JP7534862B2 - Scanning device, scanning method, and scanning program - Google Patents

Description

The present invention relates to a scanning device and a scanning method for scanning light.

Distance measuring devices that use the TOF (Time Of Flight) method are known, and measure the distance to an object by irradiating the object with light and detecting the light reflected by the object.

Patent document 1 also discloses an imaging system that uses the TOF method to measure distances to multiple objects by optically scanning the irradiated light, and generates image data (hereinafter referred to as a distance measurement image) that shows a two-dimensional distance distribution.

JP 2018-124271 A

For example, a distance measuring device and an imaging device using the same are provided with a light projecting unit that projects laser light for distance measurement, and a light receiving unit that receives light reflected by an object. In addition, as a configuration of the light projecting unit and the light receiving unit, for example, the light projecting unit projects laser light of a predetermined elongated beam shape (hereinafter, sometimes simply referred to as line laser light) so as to scan the target area, and the light receiving unit receives the reflected light from the target with multiple light receiving elements. In this case, light can be projected and received simultaneously on multiple target areas (multiple objects or multiple surface areas of the objects, etc.).

However, in cases where multiple line laser beams are offset vertically to project and receive light onto multiple target areas in order to project and receive light onto a wider range of target areas, the generated distance measurement image may become distorted due to the time difference when scanning each of the multiple target areas.

The present invention has been made in consideration of the above points, and one of its objectives is to provide a scanning device, a scanning method, and a scanning program that can obtain clear distance measurement images with little distortion even when scanning multiple target areas with multiple line laser beams.

The invention described in claim 1 includes an irradiation unit that irradiates one or more linear irradiation lights extending in one direction, an irradiation control unit that controls the irradiation by the irradiation unit, and a scanning unit that scans the irradiation light in a scanning direction along a direction around a first axis and irradiates each of a plurality of regions that are offset in a direction perpendicular to the scanning direction, and the irradiation control unit controls the irradiation unit so that the irradiation light is irradiated to different regions between each of a plurality of scans, and the irradiation control unit controls the irradiation unit so that, in the scanning of the plurality of regions with the irradiation light, each of the plurality of regions is scanned once in sequence, thereby repeatedly scanning the entirety of the plurality of regions.

The invention described in claim 7 is a scanning method for a scanning device that scans multiple regions with one or more irradiation light beams, and includes a scanning step of irradiating one or more linear irradiation light beams extending in one direction, scanning the irradiation light beam in a scanning direction along a direction around a first axis, and irradiating each of multiple regions that are offset in a direction perpendicular to the scanning direction, and is characterized in that in the scanning step, the irradiation light beam irradiates different regions between each of the multiple scans, and in the scanning step, the one or more irradiation light beams are irradiated so that scanning of the entire multiple regions is repeated by sequentially scanning each of the multiple regions once in the scanning of the multiple regions with the irradiation light.

The invention described in claim 8 is a scanning program executed by a computer, which causes the computer to execute a scanning step of irradiating one or more linear irradiation lights extending in one direction, scanning the irradiation light in a scanning direction along a direction around a first axis, and irradiating each of a plurality of regions offset in a direction perpendicular to the scanning direction, and in the scanning step, the irradiation light irradiates different regions during each of a plurality of scans, and in the scanning step, the one or more irradiation lights are irradiated so that scanning of the entirety of the plurality of regions is repeated by sequentially scanning each of the plurality of regions once in the scanning of the plurality of regions with the irradiation light.

1 is a diagram showing an overall configuration of a scanning device according to an embodiment of the present invention; 3 is a diagram showing an irradiation area of a scanning area of the scanning device according to the present embodiment. FIG. 3 is a diagram showing an irradiation area of a scanning area of the scanning device according to the present embodiment. FIG. FIG. 2 shows an actual view seen by a scanning device while a car is moving. 1 is a comparative example of a range image generated by a conventional scanning method. 13 is an example image RI2 of a distance measurement image generated by the scanning method according to the present embodiment.

The following describes in detail preferred embodiments of the present invention. In the following descriptions of each embodiment and in the accompanying drawings, substantially the same or equivalent parts are designated by the same reference numerals.

Figure 1 is a diagram showing the overall configuration of a scanning device 10 according to this embodiment. The scanning device 10 is a scanning device that performs optical scanning of a first scanning area R1 and a second scanning area R2, which are predetermined areas (hereinafter referred to as scanning areas), and generates a distance measurement image of an object OB present in the first and second scanning areas. The scanning device 10 will be described using Figure 1. Note that Figure 1 shows a schematic diagram of the first scanning area R1, the second scanning area R2, and the object OB. Note that in this embodiment, a case will be described in which there are two light sources that emit two line laser beams.

First, the scanning device 10 has an irradiation unit 11 including a light source 11A that generates and emits a first emitted light (hereinafter, sometimes simply referred to as the emitted light), and a light source 11B that generates and emits a second emitted light (hereinafter, sometimes simply referred to as the emitted light) that is arranged offset in the vertical direction from the first pulsed light. In this embodiment, the light sources 11A and 11B generate laser light having a peak wavelength in the infrared region as the emitted light, and emit this intermittently in a pulsed form. In addition, the light sources 11A and 11B are arranged, for example, offset from the center of the optical axis so that the emitted light is continuous in the vertical direction. In addition, the light sources 11A and 11B are arranged, for example, offset by a predetermined distance from the center of the optical axis of the emitted light in the horizontal direction.

The scanning device 10 has an imaging optical system 12 that forms an image showing the cross-sectional shape of each of the emitted lights emitted from the irradiation unit 11. The imaging optical system 12 includes, for example, collimating lenses 12A and 12B. In this embodiment, the same shaped collimating lenses 12A and 12B are attached to the emission ports of the line laser lights of the light sources 11A and 11B. In addition, each of the emitted lights emitted from the light sources 11A and 11B and incident on the collimating lenses 12A and 12B is incident at an offset position that is the same as the vertical and horizontal offset amounts from the center of the optical axis.

The scanning device 10 has a projection optical system 15 that projects the emitted light. The projection optical system 15 includes, for example, at least one lens that collects and shapes the emitted light and emits it.

The scanning device 10 has a deflection element 16 as a scanning unit that deflects the emitted light in a variable direction and projects the light. The deflection element 16 operates periodically to periodically change the deflection direction of the emitted light. The deflection element 16 outputs the emitted light while bending the traveling direction of the emitted light, and also periodically changes the bending direction. The emitted light deflected by the deflection element 16 is projected as scanning light toward the first scanning region R1 and the second scanning region R2, respectively.

In this embodiment, the deflection element 16 has at least one oscillating mirror 16A that oscillates around an oscillation axis AY and reflects the emitted light. For example, the deflection element 16 includes a one-axis oscillating MEMS (Micro Electro Mechanical System) mirror or a galvanometer mirror. Note that in this embodiment, the deflection element 16 is described as being an MEMS mirror. The deflection element 16 periodically changes the projection direction of the scanning light by reflecting the emitted light while the oscillating mirror 16A oscillates.

The first and second scanning regions R1 and R2 are virtual three-dimensional spaces into which the scanning light that has passed through the deflection element 16 is projected. In FIG. 1, the outer edges of the first and second scanning regions R1 and R2 are shown diagrammatically by dashed lines.

In this embodiment, the light sources 11A and 11B emit laser light having a linear cross-sectional shape extending along the axial direction of the oscillation axis AY of the oscillating mirror 16A as the scanning light. Therefore, for example, the first and second scanning regions R1 and R2 can be defined as a cone-shaped space having a height direction range along the longitudinal direction of the cross section of the scanning light, a width direction range along the scanning direction SL which corresponds to the variable range of the deflection direction of the scanning light by the deflection element 16, and a distance direction range in which the scanning light can maintain a predetermined intensity, i.e., a depth range.

The position of the emitted light incident on the oscillating mirror 16A of the deflection element 16 is, for example, offset from the center point of the oscillating mirror 16A by the same amount as the vertical and horizontal offset of each emitted light from the center of the optical axis. Therefore, the vertical direction of the first scanning region R1 and the second scanning region R2 has a range that is continuous in the vertical direction corresponding to the positional relationship of the emitted light emitted from the light sources 11A and 11B. In addition, the horizontal direction of the first scanning region R1 and the second scanning region R2 causes a shift in the scanning region according to the offset amount from the center of the optical axis of each emitted light.

Also, as shown in FIG. 1, if an object OB (i.e., an object or material that is reflective or scattering to the line laser light, which is the scanning light) is present in the first and second scanning regions R1 and R2, the scanning light is reflected or scattered by the object OB. A portion of the scanning light reflected by the object OB travels as reflected light along substantially the same optical path as the scanning light in the opposite direction to the scanning light, and returns to the deflection element 16.

The scanning device 10 has a deflection element SP that is provided on the optical path of the reflected light, in this embodiment, on the optical path common to the emitted light and reflected light between the deflection element 16 and the projection optical system 15, and deflects the reflected light. For example, the deflection element SP is a light separation element that separates the emitted light and the reflected light by transmitting the emitted light and reflecting the reflected light, and in this embodiment, is a beam splitter.

In this embodiment, the deflection element 16 is a movable deflection element for scanning that deflects the emitted light in a variable direction when operated. On the other hand, the deflection element SP is a fixed type deflection element.

The scanning device 10 has a light receiving optical system 17 that receives the reflected light deflected by the deflection element SP. The light receiving optical system 17 collects and shapes the reflected light. The light receiving optical system 17 includes, for example, at least one lens.

The scanning device 10 also has a light receiving unit 18 including light receiving elements 18A and 18B that receive each of the reflected lights. The light receiving elements 18A and 18B are arranged, for example, at the respective focal positions of the reflected lights collected by the light receiving optical system 17. For example, the light receiving element 18A detects the reflected light emitted from the light source 11A and reflected by the object OB, and the light receiving element 18B detects the reflected light emitted from the light source 11B and reflected by the object OB. Each of the light receiving elements 18A and 18B also has a detection element that generates an electrical signal in response to the reflected light.

Each of the light receiving elements 18A and 18B generates the electrical signal as a detection result of the reflected light (light receiving result). That is, the scanning device 10 generates the electrical signal generated by the light receiving element 18A as a scanning result of the first scanning region R1, and generates the electrical signal generated by the light receiving element 18B as a scanning result of the second scanning region R2.

That is, the emitted light, which is a line-shaped pulsed laser light emitted from light sources 11A and 11B, is incident on deflection element 16 via imaging optical system 12 and light projection optical system 15, and is deflected by deflection element 16 and projected as scanning light onto first scanning region R1 and second scanning region R2. In addition, the scanning light projected onto first scanning region R1 and second scanning region R2 is reflected by object OB and is incident on deflection element SP as reflected light via the same optical path as the emitted light. The reflected light is reflected by deflection element SP and is received by light receiving elements 18A and 18B via light receiving optical system 17.

As described above, the irradiation unit 11 has a plurality of light sources 11A and 11B, each of which intermittently irradiates a plurality of line-shaped irradiation lights.

The scanning device 10 has a control unit 20 that drives and controls the irradiation unit 11, the deflection element 16, and the light receiving unit 18. For example, in this embodiment, the control unit 20 includes a light source control unit 21 that serves as an irradiation control unit that independently drives and controls each of the light sources 11A and 11B. The control unit 20 also independently drives each of the deflection element 16 and the light receiving elements 18A and 18B.

The control unit 20 also has a distance measurement unit 22 that measures the distance to the object OB based on the result of receiving the reflected light by the light receiving elements 18A and 18B. In this embodiment, the distance measurement unit 22 detects a pulse indicating the reflected light from the electrical signal. The distance measurement unit 22 also measures the distance to the object OB or a part of its surface area by a TOF method based on the time difference between the timing of projecting the scanning light and the timing of receiving the reflected light. The distance measurement unit 22 also generates distance measurement data that indicates distance information measured in the first and second scanning regions R1 and R2.

The control unit 20 also has an image generation unit 23 as a distance measurement image generation unit that generates distance measurement images of the first and second scanning regions R1 and R2 based on the first and second distance measurement data generated by the distance measurement unit 22 and information indicating the displacement of the oscillating mirror 16A. In this embodiment, the image generation unit 23 associates the distance measurement data generated by the distance measurement unit 22 with information indicating the displacement of the oscillating mirror 16A, and generates a distance measurement image that is two-dimensional image data of the entire scanning region including the first and second scanning regions R1 and R2, showing the distance values of the distance measurement data as pixels.

In addition, in this embodiment, the scanning device 10 controls the light source 11A or 11B so that the scanning light is irradiated onto either the first scanning region R1 or the second scanning region R2 during one scan of the oscillating mirror 16A. That is, the scanning device 10 is configured to drive two light sources and two light receiving elements for one distance measuring unit 22. Therefore, the distance measuring unit 22 performs distance measurement based on the light receiving result of either the light receiving element 18A or 18B during one scan of the oscillating mirror 16A.

In addition, the scanning device 10 of this embodiment employs a horizontal interlace method in which the first and second scanning regions R1 and R2 are each scanned multiple times to obtain one distance measurement data, in order to densely irradiate the scanning light in the scanning direction SL of each of the first and second scanning regions R1 and R2.

Specifically, in each of the first and second scanning regions R1 and R2, a plurality of stripe-shaped irradiation regions are defined that are arranged along the scanning direction SL and extend along a direction perpendicular to the scanning direction SL. Each of the plurality of irradiation regions is an area to which one pulse of light is irradiated during scanning. In one scan, the pulse of light is irradiated only to a portion of the plurality of irradiation regions in each of the scanning regions.

In each of the first and second scanning regions R1 and R2, a plurality of irradiation region groups are defined, each of which is made up of a plurality of irradiation regions arranged at a predetermined interval. The scanning device 10 controls the light sources 11A and 11B so that, in one scan of the oscillating mirror 16A, the scanning light is irradiated onto one irradiation region group of either the first scanning region R1 or the second scanning region R2.

In other words, in this embodiment, the scanning device 10 scans the first scanning region R1 with the scanning light a number of times equal to the number of irradiation region groups contained in the first scanning region R1, and scans the second scanning region R2 a number of times equal to the number of irradiation region groups contained in the second scanning region R2 to generate distance measurement data and a distance measurement image.

In this embodiment, a case will be described in which the first and second scanning regions R1 and R2 each have four irradiation region groups. That is, in this embodiment, the first and second scanning regions R1 and R2 are each scanned four times, for a total of eight scans, to generate distance measurement data and distance measurement images.

Figures 2 and 3 are diagrams showing the irradiation areas of the scanning area of the scanning device 10 according to this embodiment. Figure 2 shows a top view of the irradiation area of the first scanning area R1, and Figure 3 shows a top view of the irradiation area of the second scanning area R2. As mentioned above, this embodiment describes a case where each of the first and second scanning areas R1 and R2 has four irradiation area groups.

The first scanning region R1 has a first irradiation region P11 belonging to the first irradiation region group, a second irradiation region P12 belonging to the second irradiation region group, a third irradiation region P13 belonging to the third irradiation region group, and a fourth irradiation region P14 belonging to the fourth irradiation region group. The irradiation regions P11 to P14 are arranged in the order of irradiation regions P11, P12, P13, P14, P11, ..., P14 from the scanning start position with respect to the scanning direction SL, for example. Each of the irradiation regions P11 to P14 is arranged so as to have equal intervals (equal angular intervals) with respect to the scanning direction SL based on the emission interval of the pulsed emission light emitted by the light source 11A. The light source 11A is controlled so that the positions of the irradiation regions P11 to P14 are fixed with respect to the scanning position in the scanning direction SL. Specifically, for example, the emission interval of the pulsed emission light emitted by the light source 11A may be calculated from the oscillation speed of the oscillating mirror 16A, or the displacement position of the oscillating mirror 16A may be monitored and the emission of the light emitted by the light source 11A may be controlled based on the monitoring results.

Similarly, the second scanning region R2 has a fifth irradiation region P21 belonging to the fifth irradiation region group, a sixth irradiation region P22 belonging to the sixth irradiation region group, a seventh irradiation region P23 belonging to the seventh irradiation region group, and an eighth irradiation region P24 belonging to the eighth irradiation region group. The irradiation regions P21 to P24 are arranged in the order of irradiation regions P21, P22, P23, P24, P21, ..., P24 from the scanning start position in the scanning direction SL, for example. The irradiation regions P21 to P24 are arranged at equal intervals (equal angular intervals) in the scanning direction SL based on the emission interval of the pulsed emission light emitted by the light source 11B. The light source 11B is controlled so that the positions of the irradiation regions P21 to P24 are fixed with respect to the scanning position in the scanning direction SL. Specifically, for example, the emission interval of the pulsed emission light emitted by the light source 11B may be calculated from the oscillation speed of the oscillating mirror 16A, or the displacement position of the oscillating mirror 16A may be monitored and the emission of the light emitted by the light source 11B may be controlled based on the monitoring results.

As described above, the scanning device 10 controls the light source 11A or 11B so that, in one scan of the oscillating mirror 16A, either the scanning light emitted from the light source 11A or 11B is irradiated onto one irradiation area of either the first scanning area R1 or the second scanning area R2. Specifically, for example, when the scanning light is irradiated onto the irradiation area P11 of the first scanning area R1, as shown in FIG. 2, the scanning light is irradiated onto the irradiation area P11 of the first scanning area R1 in order from the scanning start position in the scanning direction SL, and is not irradiated onto the other irradiation areas P12 to P24.

In addition, the light receiving element 18A receives the reflected light of the scanning light of P11 reflected by the object OB, and the distance measuring unit 22 generates distance measurement data for the position corresponding to the irradiation area P11 based on the light receiving result.

The above process is performed for all of the irradiation areas P11 to P24, and based on the light reception results of the reflected light from each of these areas, the distance measurement unit 22 generates distance measurement data for the positions corresponding to each of the irradiation areas. In addition, the image generation unit 23 generates distance measurement images for the corresponding positions based on each of the distance measurement data, and combines these to generate a single distance measurement image that shows the entire scanning area.

In this embodiment, the order of irradiation areas to which the scanning light is irradiated is shown in Figures 2 and 3. For example, in a conventional scanning method such as a raster scan method, the distance measurement image is completed by scanning from the top. That is, the scanning of the first scanning area R1 is first completed, distance measurement data and a distance measurement image of the first scanning area R1 are generated, and then the second scanning area R2 is scanned to generate distance measurement data and a distance measurement image of the second scanning area R2. Specifically, the order of irradiation areas to which the scanning light is irradiated is as follows: the scanning light from the light source 11A is irradiated to the irradiation areas P11, P12, P13, and P14 in this order, and then the scanning light from the light source 11B is irradiated to the irradiation areas P21, P22, P23, and P24 in this order.

In the above scanning method, there is a time difference between when scanning of the first scanning area R1 starts and when scanning of the second scanning area R2 starts. During this time, the car is still traveling ahead, and the scenery may change significantly.

In this embodiment, the irradiation area P11 of the first scanning area R1 is scanned to generate a distance measurement image, and then the irradiation area P21 of the second scanning area R2 is scanned to generate a distance measurement image. That is, the light sources 11A and 11B are controlled so that the scanning light from the light source 11A or 11B is alternately emitted for each scan of the oscillating mirror 16A. Specifically, the scanning light is scanned in the order of the irradiation areas P11, P21, P12, P22, P13, P23, P14, and P24 to generate respective distance measurement images, and each of the distance measurement images is synthesized to generate one distance measurement image showing the entire scanning area.

In this way, by alternately scanning the first scanning area R1 and the second scanning area R2, it is possible to reduce the time difference between the ranging image of the first scanning area R1 and the ranging image of the second scanning area R2.

Figures 4 to 6 are diagrams showing distance measurement images that are generated when the scanning device 10 is mounted so that the scanning light scans the scenery in front of the vehicle to generate distance measurement images. In this embodiment, we will explain the case where distance measurement images are generated at predetermined timing while the vehicle is traveling.

Figure 4 shows an actual scene SC as seen by the scanning device 10 while the car is moving. Also, Figure 5 shows a comparative example RI1 of a distance measurement image generated by a conventional scanning method. Also, Figure 6 shows an example image RI2 of a distance measurement image generated by the scanning method according to the present embodiment.

As shown in FIG. 5, in the conventional scanning method, after generating distance measurement data and a distance measurement image of the first scanning area R1 as described above, the second scanning area R2 is scanned to generate distance measurement data and a distance measurement image of the second scanning area R2. Therefore, the generated distance measurement image is distorted due to the time difference between the distance measurement image of the first scanning area R1 and the distance measurement image of the second scanning area R2. In particular, continuity is lost between the bottom end of the distance measurement image of the first scanning area R1 and the top end of the distance measurement image of the second scanning area R2.

In the scanning method of this embodiment, in order to prevent problems caused by time differences in scanning of the scanning areas that occurred in the conventional scanning method described above, as described above, for example, the scanning light is irradiated to the irradiation areas in the order of P11, P21, P12, P22, P13, P23, P14, P24, etc.

In this way, in this embodiment, by alternately irradiating the first scanning region R1 and the second scanning region R2 with the scanning light for each scan of the oscillating mirror 16A, it is possible to reduce the time difference between the distance measurement image of the first scanning region R1 and the distance measurement image of the second scanning region R2, and it is possible to generate a distance measurement image with less distortion.

The order in which the scanning light is irradiated to the irradiation areas is not limited to the above order. For example, the scanning light may be irradiated in the order of P11, P22, P13, P24, P21, P12, P23, P14, etc. This makes it possible to reduce the time difference between irradiation areas arranged horizontally.

That is, the scanning device 10 according to the present invention includes light sources 11A and 11B that irradiate one or more line-shaped emitted light beams extending in one direction, a light source control unit 21 that controls the irradiation by the light sources 11A and 11B, and a deflection element 16 that scans the emitted light in a scanning direction SL along a direction around a first axis and irradiates each of a first scanning region R1 and a second scanning region R2 that are offset in a direction perpendicular to the scanning direction SL, and the light source control unit 21 controls the light sources 11A and 11B so that the scanning light is irradiated to different regions between each of multiple scans, and the light source control unit 21 controls the light sources 11A and 11B so that in scanning the first scanning region R1 and the second scanning region R2 with the emitted light, the first scanning region R1 and the second scanning region R2 are each sequentially scanned once, thereby repeatedly scanning the entire first scanning region R1 and the second scanning region R2. In other words, the scanning device 10 according to the present invention includes light sources 11A and 11B that each emit a line-shaped emitted light extending in one direction, a light source control unit 21 that controls the emission of each of the emitted lights by the light sources 11A and 11B, and a deflection element 16 that scans each of the emitted lights in a scanning direction SL along a direction around the oscillation axis AY and irradiates each of the first scanning region R1 and the second scanning region R2 that are offset in a direction perpendicular to the scanning direction SL, and the light source control unit 21 controls the light sources 11A and 11B so that each of the scanning lights is irradiated to a different region between each of a plurality of scans, and the light source control unit 21 controls the light sources 11A and 11B so that in the scanning of the first scanning region R1 and the second scanning region R2 by the scanning light, the first scanning region R1 and the second scanning region R2 are each sequentially scanned once, thereby repeating the scanning of the entire first scanning region R1 and the second scanning region R2.

The scanning device 10 further includes light receiving elements 18A and 18B that receive the reflected light of each of the scanning lights reflected by the object OB, a distance measuring unit 22 that measures the distance to the object OB based on the light receiving results by the light receiving elements 18A and 18B, and an image generating unit 23 that generates a distance measurement image of the entire first scanning area R1 and the second scanning area R2 based on the distance measurement results by the distance measuring unit 22.

The image generating unit 23 also generates a distance measurement image based on the distance measurement results obtained by multiple scans using the scanning light for each of the first scanning region R1 and the second scanning region R2.

The present invention can also be implemented as a scanning method of the scanning device 10 by executing steps corresponding to the operation of the control unit 20, for example. That is, for example, the scanning method of the scanning device 10 is a scanning method of the scanning device 10 that scans the first scanning region R1 and the second scanning region R2 multiple times with one or more irradiation lights, and includes a scanning step of irradiating one or more linear emission lights extending in one direction, scanning the emission light in a scanning direction SL along a direction around a first axis, and irradiating each of the first scanning region R1 and the second scanning region R2 offset in a direction perpendicular to the scanning direction SL, in which the emission light irradiates different regions from each other during each of the multiple scans, and in the scanning step, in the scanning of the first scanning region R1 and the second scanning region R2 by the scanning light, one or more scanning lights are irradiated so that the scanning of the entire first scanning region R1 and the second scanning region R2 is repeated by sequentially scanning each of the first scanning region R1 and the second scanning region R2 once.

The present invention can also be implemented as a program that causes a computer to function as the control unit 20. That is, for example, the scanning program of the scanning device 10 is a scanning program executed by a computer, and includes a scanning step in which the computer irradiates one or more linear emission lights extending in one direction, scans the emission light in a scanning direction SL along a direction around a first axis, and irradiates each of a first scanning region R1 and a second scanning region R2 that are offset in a direction perpendicular to the scanning direction SL, and in the scanning step, the emission light irradiates different regions between each of a plurality of scans, and in the scanning step, in the scanning of the first scanning region R1 and the second scanning region R2 by the scanning light, one or more scanning lights are irradiated so that the scanning of the entire first scanning region R1 and the second scanning region R2 is repeated by sequentially scanning each of the first scanning region R1 and the second scanning region R2 once.

The present invention can also be implemented as, for example, a recording medium on which the above-mentioned scanning program is recorded. This makes it possible to provide a scanning program for the scanning device 10 that generates a distance measurement image with little distortion, and a recording medium on which the program is recorded.

In this embodiment, the scanning device 10 is described as having two light sources 11A and 11B that emit emission light in a vertically continuous manner, but the number of light sources provided in the scanning device 10 is not limited to this. Specifically, the scanning device 10 may be provided with multiple light sources that emit emission light in a vertically continuous manner, and the light source that emits the emission light may be changed in sequence for multiple scanning regions that are irradiated with each scanning light for each scan of the oscillating mirror 16A.

In addition, the order in which the emitted light is emitted from multiple light sources is not limited to vertically starting from the top. For example, irradiation of the scanning light may start near the center of the multiple scanning areas, or the scanning light irradiation portion of the multiple scanning areas may be alternately irradiated from the top and bottom ends toward the center. Also, the importance of each of the multiple scanning areas may be determined in advance, and irradiation may start from the scanning area with the highest importance.

In addition, the present invention is not limited to having multiple light sources. For example, a light source having multiple light-emitting segments arranged in a vertical direction may be used, and the light-emitting segments in the area that emits the emitted light may be controlled to emit light with each scan of the oscillating mirror 16A.

In the present embodiment, the scanning device 10 is described as having light sources 11A and 11B that intermittently emit line-shaped laser light. However, the method of emitting line-shaped laser light is not limited to this. For example, the scanning device 10 may further include an optical system such as a cylindrical lens or a fly-eye lens, and may emit laser light having a dot-like cross-sectional shape so as to be shaped into a line-shaped laser light.

In addition, in this embodiment, a case has been described in which the scanning light is scanned in the horizontal scanning direction SL in each of the first scanning region R1 and the second scanning region R2 obtained by dividing the scanning region in the horizontal direction, but the dividing direction and the scanning direction of the scanning region are not limited to this. For example, a line-shaped scanning light extending in the horizontal direction may be scanned in the vertical direction in each of a plurality of scanning regions obtained by dividing the scanning region in the vertical direction.

In addition, in this embodiment, the case where the scanning device 10 generates one ranging image has been described, but what is generated is not limited to an image. For example, the process of generating one ranging image may be continuously repeated to generate a ranging video.

In addition, when generating a ranging video by scanning multiple light sources and scanning areas, it is not necessary to generate ranging images of all scanning areas in all frame images of the ranging video. Specifically, scanning may be performed in all frames in scanning areas of high importance among multiple scanning areas, and one ranging image may be generated every two frames in scanning areas of low importance. This makes it possible to improve the frame rate of the ranging video.

In addition, in this embodiment, the scanning direction SL of the oscillating mirror 16A is described as being scanned in one direction, but the scanning direction is not limited to this. Specifically, for example, odd-numbered rows from the top of multiple scanning areas may be scanned on the outward path of the oscillating mirror 16A (corresponding to the scanning direction SL), and even-numbered rows from the top may be scanned on the return path of the oscillating mirror 16A (corresponding to the opposite direction to the scanning direction SL). This makes it possible to project and receive light by oscillating back and forth with the oscillating mirror 16A, and makes it possible to further reduce the time difference that occurs between multiple scanning areas of the generated distance measurement image.

In addition, in this embodiment, a case has been described in which a scanning light is irradiated once onto one irradiation area to generate a distance measurement image, but the number of times that a scanning light is irradiated onto one irradiation area is not limited to this. For example, a scanning light may be irradiated onto one irradiation area multiple times, and the light reception results of the reflected light, i.e., the detection signals of each of the light receiving units 18, may be accumulated. This makes it possible to generate a clearer distance measurement image.

In the present embodiment, the case has been described where the oscillating mirror 16A, which is a MEMS mirror of the deflection element 16, reflects the light emitted from the multiple light sources to scan the multiple scanning regions with the scanning light. However, the method of scanning the multiple scanning regions with the scanning light is not limited to this.

For example, instead of multiple light sources and the oscillating mirror 16A, a single light source and a rotating mirror may be used. The rotating mirror may be, for example, a multi-faceted mirror, which irradiates scanning light onto different areas for each combination of light source and each mirror surface. Specifically, the rotating mirror is a polygonal body with multiple reflective surfaces having different reflection angles, and the rotational movement of the rotating mirror irradiates scanning light onto multiple irradiation areas. Note that even when a rotating mirror is used, the scanning device may be equipped with multiple light sources.

10 Scanning device 11 Light source 12 Imaging optical system 15 Light projection optical system 16 Deflection element 17 Light receiving optical system 18 Light receiving unit 20 Control unit 21 Light source control unit 22 Distance measuring unit 23 Image generating unit

Claims (8)

An irradiation unit that irradiates one or more linear irradiation lights extending in one direction;
an irradiation control unit that controls irradiation by the irradiation unit;
a scanning unit that scans the one or more irradiation lights in a scanning direction along a direction around a first axis and irradiates each of a plurality of regions that are offset in a direction perpendicular to the scanning direction;
a light receiving unit that receives each of the reflected lights of the one or more irradiation lights reflected by an object;
a distance measuring unit that measures a distance to the object based on a result of light reception by the light receiving unit;
a distance measurement image generating unit that generates a distance measurement image that represents all of the plurality of regions as a two-dimensional image by performing a display that indicates a distance value to the object for each pixel based on a distance measurement result by the distance measuring unit,
the irradiation control unit controls the irradiation unit so that the one or more irradiation lights are irradiated onto different regions during each of a plurality of scans, and the irradiation control unit controls the irradiation unit so that, in the scanning of the plurality of regions with the one or more irradiation lights, a level of importance is determined in advance for each of the plurality of regions, and the irradiation control unit controls the irradiation unit so as to repeatedly scan the entirety of the plurality of regions by sequentially scanning each of the plurality of regions once in order of increasing importance . 2. The scanning device of claim 1,
An irradiation unit that irradiates a plurality of linear irradiation lights each extending in one direction;
an irradiation control unit that controls irradiation of each of the plurality of irradiation lights by the irradiation unit;
a scanning unit that scans each of the plurality of irradiation lights in a scanning direction along a direction around a first axis and irradiates each of a plurality of regions that are offset in a direction perpendicular to the scanning direction,
the irradiation control unit controls the irradiation unit so that each of the plurality of irradiation lights is irradiated onto a different region during each of a plurality of scans;
the irradiation control unit controls the irradiation unit so that, in scanning the multiple regions with the multiple irradiation light beams, a level of importance of each of the multiple regions is determined in advance, and the irradiation unit controls the irradiation unit so as to repeatedly scan the entire multiple regions by sequentially scanning each of the multiple regions once in order of importance. The scanning device according to claim 1 or 2, characterized in that the irradiation unit has a plurality of line laser light sources, each of which intermittently irradiates each of the plurality of line-shaped irradiation lights. The scanning device according to any one of claims 1 to 3, characterized in that the distance measurement image generating unit generates one image for each of the multiple regions based on the distance measurement results obtained by multiple scans using the multiple irradiation lights. The irradiation unit irradiates a line-shaped irradiation light,
5. The scanning device according to claim 1, wherein the scanning section is a polygonal mirror, each of whose surfaces irradiates the irradiation light onto a different area of the plurality of areas. A scanning method for a scanning device that scans a plurality of regions with one or a plurality of irradiation lights multiple times, comprising the steps of:
a scanning step of irradiating one or more linear irradiation lights extending in one direction, scanning the irradiation light in a scanning direction along a direction around a first axis, and irradiating each of a plurality of regions offset in a direction perpendicular to the scanning direction;
a distance measuring step of measuring a distance to the object based on a light receiving result of each of a plurality of reflected lights obtained by reflecting each of the one or a plurality of irradiated lights by the object;
a distance measurement image generating step of generating a distance measurement image that represents all of the plurality of regions as a two-dimensional image by performing a display showing a distance value to the object for each pixel based on the distance measurement result of the distance measurement step,
In the scanning step, the irradiation light is irradiated onto different regions during each of a plurality of scans,
a scanning method characterized in that, in the scanning step, in scanning the plurality of regions with the irradiation light, a level of importance is determined in advance for each of the plurality of regions, and the one or more irradiation lights are irradiated so as to repeatedly scan the entire plurality of regions by sequentially scanning each of the plurality of regions once in order of increasing importance. A scanning program executed by a computer, comprising:
a scanning step of irradiating the computer with one or more linear irradiation lights extending in one direction, scanning the irradiation light in a scanning direction along a direction around a first axis, and irradiating each of a plurality of regions offset in a direction perpendicular to the scanning direction;
a distance measuring step of measuring a distance to the object based on a light receiving result of each of a plurality of reflected lights obtained by reflecting each of the one or a plurality of irradiated lights by the object;
a distance measurement image generating step of generating a distance measurement image that represents all of the plurality of regions as a two-dimensional image by displaying a distance value to the object for each pixel based on the distance measurement result of the distance measurement step,
a scanning program characterized in that, in the scanning step, the irradiation light is irradiated onto different areas during each of a plurality of scans, and, in the scanning step, in scanning the plurality of areas with the irradiation light, a level of importance is determined in advance for each of the plurality of areas, and each of the plurality of areas is scanned once in order of increasing importance , thereby repeatedly scanning the entirety of the plurality of areas by irradiating the one or more irradiation lights. A computer-readable recording medium storing the scanning program according to claim 7.

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