Patent Application
20220003866
The present disclosure relates to a distance-measuring device that measures a distance to a target, and an optical module to be used in such a distance-measuring device.
Distance-measuring devices use, for example, a passive method of not applying light and an active method of applying light. Passive methods include a multi-eye method, etc., and active methods include a TOF (time of flight) method, etc.
The TOF method is a method of measuring delay time of light reflected back by a measurement target, and measuring a distance to the target on the basis of the delay time (e.g., see PTL 1).
PTL 1: U.S. Unexamined Patent Application Publication No. 2018/0026058
Incidentally, in a distance-measuring device, it is desirable to more easily provide an optical path for calibration of a distance to a distance-measuring target obtained from the distance-measuring device.
It is desirable to provide a distance-measuring device that makes it possible to more easily provide an optical path for calibration of a distance to a distance-measuring target, and an optical module to be used in the distance-measuring device.
An optical module according to one embodiment of the present disclosure includes a light-emitting section, a light-receiving section, a first cover part, and a second cover part. The light-emitting section is configured to emit light. The light-receiving section includes a first light-receiving section and a second light-receiving section. The first cover part is provided on a light emission side of the light-emitting section. The first cover part is configured to guide first light that is a portion of the light emitted from the light-emitting section in a direction of a target and guide second light that is another portion of the light emitted from the light-emitting section in a direction different from the direction of the target. The second cover part is provided on a light incidence side of the light-receiving section. The second cover part is configured to guide reflected light that is the first light reflected by the target in a direction of the first light-receiving section and guide the second light guided from the first cover part in a direction of the second light-receiving section.
A distance-measuring device according to one embodiment of the present disclosure includes a light-emitting section, a light-receiving section, a first cover part, a second cover part, and a processor. The light-emitting section is configured to emit light. The light-receiving section includes a first light-receiving section and a second light-receiving section. The first cover part is provided on a light emission side of the light-emitting section. The first cover part is configured to guide first light that is a portion of the light emitted from the light-emitting section in a direction of a target and guide second light that is another portion of the light emitted from the light-emitting section in a direction different from the direction of the target. The second cover part is provided on a light incidence side of the light-receiving section. The second cover part is configured to guide reflected light that is the first light reflected by the target in a direction of the first light-receiving section and guide the second light guided from the first cover part in a direction of the second light-receiving section. The processor is configured to calculate a distance to the target on the basis of a first pixel signal outputted from the first light-receiving section in response to the reflected light incident on the first light-receiving section. The processor is also configured to calibrate the distance on the basis of a second pixel signal outputted from the second light-receiving section in response to the second light incident on the second light-receiving section.
In the optical module according to one embodiment of the present disclosure, the first light that is a portion of the light emitted from the light-emitting section is transmitted through the first cover part to enter the target, and the reflected light from the target is transmitted through the second cover part to enter the first light-receiving section. On the other hand, the second light that is another portion of the light emitted from the light-emitting section is guided in the direction different from the target by the first cover part and is guided to the second light-receiving section by the second cover part to enter the second light-receiving section.
In the distance-measuring device according to one embodiment of the present disclosure, the first light that is a portion of the light emitted from the light-emitting section is transmitted through the first cover part to enter the target, and the reflected light from the target is transmitted through the second cover part to enter the first light-receiving section. Then, on the basis of the first pixel signal from the first light-receiving section, the distance to the target is calculated. On the other hand, the second light that is another portion of the light emitted from the light-emitting section is guided in the direction different from the target by the first cover part and is guided to the second light-receiving section by the second cover part to enter the second light-receiving section. Then, on the basis of the second pixel signal from the second light-receiving section, the distance to the target is calibrated.
In the following, description is given of embodiments of the present disclosure in detail with reference to the drawings. It is to be noted that the description is given in the following order.
The light-emitting section 10 includes, for example, any light-emitting body serving as a light source, such as a laser (LASER (Light Amplification by Stimulated Emission)) or an LED (Light Emitting Diode), and is configured to emit light. The laser may include, for example, a VCSEL (Vertical Cavity Surface Emitting LASER). The light emitted from the light-emitting section 10 is, for example, infrared light. Further, the light emitted from the light-emitting section 10 is, for example, pulsed light. Partial light (light L1) of the light emitted from the light-emitting section 10 is emitted to the outside through the first cover part 30 to irradiate the distance-measuring target 2.
The light-receiving section 20 is configured to receive incident light and convert it into an electric signal. The light-receiving section 20 has sensitivity to at least the light emitted from the light-emitting section 10. The light-receiving section 20 includes a first light-receiving section 21A and a second light-receiving section 21B. The first light-receiving section 21A includes one or more pixels. The first light-receiving section 21A is configured such that the reflected light L1R emitted from the light-emitting section 10 and reflected by the distance-measuring target 2 enters through the second cover part 40. The first light-receiving section 21A converts the reflected light L1R reflected by the distance-measuring target 2 into a first pixel signal S1, and outputs the first pixel signal S1 to the processor 50. Further, the second light-receiving section 21B of the light-receiving section 20 includes one or more pixels. Light received by the second light-receiving section 21B and a pixel signal generated by the second light-receiving section 21B will be described later.
The first cover part 30 is provided on a light emission side of the light-emitting section 10. For example, the first cover part 30 is held by a holder or the like so as to be spaced apart from the light-emitting section 10. Alternatively, in a case where the light-emitting section 10 is a packaged light-emitting section, a cap of the package may be configured to be the first cover part 30. The first cover part 30 includes a material that is transparent to the light emitted from the light-emitting section 10, and includes, for example, glass or plastic. The first cover part 30 has a plate-like shape as a whole. The first cover part 30 prevents dust or the like from adhering to the light-emitting section 10, protecting the light-emitting section 10 from the outside atmosphere.
In the present embodiment, the first cover part 30 is partly provided with a first reflecting surface 31. In a portion of the first cover part 30 where the first reflecting surface 31 is not provided, partial light of the light emitted from the light-emitting section 10 is transmitted through the first cover part 30 to be guided in a direction of the distance-measuring target 2. The light transmitted through the first cover part 30 to be guided in the direction of the distance-measuring target 2 corresponds to the light L1 applied to the distance-measuring target 2. Further, in a portion of the first cover part 30 where the first reflecting surface 31 is provided, other partial light of the light emitted from the light-emitting section 10 is reflected by the first reflecting surface 31 to be guided in a direction different from the direction of the distance-measuring target 2. The light reflected by the first reflecting surface 31 to be guided in the direction different from the direction of the distance-measuring target 2 is illustrated as light L2 in
The second cover part 40 is provided on a light incidence side of the light-receiving section 20. For example, the second cover part 40 is held by a holder or the like so as to be spaced apart from the light-receiving section 20. Like the first cover part 30, the second cover part 40 includes a material that is transparent to the light emitted from the light-emitting section 10, and includes, for example, glass or plastic. The second cover part 40 has a plate-like shape as a whole. The second cover part 40 prevents dust or the like from adhering to the light-receiving section 20, protecting the light-receiving section 20 from the outside atmosphere.
In the present embodiment, the second cover part 40 is partly provided with a second reflecting surface 41. In a portion of the second cover part 40 where the second reflecting surface 41 is not provided, the reflected light L1R reflected by the distance-measuring target 2 is transmitted through the second cover part 40 to be guided in a direction of the first light-receiving section 21A of the light-receiving section 20. The second reflecting surface 41 is an oblique surface having an angle of 45° with respect to a principal surface 40P of the second cover part 40. Here, the principal surface 40P of the second cover part 40 refers to a surface of the second cover part 40 that is substantially parallel to the XY plane and located on the far side in the Z-axis direction as viewed from the light-receiving section 20. The light L2 reflected by the first reflecting surface 31 to be guided to the second cover part 40 is reflected by the second reflecting surface 41 to be guided in a direction of the second light-receiving section 21B of the light-receiving section 20. As described above, the second cover part 40 guides the light (reflected light L1R) reflected by the distance-measuring target 2 in the direction of the first light-receiving section 21A and guides the light (light L2) guided from the first cover part 30 in the direction of the second light-receiving section 21B.
The reflected light L1R reflected by the distance-measuring target 2 enters the first light-receiving section 21A of the light-receiving section 20 to be converted into the first pixel signal S1. The first pixel signal S1 is outputted to the processor 50. Further, other partial light (light L2) emitted from the light-emitting section 10 and reflected by the first reflecting surface 31 of the first cover part 30 and the second reflecting surface 41 of the second cover part enters the second light-receiving section 21B of the light-receiving section 20 to be converted into a second pixel signal S2. The second pixel signal S2 is outputted to the processor 50.
The processor 50 is configured to drive the light-emitting section 10 to cause each light-emitting body 11 of the light-emitting section 10 to emit light. Further, the processor 50 is configured to calculate the distance between the distance-measuring device 1 and the distance-measuring target 2 on the basis of the first pixel signal S1 outputted from the first light-receiving section 21A in response to the reflected light L1R incident on the first light-receiving section 21A of the light-receiving section 20. The processor 50 is also configured to calibrate the distance between the distance-measuring device 1 and the distance-measuring target 2 on the basis of the second pixel signal S2 outputted from the second light-receiving section 21B in response to the light L2 incident on the second light-receiving section 21B of the light-receiving section 20 through the first cover part 30 and the second cover part 40.
In the distance-measuring device 1, a light diffuser, an optical filter such as a band-pass filter, a lens, or another optical member may be appropriately provided, as necessary, on an optical path taken until partial light of the light emitted from the light-emitting section 10 is reflected by the distance-measuring target 2 to enter the first light-receiving section 21A of the light-receiving section 20. Similarly, a light diffuser, an optical filter such as a band-pass filter, a lens, or another optical member may be appropriately provided, as necessary, on an optical path taken until other partial light of the light emitted from the light-emitting section 10 enters the second light-receiving section 21B of the light-receiving section 20 through the first cover part 30 and the second cover part 40.
The light-emitting section 10 includes a light-emitting section substrate 10S, and a plurality of light-emitting bodies 11 (light-emitting bodies 11A, 11B, 11C, 11D . . . ) arranged in a matrix on the light-emitting section substrate 10S. Although four by four (four in an X-axis direction and four in a Y-axis direction), i.e., sixteen, light-emitting bodies 11 are arranged in the drawing, this number is non-limiting, and it is sufficient that one or more light-emitting bodies are provided. The light-emitting body 11 includes, for example, a laser such as a VCSEL, an LED, or the like. Partial light of the light emitted from the light-emitting section 10 is light (light L1) guided in the direction of the distance-measuring target 2 described above to irradiate the distance-measuring target 2. Other partial light of the light emitted from the light-emitting section 10 is light (light L2) that enters the second light-receiving section 21B of the light-receiving section 20 through the first cover part 30 and the second cover part 40. The light L2 is also referred to as monitoring light, and a light-emitting body that emits the light L2 is also referred to as a monitoring light-emitting body 11M. One light-emitting body 11 is illustrated as the monitoring light-emitting body 11M in
The light-receiving section 20 is provided on the X-axis direction side of the light-emitting section 10. The light-receiving section 20 includes a light-receiving section substrate 20S, and the first light-receiving section 21A and the second light-receiving section 21B provided on the light-receiving section substrate 20S. The first light-receiving section 21A is provided on the far side in the X-axis direction as viewed from the light-emitting section 10, and the second light-receiving section 21B is provided on the near side. Pixels of the first light-receiving section 21A and the second light-receiving section 21B each receive incident light, and output an electric signal corresponding to an amount of the received light. The first light-receiving section 21A is a pixel array and includes, for example, n×m (m in the X-axis direction and n in the Y-axis direction) pixels arranged in a matrix (pixels A11 to Anm). Each pixel includes a light-receiving element such as a PD (photodiode, photodiode). In addition, the second light-receiving section 21B includes one pixel. Although illustrated to include one pixel in the drawing, it may include two or more pixels. The second light-receiving section 21B includes a light-receiving element such as a PD. In this example, the first light-receiving section 21A and the second light-receiving section 21B are configured as separate bodies. In the configuration of the light-emitting section 10 and the light-receiving section 20 illustrated in
The second cover part 40 has a plate-like shape, and is partly provided with a second recess 42. A portion of an inner wall of the second recess 42 is the second reflecting surface 41 that is an oblique surface having an angle of 45° with respect to the principal surface 40P of the second cover part 40. The inner wall of the second recess 42 is in contact with the air. The second recess 42 may be formed in a manner similar to that of the first recess 32. The second reflecting surface 41 reflects monitoring light emitted from the monitoring light-emitting body 11M and reflected by the first reflecting surface 31 in accordance with a difference between a refractive index of the material constituting the second cover part 40 and the refractive index of the air, and guides the monitoring light in the direction of the second light-receiving section 21B. To increase reflectance of light on the second reflecting surface 41, for example, a reflective film including silver or another metallic film or the like may be provided on the second reflecting surface 41, a light-shielding material film may be provided on the second reflecting surface 41, the second recess 42 may be filled with a material having a refractive index different from that of the material constituting the second cover part 40, or the second recess 42 may be filled with a light-shielding material. Further, the second reflecting surface 41 may not necessarily be totally reflective or highly reflective.
The first cover part 30 and the second cover part 40 are aligned such that an optical path of the monitoring light L2 is provided. The first cover part 30 and the second cover part 40 are large enough to make it possible to easily adjust the optical path of the monitoring light L2.
Further, the light-receiving section 20 is disposed on the substrate 100 inside the light-receiving section opening 101B. The second cover part 40 is provided on the light incidence side of the light-receiving section 20. The second cover part 40 is provided with the second reflecting surface 41. Further, the second cover part 40 is provided with an infrared filter 43 for transmission of infrared light that is light from the light-emitting section 10. Further, a lens holder 102 is provided inside the light-receiving section opening 101B. The lens holder 102 holds lenses 103 and 104. Further, the substrate 100 may be provided with the processor 50 coupled to the light-emitting section 10 and the light-receiving section 20. Alternatively, the light-emitting section 10 and the light-receiving section 20 may be coupled to the processor 50 provided separately via the substrate 100. In addition to the above, further optical members may be appropriately provided in the light-emitting section opening 101A and the light-receiving section opening 101B.
Here, the light-emitting section 10 corresponds to one specific example of a “light-emitting section” in the present disclosure. The light-receiving section 20 corresponds to one specific example of a “light-receiving section” in the present disclosure. The first cover part 30 corresponds to one specific example of a “first cover part” in the present disclosure. The second cover part 40 corresponds to one specific example of a “second cover part” in the present disclosure. The processor 50 corresponds to one specific example of a “processor” in the present disclosure.
Next, the operation and workings of the distance-measuring device of the present embodiment will be described.
First, an overview of the overall operation of the distance-measuring device will be described with reference to
Partial light (light L1) of the light incident on a portion of the first cover part 30 where the first recess 32 is not provided is transmitted through the first cover part 30 and guided in the direction of the distance-measuring target 2 to irradiate the distance-measuring target 2. The light L1 is reflected by the distance-measuring target 2 to become the reflected light L1R, and enters the first light-receiving section 21A of the light-receiving section 20.
On the other hand, other partial light (monitoring light L2) of the light incident on a portion of the first cover part 30 where the first recess 32 is provided is reflected by the first reflecting surface 31 provided in the first recess 32 to be guided in the direction of the second cover part 40. The monitoring light L2 guided to the second cover part 40 is reflected by the second reflecting surface 41 provided in the second recess 42 to enter the second light-receiving section 21B of the light-receiving section 20.
The first light-receiving section 21A receives the reflected light L1R and outputs the first pixel signal S1 to the processor 50. Each of the n×m pixels arranged in a matrix in the first light-receiving section 21A outputs the first pixel signal S1. Further, the second light-receiving section 21B receives the monitoring light L2 and outputs the second pixel signal S2 to the processor 50.
For the measurement of the distance to the distance-measuring target 2 by the distance-measuring device 1 illustrated in
The processor 50 measures the time taken until the light emitted from the light-emitting section 10 is reflected by the distance-measuring target 2 to enter the light-receiving section 20 on the basis of the first pixel signal S1 outputted from the first light-receiving section 21A of the light-receiving section 20 by the direct method, and calculates the distance between the distance-measuring device 1 and the distance-measuring target 2 on the basis of the obtained time, in the following manner.
The optical input waveform of the light-receiving section 20 ((B) of
In the calculation of the distance to the distance-measuring target 2 described above, there may be a deviation between the distance obtained in the calculation (measured distance) and the actual distance (actual distance). This deviation is due to, for example, circuitry delay or the like in the light-emitting section 10, the light-receiving section 20, and the processor 50.
In the present embodiment, the measured distance is calibrated as follows. The processor 50 calibrates the measured distance on the basis of the second pixel signal S2 outputted from the second light-receiving section 21B in response to other partial light (monitoring light L2) incident on the second light-receiving section 21B. Specifically, the processor 50 performs correction value table creation operation and normal operation (distance measuring). The correction value table creation operation is performed, for example, prior to the normal operation. The correction value table creation operation may be performed at any timing as long as the normal operation is not performed. In the correction value table creation operation, the processor 50 creates a correction value table on the basis of the second pixel signal S2. Specifically, while performing control to change emission timing of the monitoring light L2 to various timings, the processor 50 detects light-receiving timing at which the second light-receiving section 21B receives the monitoring light L2, and obtains the measured distance corresponding to each emission timing on the basis of the second pixel signal S2. On the other hand, the processor 50 multiplies an amount (time) of change in the emission timing, which is known for the processor 50, by the speed of light to obtain the actual distance. The processor 50 calculates a difference between the measured distance obtained on the basis of the second pixel signal S2 and the actual distance obtained from the amount (time) of change in the emission timing. The calculated difference value is a correction value corresponding to the measured distance obtained on the basis of the second pixel signal S2. The processor 50 creates the correction value table by obtaining the correction value for each emission timing. In the normal operation (distance measuring), on the basis of the first pixel signal S1, the processor 50 measures the time taken until the light emitted from the light-emitting section 10 is reflected by the distance-measuring target 2 to enter the light-receiving section 20, and calculates the distance to the distance-measuring target 2 from the obtained time. For each of the n×m pixels of the first light-receiving section 21A, the measurement of the time taken until the light emitted from the light-emitting section 10 is reflected by the distance-measuring target 2 to enter the light-receiving section 20, and the calculation of the measured distance to the distance-measuring target 2 based on the obtained time are performed. Further, the processor 50 refers to the correction value table created in advance on the basis of the second pixel signal S2 to obtain the correction value corresponding to the measured distance obtained from the first pixel signal S1, and calibrates the measured distance to the distance-measuring target 2 with the obtained correction value. The calibration of the distance to the distance-measuring target 2 is performed for each of the n×m pixels of the first light-receiving section 21A.
In the distance-measuring device 1 as described above, in the first cover part 30, partial light of the light emitted from the light-emitting section 10 is applied to the distance-measuring target 2, the reflected light L1R thereof entering the first light-receiving section 21A of the light-receiving section 20. Other partial light enters the second light-receiving section 21B of the light-receiving section 20 through the first cover part 30 and the second cover part 40. This makes it possible to provide the optical path of the monitoring light L2. It is possible to create the correction value table to be used for distance calibration from the second pixel signal S2 outputted by the second light-receiving section 21B receiving the monitoring light L2. Therefore, it is possible to correct the distance to the distance-measuring target 2 by referring to the correction value table, which increases accuracy of the distance to the distance-measuring target 2. That is, it is possible to calibrate the distance to the distance-measuring target 2 on the basis of the second pixel signal S2 outputted from the second light-receiving section 21B.
Further, in the distance-measuring device 1, the first cover part 30 having the first reflecting surface 31 is disposed on the light emission side of the light-emitting section 10, and the second cover part 40 having the second reflecting surface 41 is disposed on the light incidence side of the light-receiving section 20, which makes it possible to easily provide the optical path of the monitoring light L2. Furthermore, the first cover part 30 and the second cover part 40 are large enough for adjustment of the optical path of the monitoring light L2, which makes it possible to easily adjust the optical path of the monitoring light L2.
In the present embodiment as described above, the first cover part having the first reflecting surface and the second cover part having the second reflecting surface are provided, which makes it possible to easily provide the optical path of the monitoring light for acquisition of the second pixel signal. Therefore, it is possible to easily calibrate the distance to the distance-measuring target on the basis of the second pixel signal.
In the above embodiment, the second light-receiving section 21B has such a size as to be localized at a position corresponding to the vicinity of the middle of the first light-receiving section 21 in the Y-axis direction, but is not limited thereto. Alternatively, for example, the second light-receiving section 21B may extend elongated in one direction D (a direction parallel to the Y-axis direction). Further, the second reflecting surface 41 of the second cover part 40 may also extend in the one direction D to correspond to the second light-receiving section 21B extending in the one direction D.
In the distance-measuring device 1A of the present modification example, the monitoring light L2 of the light emitted from the light-emitting section 10 is reflected by the first reflecting surface 31 of the first cover part 30 and guided in the direction of the second cover part 40 so as to be spread in the same direction as the one direction D. The monitoring light L2 spread in the same direction as the one direction D is reflected by the second reflecting surface 41 extending elongated in the one direction D and guided in the direction of the second light-receiving section 21B extending elongated in the one direction D to enter. Except for the above point, it is similar to the above embodiment.
In the distance-measuring device 1A of the present modification example, the monitoring light L2 is spread in the same direction as the one direction D, and is reflected by the second reflecting surface 41 to enter the second light-receiving section 21B extending elongated in the one direction D. This configuration therefore easily causes the monitoring light L2 to enter the second light-receiving section 21B. Thus, an allowable range of alignment in the one direction D between the first cover part 30 and the second cover part 40 is broadened. Further, the allowable range of alignment in the one direction D between the second cover part 40 and the light-receiving section 20 (second light-receiving section 21B) is broadened. This makes it possible to easily adjust the optical path of the monitoring light L2.
In Modification Example 1 described above, the second light-receiving section 21B is configured to be a single pixel having a shape extending elongated in the one direction D, but is not limited thereto. Alternatively, for example, the second light-receiving section 21B may include a plurality of pixels arranged elongated in the one direction D.
In the distance-measuring device 1B of the present modification example, the monitoring light L2 is spread in the same direction as the one direction D, and is reflected by the second reflecting surface 41 to enter the second light-receiving section 21B arranged elongated in the one direction D. This configuration therefore easily causes the monitoring light L2 to enter the second light-receiving section 21B. Thus, an allowable range of alignment in the one direction D between the first cover part 30 and the second cover part 40 is broadened. Further, the allowable range of alignment in the one direction D between the second cover part 40 and the light-receiving section 20 (second light-receiving section 21B) is broadened. This makes it possible to easily adjust the optical path of the monitoring light L2.
In Modification Example 1 described above, the second recess 42 of the second cover part 40 extends elongated in the one direction D, and the second reflecting surface 41 extends elongated in the one direction D, but this example is non-limiting. Alternatively, for example, an end face of the second cover part 40 may be a second reflecting surface 44.
In the distance-measuring device 1C of the present modification example, a surface to be the second reflecting surface 44 is provided on the end face of the second cover part 40. Processing the end face of the second cover part 40 into the oblique surface having an angle of 45° with respect to the principal surface 40P of the second cover part 40 is easier than forming the second recess as in Modification Example 1.
Further, similarly, the first reflecting surface may be provided on an end face of the first cover part 30. That is, the end face of the first cover part 30 on the light-receiving section 20 side may be an oblique surface having an angle of 45° with respect to the principal surface 30P of the first cover part 30, and the oblique surface may be configured to be the first reflecting surface. In this case, of the light emitted from the light-emitting section 10, light that enters the end face of the first cover part 30 serves as the monitoring light L2.
In Modification Example 3 described above, the second light-receiving section 21B extends elongated in the one direction D, but is not limited thereto. Alternatively, for example, the second light-receiving section 21B may not extend elongated in the one direction D, and may have such a size as to be localized at a position corresponding to the vicinity of the middle of the first light-receiving section 21 in the Y-axis direction.
In the distance-measuring device 1D of the present modification example, the monitoring light L2 of the light emitted from the light-emitting section 10 is reflected by the first reflecting surface 31 of the first cover part 30 to be guided in the direction of the second cover part 40. The monitoring light L2 is reflected by the second reflecting surface 44 and guided in the direction of the second light-receiving section 21B to enter. The first reflecting surface 31 may reflect the monitoring light L2 so as to spread it in the one direction D, or may reflect the monitoring light L2 so as not to spread it. In a case where the first reflecting surface 31 spreads the monitoring light L2 in the one direction D, only a portion of the monitoring light L2 spread in the one direction D enters the second light-receiving section 21B. In this case, even if the optical path of the monitoring light L2 is shifted in the one direction D, the light entering the second light-receiving section 21B hardly fluctuates. This broadens the allowable range of alignment in the one direction D between the second cover part 40 and the light-receiving section 20 (second light-receiving section 21B). This makes it possible to easily adjust the optical path of the monitoring light L2. In a case where the first reflecting surface 31 does not spread the monitoring light L2 in the one direction D, this configuration differs from the configuration illustrated in
In the above embodiment, the first cover part 30 and the second cover part 40 are separate members, but this example is non-limiting. Alternatively, for example, the first cover part 30 and the second cover part 40 may be integrally configured.
In the present modification example, a first reflecting surface 61 is provided in a portion of the common cover part 60 on the light-emitting section 10 side. The first reflecting surface 61 is provided on an inner wall of a first recess 62 provided in a portion of the common cover part 60 on the light-emitting section 10 side. The first reflecting surface 61 is an oblique surface having an angle of 45° with respect to a principal surface 60P of the common cover part 60. Further, a second reflecting surface 63 is provided in a portion of the common cover part 60 on the light-receiving section 20 side. The second reflecting surface 63 is provided on an inner wall of a second recess 64 provided in a portion of the common cover part 60 on the light-receiving section 20 side. The second reflecting surface 63 is an oblique surface having an angle of 45° with respect to the principal surface 60P of the common cover part 60.
Like the light L1 illustrated in
In the distance-measuring device 1E of the present modification example, the common cover part 60 is provided, and the common cover part 60 has a configuration in which the first cover part and the second cover part are integrated. Therefore, the relative position between the first reflecting surface 61 and the second reflecting surface 63 is already determined. It is possible to provide the optical path of the monitoring light (light L2) only by disposing the one common cover part 60 on the light emission side of the light-emitting section 10 and the light incidence side of the light-receiving section 20. It is possible to perform alignment of the first reflecting surface 61 and the second reflecting surface 63 with respect to the light-emitting section 10 and the light-receiving section 20 only by adjusting alignment between the common cover part 60 and the light-receiving section 20 (second light-receiving section 21B), which makes it possible to easily adjust the optical path of the monitoring light L2.
In the above embodiment, a portion of the inner wall of the first recess 32 is made to function as the first reflecting surface 31, and a portion of the inner wall of the second recess 42 is made to function as the second reflecting surface 41, but this example is non-limiting. Alternatively, for example, a portion of the first cover part 30 may be provided with a first protrusion whose surface functions as a first reflecting surface, and a portion of the second cover part 40 may be provided with a second protrusion whose surface functions as a second reflecting surface.
Like the light L1 illustrated in
In the distance-measuring device 1F of the present modification example, a protrusion having a reflecting surface is provided on each of the first cover part 30 and the second cover part 40. This may be preferably carried out in a case where it is easy to provide a protruding shape on the surface of the cover part, like plastic molding.
In the above embodiment, the second light-receiving section 21B is located on the shortest line coupling a pixel included in the first light-receiving section 21A and the monitoring light-emitting body 11M, but is not limited thereto. Alternatively, for example, the second light-receiving section 21B may be provided at a position shifted from on the shortest line coupling the pixel included in the first light-receiving section 21A and the monitoring light-emitting body 11M.
The second light-receiving section 21B may not necessarily be located on the shortest line coupling the pixel included in the first light-receiving section 21A and the monitoring light-emitting body 11M.
The above embodiment has described an example in which the measurement of the distance to the distance-measuring target 2 by the distance-measuring device 1 is performed by the direct method, but this example is non-limiting. Alternatively, for example, this distance may be measured by the indirect method. An example in which this distance is measured by the indirect method is described below.
The optical input waveform of the light-receiving section 20 ((B) and (C) of
In the indirect method, a pixel of the first light-receiving section 21A accumulates signal charge Q1 in any period in a period T1 in which the light-emitting section 10 emits light, accumulates signal charge Q2 in any period in a period T2 in which the light-emitting section 10 does not emit light, and obtains a charge ratio between the signal charge Q1 and the signal charge Q2. In the examples of (B) and (C) of
In the calculation of the distance to the distance-measuring target 2 described above, there may be a deviation between the distance obtained in the calculation (measured distance) and the actual distance (actual distance). This is due to, for example, circuit delay in the light-emitting section 10, the light-receiving section 20, and the processor 50, a circuit configuration of the light-receiving section 20, the shape of the emitted pulse, or the like.
In the present embodiment, the measured distance is calibrated as follows. The processor 50 calibrates the measured distance on the basis of the second pixel signal S2 outputted from the second light-receiving section 21B pixel in response to other partial light (monitoring light L2) incident on the second light-receiving section 21B. Specifically, the processor 50 performs the correction value table creation operation and the normal operation (distance measuring) in a manner similar to that of the operation in the direct method described above. In the correction value table creation operation, the processor 50 creates the correction value table by detecting light-receiving timing at which the second light-receiving section 21B receives the monitoring light L2, while performing control to change emission timing of the monitoring light L2 to various timings. In the normal operation (distance measuring), the processor 50 calculates the distance to the distance-measuring target 2 on the basis of the first pixel signal S1, refers to the correction value table to obtain the correction value, and calibrates the measured distance to the distance-measuring target 2.
As described above, the present technology is also applicable to the indirect method. It is possible to more precisely measure the time taken until the light emitted from the light-emitting section 10 is reflected by the distance-measuring target 2 and received by the light-receiving section 20, and the distance to the distance-measuring target 2 converted from the time. Further, it is also possible to calibrate the distance to the distance-measuring target 2 obtained by the indirect method on the basis of the second pixel signal S2 outputted from the second light-receiving section 21B.
The above embodiment and Modification Examples 1 to 8 may be appropriately combined as necessary.
The technology (the present technology) according to the present disclosure is applicable to a variety of products. For example, the technology according to the present disclosure may be achieved as a device mounted on any type of mobile body such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility, an airplane, a drone, a vessel, or a robot.
The vehicle control system 12000 includes a plurality of electronic control units connected to each other via a communication network 12001. In the example depicted in
The driving system control unit 12010 controls the operation of devices related to the driving system of the vehicle in accordance with various kinds of programs. For example, the driving system control unit 12010 functions as a control device for a driving force generating device for generating the driving force of the vehicle, such as an internal combustion engine, a driving motor, or the like, a driving force transmitting mechanism for transmitting the driving force to wheels, a steering mechanism for adjusting the steering angle of the vehicle, a braking device for generating the braking force of the vehicle, and the like.
The body system control unit 12020 controls the operation of various kinds of devices provided to a vehicle body in accordance with various kinds of programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various kinds of lamps such as a headlamp, a backup lamp, a brake lamp, a turn signal, a fog lamp, or the like. In this case, radio waves transmitted from a mobile device as an alternative to a key or signals of various kinds of switches can be input to the body system control unit 12020. The body system control unit 12020 receives these input radio waves or signals, and controls a door lock device, the power window device, the lamps, or the like of the vehicle.
The outside-vehicle information detecting unit 12030 detects information about the outside of the vehicle including the vehicle control system 12000. For example, the outside-vehicle information detecting unit 12030 is connected with an imaging section 12031. The outside-vehicle information detecting unit 12030 makes the imaging section 12031 image an image of the outside of the vehicle, and receives the imaged image. On the basis of the received image, the outside-vehicle information detecting unit 12030 may perform processing of detecting an object such as a human, a vehicle, an obstacle, a sign, a character on a road surface, or the like, or processing of detecting a distance thereto.
The imaging section 12031 is an optical sensor that receives light, and which outputs an electric signal corresponding to a received light amount of the light. The imaging section 12031 can output the electric signal as an image, or can output the electric signal as information about a measured distance. In addition, the light received by the imaging section 12031 may be visible light, or may be invisible light such as infrared rays or the like.
The in-vehicle information detecting unit 12040 detects information about the inside of the vehicle. The in-vehicle information detecting unit 12040 is, for example, connected with a driver state detecting section 12041 that detects the state of a driver. The driver state detecting section 12041, for example, includes a camera that images the driver. On the basis of detection information input from the driver state detecting section 12041, the in-vehicle information detecting unit 12040 may calculate a degree of fatigue of the driver or a degree of concentration of the driver, or may determine whether the driver is dozing.
The microcomputer 12051 can calculate a control target value for the driving force generating device, the steering mechanism, or the braking device on the basis of the information about the inside or outside of the vehicle which information is obtained by the outside-vehicle information detecting unit 12030 or the in-vehicle information detecting unit 12040, and output a control command to the driving system control unit 12010. For example, the microcomputer 12051 can perform cooperative control intended to implement functions of an advanced driver assistance system (ADAS) which functions include collision avoidance or shock mitigation for the vehicle, following driving based on a following distance, vehicle speed maintaining driving, a warning of collision of the vehicle, a warning of deviation of the vehicle from a lane, or the like.
In addition, the microcomputer 12051 can perform cooperative control intended for automatic driving, which makes the vehicle to travel autonomously without depending on the operation of the driver, or the like, by controlling the driving force generating device, the steering mechanism, the braking device, or the like on the basis of the information about the outside or inside of the vehicle which information is obtained by the outside-vehicle information detecting unit 12030 or the in-vehicle information detecting unit 12040.
In addition, the microcomputer 12051 can output a control command to the body system control unit 12020 on the basis of the information about the outside of the vehicle which information is obtained by the outside-vehicle information detecting unit 12030. For example, the microcomputer 12051 can perform cooperative control intended to prevent a glare by controlling the headlamp so as to change from a high beam to a low beam, for example, in accordance with the position of a preceding vehicle or an oncoming vehicle detected by the outside-vehicle information detecting unit 12030.
The sound/image output section 12052 transmits an output signal of at least one of a sound and an image to an output device capable of visually or auditorily notifying information to an occupant of the vehicle or the outside of the vehicle. In the example of
In
The imaging sections 12101, 12102, 12103, 12104, and 12105 are, for example, disposed at positions on a front nose, sideview mirrors, a rear bumper, and a back door of the vehicle 12100 as well as a position on an upper portion of a windshield within the interior of the vehicle. The imaging section 12101 provided to the front nose and the imaging section 12105 provided to the upper portion of the windshield within the interior of the vehicle obtain mainly an image of the front of the vehicle 12100. The imaging sections 12102 and 12103 provided to the sideview mirrors obtain mainly an image of the sides of the vehicle 12100. The imaging section 12104 provided to the rear bumper or the back door obtains mainly an image of the rear of the vehicle 12100. The imaging section 12105 provided to the upper portion of the windshield within the interior of the vehicle is used mainly to detect a preceding vehicle, a pedestrian, an obstacle, a signal, a traffic sign, a lane, or the like.
Incidentally,
At least one of the imaging sections 12101 to 12104 may have a function of obtaining distance information. For example, at least one of the imaging sections 12101 to 12104 may be a stereo camera constituted of a plurality of imaging elements, or may be an imaging element having pixels for phase difference detection.
For example, the microcomputer 12051 can determine a distance to each three-dimensional object within the imaging ranges 12111 to 12114 and a temporal change in the distance (relative speed with respect to the vehicle 12100) on the basis of the distance information obtained from the imaging sections 12101 to 12104, and thereby extract, as a preceding vehicle, a nearest three-dimensional object in particular that is present on a traveling path of the vehicle 12100 and which travels in substantially the same direction as the vehicle 12100 at a predetermined speed (for example, equal to or more than 0 km/hour). Further, the microcomputer 12051 can set a following distance to be maintained in front of a preceding vehicle in advance, and perform automatic brake control (including following stop control), automatic acceleration control (including following start control), or the like. It is thus possible to perform cooperative control intended for automatic driving that makes the vehicle travel autonomously without depending on the operation of the driver or the like.
For example, the microcomputer 12051 can classify three-dimensional object data on three-dimensional objects into three-dimensional object data of a two-wheeled vehicle, a standard-sized vehicle, a large-sized vehicle, a pedestrian, a utility pole, and other three-dimensional objects on the basis of the distance information obtained from the imaging sections 12101 to 12104, extract the classified three-dimensional object data, and use the extracted three-dimensional object data for automatic avoidance of an obstacle. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 as obstacles that the driver of the vehicle 12100 can recognize visually and obstacles that are difficult for the driver of the vehicle 12100 to recognize visually. Then, the microcomputer 12051 determines a collision risk indicating a risk of collision with each obstacle. In a situation in which the collision risk is equal to or higher than a set value and there is thus a possibility of collision, the microcomputer 12051 outputs a warning to the driver via the audio speaker 12061 or the display section 12062, and performs forced deceleration or avoidance steering via the driving system control unit 12010. The microcomputer 12051 can thereby assist in driving to avoid collision.
At least one of the imaging sections 12101 to 12104 may be an infrared camera that detects infrared rays. The microcomputer 12051 can, for example, recognize a pedestrian by determining whether or not there is a pedestrian in imaged images of the imaging sections 12101 to 12104. Such recognition of a pedestrian is, for example, performed by a procedure of extracting characteristic points in the imaged images of the imaging sections 12101 to 12104 as infrared cameras and a procedure of determining whether or not it is the pedestrian by performing pattern matching processing on a series of characteristic points representing the contour of the object. When the microcomputer 12051 determines that there is a pedestrian in the imaged images of the imaging sections 12101 to 12104, and thus recognizes the pedestrian, the sound/image output section 12052 controls the display section 12062 so that a square contour line for emphasis is displayed so as to be superimposed on the recognized pedestrian. The sound/image output section 12052 may also control the display section 12062 so that an icon or the like representing the pedestrian is displayed at a desired position.
The above has described the example of the vehicle control system to which the technology according to the present disclosure may be applied. The technology according to the present disclosure may be applied to the imaging section 12031 among the above-described components. Specifically, the distance-measuring device 1 illustrated in
Although the present technology has been described above with reference to some embodiments and modification examples, the present technology is not limited to these embodiments and the like, and may be modified in a variety of ways.
The above embodiment has described the distance-measuring device that measures the distance to the distance-measuring target, but this example is non-limiting. Alternatively, it may be a time measurement device that irradiates a target with light and measures time taken until the light returns.
In the above embodiment and modification examples, as illustrated in
It is to be noted that the effects described in this specification are merely illustrative and non-limiting, and other effects may be provided.
It is to be noted that the present technology may have the following configurations. According to the present technology having the following configurations, it is possible to more easily provide an optical path for calibration of a distance to a distance-measuring target.
(1)
An optical module including:
a light-emitting section configured to emit light;
a light-receiving section including a first light-receiving section and a second light-receiving section;
a first cover part provided on a light emission side of the light-emitting section, and configured to guide first light that is a portion of the light emitted from the light-emitting section in a direction of a target and guide second light that is another portion of the light emitted from the light-emitting section in a direction different from the direction of the target; and
a second cover part provided on a light incidence side of the light-receiving section, and configured to guide reflected light that is the first light reflected by the target in a direction of the first light-receiving section and guide the second light guided from the first cover part in a direction of the second light-receiving section.
(2)
The optical module according to (1), in which the first cover part has, in a portion of the first cover part, a first reflecting surface provided obliquely with respect to a principal surface of the first cover part and configured to reflect the second light in the direction different from the direction of the target.
(3)
The optical module according to (2), in which
the first cover part has a first recess provided in the portion of the first cover part, and
the first reflecting surface is an inner wall of the first recess.
(4)
The optical module according to (2), in which the first reflecting surface is an end face of the first cover part.
(5)
The optical module according to any one of (1) to (4), in which the second cover part has, in a portion of the second cover part, a second reflecting surface provided obliquely with respect to a principal surface of the second cover part and configured to reflect the second light in the direction of the second light-receiving section.
(6)
The optical module according to (5), in which
the second cover part has a second recess provided in the portion of the second cover part, and
the second reflecting surface is an inner wall of the second recess.
(7)
The optical module according to (5), in which the second reflecting surface is an end face of the second cover part.
(8)
The optical module according to any one of (1) to (7), in which
the second light-receiving section is provided to extend elongated in one direction,
the first cover part has, in a portion of the first cover part, a first reflecting surface provided obliquely with respect to a principal surface of the first cover part and configured to reflect the second light in the direction different from the direction of the target to spread the second light in a same direction as the one direction, and
the second cover part has, in a portion of the second cover part, a second reflecting surface provided obliquely with respect to a principal surface of the second cover part and configured to reflect the second light reflected by the first reflecting surface in the direction of the second light-receiving section.
(9)
The optical module according to (8), in which the second light-receiving section is a single pixel having a shape extending elongated in the one direction.
(10)
The optical module according to (8), in which the second light-receiving section includes a plurality of pixels arranged elongated in the one direction.
(11)
The optical module according to any one of (1) to (10), in which the first cover part and the second cover part are integrally configured.
(12)
The optical module according to any one of (1) to (11), in which the first light-receiving section and the second light-receiving section are integrally configured.
(13)
A distance-measuring device including:
a light-emitting section configured to emit light;
a light-receiving section including a first light-receiving section and a second light-receiving section;
a first cover part provided on a light emission side of the light-emitting section, and configured to guide first light that is a portion of the light emitted from the light-emitting section in a direction of a target and guide second light that is another portion of the light emitted from the light-emitting section in a direction different from the direction of the target;
a second cover part provided on a light incidence side of the light-receiving section, and configured to guide reflected light that is the first light reflected by the target in a direction of the first light-receiving section and guide the second light guided from the first cover part in a direction of the second light-receiving section; and
a processor configured to calculate a distance to the target on the basis of a first pixel signal outputted from the first light-receiving section in response to the reflected light incident on the first light-receiving section, and configured to calibrate the distance on the basis of a second pixel signal outputted from the second light-receiving section in response to the second light incident on the second light-receiving section.
(14)
The distance-measuring device according to (13), in which the processor is configured to calculate the distance by a direct method.
(15)
The distance-measuring device according to (13), in which the processor is configured to calculate the distance by an indirect method.
This application claims the benefit of Japanese Priority Patent Application No. 2018-212133 filed with the Japan Patent Office on Nov. 12, 2018, the entire contents of which are incorporated herein by reference.
It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-212133 | Nov 2018 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/040888 | 10/17/2019 | WO | 00 |
