WO2018100648A1 - Optical scanning device and optical rangefinder - Google Patents

Abstract

In the present invention, when external vibration is applied to a scanning device, the influence of the external vibration is efficiently reduced. Provided is an optical scanning device 200 provided with a light deflector 213 for deflecting measurement light that has been projected in a projection direction determined by a pivoting direction and a translation direction intersecting the pivoting direction, a light projector 211 for projecting the measurement light toward the light deflector, a light receiver 221 for receiving the measurement light reflected by an object, a propagation direction controller 216 for controlling the driving of the light deflector 213 so that the pivoting direction becomes the primary vibration direction that is the primary direction of the vibration of the optical scanning device 200, and an output unit 266 for outputting information obtained from the reflected light as output information.

Description

Optical scanning device and optical distance measuring device

The present invention relates to optical scanning technology and optical ranging technology.

There is a technology for scanning a light spot using a scanner mounted on a moving body such as an automobile. For example, in-vehicle sensors such as an in-vehicle camera that processes the reflected light and obtains surrounding information in a time-sharing manner, and the light distribution of automobile headlights to prevent dazzling the driver of oncoming vehicles and forward vehicles. Used for ADB (Adaptive Driving Beam) to be controlled. Since these are mounted on the moving body, they are subject to external vibration. As a result, the in-vehicle sensor generates a visual field error in the obtained image. Further, in ADB, the light distribution area deviates from the intended area.

For example, there is a technique disclosed in Patent Document 1 as a prior art for solving the influence of vibration in an in-vehicle sensor. According to the present technology, “the moving component that moves up and down in the image in accordance with the vibration of the vehicle in the captured image captured by the camera is identified, and the intensity of the vibration frequency of the moving component is determined based on the movement history of the identified moving component. The vibration frequency range having the highest vibration frequency intensity is extracted, the equilibrium image captured at the vibration equilibrium point within the extracted predetermined frequency range is extracted, and based on the extracted equilibrium image, the vehicle The vanishing point, which is the center position of the displacement in the image displaced by vibration, is detected, and the detected vanishing point is monitored to calculate the amount of image displacement due to vehicle vibration in each captured image (summary extract). " .

JP 2006-170961 A

In the technique disclosed in Patent Document 1, it is assumed that a non-scanning sensor that detects surrounding information at once using a two-dimensional image sensor such as a camera such as a CCD or CMOS is used. In the non-scanning sensor, the influence of external vibration appears as a shift between the frames.

However, in the scanning sensor as described above, the influence of vehicle vibration is observed as distortion in the detection result of a single frame. For this reason, in the scanning sensor, different solution means are required to correct the influence of external vibration in the obtained image and obtain a detection result without distortion. At this time, we want to use the acquired data efficiently. Also in ADB, the influence of the vibration of the vehicle appears as distortion of the irradiation area of the headlight. For this reason, the optical scanning headlight requires a solution means for correcting the influence of external vibration and obtaining a detection result without distortion.

The present invention has been made in view of the above circumstances, and an object of the present invention is to efficiently reduce the influence of external vibration when external vibration is applied to a scanning apparatus.

The present invention provides a light deflector that deflects measurement light, which is light to be projected, in a light projecting direction determined by a rocking direction and a translation direction that intersects the rocking direction, and the light deflecting the measurement light A light projecting unit that projects light toward the unit, a light receiving unit that receives reflected light of the measurement light from the object, and the light so that the oscillation direction is a main vibration direction that is a main vibration direction of the light. Provided is an optical scanning device comprising: a propagation direction control unit that drives and controls a deflection unit; and an output unit that outputs information obtained from the reflected light as output information.

Further, the distortion of the distance image due to the main vibration is corrected by using the optical scanning device, a distance image generating unit that generates a distance image from the output information, and a displacement amount of the optical scanning device, An optical distance measuring device comprising: a correction unit that outputs a distance image.

According to the present invention, even when external vibration is applied to the scanning type sensor, detection without distortion in the frame can be realized. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is a schematic block diagram of the optical distance measuring device of 1st embodiment. It is a block diagram of the optical ranging apparatus of 1st embodiment. It is explanatory drawing for demonstrating for demonstrating the scanning method of the optical scanning device of 1st embodiment. (A) is a flowchart of the swing direction control process of the first embodiment, and (b) is a flowchart of the distance measurement process of the first embodiment. (A) And (b) is explanatory drawing for demonstrating for demonstrating the time history of the displacement observed by the vibration detection apparatus at the time of the external vibration of 1st embodiment, (c), It is explanatory drawing for demonstrating the mode of a vibration of an optical ranging device. (A) is explanatory drawing for demonstrating the relationship between a light emission area | region, a non-light emission area | region, and a visual field, respectively, when there is no external vibration and (b) is an external vibration. (A)-(c) is explanatory drawing for demonstrating the influence on the detection result when external vibration is added to the optical ranging apparatus. (A) And (b) is the simulation result of the locus | trajectory which a propagation direction draws when a rocking | fluctuation direction is an X-axis direction and there is no external vibration. (A) And (b) is the simulation result of the locus | trajectory which a propagation direction draws when the rocking | fluctuation direction of a scanner is an X-axis direction and there exists an external vibration in a Y-axis direction. (A)-(e) is explanatory drawing for demonstrating the influence of a vibration, and the effect of a correction | amendment when the rocking direction and external vibration direction of a scanner are set substantially parallel. It is a block diagram of the optical ranging apparatus of 2nd embodiment. (A) And (b) is explanatory drawing for demonstrating the distance image of 2nd embodiment. (A)-(c) is explanatory drawing for demonstrating the relationship between the detection result of 2nd embodiment, and actual information. (A) is a detection area in the second embodiment, (b) is an example of waveform distortion caused by external vibration, and (c) is a waveform distortion when the shape of the object has distortion. It is explanatory drawing for demonstrating an example, respectively. It is a flowchart of the displacement amount calculation process of 2nd embodiment. (A)-(d) is explanatory drawing for demonstrating the displacement amount calculation method of 2nd embodiment. (A) And (b) is explanatory drawing for demonstrating the displacement amount calculation method of 2nd embodiment. It is a block diagram of the optical ranging apparatus of 3rd embodiment. (A) illustrates the change in the visual field when an external vibration is applied to the scanning sensor, and (b) illustrates the change in the visual field when an external vibration is applied to the non-scanning sensor. It is explanatory drawing for. It is a flowchart of the displacement amount calculation process of 3rd embodiment. (A)-(c) is explanatory drawing for demonstrating the process of calculating pixel deviation | shift amount when a vibration direction is a Y-axis direction. (A)-(c) is explanatory drawing for demonstrating the process of calculating pixel deviation | shift amount when a vibration direction is (theta) F direction with respect to an X-axis.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Hereinafter, in this specification, those having the same function are denoted by the same reference numerals unless otherwise specified, and repeated description is omitted.

<< First Embodiment >>
A first embodiment of the present invention will be described. In this embodiment, a vibration detection sensor is provided, and its output is used to determine the swinging direction of the scanning optical distance measuring device. Further, the distortion of the distance image due to the vibration of a moving body such as a vehicle on which the optical distance measuring device is mounted is corrected using the detection result by the vibration detection sensor. Hereinafter, in the present embodiment, a case where the moving body is an automobile or a vehicle will be described as an example.

1 and 2 are configuration diagrams of the optical distance measuring device 100 of the present embodiment. The optical distance measuring device 100 of the present embodiment corrects the optical scanning device 200, the distance image generation unit 110 that generates a distance image from the output information of the optical scanning device 200, and the distance image generated by the distance image generation unit 110. And a correction unit 120. For example, the optical distance measuring device 100 is connected to the ECU 300, and the distance image corrected by the correction unit 120 is output to the ECU 300. The ECU 300 is an engine control unit that controls an automobile engine.

[Optical scanning device]
The optical scanning device 200 is a scanning sensor that acquires surrounding information in a time-division manner by scanning a light spot using a driving scanner. For example, as shown in FIG. 3, the scanner is oscillated in a predetermined oscillating direction 402 with a predetermined oscillating amplitude, while being translated in a translation direction 403 that intersects the oscillating direction. The light is projected, and a predetermined distance measurement area (field-of-view range) 401 is scanned. In the figure, a black arrow indicates a locus 404 drawn by the propagation direction of the scanner.

In the optical scanning device 200 (optical distance measuring device 100) of the present embodiment, the orthogonal two-dimensional axes in the field of view are substantially parallel to the X axis and the Y axis, which are two-dimensional axes of the vibration detection device 240 described later. Install as follows. Hereinafter, in order to simplify the description, the horizontal axis (horizontal axis) and the vertical axis (vertical axis) in the field of view of the optical scanning device 200 (optical ranging device 100) are also expressed as the X axis and the Y axis.

In order to realize this, the optical scanning device 200 includes a light projecting unit 211, a scanner 212, a scanning angle detection unit 215, a propagation direction control unit 216, a light receiving unit 221, an I / V conversion unit 222, and an amplification. A circuit 223, an ADC 224, a signal processing unit 225, and a control unit 230 are provided.

The light projecting unit 211 projects laser light (light spot) toward the scanner 212. The light projection is performed at a predetermined light projection timing. Further, the laser light is modulated into a pulse shape or a sine wave shape, and projected as modulated light. The light projecting unit 211 includes, for example, a laser diode, a collimating lens that shapes the laser diameter to a desired laser diameter, and the like.

The scanner 212 includes an optical deflection unit 213 and a drive unit 214.

The light deflection unit 213 has a mirror surface that deflects light. The light deflection unit 213 has at least one drive shaft. The light deflecting unit 213 may have, for example, a two-dimensional swing axis that is a long axis and a high speed swing axis and a short axis and a low speed swing axis.

The drive unit 214 supports the light deflection unit 213 and drives the drive shaft according to the drive signal. In the present embodiment, the drive unit 214 swings the light deflection unit 213 in a desired direction with a desired amplitude by driving each drive axis in accordance with a drive signal from a propagation direction control unit 216 described later. While being driven, it is translationally driven in a desired direction.

Note that the light projection destination of the light projecting unit 211 is, for example, the substantially swing center of the light deflecting unit 213. The modulated light projected by the light projecting unit 211 is deflected by the light deflecting unit 213 and is irradiated to the distance measuring range as measurement light. The measurement light is reflected by objects around the vehicle on which the optical distance measuring device 100 is mounted.

The scanning angle detection unit 215 detects the angle of the light deflection unit 213. Then, the detection result is output to the propagation direction control unit 216. The scanning angle detection unit 215 may be any device that can detect the angle of the light deflection unit 213. For example, a capacitance type rotary encoder or an optical encoder is used. The rotary encoder is attached to the actuator unit. Note that the optical encoder uses back surface reflection or the like opposite to the light projecting unit 211 side with the light deflecting unit 213 interposed therebetween. For this reason, the optical encoder is provided at a position where the back surface reflection can be received.

The propagation direction control unit 216 controls the swing of the scanner 212 (light deflecting unit 213) in accordance with an instruction from the control unit 230. The control is performed using the drive signal received from the control unit 230 and the output of the scanning angle detection unit 215 in accordance with the control timing signal received from the control unit 230. A drive signal is output for each drive axis of the scanner 212 (light deflector 213). The propagation direction control unit 216 controls the swinging direction of the scanner 212 (light deflecting unit 213) substantially parallel to the main vibration direction, and the amplitude and the translation amount in the translation direction cover the visual field range 401. Control as follows.

The light receiving unit 221 receives the reflected light of the measurement light and performs photoelectric conversion. The light receiving unit 221 includes, for example, a photodiode that performs photoelectric conversion and an optical system that includes a condensing mirror that guides reflected light to the photodiode.

Note that the information (current value) of the reflected light photoelectrically converted by the light receiving unit 221 is converted and signal processed by the output unit 226 and output to the distance image generation unit 110. The output unit 226 includes, for example, an I / V conversion unit (current / voltage conversion unit) 222, an amplifier circuit 223, an ADC (analog / digital converter) 224, and a signal processing unit 225.

The reflected light information is converted into voltage information by an I / V conversion unit (current / voltage conversion unit) 222. Then, the converted information is subjected to analog noise removal and amplification or reduction to an appropriate voltage value by the amplification circuit 223, and then converted from an analog voltage amount to a digital value by the ADC 224.

The signal processing unit 225 instructs the light projecting unit 211 to project the modulated light, processes the reflected light received by the light receiving unit 221, and calculates a delay amount from light projection to light reception. The light projection instruction is performed by outputting a light projection timing signal to the light projecting unit 211. The light projection timing signal is generated according to a control timing signal output from a pulse signal generation unit 235 described later. In accordance with the control timing signal, the propagation direction of the light deflecting unit 213 is determined, and the timing for causing the light projecting unit 211 to emit light in order to project the modulated light is controlled. That is, the signal processing unit controls the timing of light projection so that the light projection range by the light deflection unit 213 becomes a predetermined visual field range.

In addition, as processing of reflected light, digital filter processing and binarization processing are performed on information converted into digital values by the ADC 224. The binarization process is performed by, for example, a digital comparator. The calculated delay amount is output to the distance image generation unit 110 described later.

The control unit 230 is configured such that the swing direction of the scanner 212 (light deflecting unit 213) is the vibration direction (main vibration direction) of the optical distance measuring device 100 due to the main vibration of the vehicle (device) on which the optical distance measuring device 100 is mounted. And the operation of the entire optical distance measuring device 100 is controlled.

In order to realize this, the control unit 230 of the present embodiment includes a distance calculation unit 231, an intensity calculation unit 232, a vibration analysis unit 233, an output processing unit 234, and a pulse signal generation unit 235.

In this embodiment, the vibration detection device 240 is traversed separately from the optical distance measuring device 100 in a vehicle on which the optical distance measuring device 100 is mounted. The vibration detection device 240 is a vibration detection sensor that obtains a displacement amount due to external vibration of a vehicle on which the optical distance measuring device 100 is mounted. The external vibration is, for example, a vibration amount of the optical distance measuring device 100 due to road surface vibration. In this embodiment, the displacement from the steady state without external vibration is detected as the vibration amount. Hereinafter, the displacement from the steady state is referred to as a displacement amount. The amount of displacement is, for example, a value (Ax, Ay) in each axial direction of two predetermined orthogonal axes (X axis and Y axis).

The vibration detection device 240 is realized by, for example, a displacement sensor having a plurality of detection axes. Note that the vibration detection device 240 is not limited to a displacement sensor having a plurality of detection axes, and for example, an amount of displacement due to external vibration of the optical distance measuring device 100 such as an acceleration sensor having a plurality of detection axes. Anything that can be estimated is acceptable. The obtained displacement amount is output to the control unit 230 and the correction unit 120.

The vibration analysis unit 233 acquires the angle (main vibration angle) θM of the vibration direction (main vibration direction) from a predetermined direction from the amount of displacement of the optical distance measuring device 100 detected by the vibration detection device 240. The acquired main vibration angle θM is output to the propagation direction control unit 216 as a drive signal for each drive axis via the pulse signal generation unit 235.

The main vibration angle θM is calculated as follows. For example, the displacements in the X-axis and Y-axis directions detected by the vibration detection device 240 at the same time are Ax and Ay, respectively. In this case, the combined displacement (amplitude; amplitude due to external vibration) Acom of the X axis and the Y axis is expressed by the following equation (1).

The main vibration direction θM is calculated by the following equation (2) as the vibration direction of the composite displacement with respect to the X axis.

The pulse signal generation unit 235 generates various control signals and outputs them to each unit. In the present embodiment, for example, a control timing signal for synchronizing various processes, the above-described drive signal, and the like are generated and output. The control timing signal is output to, for example, the propagation direction control unit 216, the distance calculation unit 231, the correction unit 120, and the like. The drive signal is output to the propagation direction control unit 216. The control timing signal may also be output to the intensity information memory 132, the signal processing unit 225, and the like.

The control timing signal is generated based on the periodic signal transmitted from the distance calculation unit 231. Further, the drive signal is generated based on the main vibration direction θM calculated by the vibration analysis unit 233. In this embodiment, the drive signal is swung and translated so that the swinging direction 402 of the scanner 212 (light deflecting unit 213) is substantially parallel to the main vibration direction θM and the visual field range 401 is covered. Generated to move.

[Distance image generator]
Next, the distance image generation unit 110 will be described. The distance image generation unit 110 includes a distance calculation unit 231, an intensity calculation unit 232, and a distance information memory 131 and an intensity information memory 132 that store respective calculation results.

The distance calculation unit 231 calculates the distance to the object (object) using the delay amount received from the signal processing unit 225. The obtained distance value (distance value) is converted into a value and size considering the memory storage time, and then stored in the distance information memory 131 in units of frames, for example. Each distance value is stored in a memory having an address associated in advance according to the driving amount of the scanner 212 at the time of acquiring the delay amount according to the control timing signal. Hereinafter, a plurality of distance values stored in the distance information memory 131 in units of frames are collectively referred to as a distance image.

The intensity calculation unit 232 calculates the intensity value using the delay amount received from the signal processing unit 225. The obtained intensity value is converted into a value and a size considering the memory storage time, and then stored in the intensity information memory 132 in units of frames, for example. Each intensity value is also stored in a memory having an address associated in advance according to the driving amount of the scanner 212 when the delay amount is acquired. Hereinafter, a plurality of intensity values stored in the intensity information memory 132 in units of frames are collectively referred to as intensity images.

[Correction section]
The correction unit 120 corrects the influence of external vibration on the distance value stored in the distance information memory 131 and the intensity value stored in the intensity information memory 132. The correction is performed using the displacement amounts Ax and Ay acquired from the vibration detection device 240. As the displacement amount, a value obtained at the timing when the delay amount for calculating the distance value and the intensity value is acquired is used.

The correction unit 120 performs correction by converting the address of the pixel. Then, the converted results are stored again in the distance information memory 131 and the intensity information memory 132, respectively. The correction performed by the correction unit 120 of the present embodiment corrects distortion within one frame, as will be described later. For this reason, this correction is called distortion correction processing.

For example, in the distance information memory 131 or the intensity information memory 132, the X-axis and Y-axis pixel addresses are Px and Py, respectively, and the X-axis and Y-axis displacements corresponding to the pixel coordinates are respectively the displacement amounts Ax , Ay. At this time, the correction unit 120 converts the address of the pixel into Pcx and Pcy according to the following equation (3).

Here, Bx and By in Expression (3) represent conversion coefficients of pixel movement amounts with respect to displacement amounts detected by the X-axis and Y-axis vibration detection devices 240, respectively. ROUND is a function that rounds off the value in parentheses for integerization. In addition, the function for integerization in Formula (3) is not necessarily limited to the rounding-off process. It may be a function that rounds up or down.

The output processing unit 234 performs various processes on the intensity information stored in the intensity information memory 132, for example, and outputs the processed intensity information. As various types of processing, for example, image processing, conversion processing to a digital broadcast signal, and the like are performed. The image processing performed here is, for example, gamma correction. Also, the conversion process to digital broadcasting is, for example, ATSC, DVB-T, ISDB-T, or the like. The output destination is the ECU 300 or the like.

The functions included in the control unit 230, that is, the vibration analysis unit 233, the pulse signal generation unit 235, the distance calculation unit 231, the intensity calculation unit 232, the output processing unit 234, and the correction unit 120 include, for example, a CPU and a memory And an information processing device including a storage device. Here, the CPU is realized by loading a program stored in a storage device in advance into a memory and executing the program. All or some of the functions may be realized by hardware such as ASIC (Application Specific Integrated Circuit) or FPGA (Field-programmable gate array).

Also, various data necessary for the process and various data obtained by the process are stored in the storage device. In the present embodiment, the distance information memory 131 and the intensity information memory 132 are constructed in a storage device.

The flow of the swinging direction control process of the scanner 212 (light deflecting unit 213) by the above-described units will be described with reference to FIG. This process is started when the optical distance measuring device 100 is activated.

When the optical distance measuring device 100 is activated, the vibration analysis unit 233 calculates the main vibration direction θM using the displacement received from the vibration detection device 240 (step S1101). At this time, the scanning angle detector 215 detects the current angle θc of the light deflector 213. The pulse signal generation unit 235 generates a drive signal from the main vibration direction θM (step S1103) and transmits it to the propagation direction control unit 216.

The propagation direction control unit 216 controls the drive unit 214 according to the drive signal and the current angle θc so that the swing direction θF of the light deflection unit 213 becomes the main vibration direction θM and the visual field range 401 is scanned. (Step S1104). The optical scanning device 200 continues the above process according to the control timing signal until an end instruction is received (step S1101). Thereby, in this embodiment, a rocking | fluctuation direction changes in real time. That is, the swing direction can always be kept substantially parallel to the main vibration direction.

Next, the flow of distance measurement processing by the optical distance measuring device 100 of the present embodiment will be described. FIG. 4B is a processing flow of the distance measuring process of the present embodiment. The processing of the present embodiment is started when the optical distance measuring device 100 is activated.

The signal processing unit 225 transmits a light projection timing signal to the light projecting unit 211. Receiving the light projection timing signal, the light projecting unit 211 projects the modulated light to the approximate swing center of the light deflecting unit 213 (step S1202). The modulated laser light is irradiated as a measurement light in a predetermined direction by the light deflecting unit 213 and diffusely reflected by objects around the vehicle.

The light receiving unit 221 detects light reflected by diffuse reflection (step S1203). Then, the obtained reflected light information is processed by the output unit 226 and input to the signal processing unit 225.

The signal processing unit 225 calculates a delay amount from the emission of the measurement light to the reception of the reflected light from the converted reflected light information, and performs signal processing for calculating the intensity information of the reflected light (step S1204). Then, the calculated delay amount and intensity information are output to the distance calculator 231 and the intensity calculator 232, respectively.

The distance calculation unit 231 calculates the distance to the object using the received delay amount and stores it in the distance information memory 131. In addition, the intensity calculator 232 stores the intensity information in the intensity information memory 132 (step S1206).

When data for one frame is stored in each of the distance information memory 131 and the intensity information memory 132, that is, when a distance image and an intensity image are generated, the correction unit 120 performs a distortion correction process (step S1206). . Here, the correction unit 120 performs the distortion correction process on the distance image and the intensity image by the above method using the displacement received from the vibration detection device 240 according to the control timing signal. Then, the corrected distance image is output to ECU 300. Further, the corrected intensity image is output to ECU 300 via output processing unit 234.

The optical distance measuring device 100 continues the above process according to the control timing signal until an end instruction is received (step S1201).

Next, the necessity for the distortion correction processing by the correction unit 120 will be described. In the optical distance measuring device 100 of the present embodiment, vibration from the road surface is applied as external vibration depending on the traveling environment of the vehicle on which the optical distance measuring device 100 is mounted.

FIG. 5A and FIG. 5B exemplify the time history of displacement observed by the vibration detection device 240 in the Y-axis direction and the X-axis direction (changes in the time-axis direction), respectively. is there. Here, black dots 411 and 412 in FIGS. 5A and 5B represent actual sampled measurement points.

Normally, the displacement waveform due to external vibration applied to the optical distance measuring device 100 depending on the road surface condition is the same as the X axis as shown in FIGS. With respect to the Y axis, the frequency and phase are substantially the same and only the amplitude is different. Alternatively, the frequencies are substantially the same, the phases are different by 180 degrees, and the amplitudes are different. At this time, as shown in FIG. 5C, the mounted vehicle continues to vibrate in the direction of the angle θM, so the main vibration angle θM of the optical distance measuring device 100 does not depend on the passage of time. It is almost constant.

The effect of such external vibration on the detection result of the optical distance measuring device 100 will be described.

FIG. 6A shows the relationship between the light emitting region 424, the non-light emitting region 425, and the visual field range 422 when there is no external vibration. Here, the light deflection unit 213 is swung in a direction substantially parallel to the angle θM, and is translated so as to cover the field of view range.

In this figure, a white arrow indicates a trajectory 421 drawn by the propagation direction of the scanner 212, a rectangular area drawn by a broken line indicates a visual field range 422, and a plurality of rectangular band areas drawn by solid lines indicate column units at the time of scanning. Further, 423, a dark color region in the rectangular band represents a light emitting region 424, and a light color region represents a non-light emitting region 425. Note that the light emitting area 424 is an area in which the distance is measured by actually causing the light projecting unit 211 to emit light. Further, the non-light emitting area 425 is an area in which the distance measurement is not performed without causing the light projecting unit 211 to emit light.

When there is no external vibration, the light emitting region 424 is substantially rectangular with the rectangular region (view range 422) drawn with a broken line. For this reason, distance information of the entire visual field can be obtained only by drive control.

However, actually, since the external vibration is generated in the angle θM direction, the visual field range 422 cannot be kept rectangular. FIG. 6B shows a relationship between the light emitting region 424, the non-light emitting region 425, and the visual field range 422 when external vibration is generated in the θM direction. Here, the drive control of the light deflection unit 213 is the same as that in FIG.

In this figure, a rectangular area drawn with a broken line indicates a visual field range 422 when there is no external vibration, and a plurality of rectangular band areas drawn with a solid line show a column unit 433 during scanning and a column unit 433. Among these, the dark color region represents the light emitting region 434, and the light color region represents the non-light emitting region 435.

When there is external vibration, the light emitting region 434 vibrates in the angle θM direction due to this vibration. For this reason, the light emitting region 434 is displaced from the original rectangle (original visual field range 422). Regardless of the presence or absence of external vibration, the distance information detection result is given an array address on the premise of the original visual field range 422. As a result, the detection result of the optical distance measuring device 100 is affected.

7A to 7C are used to explain the influence on the detection result when external vibration is applied to the optical distance measuring device 100. FIG. Here, a white thick line 441 on the X axis in the visual field range 422 shown in FIG.

Here, as shown in FIG. 7B, it is assumed that external vibration has occurred in a direction inclined from the X axis by an angle θ (in this figure, θ = 45 degrees). In this case, a change in the time direction of the external vibration is indicated by a thick curve 444.

In the case of using the scanning optical scanning device 200 as in the present embodiment, when such external vibration is applied, the thick line 441 that is the detection target 441 is detected in a distorted shape like a white curve 443. That is, a visual field different from the original visual field range 422 is detected by the external vibration, and thereby a detection result 442 different from the actual shape of the detection target 441 is erroneously detected.

The correction unit 120 performs distortion correction processing on the detection result 442 according to the above equation (3), so that the shape of the original detection target 441 is obtained as indicated by a white bold line 441a in FIG. Detection result 441a can be obtained. However, the visual field range 422a obtained by performing the distortion correction process is smaller than the visual field range 422 before correction.

Note that, after the corrected visual field range 422a is found, the signal processing unit 225 may control the light projection timing signal so that light is emitted only within the corrected visual field range 422a. The corrected visual field range 422a is obtained by the correction unit 120 performing correction processing. The corrected visual field range 422a can also be calculated from the amount of displacement detected by the vibration detection device 240. In this case, the displacement detected by the vibration detection device 240 is also output to the signal processing unit 225, and the signal processing unit 225 controls light projection accordingly.

Next, the effect of swinging and driving substantially parallel to the direction of external vibration (main vibration direction) will be described with reference to FIGS. 8 (a) to 11 (e).

FIGS. 8A and 9A show simulation results of the trajectory drawn by the propagation direction when the swinging direction of the scanner 212 is the X-axis direction. FIG. 8A shows an ideal state where there is no external vibration, and FIG. 9A shows a simulation result when external vibration occurs in the Y-axis direction. In FIG. 9A, unlike the control of the present embodiment, the swing direction is set to be perpendicular to the external vibration direction. Table 1 shows other simulation conditions at this time.

8 (b) and FIG. 9 (b) are partially enlarged views of FIG. 8 (a) and FIG. 9 (a), respectively. Note that the horizontal axis and the vertical axis in each of these figures represent the pixel (column) number in the X-axis direction and the pixel (row) number in the Y-axis direction, respectively, in the visual field at the time of detection.

When there is no external vibration, as shown in FIG. 8A, the locus of the sine wave is drawn without distortion in the X-axis direction. Further, as shown in FIG. 8B, a uniform trajectory can be obtained without deviation in each of the rows with row numbers 0 to 99.

On the other hand, when there is external vibration in the Y-axis direction, as shown in FIG. 9A, the trajectory in the propagation direction is divided into a region in which the density of the sine wave is sparse and a region in which the density of the sine wave is dense in the Y-axis direction. , Drawn repeatedly. As can be seen from the enlarged view of FIG. 9B, in the region where the density is sparse, the trajectory hardly passes and detection is not possible.

As described above, when the detection density is sparse and dense, even if the detection is corrected to the correct shape by the distortion correction process, the detection itself is hardly performed in the region where the density is sparse. Missing. On the contrary, in the region where the density is high, the detection information is excessive, and the detection information overlaps with one pixel after distortion correction. Therefore, it is not desirable from the viewpoint of data utilization efficiency.

Next, FIG. 10A to FIG. 10E show the influence of the vibration and the effect of the correction processing when the scanner 212 is swung in the same direction as the external vibration as in this embodiment. . Here, a case where the main vibration direction and the swing direction are the Y-axis direction will be described as an example. FIG. 10A shows a visual field range 422 and a detection target 441 when there is no vibration.

FIG. 10B shows the detection result when external vibration is applied in the Y-axis direction. As shown in this figure, the detection visual field 422b vibrates with external vibration. For this reason, if the detection result is stored in the distance information memory 131 as it is, the detection result 441c is distorted as shown in FIG. However, as shown in FIGS. 9A and 9B, the detection density can be detected uniformly without sparseness. Further, the detection area is not partially lost. As a result, when distortion correction processing is performed, as shown in FIG. 10D, the detected visual field range 422a is smaller than the original visual field range 422, but as shown in FIG. 10E as the detection result 441a. The shape of the detection object 441 can be detected correctly.

Thus, as in this embodiment, by controlling the oscillation direction to be substantially parallel to the external vibration angle θ, there is no missing detection area and high data utilization efficiency is maintained. In addition, the distortion correction process can be performed.

As described above, according to the optical scanning device 200 of this embodiment, the measurement light that is the light to be projected is deflected in the light projecting direction determined by the swing direction and the translation direction intersecting the swing direction. The light deflecting unit 213, the light projecting unit 211 that projects the measurement light toward the light deflecting unit 213, the light receiving unit 221 that receives the reflected light of the measurement light from the object, and the oscillation direction is A propagation direction control unit 216 that drives and controls the light deflection unit 213 so as to be in a main vibration direction that is a main vibration direction. And the vibration analysis part 233 which acquires a main vibration direction is further provided. The vibration analysis unit 233 obtains the main vibration direction using the output from the vibration detection device 240 that is a displacement sensor that detects displacement in response to external vibration.

Therefore, according to this embodiment, the swinging direction of the optical scanning device 200 is controlled so as to be always substantially parallel to the vibrating direction. For this reason, as described above, the detection density in the scanning region does not vary. For this reason, data can be used efficiently. That is, even when external vibration is applied, it is possible to realize uniform detection without causing sparseness in detection density.

Furthermore, according to the optical distance measuring device 100 of the present embodiment, the distance image generation unit 110 that generates a distance image from the output information of the optical scanning device 200 and the output of the vibration detection device 240 are used to detect the distance image by vibration. And a correction unit 120 that corrects distortion.

Therefore, according to the present embodiment, it is possible to obtain a detection result obtained by correcting the distortion in the frame while efficiently using the acquired data in the scanning sensor. That is, in the scanning type apparatus, distortion of the detection target due to external vibration can be efficiently reduced.

In the above embodiment, the main vibration direction θM due to external vibration is detected, and the swing direction is controlled to be substantially parallel to the main vibration direction θM. However, it is not limited to this method. For example, when the main vibration direction is specified in advance, the control may be performed such that the main vibration direction is always swung in the direction. In this case, the light deflecting unit 213 may have a configuration having a drive axis only in the direction, that is, uniaxial drive. In this case, the vibration detection device 240 and the vibration analysis unit 233 may not be provided.

For example, when the mounting destination of the optical distance measuring device 100 is an automobile, the external vibration that the optical distance measuring device 100 receives during traveling is vibration due to the road surface. And this vibration is dominant in the direction of gravity. Therefore, in such a case, the swinging direction may be set substantially parallel to the gravity direction.

Further, when the external vibration direction is only the gravitational direction (Y-axis direction), in the distance information memory 131 and the intensity information memory 132, in the pixels having the same address value Pcx in the X-axis direction, the shift amount AxBx and AyBy has substantially the same value. In such a case, the shift amount need not be calculated for each pixel. The above-described distortion correction processing may be performed in an offset manner using the deviation amounts AxBx and AyBy calculated for one pixel.

In addition, in a pixel whose address has a geometrical relationship substantially parallel to the external vibration direction, the shift amounts AxBx and AyBy have substantially the same value. This is the case, for example, when the value of θM obtained from equation (2) or the value of a trigonometric function such as tan based on θM is substantially the same. Also in this case, the above-described distortion correction processing may be performed in an offset manner using the deviation amounts AxBx and AyBy calculated for one pixel. That is, the same value may be used for the address string that is substantially parallel to the main vibration direction in the memory that stores the pixel values of the distance image.

The control that makes the oscillation direction substantially parallel to the main vibration direction θM of external vibration, which is a feature of the present embodiment, is not limited to the optical distance measuring device 100, but various light that requires scanning of a light spot. It can be applied to a scanning device. Examples of such an optical scanning device include an automobile headlight or a video projection projector.

According to this embodiment, even in such an optical scanning device, even when external vibration is applied, a uniform field of view or projection image in which the density of projection of the light spot does not occur can be realized. That is, it is possible to irradiate the desired area without distortion by efficiently using the acquired data.

In this embodiment, the distance information is temporarily stored in the distance information memory 131, a distance image is obtained, and distortion associated with external vibration applied to the optical distance measuring device 100 is corrected for the distance image. However, it is not limited to this method.

For example, a displacement sensor having a high sampling frequency may be used as the vibration detection device 240. In this case, external vibration applied to the optical distance measuring device 100 can be detected at high speed. For this reason, the correction unit 120 can perform distortion correction in real time.

The propagation direction control unit 216 controls the control amplitudes AMPcx and AMPcy at the time of swinging when the scanner 212 translates so as to cover the field of view range while swinging in a direction substantially parallel to the vibration direction θM. Derived in real time according to the following equation (4).

Here, AMPx and AMPy in Equation (6) are the X-axis and Y-axis components of the control amplitude when rocking with respect to the vibration direction θM. Ax and Ay are the X-axis and Y-axis displacement amounts detected by the vibration detection device 240. Fx and Fy are conversion coefficients of control amplitude with respect to detection values by the X-axis and Y-axis vibration detection devices 240.

That is, when using such a displacement sensor, the distortion is corrected by feeding back the vibration amplitude of the external vibration detected in real time to the amplitude of the swing control. However, it is not limited to this method. For example, when the pavement of the roadway is a periodic stone pavement, it is considered that the external vibration received by the optical distance measuring device 100 from the road surface is periodic. In such a case, the feedforward correction may be performed by estimating the frequency of the external vibration from the time history of the displacement amount of the external vibration detected by the vibration detection device 240.

Using such a displacement sensor and performing the above-described correction, unlike the example shown in FIG. 6C, the corrected visual field range does not become small. Therefore, it is possible to correct the distortion in the frame while maintaining the original wide visual field range.

<< Second Embodiment >>
A second embodiment of the present invention will be described. In the present embodiment, the temporal change of the distance image and the intensity image acquired by the optical distance measuring device is used to correct the influence of external vibration of these distance image and intensity image.

In this embodiment, the output of an external vibration detection sensor is not used. For example, when the device to be mounted is a vehicle or the like, the main vibration direction during traveling is substantially vertical. In this embodiment, the main vibration direction is determined in advance, and the swinging direction of the scanner (light deflection unit) is set to this main vibration direction. Hereinafter, in the present embodiment, a case where the mounting destination is a vehicle and the main vibration direction is the Y-axis direction will be described as an example.

FIG. 11 is a configuration diagram of the optical distance measuring device 100a of the present embodiment. The optical distance measuring device 100a of this embodiment basically has the same configuration as that of the first embodiment. However, in the present embodiment, unlike the first embodiment, the output of the external vibration detection sensor (vibration detection device 240) is not used. Therefore, the vibration analysis unit 233 that processes the output of the vibration detection device 240 is not provided.

Also, the correction unit 120a does not use the output of the vibration detection device 240 at the time of correction. Hereinafter, the present embodiment will be described focusing on distortion correction processing by the correction unit 120a different from the first embodiment.

Also in this embodiment, the distance calculator 231 and the intensity calculator 232 temporarily store the calculated distance value and the intensity value of the reflected light in the distance information memory 131 and the intensity information memory 132, respectively. Then, the correction unit 120a corrects the influence of external vibration by converting these addresses using the correction value in units of one frame. At this time, in the present embodiment, the correction value is calculated using a distance image of a plurality of frames.

To realize this, the optical distance measuring device 100 according to the present embodiment further includes an information matching unit 140 that detects distortion of the distance image and the intensity image due to vibration and calculates a correction amount.

As in the first embodiment, when the optical distance measuring device 100 receives external vibration, as shown in FIG. 12A, the field of view 451 different from the original field of view range 422 (dotted rectangle in the drawing) Detected. Regardless of the presence or absence of external vibration, the distance information detection result is given a rectangular array address as shown in FIG. 12B on the premise of the original visual field range 422. The distance information 452 stored in the distance information memory 131 has distortion.

In this embodiment, the external vibration detection device 240 is not provided. For this reason, when a detection result having distortion in the Y-axis direction is obtained as shown in FIG. 13A, the actual detection target shape itself is distorted as shown in FIG. 13B. However, as shown in FIG. 13C, the actual shape of the detection target is not distorted, and it cannot be determined whether the field of view is distorted by external vibration.

The information matching unit 140 according to the present embodiment determines whether the detection result with distortion is due to distortion of the shape of the detection target or due to external vibration. If it is determined that the vibration is due to external vibration, Ax and Ay are calculated and output as the displacement amounts of vibration in the X-axis direction and Y-axis direction. As described above, in the present embodiment, since the main vibration direction is the Y-axis direction, Ay is calculated as the displacement amount.

To realize this, the information matching unit 140 of the present embodiment includes a distortion detection unit 141 and a distortion amplitude detection unit 142.

The distortion detection unit 141 calculates the distortion of the same object in the first area and the distortion in the second area, which is closer to the host vehicle than the first area, and determines the cause of the distortion. The distortion detection unit 141 calculates distance information (first distance information) in the first region and distance information (second distance information) in the second region. When calculating the second distance information, the speed of the host vehicle is taken into consideration. The speed information of the host vehicle is acquired from the ECU 300.

As shown in FIG. 14A, the first area and the second area are set based on an optical vanishing point 521 in the visual field range of the optical distance measuring device 100a. For example, the first region 522 is set at a position (far distance) close to the optical vanishing point, as shown in FIG. The second region 523 is set to a region (medium distance) obtained by projecting the first region from the vanishing point in an enlarged manner. Here, a case where each is set to a rectangular area will be described as an example.

At this time, the distance information acquired at the timing when the same object is acquired at each position is used. Accordingly, the frames for calculating the distance information of the first position and the second position are different. For this reason, the distance information memory 131 of this embodiment can secure the distance information memory for at least two frames.

When it is determined that the cause of distortion is due to external vibration, the distortion amplitude detection unit 142 calculates the distortion width, that is, the displacement amount Ay. As the displacement amount, a result calculated by the strain detection unit 141 at the time of determination is used.

Hereinafter, the displacement amount calculation processing by the information matching unit 140 of the present embodiment will be described according to the processing flow of FIG.

First, distance information of the first area 522 is calculated (step S2101).

Here, the calculation of the distance region in the first region 522 will be described with reference to FIGS. 16 (a) to 17 (b).

FIG. 16A shows the distance detection result of the first region 522 when there is no external vibration, and FIG. It is a distance image expressed by a difference.

When there is no external vibration, the road surface on which the vehicle travels is generally flat. That is, the distance value of the same distance from the optical distance measuring device 100a is substantially constant. In the case of a distance image, as shown in FIG. 16A, the distance values of pixel rows having the same coordinate in the Y-axis direction are substantially the same. Further, the distance value increases as the value in the Y-axis direction increases. In terms of the distance image, in the pixel row having the same X-axis coordinate, the distance value increases toward the back side.

In such a situation, when the average value D of the distance information is calculated for each pixel row (pixel group having the same X-axis coordinate) in the area for calculating the distance information, as shown in FIG. In all the columns, substantially the same value is obtained.

On the other hand, when there is an external vibration, the field of view also vibrates in the Y-axis direction. Therefore, as shown in FIG. 16C, the distance information is also a distortion synchronized with the vibration (referred to as waveform distortion). Have. Therefore, when the average value D of the distance information is calculated for each pixel column in the area for calculating the distance information in such a situation, the value vibrates as shown in FIG.

First, the distortion detection unit 141 of the present embodiment calculates the average value D for each pixel column as described above for the first region 522, and determines the presence or absence of waveform distortion. For example, it is determined whether or not each calculated average value D is within a predetermined threshold.

Here, as shown in FIGS. 16B and 16D, the average value D for each pixel column is calculated, and the average value (average value of all data) Dave is calculated.

The distortion detector 141 determines whether or not there is distortion depending on whether or not the average value D of each pixel column is within the range of Dave ± Dth (step S2102). Note that Dth is determined in advance.

The distortion detection unit 141 determines that there is distortion when it does not fit. If it is determined that there is distortion, the waveform distortion amplitude Ad is further calculated.

If it is determined that there is distortion, the distortion detector 141 further calculates the waveform distortion of the second region 523 after a predetermined time (step S2103). Here, first, the distortion detection unit 141 calculates the average value Ad2 of the waveform distortion by calculating the average value for each pixel column of the second area 523 by the same method as that of the first area 522.

Furthermore, the time history of the speed information of the host vehicle received from the engine control unit 300 and the elapsed time from the frame acquisition for calculating the distance information of the first area 522 to the frame acquisition for calculating the second area 523 And the movement distance between frames is estimated. Then, based on the information of the movement distance, the magnification at the time of projection of the waveform distortion is calculated.

Then, the distortion detection unit 141 determines the cause of the distortion (step S2104). The cause of the distortion is determined by whether or not the amplitude of the waveform distortion calculated in the first area 522 and the amplitude of the waveform distortion calculated in the second area 523 are constant. If it is constant, it is determined that it is due to external vibration.

FIG. 14B and FIG. 14C show the difference in generation between waveform distortion caused by external vibration and waveform distortion caused when the detection target itself is distorted.

As shown in these drawings, the amplitude and frequency of the waveform distortion detected due to external vibration are substantially the same in any distance region as shown in FIG. 14B. On the other hand, when the detection target itself is distorted, the amplitude of the waveform distortion increases substantially linearly with respect to the distance from the optical vanishing point 521 as shown in FIG.

For example, it is assumed that the amplitude of the distance information calculation result in the first region 522 is Ad. When detected by external vibration, the amplitude of waveform distortion is Ad at all distances, as shown in FIG. On the other hand, when the shape of the detection target is distorted, the distance to the first region 522, the distance to the second region 523, and the distance to the third region 524 (short distance) are equally spaced. Assuming that, as shown in FIG. 14C, 2Ad and 3Ad are obtained in the second region and the third region.

When the distortion detector 141 determines that the cause of distortion is due to external vibration (step S2105), the distortion amplitude detector 142 calculates a displacement amount used for correction by the correction unit 120 (step S2106).

Here, for example, as illustrated in FIG. 17A, the distortion amplitude detection unit 142 calculates the average value Dave of all data in the second region 523 by the same method as that of the first region 522. Then, as shown in FIG. 17B, a difference Dy between the average value D in each column direction and the average value Dave of all data is calculated.

The correction unit 120 corrects the address of each pixel value of the distance image and the intensity image using the difference Dy as the displacement amount Ay (step S2107), and ends the process.

The correction is performed according to the following equation (5).

Here, P _x and P _y are addresses of X-axis and Y-axis pixels in the distance information memory 131 or the intensity information memory 132. P _cx and P _cy are addresses after the conversion.

If it is determined in step S2102 that there is no distortion, and if it is determined in step S2105 that the cause of distortion is due to the shape, the process returns to step S2101 and the process is repeated.

Note that the determination of the factor in step S2104 is not necessarily performed based on the amplitude. Any standard that can determine whether the detected distortion is the actual shape of the detection target or the external vibration may be used. For example, a frequency obtained as a result of image analysis may be used.

In the above example, the correction amount Ay is calculated from the distance information (waveform distortion) of the second region 523, but is not limited to this. For example, as shown in FIG. 14 (a), even if there are three or more positions, a far distance position closer to the vanishing point 521, a middle distance position farther from the vanishing point than the far distance position, and a near distance position farther from the vanishing point. Good. In this case, for example, the three positions may be set at equal intervals from the optical vanishing point 521. In this case, the distance information memory 131 can secure the distance information memory for at least the number of frames equal to the number of positions for calculating the distance information. The third area 524 is preferably an area that covers data of all columns of the visual field.

Further, the shape of the area for calculating the distance information is not necessarily limited to a rectangle as shown in FIG. 14A, and any shape can be used as long as the projection from the vanishing point 521 is possible.

As described above, according to the present embodiment, distortion due to external vibration can be corrected using the distance image itself acquired by the optical distance measuring device 100a. As in the first embodiment, a vibration detection sensor that is separate from the optical distance measuring device 100 is not used. Therefore, even when an external vibration is applied to the scanning sensor only with the optical distance measuring device 100a, a detection result in which distortion in the frame is corrected can be obtained. That is, it is possible to obtain a high-quality image with a simpler configuration and free from the influence of distortion due to vibration.

Further, when the direction of external vibration is known in advance, the acquired data can be used efficiently as in the first embodiment by setting the swing direction to the vibration direction.

<< Third Embodiment >>
A third embodiment of the present invention will be described. In the present embodiment, the main vibration direction of external vibration is specified using an image acquired by an image acquisition device separate from the optical distance measuring device. In addition, the image is used to correct distortion due to external vibration of the distance image and the intensity image.

FIG. 18 is a configuration diagram of the optical distance measuring device 100b of the present embodiment. As shown in the figure, the optical distance measuring device 100b of this embodiment basically has the same configuration as the optical distance measuring device 100 of the first embodiment. Hereinafter, the present embodiment will be described focusing on the configuration different from the first embodiment.

In the present embodiment, the displacement amounts Ax and Ay and the main vibration direction θM of the optical distance measuring device 100b are calculated using information from the image acquisition device 600 outside the optical distance measuring device 100b. Then, using this, the propagation direction control unit 216 controls the swinging direction of the scanner 212 (light deflection unit 213), and the correction unit 120 corrects the influence of external vibration.

In order to realize this, the optical distance measuring device 100b of the present embodiment includes a camera image information memory 133 that stores data acquired by the image acquisition device 600 (hereinafter referred to as a camera image). Further, an information collating unit 140b that calculates correction amounts (displacement amounts) Ax and Ay is provided. The information matching unit 140b includes a distortion amplitude detection unit 142b, a viewpoint conversion unit 143, and an image processing unit 144.

In addition, the vibration analysis unit 233 of the present embodiment obtains the displacement amounts Ax and Ay from the distortion amplitude detection unit 142 and specifies the main vibration angle θM in the main vibration direction.

The propagation direction control unit 216 controls the swing direction of the scanner 212 so as to be substantially parallel to the main vibration direction θM, as in the first embodiment.

Note that the image acquisition device 600 is a non-scanning sensor that can acquire pixel values for one frame at a time. The image acquisition apparatus 600 is a camera having a non-scanning image sensor such as a CCD or a CMOS, for example. The image acquisition device 600 has the same or higher frame rate as the optical distance measuring device 100b, and can capture frames at the same timing as the optical distance measuring device 100b by performing synchronization control. And

Prior to the detailed description of each part, using the camera image acquired by the non-scanning sensor and the intensity image acquired by the scanning sensor such as the optical distance measuring device 100b of this embodiment, the vibration of the distance image and the intensity image is performed. The reason why the distortion (displacement amount) can be calculated will be described.

FIG. 19A is a schematic diagram showing a state of the visual field 461 when external vibration is applied to the scanning sensor. In the case of a scanning sensor, the field of view 461 is distorted in synchronism with the vibration as shown in FIG.

FIG. 19B is a schematic diagram showing the state of the visual field 471 when external vibration is applied to the non-scanning sensor. In the case of a non-scanning sensor, visual field distortion can be sufficiently ignored if the sensor is an ideal sensor with a short exposure time. As a detection result, a result in which the entire visual field is shifted by the vibration amplitude at the timing of exposure is obtained.

Therefore, the cause of the distortion of the shape of the detection target obtained by the scanning sensor can be specified by collating the acquisition result of the non-scanning sensor and the information of the scanning sensor acquisition result. That is, it is possible to distinguish whether the detection target itself has a distorted shape or whether the field of view is distorted due to intra-frame distortion due to external vibration.

The details of the displacement amount calculation processing by the information matching unit 140b of this embodiment will be described with reference to FIG.

The viewpoint conversion unit 143 performs viewpoint conversion for converting the intensity information (intensity image) stored in the intensity information memory 132 into the viewpoint direction of the camera image acquired by the image acquisition apparatus 600 (step S2101). For the viewpoint conversion, distance information (distance image) stored in the distance information memory 131 is used. The viewpoint conversion is performed by a known method using information such as the installation position and field of view of the optical distance measuring device 100b and the installation position and field of view of the image acquisition device 600.

Since the optical distance measuring device 100b and the image acquisition device 600 are separate bodies, their fields of view are different. Therefore, the viewpoint conversion is performed from the distance image to the viewpoint of the camera image before information collation. However, when the optical distance measuring device 100b and the image acquisition device 600 are installed at a close distance such that the visual field shift between them can be ignored, the viewpoint conversion is not necessarily performed. In this case, the viewpoint conversion unit 143 may not be provided.

The image processing unit 144 performs various types of image processing on the intensity image and the camera image after the viewpoint conversion (step S3102). Here, for example, lens distortion correction, light amount correction, gamma correction, range conversion by bit number conversion, image size conversion, and the like are performed. By performing such image processing, comparison between the intensity image and the camera image becomes possible.

The distortion amplitude detection unit 142b compares the processed intensity image with the camera image, calculates the pixel shift amount, and calculates the displacement amount (step S3103). The calculation result is output to the vibration analysis unit 233 and the correction unit 120.

The shift amount is calculated by matching processing using a template in the image. Details of the shift amount calculation will be described with reference to FIGS. 21 (a) to 22 (c).

First, the process of calculating the pixel shift amount between the processed intensity image 620 and the camera image 610 when the swinging direction is the Y-axis direction will be described with reference to FIGS. 21 (a) to 21 (c). The pixel shift amount is calculated by matching processing using the template 611 in the camera image 610. The pixel shift amount is calculated for each column of the intensity image 620 in the swing direction.

For example, assume that the template 611 shown in FIG. As the region used as the template 611, only the number M of pixels in the predetermined column, for example, near the center in the camera image 610 is used. The reason for not using all the pixels in the swinging direction is that the pixel value at the end of the camera image 610 may be missing in the intensity image 620 that is a comparison target due to vibration.

Note that the region used for the template 611 is not limited to the pixel near the center of the column. You may use the pixel of an edge part.

The distortion amplitude detection unit 142b uses the extracted template 611 to search for a matching part in the intensity image 620. Here, for example, as shown in FIG. 21B, a raster scan search is performed in the swing direction. That is, the matching process is performed by raster scanning on the region of the intensity image 620 having the same number of pixels M as the template 611.

The matching is performed by evaluating by an SSD (Sum of Squared Difference) method. That is, the distortion amplitude detection unit 142b sets the region where the dissimilarity R_SSD expressed by the following formula (6) is the smallest as the matching region 512.

Note that the number of each pixel in the template 611 is i (i = 0 to M−1), the luminance value of the pixel i of the template 611 is T (i), and the correspondence in the region in the intensity image 620 to be compared. Let I (i) be the luminance value of the pixel with the number i.

FIG. 21 (c) shows an example in which the matching region 612 is determined to be a position shifted by Ax in the X axis direction and Ay in the Y axis direction with respect to the camera image 610 as a result of matching. In this case, the distortion amplitude detection unit 142b sets the deviation Ay as a displacement. In the example of FIG. 20C, since the swinging direction is the Y-axis direction, Ax = 0.

Next, with reference to FIGS. 22A to 22C, a description will be given of a deviation amount calculation processing example when the swinging direction is the θF direction with respect to the X axis. In this case, the template 611 is extracted along the swing direction θF at that time. However, the region used for the template 611 is not all the pixels in the column of the swing direction θF in the camera image 610, for example, the number of pixels near the center of the column in the same direction of the camera image 610, as in FIG. Only M is used.

Also in this case, the distortion amplitude detection unit 142b uses the extracted template 611 to search for a matching portion in the intensity image 620 by raster scanning. A region where the dissimilarity R_SSD expressed by the above formula (6) is the smallest is set as a matching region 612.

FIG. 22C shows a state in which the value of the difference R_SSD is the smallest at a position shifted by Ax in the horizontal direction and Ay in the vertical direction with respect to the camera image 610 as a result of matching.

The distortion amplitude detector 142b calculates the pixel shift amounts Ax and Ay obtained as a result of the matching as displacement amounts.

The correction unit 120 that has received the displacement amounts Ax and Ay from the distortion amplitude detection unit 142b performs correction by the same method as in the first embodiment (step S3104).

The vibration analysis unit 233 also calculates the main vibration direction θM and the combined displacement (amplitude) Acom by the same method as in the first embodiment.

Note that the matching process with the template in this embodiment is not limited to the SSD method, but the SAD (Sum of Absolute Difference) method, the NCC (Normalized Cross-Correlation) method, or the ZNCC (Zero-mean Normalized Cross-Cross-Corresion-Cross-Corress The method may be used.

As described above, according to the present embodiment, the swing direction of the optical scanning device 200 is controlled to be always substantially parallel to the swing direction. For this reason, as in the first embodiment, the detection density in the scanning region does not vary, and data can be used efficiently. That is, even when external vibration is applied, it is possible to realize uniform detection without causing sparseness in detection density.

Also, distortion caused by vibration of the distance image is corrected using the output of the image acquisition device 600. Therefore, as in the first embodiment, in the scanning sensor, the distortion of the detection target can be corrected by external vibration while efficiently using the acquired data.

In addition, although the optical ranging apparatus 100 in each of the above-described embodiments has been described by taking as an example the case of being mounted on an automobile or the like for the purpose of explanation, the mounting target is not limited to an automobile. For example, what is necessary is just to acquire the surrounding information, such as a self-propelled conveyance vehicle like an automatic guided vehicle, and a robot.

100: Optical distance measuring device, 100a: Optical distance measuring device, 100b: Optical distance measuring device, 110: Distance image generation unit, 120: Correction unit, 120a: Correction unit, 131: Distance information memory, 132: Intensity information memory, 133: Camera image information memory, 140: Information collation unit, 140b: Information collation unit, 141: Distortion detection unit, 142: Distortion amplitude detection unit, 142b: Distortion amplitude detection unit, 143: View point conversion unit, 144: Image processing unit ,
200: optical scanning device, 211: light projecting unit, 212: scanner, 213: light deflecting unit, 214: drive unit, 215: scanning angle detection unit, 216: propagation direction control unit, 221: light receiving unit, 222: I / V conversion section, 223: amplification circuit, 225: signal processing section, 226: output section, 230: control section, 231: distance calculation section, 232: intensity calculation section, 233: vibration analysis section, 234: output processing section, 235 : Pulse signal generation unit, 240: vibration detection device,
300: ECU,
401: viewing range, 402: swinging direction, 403: translational direction, 404: locus, 411: black point, 412: black point, 421: locus, 422: field of view range, 422a: field of view range, 422b: detection field of view, 423: column Unit: 424: light emitting area, 425: non-light emitting area, 433: row unit, 434: light emitting area, 435: non light emitting area, 441: detection target, 441a: detection result, 441c: detection result, 442: detection result, 443 : Detection result, 444: vibration, 451: visual field, 452: distance information, 461: visual field, 471: visual field,
512: matching region, 521: vanishing point, 522: first region, 523: second region, 524: third region,
600: Image acquisition device, 610: Camera image, 611: Template, 612: Matching area, 620: Intensity image

Claims (12)

1. A light deflector that deflects measurement light that is light to be projected in a light projecting direction determined by a rocking direction and a translation direction that intersects the rocking direction;
   A light projecting unit that projects the measurement light toward the light deflecting unit;
   A light receiving unit for receiving the reflected light of the measurement light from the object;
   A propagation direction control unit that drives and controls the light deflection unit so that the oscillation direction is a main oscillation direction that is the main oscillation direction of the device;
   And an output unit that outputs information obtained from the reflected light as output information.
2. The optical scanning device according to claim 1,
   A vibration analysis unit for calculating the main vibration direction;
   The vibration analysis unit acquires a displacement amount of the optical scanning device due to the main vibration, and calculates the main vibration direction from the acquired displacement amount.
3. The optical scanning device according to claim 2,
   The vibration analysis unit acquires the amount of displacement from a displacement sensor that detects displacement caused by external vibration.
4. The optical scanning device according to claim 2,
   The vibration analysis unit acquires the displacement amount using an image acquired by a non-scanning image acquisition device.
5. The optical scanning device according to claim 2,
   The vibration analysis unit further calculates an amplitude of the main vibration from the displacement amount,
   The propagation direction control unit controls the amplitude in the swing direction to be within a predetermined visual field range using the calculated amplitude.
6. The optical scanning device according to claim 5, wherein
   A signal processing unit for instructing the timing of projecting the measurement light;
   The signal processing unit controls the light projection timing so that a light projection range by the light deflecting unit becomes a predetermined visual field range.
7. An optical scanning device according to claim 1;
   A distance image generation unit that generates a distance image from the output information;
   And a correction unit that corrects distortion of the distance image due to the main vibration using the displacement amount of the main vibration of the optical scanning device, and outputs a corrected distance image. apparatus.
8. The optical distance measuring device according to claim 7,
   The optical distance measuring device is characterized in that the displacement amount is obtained from a displacement sensor that detects a displacement caused by external vibration.
9. The optical distance measuring device according to claim 7,
   The optical distance measuring device is characterized in that the displacement amount is calculated using the distance images acquired at different times.
10. The optical distance measuring device according to claim 7,
    The displacement amount is acquired using an image acquired by a non-scanning image acquisition apparatus.
11. The optical distance measuring device according to claim 7,
    The displacement amount is acquired for each memory in which each pixel value of the distance image is stored,
    The optical distance measuring device, wherein the correction unit corrects the distortion by displacing the address of the memory by the displacement amount.
12. The optical distance measuring device according to claim 11,
    The optical distance measuring device according to claim 1, wherein the same amount of displacement is used for an address string substantially parallel to the main vibration direction in a memory storing each pixel value of the distance image.
    

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