a mechanical mechanism to swing the beam. On the other hand, the batch irradiation type does not require a mechanical mechanism to scan, so it is easy to miniaturize, but since the laser light intensity on the object becomes weaker than the scan type, when the distance to the object increases, The signal strength decreases and the distance measurement accuracy decreases.

As for time of flight measurement, the pulse laser beam is emitted multiple times in order to directly measure the time measurement accuracy to the distance accuracy, and the time measurement from light emission to light reception is repeated, and the histogram (horizontal axis: time, vertical axis: frequency) There is a way to configure and determine flight times. This is a method called TCSPC (Time-Correlated-Single-Photon-Counting). As a light receiving element, SPAD (Single-Photon-Avalanche-Diode: single photon avalanche multiplication photodiode) is used. Since this method has a large circuit scale per pixel, it is not used in an imager in which pixels are two-dimensionally arrayed in a large scale (deletion), and is mainly used in combination with a scan type (Patent Document 2 and Non-Patent Document 1).

On the other hand, in the batch irradiation type, the current of the photodiode is measured, and the flight time is determined by comparing with the determination value. Further, there is also a case where the current is sequentially accumulated in capacitors arranged in time series, and determination is made based on the accumulated amount. According to this mechanism, since a three-dimensional image is formed by one laser irradiation, as in the case of taking a picture by applying a flash in terms of photography, simultaneousness is ensured over the entire field of view. Each point in the field of view differs greatly from the scan type with a different time, and is described as "flash" (see Patent Document 3 and Patent Document 4).

Japanese Patent Publication "Japanese Patent Application Laid-Open No. 2015-78953 (Apr. 23, 2015)" U.S. Patent No. 5892575 (April 6, 1999) U.S. Patent No. 56,965,77 (Dec. 9, 1997) U.S. Pat. No. 8,130,367 (March 6, 2012)

However, the above-described conventional techniques have the following problems.

Since the optical radar device is used by being attached to a moving object (main body, moving body), such as a vehicle, a robot, a drone, a wand for the visually impaired, the direction of the object view often changes from time to time. For example, with the movement of the main body, the inclination of the ground and the inclination of the main body may change, and the center (optical axis) of the object view of the light radar device may be vertically oscillated. Also, the field of view may rotate around the optical axis. For example, when there is an up and down swing, an object that is originally at the front center is recognized as being above or below the actual, or an object that is stationary is recognized as being moving up and down There is a risk of misrecognition. When the field of view rotates around the optical axis, a flat passage may be misrecognized as an inclined passage, or an inclined ground may be misrecognized as flat. In order to avoid such misrecognition, another horizontal sensor or a 2-axis accelerometer is provided on the main body, and it is monitored how the main body is inclined with respect to the vertical line, and the inclination information of the main body is used. In addition, it is necessary to reinterpret the 3D image information output from the light radar device.

When the main body is a large vehicle and equipped with a high-performance CPU, processing of the above data can be done without a large time delay, but when a smaller-sized mobile unit is not equipped with a powerful CPU. The above data processing is a major obstacle. In addition, in the case where a large vehicle is equipped with a plurality of light radar devices, the inclination from the vertical line may be different for each light radar device. This is because the larger the body, the greater the amount of deformation, as long as the body is not completely rigid.

One aspect of the present invention is to realize an optical radar device capable of outputting a 3D image in which the positional relationship of the optical laser device with respect to the vertical line is constant, and the position of an object can be accurately recognized with a small amount of data processing. I assume.

In order to solve the above problems, according to one aspect of the present invention, an optical radar device is an optical radar device that measures the distance to an object present in a predetermined target area by a time-of-flight method. A light source for emitting pulsed light, a pulsed light illumination system for irradiating at least a part of the target area with pulsed light emitted from the light source, and the target for pulsed light emitted by the pulsed light illumination system A light receiving system for detecting the reflected light from the object to measure the distance to the object, and a horizontal sensor for detecting an inclination angle of the optical axis of the light receiving system with respect to the horizontal plane; The tilt of the optical axis of the light receiving system with respect to the horizontal plane is corrected by the tilt angle detected by the horizontal sensor.

According to one aspect of the present invention, the positional relationship of the 3D image output from the optical laser device with respect to the horizontal surface is constant, and a 3D image capable of accurately recognizing the position of the object with a small amount of data processing can be output. Play.

It is a schematic diagram which shows the structure of the optical radar apparatus which concerns on Embodiment 1 and 2 of this invention. It is a schematic diagram which shows the structure of the fan-shaped light irradiation system of the pulsed light illumination system which comprises the optical radar apparatus shown in FIG. FIG. 2 is a schematic view showing the relationship between a target area, a measurable area, and a pulsed light irradiation area in the optical radar device shown in FIG. It is a schematic diagram of the ToF sensor which comprises the optical radar apparatus shown in FIG. The optical radar apparatus which concerns on Embodiment 2 of this invention WHEREIN: It is a schematic diagram which shows the relationship between an object area | region, a measurable area | region, and a pulsed light irradiation area | region. It is a schematic diagram which shows the structure of the optical radar apparatus based on Embodiment 3 of this invention. FIG. 7 is a schematic view showing the relationship between a target area, a measurable area, and a pulsed light irradiation area in the optical radar device shown in FIG. 6; It is a schematic diagram which shows the structure of the optical radar apparatus based on Embodiment 4 of this invention. FIG. 9 is a schematic view showing the relationship between a target area, a measurable area, and a pulsed light irradiation area in the optical radar device shown in FIG. 8;

Embodiment 1
It will be as follows if one embodiment of the present invention is described. Hereinafter, for convenience of explanation, the same reference numerals may be added to the configurations having the same functions as the configurations described in the specific embodiment, and the description thereof may be omitted.

(Outline of optical radar system)
FIG. 1 is a schematic view of an optical radar device 100 according to the first embodiment.

The optical radar device 100, as shown in FIG. 1, includes a pulse light illumination system 110 for irradiating a pulse light irradiation area 10 with fan-shaped pulse light 124 (hereinafter sometimes referred to simply as pulse light); It consists of a light receiving system 150 for receiving light from at least a part of 10, and a horizontal sensor 140.

The pulsed light illumination system 110 includes a light source 122 that emits pulsed light, and a fan-shaped light irradiation system 123 that irradiates the pulsed light irradiation area 10 with the pulsed light emitted by the light source 122.

The fan-shaped light irradiation system 123 converts the pulse light from the light source 122 into a band-shaped pulse light having a narrow band width spread in the horizontal direction, and scans the band-shaped pulse light one-dimensionally in the vertical direction. Pulse light (fan-shaped pulse light 124) is irradiated.

The light receiving system 150 includes a ToF sensor (including a three-dimensional image element) 153, an imaging optical system 151 that forms an image on the light receiving unit 154 of the ToF sensor 153, and an optical band pass filter 152. The ToF sensor 153 also includes functions such as control of the pulsed light illumination system 110 and communication with the external system 170.

The horizontal sensor 140 constantly monitors the inclination angle of the light axis of the light receiving system 150 with respect to the horizontal plane, and outputs the monitoring result to the ToF sensor 153. In this embodiment, the case of correcting the inclination of the light axis of the light receiving system 150 with respect to the horizontal plane will be described.

In the present embodiment, in the coordinate setting shown in FIG. 1 and FIG. 2, the Z axis is the vertical direction, and the XY plane is the horizontal plane. The coordinate axes fixed to the environment are represented by X, Y, Z, and the coordinate axes fixed to the light radar device 100 are represented by Xr, Yr, Zr. When the light radar device 100 is not tilted, the two coincide. The case where the Y-axis direction is the front of the optical radar device 100 and the Yr-axis is inclined with respect to the Y-axis is called forward inclination, and the case where the Xr-axis is inclined with respect to the X-axis is called lateral inclination. In the following description of each component, the Y-axis direction is the central portion of the pulsed light irradiation region 10 on the assumption that the optical radar device 100 is not inclined in any direction with respect to the horizontal surface unless otherwise specified. A case where the light receiving system 150 is in the optical axis direction will be described. Further, the present embodiment is directed to the case where the left and right inclination of the light radar device 100 can be ignored.

(Pulsed light illumination system 110)
The pulsed light illumination system 110 of the light radar device 100 will be described below with reference to FIGS. 2 and 3. FIG. 2 is a schematic view showing a configuration of a fan-shaped light irradiation system 123 of the pulsed light illumination system 110 shown in FIG. FIG. 3 is a schematic view showing the relationship between a target area, a measurable area, and a pulsed light irradiation area in the optical radar device shown in FIG.

First, the fan-shaped pulsed light 124 irradiated by the fan-shaped light irradiation system 123 will be described. The fan-shaped pulse light 124 spreads like a fan in the horizontal direction, and its spread angle is denoted by θh. On the other hand, the spread angle in the vertical direction is small, and the beam thickness is θw (half width). θ h >> θ w By scanning the fan-shaped pulse light 124 in the vertical direction within the vertical irradiation angle θv, it is possible to sequentially irradiate the pulsed light irradiation region 10 with the horizontal spread angle θh and the vertical spread angle θv. In addition. It is θv> θw. When it is necessary to distinguish the fan-shaped pulse lights 124 which are irradiated at different angles in the vertical direction, they are described as 124-1 to 124-Ns. Ns is the total number of scans in the vertical direction.

If θh> θv, many of the objects in the field of view can be detected by the initial few scans, without completing all of the vertical scans. On land, it is rare when the obstacle to be detected floats in the air, and it often stands vertically from the road surface or the ground, so for example from a low height, fan-shaped pulse light just parallel to the horizontal plane If irradiated, most obstacles can be detected. Therefore, there is a feature that an obstacle can be detected quickly before the end of one field period. On the other hand, in applications where the road surface is to be monitored far, θ h ≦ θ v may be used, and can be changed according to the application.

It is preferable that the fan-shaped pulse light 124 be uniform in the object field of view, but the detection sensitivity of the place where the light intensity is high is high. It is also possible to make the light intensity distribution in which the intensity in the vicinity is strengthened.

Next, the configuration of the fan-shaped light irradiation system 123 will be described.

The fan-shaped light irradiation system 123, as shown in FIG. 2, includes a collimated light generator 130 for shaping the light of the light source 122 (FIG. 1) into substantially parallel spot light 133 (in YZ plane); At least in the vertical direction (Z direction), and at least a fan-shaped beam generator 132 for spreading the spot light whose traveling angle in the vertical direction has been changed by the one-dimensional scan device 131 in a fan-like shape.

The one-dimensional scanning device 131 is configured of a MEMS mirror element or the like having a reflective surface that rotates about one axis (X axis) in a horizontal plane (XY plane).

The fan beam generator 132 includes, for example, a Powell lens. For example, a collimated light generator 130 forms a spot light 133 having a divergence angle of about 1.0 degree and a diameter of about 3 mm at the incident part of a Powell lens with an aperture of 8.9 mm, and is a one-dimensional scanning device The laser beam is shaken ± 20 degrees with respect to the horizontal plane by 131. The Powell lens emits laser light at θh = 90 ° and θw = 1 °, so this fan-shaped pulse light 124 can irradiate a range of θh = 90 ° and θv = 40 °.

The light path of the fan-shaped light irradiation system 123 is made to pass through the fan-shaped beam generator 132 after passing through the one-dimensional scanning device 131 in FIG. 2, but conversely, after passing through the fan-shaped beam generator 132 It may pass through the scanning device 131. Here, it is preferable that θv be larger than the measurement region θov in the vertical direction of the light radar device 100. For example, as shown in FIG. 3, when the optical radar device 100 is inclined downward by θiy (a forward inclination angle, downward is defined as minus), the actual horizontal plane corresponds to the pulse light irradiation region 10 of the optical radar device 100. Shift by -θiy with respect to the center. Since the target area 12 which is the area to be actually measured is in the range of the angle θov centered on the horizontal plane, the one-dimensional scanning device 131 of the pulsed light illumination system 110 shifts the light irradiation area by -θiy from the center by It is preferable to scan the range of Therefore, if an allowable maximum value of θiy is ± θmy, it is preferable that θv ≧ θov + 2 · θmy. For example, if θov = 20 degrees and θmy = 10 degrees, it is preferable that θv be 40 degrees or more. In addition, although the case where the object area | region 12 spread | spreaded centering on the horizontal surface was described here, it is the same also when the object area | region 12 is facing down and upward with respect to the horizontal surface. That is, the Y axis may be set to be shifted from the horizontal plane so as to face the center of the target area 12. The same applies to the following.

The MEMS mirror element is, for example, an electromagnetic type, and changes the swing angle of the mirror by controlling the amount of current flowed. In the electrostatic type and the piezoelectric type, the deflection angle of the mirror can be changed by controlling the applied voltage. The MEMS mirror element has the advantage that the device can be miniaturized. Control of the one-dimensional scanning device 131 is included in the ToF sensor 153. In order to detect the signal from the object irradiated with the fan-shaped pulsed light 124, it is necessary to synchronously control the deflection angle of the mirror and the light receiving system. The one-dimensional scanning device 131 may have another configuration, such as a polygon mirror or a liquid crystal waveguide method, in addition to the MEMS mirror element.

Although other configurations are possible as the fan-shaped beam generator 132, using a Powell lens has no moving parts, and the pulse light can be spread by a relatively small optical component, so the device can be miniaturized and the rigidity can be improved. There is an advantage to say.

Here, the light source 122 constituting the pulsed light illumination system 110 is a light source capable of pulse emission, such as a laser or LED, and is preferably an infrared ray having a wavelength of about 700 nm to about 1000 nm. In addition to being unobtrusive, it has the advantage that the longer the wavelength, the higher the safety for the eyes of animals because it is invisible to the human eye. Furthermore, the longer the wavelength, the lower the background light intensity. In particular, the wavelength around 940 nm to 950 nm is preferable because the intensity is lowered due to the absorption of sunlight by moisture in the air. Further, it is preferable that the emission wavelength band is narrow and the temperature fluctuation of the emission peak wavelength is small, and an infrared laser is preferable. In particular, it is preferable to use a VCSEL (Vertical Cavity Surface Emitting LASER: vertical cavity surface emitting laser) which has a narrow emission wavelength band and a small temperature fluctuation of the emission peak wavelength. Although not shown in FIG. 1, a temperature control circuit for controlling the temperature of the light source 122 may be added in order to suppress the temperature fluctuation of the light emission peak wavelength.

The light source 122 emits pulsed light in synchronization with the ToF sensor 153. The light emission intensity and the pulse width (half width of light emission time) may be variable. Here, the pulse width of the pulsed light is about 1 nsec to several hundreds nsec. The peak power of pulsed light is from several watts to hundreds of watts.

When the optical radar device 100 acquires data at 30 frames per second, and the pixel resolution Δθ of each frame is 0.5 degrees and θov = 20 degrees, for example, 40 sectors of one frame having different advancing angles in the vertical direction The pulsed lights 124-1 to 124-40 are emitted. The time allotted to the fan-shaped pulsed light 124-k is 1/1200 seconds, during which the angle of the reflective surface of the one-dimensional scanning device 131 is changed to a set value, and the light source 122 is pulsed. When the pulse emission frequency is 190 kHz, each sector pulse light 124-k emits 158 pulses to the object and integrates the measurement results for each pulse.

If the angle setting accuracy of the reflective surface of the one-dimensional scanning device 131 is not high, it is preferable that θw be approximately equal to or larger than the vertical angle resolution corresponding to one pixel of the light receiving system 150. On the other hand, when the angle setting accuracy of the reflective surface of the one-dimensional scanning device 131 is high, it is preferable that θw be approximately equal to or smaller than the vertical angle resolution of the pixel. For example, when .DELTA..theta. = 0.5 degrees and the angle setting accuracy of the reflecting surface is. +-. 0.2 degrees, .theta.w.gtoreq.0.9 degrees in order to reliably irradiate the target pixel with pulsed light. . In the case of θw = 1 degree, there may be a case where only approximately 50% of pulsed light is irradiated on the object surface projected onto the object pixel. When the angle setting accuracy of the reflective surface is ± 0.02 degrees, 90% or more of the fan-shaped pulse light 124 can be irradiated on the target object surface of the target pixel when Δθ = 0.5 degrees.

In the above description, it is assumed that the object surface corresponding to the target pixel is irradiated with light substantially uniformly. However, if it is preferred to allow irradiation of as much light as possible in consideration of nonuniformity, θw Should be as small as possible. For example, when the angle setting accuracy of the reflecting surface is ± 0.2 degrees, the minimum irradiation amount is 60% of that of the pulse light in the case of θw = 0.5 degrees, compared to the case of uniform irradiation at θw = 1 degree. Many can do. If θw = 0.05 degrees, nearly 100% of pulsed light can be emitted. Therefore, the size of θw is determined based on the vertical angle resolution corresponding to one pixel of the light receiving system, although it varies depending on the characteristics of the one-dimensional scanning device 131 and the irradiation mode to the target surface.

(Light receiving system 150)
The light receiving system 150 of the light radar device 100 will be described below.

The image forming optical system 151 constituting the light receiving system 150 is generally a lens. The focal length and the F number can be selected according to the size of the light receiving unit 154 and the viewing angle (FOV). Preferably, the transmittance is high and the aberration is small at the central wavelength of the optical band pass filter 152 described later. In the light radar device 100 shown in FIG. 1, an example in which a lens is used as the imaging optical system 151 is shown, but a reflective optical system other than a lens may be used. It is preferable to reduce the out-of-band background light by arranging the optical band pass filter 152 in the light path from the front surface of the imaging optical system 151 to the light receiving unit 154.

The optical band pass filter 152 has a transmission band in a fixed width band centered on the wavelength peak of pulsed light. The width of the transmission band (half width of wavelength distribution of transmittance) is several nm to several tens nm. The width of the transmission band is preferably about 10 nm to 20 nm. In general, when operating outdoors, the operating temperature range widens and the peak wavelength of the pulsed light changes with the temperature, so the pulsed light distribution needs to be within the transmission band at least in the operating temperature range. In the case of a VCSEL, the temperature shift of the peak wavelength is about 0.07 nm / degree, the half width of the emission peak is about 1 nm, and the temperature shift of the central wavelength of the transmission band of the optical bandpass filter is 0.025 nm / degree. The relative wavelength shift of the peak wavelength and the central wavelength of the transmission band is about 5.6 nm even if the temperature band from -40 ° C is taken into consideration, and it is possible to use an optical band pass filter of the transmission band of about 10 nm. . The optical band pass filter 152 may be incorporated in the imaging optical system 151.

When the optical radar device 100 is not tilted with respect to the horizontal plane, the optical axis of the imaging optical system 151 is in the Y-axis direction, and the light receiving unit 154 of the ToF sensor 153 is parallel to the XZ plane.

It is preferable that the measurable area 11 determined by the imaging optical system 151 and the light receiving unit 154 of the ToF sensor 153 be equal to or smaller than the pulsed light irradiation area 10.

(ToF sensor 153)
The ToF sensor 153 constituting the light receiving system 150 will be described below with reference to FIG. FIG. 4 is a schematic view of a ToF sensor constituting the light radar device shown in FIG. Here, the ToF sensor 153 receives the light from the linear portion of the pulsed light irradiation area 10 illuminated by the fan-shaped pulsed light, and measures the time of flight between the linear portion and the optical radar device 100. It is a sensor that finds the distance.

For example, as shown in FIG. 4, the ToF sensor 153 includes a light receiving unit 154 in which pixels Px (i, j) are arranged in a two-dimensional matrix, and each column forming the row of the pixels Px (i, j). The data stored in the pixel storage element Mx (j) to which the electric pulse is supplied from the pixel Px (i, j) and the pixel storage element Mx (j) are read, and the target is set for each pixel Px (i, j). And a signal processing circuit DS for acquiring at least distance information indicating a distance to an object. The pixel storage element Mx (j) has a plurality of binary counters that integrate the numbers of the electric pulses at different timings from each other, and the signal processing circuit DS is stored in the pixel storage element Mx (j). Data reading can be performed in parallel with the integration by the binary counter.

The ToF sensor 153 has a function of receiving the output of the horizontal sensor 140, controlling the pulsed light illumination system 110 based on the output value, and selecting the pixel Px (k, j) to receive light, It is not always necessary to configure one chip. It may be a combination of the three-dimensional image element and a device that performs another control function.

Specifically, as shown in FIG. 4, in the light receiving unit 154 of the ToF sensor 153, the pixels Px (i, j) are arranged in a two-dimensional matrix of M rows and N columns, and The light signal is projected by the imaging optical system 151 onto this M-row N-column two-dimensional matrix. Here, the shape of the pixel Px (i, j) is a square. In this case, when the angular resolution of the light receiving system 150 is Δθ, the FOV of the measurable region is N · Δθ in the horizontal direction and M · Δθ in the vertical direction.

The pixels Px (i, j) are not all activated at one time. Since the pulse light irradiated toward the pulse light irradiation area 10 is the fan-shaped pulse light 124, only the pixels in the k-th row corresponding to the fan-shaped pulse light 124-k are activated. That is, when the fan-shaped pulsed light 124-k is irradiated, Px (k, j) is activated. Here, that Px (k, j) is activated means that at least an output signal of Px (k, j) is transmitted to the signal storage processing unit 155, and further, other Px (i, j) ) May be stopped, and power may be supplied to only Px (k, j). Here, for convenience of explanation, the sector pulse light 124 is numbered from 1 to M from the bottom to the top, and i of the corresponding Px (i, j) is from the top to the bottom, 1 Assign numbers from to. Since the order of the two is reversed via the imaging optical system 151, they are associated in this way. Note that this correspondence can be changed depending on the nature of the imaging optical system 151.

The pixel Px (i, j) includes a light receiving element that performs photoelectric conversion, a circuit that transmits the output of the light receiving element to the signal storage processing unit 155, and the like. As a light receiving element, a photodiode such as an avalanche photodiode is used.

A row selection circuit 161 is provided in the light receiving unit 154 as a circuit for selecting the pixels Px (k, j) of the k rows corresponding to the fan-shaped pulse light 124-k. In addition, a row selection line R (i) for transmitting the signal of the row selection circuit 161 to each pixel Px (i, j) is provided. The row selection line R (i) is not limited to a single signal line, and may be a plurality of signal lines having different polarities and voltages.

The row selection circuit 161 selects k rows to be activated in synchronization with the operation of the one-dimensional scanning device 131 of the fan-shaped light irradiation system 123. A signal for synchronization is issued from the control unit 160. For example, the row selection circuit 161 may control Px (i, j) such that only the output of each Px (k, j) (j = 1 to N) is connected to the signal line Lx (j). Alternatively, a switch (not shown) may be controlled to supply power (pluralities) only to each Px (k, j) (j = 1 to N). You may do both.

The signal storage processing unit 155 includes at least one pixel storage element Mx (j) corresponding to each column j, and the pixel storage element Mx (j) includes each pixel Px (i, j) and the signal line Lx (j). It is tied by. By receiving light, the electric signal emitted from the pixel Px (k, j) is received via the signal line Lx (j) by the pixel memory element Mx (j), and the signal amount is stored in time series. That is, an electric pulse is supplied to the pixel memory element Mx (j) from each pixel forming the column of pixels, and data is accumulated.

The signal storage processing unit 155 further includes a buffer memory Bx (j), a column signal line C (j), and a signal processing circuit DS. Here, the data stored in the pixel storage element Mx (j) is read at a predetermined timing and copied to the buffer memory Bx (j) via the column signal line C (j).

The signal processing circuit DS calculates and outputs at least the distance information D (k, j) and the two-dimensional image information G1 (k, j) and G2 (k, j) based on the information in the buffer memory Bx (j). G1 (i, j) is two-dimensional image information by background light, and G2 (i, j) can be two-dimensional image information by reflected light of pulse light, but is not limited thereto.

The signal storage processing unit 155 may have a memory selection circuit 163 for selecting a part of the pixel storage element Mx (j) and a memory selection line Rm (α). When the pixel storage element Mx (j) outputs a signal to the column signal line C (j), when all outputs are output in parallel, a large amount of wiring is required. Therefore, the time for forming the pixel storage element Mx (j) By reading out the amount of each signal, the number of wires can be reduced.

The control unit 160 determines the measurement order in the target area 12 (FIG. 3), performs angle setting of the one-dimensional scanning device 131 (FIG. 2) according to this order, and determines the row k to activate the light receiving unit 154. The row selection circuit 161 is driven to activate the pixels Px (k, j) (j = 1 to N), and the light source 122 (FIG. 1) is instructed to emit light, and simultaneously the pixels Px (k, j) are measured To store the image storage element Mx (j) signal amount. When repetitive light emission of the light source 122 is finished, the data stored in the pixel memory element Mx (j) is copied to the buffer memory Bx (j), and the distance information D (k, j) and 2 are sequentially transmitted to the signal processing circuit DS. Performs a series of controls such as calculating the dimensional image information G1 (k, j) and G2 (k, j) and storing them in the memory in the ToF sensor 153 or outputting them to the external system 170 (FIG. 1) .

As described above, the control unit 160 synchronously drives the pulsed light illumination system 110 and the ToF sensor 153 to acquire a 3D image of the target area 12. Further, as described below, it has a function of specifying fan-shaped pulse light 124-k corresponding to the target area 12 and the pixel Px (k, j) whose line is to be measured, based on the output value θiy of the horizontal sensor 140. .

When the light radar device 100 is inclined as shown in FIG. 3, the actual horizontal plane is shifted by −θiy with respect to the center of the pulsed light irradiation area 10 of the light radar device 100. Since the target area 12 which is the area to be actually measured is in the range of the angle θov centered on the horizontal plane, the one-dimensional scanning device 131 of the pulsed light illumination system 110 shifts the light irradiation area by -θiy from the center by And the ToF sensor 153 synchronously with this, in the row direction of the light receiving unit 154, (θov / Δθ / 2) up and down centering on the row shifted from (-θiy / Δθ) from the center Measure the range of lines. Therefore, it is preferable that the number M of rows of the pixels Px (i, j) constituting the light receiving unit 154 be θv / Δθ or more. In this case, since the entire pulsed light irradiation area 10 can be measured, the entire target area 12 can always be measured even if the light radar device 100 is inclined as long as | θiy | ≦ θmy.

In addition, it is preferable that the control part 160 can stop the function which monitors the predetermined | prescribed object area | region 12 always by the instruction | indication from the external system 170 irrespective of the inclination of a main body. When the function is stopped, the measurable area 11 which changes in accordance with the orientation of the main body is monitored. When monitoring on the basis of a horizontal surface on a mountain road or the like with a large inclination, there are cases where only the road surface can be seen when climbing, only sky when going down, and forward monitoring can not be performed correctly. In addition, in an apparatus such as an aircraft or a drone, it may be better to be able to monitor a certain field of view with reference to the main body. In this way, the availability of the optical radar device can be increased by switching the function according to the application and the situation.

The signal storage processing unit 155 of the ToF sensor 153 can have various configurations. There are various methods, such as a circuit that handles analog signals and a circuit that handles digital signals, as to signals that pixels emit. Further, with regard to measurement methods of flight time, there are various methods such as direct method, indirect method, phase shift method, TCSPC, etc. In the present invention, any method can be adopted. Also, the ToF elements may be arranged in a line corresponding to one row instead of the above-described two-dimensional array of light receiving units, and mechanically scanned in synchronization with the one-dimensional scanning device 131.

(Horizontal sensor 140)
The horizontal sensor 140 of the optical radar device 100 will be described below.

The optical radar device 100 of the present embodiment is assumed to be used on land or in the sea, and the pulsed light irradiation region 10 extends in the vertical direction. Further, in the case where the optical axis of the light receiving system 150 is in the horizontal plane, the case of correcting the inclination of the optical axis with respect to the horizontal plane will be described.

The horizontal sensor 140 measures the inclination angle θiy of the optical axis with respect to the horizontal plane, and outputs the result to the ToF sensor 153. For example, a three-dimensional accelerometer provided on a plane parallel to the XZ plane referred to in the coordinate axes shown in FIG. 1 is attached, gravity acceleration is measured, and the result is (Gx, Gy, Gz) (coordinates fixed to horizontal sensor 140) Θiy can be obtained from θiy = Arctan (Gy / Gz) in the case of a three-dimensional vector expression (Gz <0) viewed in the system. Alternatively, an inclinometer may be provided on a plane parallel to the XY plane, and the inclination angle in the Y-axis direction may be θiy. The horizontal sensor 140 need not necessarily output θiy, and may output sin (θiy), cos (θiy), or both.

The horizontal sensor 140 is preferably installed near the ToF sensor 153. This is because distortion of the positional relationship between the ToF sensor 153 and the horizontal sensor 140 becomes larger as the main body vibrates or the like as the distance from the ToF sensor 153 increases. Further, it is preferable that the horizontal sensor 140 be mounted on the same substrate as the ToF sensor 153. When mounted on a different substrate, there is also a possibility that the positional relationship between the two is distorted due to vibration or the like, and the measured value of θiy may deviate from the inclination angle of the actual optical axis with respect to the horizontal plane.

(Description of the effect)
According to the optical radar device 100 having the above configuration, θiy is measured in each frame, and the one-dimensional scanning device 131 of the pulsed light illumination system 110 measures −θiy from the center of the light irradiation area based on the measured value of θiy. The range of θov is scanned around a line shifted as much as possible. In synchronization with this, the ToF sensor 153 measures lines in the range of (θov / Δθ / 2) above and below the line shifted from (-θiy / Δθ) from the center in the line direction of the light receiving unit 154 By doing this, it is possible to always measure the target area 12 in the range of θov around the actual horizontal plane.

Then, as long as the inclination angle of the light radar device 100 is in the range of ± θ my, the target area 12 can be kept constant no matter how the light radar device 100 is inclined.

Therefore, the external system 170 can always acquire a three-dimensional image in a fixed direction regardless of the amount of tilt of the light radar device 100, so that the object can be recognized easily and accurately. For example, the inclination of the road and the passage in front of the main body can be correctly recognized without complicated correction on the main body side, and the height of the obstacle can also be measured accurately.

With respect to the present embodiment, the same function can be realized by inclining the light radar device 100 itself by -θiy with respect to the main body according to θiy measured by the horizontal sensor. However, in this method, the entire optical radar device 100 must be mechanically moved with high speed and high accuracy for each frame, resulting in a device that is large and vulnerable to vibration. In addition, it has to be a very expensive device.

In this embodiment, even if there are some cost increase factors such as cost increase due to the field of view expansion of the light receiving system 150 and cost increase due to the scan range increase of the one-dimensional scanning device 131, it can be realized relatively easily.

Also, if such a cost increase is not desired, θov = θv, and in the case of | θiy | ≠ 0, it is necessary to measure and output only the actually measurable region of the target region 12 You can also. In this case, although the number of data of the number of rows corresponding to | θiy | / Δθ in the target area 12 is missing, it is possible to obtain measurement results that do not depend on the tilt of the optical radar device 100. If | θiy | ≦ θv / 2, at least half of the data of the measurable area 11 can be obtained. Therefore, since an object in the vicinity of the horizontal plane can be captured without fail, it sufficiently functions as an optical radar device.

Second Embodiment
It will be as follows if other embodiment of this invention is described.

The present embodiment is an application example of the present invention to an application in which the rotation around the optical axis is a problem, and measures for rotational fluctuation around the Y axis of the optical radar device 100 which were not dealt with in the first embodiment are included. There is.

The components of the optical radar device 100a according to this embodiment are the same as those of the optical radar device 100 of the first embodiment shown in FIGS. 1 and 4, but the characteristics of the respective components are different as described below. The elements of the present embodiment are distinguished from those of Embodiment 1 by appending a to the end of the element number. Only differences from the first embodiment will be described below.

The horizontal sensor 140 measures not only the forward inclination θiy of the optical radar device 100 a of FIG. 1 but also the left and right inclination amount θix. θ ix corresponds to the amount of rotation about the Y axis. For example, a three-dimensional accelerometer provided in a plane parallel to the XZ plane in FIG. 1 is attached, the gravitational acceleration in this coordinate system is measured, and the result is fixed to (Gx, Gy, Gz) (horizontal sensor 140 If it is a three-dimensional vector expression (Gz <0) viewed in the coordinate system, θiy can be obtained from θiy = Arctan (Gy / Gz), and θix can be obtained from θix = Arctan (Gx / Gz) It can. Alternatively, an inclinometer may be provided on a plane parallel to the XY plane in FIG. 1, and the inclination angle in the Y-axis direction may be θiy, and the inclination angle in the X-axis direction may be θix.

FIG. 5 is a schematic view showing the relationship between the target area, the measurable area, and the pulsed light irradiation area in the light radar device 100a.

The fan-shaped light irradiation system 123a of the pulse light illumination system 110a emits the fan-shaped pulse light 124a, and as shown in FIG. 5, the pulse light irradiation area 10a is wider than the target area 12 including θh. Therefore, in the case where the target area 12 is the same, it is preferable that the horizontal spread angle of the fan beam generator 132a be large. It is preferable that not only the number of rows but also the number of columns of the light receiving unit 154a be increased. Therefore, it is preferable that the number of columns also increases in the signal storage processing unit 155a. It also has a memory that can store distance information D (i, j) and two-dimensional image information G1 (i, j) and G2 (i, j), which are measurement results of pixels corresponding to measurement area 13a in FIG. ing.

The control unit 160a determines the measurement area 13a based on θiy and θix measured in each frame. The measurement area 13a is a part of the measurable area 11a of the optical radar device 100a that covers the entire target area 12 to be measured, and is a part of the corresponding light receiving unit 154a. The target area 12 extends in a direction parallel to the X axis and the Y axis centering on the origin, but the measurement area 13a is inclined θiy with respect to the Y axis according to the inclination of the optical radar device 100a Is also inclined by θix.

The control unit 160a irradiates a portion corresponding to the measurement area 13a with pulsed light, acquires a 3D image, and stores the 3D image in a memory in the signal storage processing unit 155a. When the measurement of the measurement area 13 a is completed, the control unit 160 a reads the measurement result corresponding to the target area 12 from the memory and outputs the result to the external system 170. In this way, data of a constant target area can be obtained for an actual target regardless of the values of θiy and θix.

The measurement area 13a has a width θsh in the horizontal direction and a width θsv in the vertical direction with the direction facing upward by -θiy from the center of the measurable area 11a in order to completely cover the target area 12 . θsh and θsv are given by the following equations (1) and (2).
θsh = θoh · cos (θix) + θov · sin (θix) (1)
θsv = θoh · sin (θix) + θov · cos (θix) (2)
Therefore, assuming that the allowable maximum value of θiy is ± θmy and the allowable maximum value of θix is ± θmx, it is preferable that θh and θv satisfy the following expressions (3) and (4). Under this condition, if the maximum allowable range of θiy and θix is satisfied, the entire area of the target area 12 can be monitored.
θhhθoh · cos (θmx) + θov · sin (θmx) (3)
θ v 2 2 · θ my + θ oh · sin (θ mx) + θ ov · cos (θ mx) · · · (4)
It is necessary to extract the measurement data corresponding to the target area 12 from the measurement result of the measurement area 13a stored in the memory and deliver it to the external system 170. For example, as data of the direction (ηx, zz) in the target area 12, data of the following pixel in the measurement area 13a may be adopted. As shown in FIG. 5, the reference of the row number (formula (5)) and the column number (formula (6)) of the measurement area 13a has the upper left as the origin.

{Θsh / 2 + ηx · cos (θix) −ηz · sin (θix)} / Δθ ···· (5)
{Θsv / 2−ηz · cos (θix) −ηx · sin (θix)} / Δθ ···· (6)
In the simplest case, the equations (5) and (6) are rounded to the nearest integer and assigned data of the corresponding row number and column number. When more accuracy is required, interpolation or extrapolation may be performed from a plurality of data having row numbers and column numbers before and after the numerical values calculated by Equations (5) and (6) ((x, η z It is also possible to obtain the data of).

(Description of the effect)
According to the above configuration, in each frame, θiy and θix are measured, and the one-dimensional scanning device 131a of the pulsed light illumination system 110a deviates by -θiy from the center of the light irradiation area from the measured values of θiy. Scan the range of θsv around the line. In synchronization with this, with respect to the row in the range of (θsv / Δθ / 2) in the row direction of the light receiving unit 154a, centering on the row shifted from (-θiy / Δθ) from the center, By measuring the range of ± (θsh / Δθ / 2) in the column direction, the target region 12 in the range of θov in the horizontal direction and always in the range of θoh in the horizontal direction is always measured. I can do things.

The allowable range of the tilt angle of the optical radar device 100a is that when the Y axis is in the range of ± θ my and the X axis is ± θ mx, θ h and θ v representing the measurable area 11 a are expressed by the equations (3) and (4) The target area 12 can be kept constant no matter how the light radar device 100 a tilts.

Therefore, the external system 170 can always acquire a three-dimensional image in a fixed direction regardless of the amount of tilt of the light radar device 100a, so that an object can be recognized easily and accurately. For example, the inclination of the road and the passage in front of the main body can be correctly recognized without complicated correction on the main body side, and the height of the obstacle can also be measured accurately.

With respect to the present embodiment, the light radar device 100a itself can be inclined with respect to the main body according to θiy and θix measured by the horizontal sensor 140 to realize the same function. However, in this method, the entire optical radar device 100 has to be mechanically moved with high speed and high accuracy for each frame with high accuracy, becoming a large and fragile device and extremely expensive. Do not get.

In this embodiment, even if there are some cost increase factors such as cost increase due to the field of view expansion of the light receiving system 150a and cost increase due to the scan range increase of the one-dimensional scanning device 131a, it can be realized relatively easily.

In addition, if such a cost increase is not desired, it can be actually measured in the target region 12 in the case of | θiy | ≠ 0, | θix | ≠ 0 as θov = θv and θoh = θh. It is also possible to measure and output only the In this case, although the target area 12 is reduced, it is possible to obtain measurement results that do not depend on the tilt of the optical radar device. If | θiy | ≦ θv / 2, at least half of the data of the measurable area 11 can be obtained. Therefore, since an object in the vicinity of the horizontal plane can be captured without fail, it sufficiently functions as an optical radar device.

[Example 3]
Further embodiments of the present invention will be described below.

The present embodiment differs from the first and second embodiments in that pulsed light is irradiated to the measurement region by a two-dimensional scanning device. The configuration of the optical radar device 100b according to the present embodiment will be described using FIGS. 6 and 7. Description of the same points as the first and second embodiments will be omitted.

FIG. 6 is a schematic view showing the configuration of an optical radar device 100b according to Embodiment 3 of the present invention.

The optical radar device 100b, as shown in FIG. 6, includes a pulsed light illumination system 110b for irradiating a pulsed light irradiation area 10b with spot pulsed light 124b (hereinafter sometimes referred to simply as pulsed light), and a pulsed light irradiation area It consists of a light receiving system 150b that receives light from at least a part of 10b, and a horizontal sensor 140.

The pulsed light illumination system 110b has a two-dimensional scanning device 123b for irradiating the entire pulsed light irradiation area 10b by two-dimensionally scanning spot pulsed light, and a light source 122 for emitting pulsed light and a collimated light generator 130 are provided. Including.

The light receiving system 150b includes a ToF sensor 153b, an imaging optical system 151b that forms an image on the light receiving unit 154b of the ToF sensor 153b, an optical band pass filter 152, and a control unit 160b. The control unit 160 b also includes functions such as signal reception from the horizontal sensor 140, control of the pulsed light illumination system 110 b, control of the ToF sensor 153 b, and communication with the external system 170.

The horizontal sensor 140 constantly monitors the inclination angle of the light radar device 100b with respect to the horizontal plane, and outputs it to the ToF sensor 153b.

(Pulsed light illumination system 110b)
The pulsed light illumination system 110b of the light radar device 100b will be described below.

The pulsed light illumination system 110b, as shown in FIG. 6, collimates the light from the light source 122 into a spot light 133 almost in parallel, and shakes the spot light 133 in the X axis direction and the Z axis direction. And a dimensional scan device 123b.

The two-dimensional scanning device 123b includes a scanning mirror 131b. The scanning mirror 131b performs rotational movement around the Z axis to control the swing of the spot pulse light 124b in the X axis direction, and rotates around one axis in the XY plane (incline 45 degrees to the X axis) By moving, control the shake in the Z-axis direction.

The two-dimensional scanning device 123 b includes, for example, a MEMS mirror element and its control device. Control of the two-dimensional scanning device 123b is included in the control unit 160b. The two-dimensional scanning device 123b may have another configuration such as a polygon mirror or a liquid crystal waveguide method, in addition to the MEMS mirror element.

The spot light 133 is reflected by the scanning mirror 131 b and is irradiated to the pulsed light irradiation area 10 b as a spot pulse light 124 b. Therefore, the spot light 133 and the spot pulse light 124 b have substantially the same dispersion angle. The dispersion angle may be different in the X-axis direction and the Y-axis direction, but in the following, the case of a circular beam in which both are substantially equal will be described. The dispersion angle θb restricts the angular resolution of the optical radar device 100b. θb is about 0.05 degree to about 1 degree.

(Light receiving system 150b)
The light receiving system 150b of the light radar device 100b will be described below.

The reflected light 125b from the object passes through the reflection by the scanning mirror 131b and the mirror 156, and is condensed by the imaging optical system 151b to the light receiving portion 154b of the ToF sensor 153b via the optical band pass filter 152. The mirror 156 is located in the optical path of the spot light 133 but has an opening 157 at the center, and the spot light 133 passes through the opening 157.

(ToF sensor 153b and control unit 160b)
The ToF sensor 153b and the control unit 160b of the light radar device 100b will be described below. FIG. 7 is a schematic view showing the relationship between the target area, the measurable area, and the pulsed light irradiation area in the optical radar device 100b.

The ToF sensor 153b is a sensor for capturing the reflected light from the circular portion illuminated by the spot pulse light 124b by the light receiving unit 154b and determining the distance between the circular portion and the optical radar device 100b by time of flight measurement.

The control unit 160b determines the measurement order in the target area 12, sets the angle of the two-dimensional scanning device 123b in accordance with this order, instructs the light source 122 to emit light, and simultaneously activates the ToF sensor 153b. Measure flight time.

The control unit 160b determines the setting angle based on the outputs θiy and θix of the horizontal sensor 140 when setting the angle of the two-dimensional scanning device 123b, and always determines the target area regardless of the inclination of the optical radar device 100b. It can be measured. For example, as shown in FIG. 7, when the spot pulse light 124b is irradiated in the direction (.eta.x, .eta.z) in the target area 12, the spot pulse light 124b is set to (.PHI.x, .PHI.z for the two-dimensional scanning device 123b. It instructs to set the scanning mirror 131b so as to irradiate in the) direction. Here, Φx is expressed by the following expression (7), and Φz is expressed by the following expression (8).
Xx = θiy · sin (θix) + ηx · cos (θix) −ηz · sin (θix) (7)
Zz = −θiy · cos (θix) + ixz · cos (θix) + ηx · sin (θix) (8)
When the X axis of the optical radar device 100b is not inclined, as shown in FIG. 6, scanning in the X axis direction is performed by rotation around the Z axis, and then the angle in the Z axis direction is changed, As in the case of scanning in the X-axis direction, two axes are not moved at the same time, but if the X-axis of the light radar device 100b is inclined, it is necessary to change the two axes simultaneously.
(Description of the effect)
According to the above configuration, in each frame, θiy and θix are measured, and based on the measured values of θiy and θix, the two-dimensional scanning device 123b of the pulsed light illumination system 110b obtains the equations (7) and (8) By irradiating the spot pulse light 124b in the (Φx, zz) direction, the light can be emitted in the direction (ηx, zz) in the target area 12, and the target is always targeted regardless of the inclination of the optical radar device 100b. Only the area 12 can be measured.

Therefore, the external system 170 can always acquire a three-dimensional image in a fixed direction regardless of the amount of tilt of the light radar device 100b, so that the object can be recognized easily and accurately. For example, the inclination of the road and the passage in front of the main body can be correctly recognized without complicated correction on the main body side, and the height of the obstacle can also be measured accurately.

In this method, in order to cover the entire target area 12, it is not necessary to measure to the extra area, and the pulse light irradiation and the ToF sensor do not perform the extra measurement, and the measurement results are temporarily stored. There is no need to select only the area, and power consumption can be reduced.

Example 4
Further embodiments of the present invention will be described below.

The present embodiment differs from the first and second embodiments in that pulsed light is irradiated to the measurement region at one time by the diffusion irradiation device. The configuration of the optical radar device 100c according to the present embodiment will be described with reference to FIGS. 8 and 9. Description of the same points as the first and second embodiments will be omitted.

FIG. 8 is a schematic view showing the configuration of an optical radar device 100c according to Embodiment 4 of the present invention.

The optical radar device 100c, as shown in FIG. 8, includes a pulsed light illumination system 110c for collectively emitting pulsed light 124c (hereinafter sometimes referred to simply as pulsed light) in a pulsed light irradiation area 10c; It includes a light receiving system 150c that receives light from at least a portion of 10c, and a horizontal sensor 140.

The light receiving system 150c includes a ToF sensor 153c, an imaging optical system 151 forming an image on the light receiving unit 154c of the ToF sensor 153c, an optical band pass filter 152, synchronous control of the pulsed light illumination system 110c and the ToF sensor 153c, It comprises a control unit 160 c and the like that bears functions such as output feedback and communication with the external system 170.

The horizontal sensor 140 constantly monitors the inclination angle of the light radar device 100c with respect to the horizontal plane, and outputs it to the control unit 160c.

(Pulsed light illumination system 110c)
The pulsed light illumination system 110c of the light radar device 100c will be described below.

As shown in FIG. 8, the pulsed light illumination system 110c includes a light source 122 that emits pulsed light, and a diffusion optical system 123c that spreads the pulsed light in two dimensions and irradiates it.

The diffusion optical system 123c is an optical device that disperses light in a predetermined range and irradiates the light, and is configured of a diffusion plate, a diffraction grating, a cylindrical lens, and the like. The pulsed light 124c can be irradiated collectively to the pulsed light irradiation area 10c having the horizontal irradiation angle θh and the vertical irradiation angle θv.
(Light receiving system 150c)
The light receiving system 150c of the light radar device 100c will be described below.

The light receiving system 150c is the same as the second embodiment except for the ToF sensor 153c. It is preferable that the measurable area 11c determined by the imaging optical system 151 and the light receiving unit 154c be equal to or smaller than the pulsed light irradiation area 10c. Here, the case where both are equal is described. Also, the measurable area 11c is larger than the target area 12 which actually outputs the measurement result, and for the horizontal spread angle θoh of the target area 12 and the vertical spread angle θov, θh> θoh and θv> θov. Is preferred.

(ToF sensor 153c and control unit 160c)
The ToF sensor 153c and the control unit 160c of the optical radar device 100c will be described below. FIG. 9 is a schematic view showing the relationship between the target area, the measurable area, and the pulsed light irradiation area in the optical radar device 100c.

Similar to the ToF sensors 153 and 153a shown in FIG. 4, the light receiving unit 154c of the ToF sensor 153c includes a group of pixels arranged in a two-dimensional array, and can cover the measurable area 11c. The ToF sensors 153 and 153a perform time-of-flight measurement row by row, while performing time-of-flight measurement of all pixels of the ToF sensor 153c in parallel. Such ToF sensors are known and will not be described in detail.

The control unit 160c emits a signal to the pulsed light illumination system 110c to emit the pulsed light 124c, and starts measurement of time of flight of the ToF sensor 153c. The measurement results of all the pixels are temporarily stored in the memory (not shown) of the ToF sensor 153c. That is, as shown in FIG. 9, all data in the measurable area 11c is stored in the memory. Based on the output of the horizontal sensor 140, the control unit 160 c selects only the part corresponding to the target area 12 from among these and outputs the selected part to the external system 170. The measurement results corresponding to the direction (ηx, zz) in the target area 12 are the directions (Φx, zz) of the measurable area 11c represented by the equations (7) and (8) described in the third embodiment. It is data.

(Description of the effect)
According to the above configuration, in each frame, time-of-flight measurement of the entire measurable area 11c is performed, and θiy and θix are measured, and from the measured values of θiy and θix, equations (7) and (8) By referring to the data in the (Φx, zz) direction satisfying the above condition, it is possible to obtain measurement data corresponding to the direction (ηx, ηz) in the target area 12. The target area 12 can always be measured regardless of the inclination of the light radar device 100c.

Therefore, the external system 170 can always acquire a three-dimensional image in a fixed direction regardless of the amount of tilt of the light radar device 100c, so that the object can be recognized easily and accurately. For example, the inclination of the road and the passage in front of the main body can be correctly recognized without complicated correction on the main body side, and the height of the obstacle can also be measured accurately.

In this method, the pulsed light illumination system 110c does not include any movable part, and after performing measurement independently of inclination, only the target area can be selected from the stored measurement results, so the system is very simple. And cost can be reduced.

It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by claims, and is intended to include all modifications within the meaning and scope equivalent to claims.

[Summary]
An optical radar device according to aspect 1 of the present invention is an optical radar device (100, 100a, 100b, 100c) that measures the distance to an object present in a predetermined target region 12 by a time-of-flight method. A pulsed light illumination system (110, 110a) for irradiating at least a part of the target area 12 with a light source 122 for emitting pulsed light, the pulsed light 124 emitted from the light source 122, and the pulsed light illumination A light receiving system (150, 150a) for detecting the reflected light from the object of the pulsed light 124 irradiated in the system (110, 110a) and measuring the distance to the object; , 150a), and the light receiving system (150, 150a) detects the tilt angle detected by the horizontal sensor 140. It is characterized in that the inclination of the optical axis of the light receiving system (150, 150a) with respect to the horizontal plane is corrected by the oblique angle θiy.

According to the above configuration, the light receiving system corrects the tilt of the light axis of the light receiving system with respect to the horizontal plane by the tilt angle detected by the horizontal sensor, so that the actual horizontal plane The distance to the object can be measured taking into account. For this reason, the target area in which the target exists is kept constant even if the light radar device itself is inclined. That is, the positional relationship of the light laser device with respect to the vertical line is constant.

Moreover, the distance to the object can be accurately measured by a simple method of correcting the inclination of the optical axis of the light receiving system with respect to the horizontal plane.

Therefore, regardless of the amount of tilt of the light radar device, the distance to the object can always be measured in a fixed direction by a simple method. As a result, the external device can always acquire a three-dimensional image in a fixed direction regardless of the amount of tilt of the light radar device, so that the object can be recognized easily and accurately.

The light radar device according to aspect 2 of the present invention may correct the light irradiation range of the pulsed light illumination system (110, 110a) by the inclination angle detected by the horizontal sensor 140.

According to the above configuration, since the light irradiation area can be concentrated to the necessary area, the power consumption can be reduced by enhancing the signal intensity to improve the measurement accuracy or reduce unnecessary light irradiation. I can do things.

In the optical radar device according to aspect 3 of the present invention, in aspect 1 or 2, the horizontal sensor 140 detects an inclination angle θiy when the optical axis (Y axis) is inclined forward with respect to the horizontal surface. May be

According to the above configuration, the horizontal sensor detects the tilt angle when the optical axis tilts forward with respect to the horizontal surface, and the light receiving system detects the tilt angle of the light receiving system by the tilt angle detected by the horizontal sensor. The forward tilt of the optical axis with respect to the horizontal plane can be corrected. That is, the target area in which the object is present is kept constant even if the light radar device itself is inclined forward with respect to the horizontal plane.

The optical radar device according to aspect 4 of the present invention is the optical radar device according to any one of the aspects 1 to 3, wherein the horizontal sensor 140 is inclined when the optical axis (Y axis) is inclined in the lateral direction with respect to the horizontal surface. The inclination angle θiy may be detected.

According to the above configuration, the horizontal sensor detects an inclination angle when the optical axis is inclined in the left-right direction with respect to the horizontal plane, and the light receiving system detects the inclination angle detected by the horizontal sensor. It is possible to correct the horizontal inclination of the optical axis of the lens with respect to the horizontal plane. That is, the target area in which the object is present is kept constant even if the light radar device itself is inclined in the lateral direction with respect to the horizontal plane.

In the optical radar device according to aspect 5 of the present invention, in any one of the aspects 1 to 4, the pulsed light irradiation area 10 of the pulsed light illumination system (110, 110a) includes at least the entire target area 12 It may be a size.

According to the above configuration, since the pulsed light irradiation area of the pulsed light illumination system has a size including at least the entire target area, the entire target area can always be measured even if the optical laser device is inclined.

In the optical radar device according to aspect 6 of the present invention, in any one of the aspects 1 to 5, the measurement area θov of the light receiving system (150, 150a) has a size including at least the entire target area 12 May be

According to the above configuration, the measurement region of the light receiving system has a size including at least the entire target region, so that the entire target region can always be measured even if the optical laser device is inclined.

In the optical radar device according to aspect 7 of the present invention, in any one of the aspects 1 to 6, the pulsed light illumination system (110, 110a) is obtained by converting the pulsed light 124 emitted from the light source 122 A one-dimensional scanning device 131 may be provided to irradiate the target light 12 with the spot light.

In the light radar device according to aspect 8 of the present invention, in aspect 7, the one-dimensional scanning device 131 preferably irradiates the spot light in the vertical direction with respect to the target area 12.

According to the above configuration, the pulse light emitted from the light source can be irradiated to the target area for scanning with a simple configuration of a one-dimensional scanning device.

In the light radar device according to aspect 9 of the present invention, in any one of the aspects 1 to 8, the light receiving system (150, 150a) may include a two-dimensional pixel array.

In the optical radar device according to aspect 10 of the present invention, in any one of the aspects 1 to 6, the pulsed light illumination system (110c) irradiates the target area 12 with pulsed light 124 emitted from the light source 122. A two-dimensional scanning device may be provided.

According to the above configuration, the target area can be scanned at one time.

In the light radar device according to aspect 11 of the present invention, in any one of the aspects 1 to 10, the pulsed light 124 may be infrared light.

According to the above configuration, it is possible to realize an optical radar device that makes use of various characteristics of infrared light.

An optical radar device according to aspect 12 of the present invention is the optical radar device according to any one of the above aspects 1 to 9,
The three-dimensional image element includes a light receiving unit 154 in which the pixels Px (i, j) are arranged in a two-dimensional matrix, and a pixel memory to which electric pulses are supplied from each pixel forming the row of the pixels Px (i, j) A signal processing circuit DS which reads out data stored in the element Mx (j) and the pixel storage element Mx (j) and obtains at least distance information indicating a distance to an object for each of the pixels Px (i, j). And the pixel storage element Mx (j) includes a plurality of binary counters that integrate the numbers of the electric pulses at different timings from each other, and the signal processing circuit DS is characterized in that the light receiving section has a three-dimensional image element which executes reading of data stored in the pixel storage element Mx (j) in parallel with integration by the binary counter.

According to the above-mentioned composition, the same effect as the above-mentioned mode 1 is produced.

Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. The present invention can be obtained by appropriately combining the technical means disclosed in different embodiments. The embodiments are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

10, 10a, 10b, 10c Pulse light irradiation area 11, 11a, 11c Measurable area 12 Target area 13a Measurement area 100, 100a, 100b, 100c Optical radar device 110, 110a, 110b, 110c Pulsed light illumination system 122 Light source 123 Fan-shaped Light irradiation system 123a fan-shaped light irradiation system 123b two-dimensional scanning device 123c diffusion optical system 124 fan-shaped pulsed light 124a fan-shaped pulsed light 124b spot pulse light 124c pulsed light 125b reflected light 130 collimated light generator 131, 131a one-dimensional scanning unit 131b scanning Mirror 132, 132a Fan-shaped beam generator 133 Spot light 140 Horizontal sensor 150, 150a, 150b, 150c Light receiving system 151, 151b Imaging optical system 152 Optical band pass filter 153, 153a, 1 53b, 153c ToF sensor 154, 154a, 154b, 154c Light receiving unit 155, 155a Signal storage processing unit 156 Mirror 157 Openings 160, 160a, 160b, 160c Control unit 161 Row selection circuit 163 Memory selection circuit 170 External system

Claims (12)

1. An optical radar device which measures a distance to an object present in a predetermined target area by a time-of-flight method,
   A light source that emits pulsed light;
   A pulsed light illumination system for irradiating at least a part of the target area with pulsed light emitted from the light source;
   A light receiving system that detects reflected light from the object of the pulsed light emitted by the pulsed light illumination system and measures a distance to the object;
   A horizontal sensor for detecting an inclination angle of the optical axis of the light receiving system with respect to a horizontal plane;
   The above light receiving system is
   An optical radar apparatus characterized by correcting the inclination of the light axis of the light receiving system with respect to the horizontal plane by the inclination angle detected by the horizontal sensor.
2. The light radar device according to claim 1, wherein the light irradiation range of the pulsed light illumination system is corrected by an inclination angle detected by the horizontal sensor.
3. The optical radar device according to claim 1, wherein the horizontal sensor detects an inclination angle when the optical axis is inclined forward with respect to the horizontal surface.
4. The optical radar device according to any one of claims 1 to 3, wherein the horizontal sensor detects an inclination angle when the optical axis is inclined in the left-right direction with respect to the horizontal plane.
5. The optical radar device according to any one of claims 1 to 4, wherein the pulsed light irradiation area of the pulsed light illumination system has a size including at least the entire target area.
6. The optical radar device according to any one of claims 1 to 5, wherein the measurement area of the light receiving system has a size including at least the entire target area.
7. The above pulsed light illumination system
   7. The apparatus according to claim 1, further comprising a one-dimensional scanning device for irradiating the target area with linearly spread light obtained by converting pulsed light emitted from the light source. Optical radar device as described.
8. The optical radar device according to claim 7, wherein the one-dimensional scanning device irradiates the light which spreads linearly in the vertical direction with respect to the target area.
9. The light radar device according to any one of claims 1 to 8, wherein the light receiving system includes a two-dimensional pixel array.
10. The above pulsed light illumination system
    The optical radar device according to any one of claims 1 to 6, further comprising a two-dimensional scanning device for irradiating the target area with pulsed light emitted from the light source.
11. The optical radar device according to any one of claims 1 to 10, wherein the pulse light is an infrared ray.
12. A light receiving unit in which pixels are arranged in a two-dimensional matrix;
    A pixel storage element to which an electric pulse is supplied from each of the pixels constituting the row of pixels;
    A signal processing circuit for reading out data stored in the pixel storage element and acquiring at least distance information indicating a distance to an object for each of the pixels.
    The pixel storage element has a plurality of binary counters that integrate the number of electrical pulses at different timings from each other,
    The signal processing circuit according to any one of claims 1 to 9, wherein the light receiving unit includes a three-dimensional image element that executes reading of data stored in the pixel storage element in parallel with integration by the binary counter. The light radar device according to any one of the preceding claims.

Images