WO2023008465A1 - 測距装置および測距方法 - Google Patents
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/88—Lidar systems specially adapted for specific applications
- G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging
- G01S17/894—3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4816—Constructional features, e.g. arrangements of optical elements of receivers alone
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
- G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
- G01S17/32—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/491—Details of non-pulse systems
- G01S7/4911—Transmitters
Definitions
- the present disclosure relates to a ranging device and a ranging method.
- Patent Document 1 discloses a distance measuring device based on TOF (Time Of Flight) distance calculation.
- the present disclosure has been made in view of such problems, and aims to provide a distance measuring device and a distance measuring method that reduce the influence of ambient light.
- a distance measuring device includes a light source that emits irradiation light, and a plurality of packets that hold signal charges generated at a plurality of different exposure timings for the irradiation light. and a signal processing circuit for calculating a distance value based on the plurality of packets, wherein the signal processing circuit uses the corresponding plurality of packets for each pixel.
- the presence or absence of ambient light is determined, and if it is determined that there is no ambient light, the distance value of the pixel is calculated by the first process, and if it is determined that there is ambient light, the second process different from the first process is performed to calculate the distance value of the pixel. Calculate the distance value.
- a distance measurement method is a distance measurement method using a light source that emits irradiation light and a solid-state imaging device, wherein signal charges generated at a plurality of different exposure timings for the irradiation light are A plurality of packets to be held are generated for each pixel, and the presence or absence of disturbance light is determined for each pixel using the corresponding plurality of packets. is calculated, and when it is determined that there is ambient light, the distance value of the pixel is calculated by a second process different from the first process.
- the ranging device and ranging method of the present disclosure it is possible to reduce the influence of ambient light.
- FIG. 1 is a block diagram showing a configuration example of a distance measuring device according to Embodiment 1.
- FIG. FIG. 2 is a block diagram showing a configuration example of the solid-state imaging device in FIG.
- FIG. 3 is an explanatory diagram showing examples of six types of packets formed during the ranging operation according to the first embodiment.
- 4A is a time chart showing an operation example of the distance measuring device according to Embodiment 1.
- FIG. 4B is a time chart showing an operation example of the distance measuring device according to Embodiment 1.
- FIG. FIG. 5 is a flow chart showing an operation example of the distance measuring device according to the first embodiment.
- FIG. 6 is a flow chart showing an example of ambient light determination processing in FIG.
- FIG. 1 is a block diagram showing a configuration example of a distance measuring device according to Embodiment 1.
- FIG. FIG. 2 is a block diagram showing a configuration example of the solid-state imaging device in FIG.
- FIG. 3 is an explanatory diagram showing examples of six
- FIG. 7A is a diagram showing an example of packet signal amounts when there is no ambient light.
- FIG. 7B is a diagram showing an example of the signal amount of packets when there is disturbance light.
- FIG. 7C is a diagram showing another example of the packet signal amount in the presence of ambient light.
- FIG. 7D is a diagram illustrating another example of packet signal amounts when there is no disturbance light.
- FIG. 8 is a flow chart showing an operation example of the distance measuring device according to the second embodiment.
- FIG. 9 is a flowchart showing an example of flare determination processing in FIG.
- FIG. 10A is a diagram showing an example of the signal amount of a packet with flare.
- FIG. 10B is a diagram illustrating an example of packet signal amounts when there is no flare.
- FIG. 10A is a diagram showing an example of the signal amount of a packet with flare.
- FIG. 10B is a diagram illustrating an example of packet signal amounts when there is no flare.
- FIG. 10A is a diagram showing an example of
- FIG. 10C is a diagram showing another example of packet signal amounts when there is no flare.
- FIG. 11 is a flow chart showing an example of the second process in FIG.
- FIG. 12 is an explanatory diagram schematically showing an example of a packet to which the second process of FIG. 11 is applied.
- FIG. 13 is a flowchart showing an example of correction processing in FIG. 14A is an explanatory diagram schematically showing the correction processing in FIG. 8.
- FIG. 14B is an explanatory diagram of indexes corresponding to the selection results in FIG.
- FIG. 15 is an explanatory diagram showing target pixels and peripheral pixels used in the correction process in FIG.
- FIG. 16 is an explanatory diagram showing target pixels and peripheral pixels used in the correction process in FIG.
- FIG. 17A and 17B are explanatory diagrams showing an example of irradiation light and a plurality of packets generated from one pixel in the distance measuring device according to the third embodiment.
- FIG. 18 is a flowchart illustrating an example of ambient light determination processing according to the third embodiment.
- FIG. 19 is an explanatory diagram of ambient light determination processing according to the third embodiment.
- FIG. 20 is a flow chart showing an operation example of the distance measuring device according to the fourth embodiment.
- 21 is a flowchart showing an example of the second process in FIG. 20.
- FIG. FIG. 22 is an explanatory diagram schematically showing an example of a packet to which the second process in FIG. 20 is applied.
- FIG. 23 is a flow chart showing an operation example of the distance measuring device according to the fifth embodiment.
- FIG. 24 is a flow chart showing an example of the first flare determination process in FIG. 25 is a diagram for explaining an example of a specific operation of the first flare determination process in FIG. 23.
- FIG. FIG. 26 is a plan view schematically showing how the solid-state imaging device according to Embodiment 6 includes a plurality of OB pixels.
- 27 is a flowchart illustrating an operation example of the distance measuring device according to Embodiment 6.
- FIG. 28 is a flow chart showing an example of the second flare determination process in FIG. 27.
- FIG. 29A is a diagram for explaining an example of a specific operation of the second flare determination process in FIG. 28.
- FIG. 29B is a diagram for explaining an example of a specific operation of the second flare determination process in FIG. 28.
- FIG. 30 is a flow chart showing an operation example of the distance measuring device according to the seventh embodiment.
- 31 is a flow chart showing an example of the third flare determination process in FIG. 30.
- FIG. 32A is a diagram for explaining an example of a specific operation of the third flare determination process in FIG. 30;
- FIG. 32B is a diagram for explaining an example of a specific operation of the third flare determination process in FIG. 30.
- FIG. 32C is a diagram for explaining an example of a specific operation of the third flare determination process in FIG. 30.
- FIG. 33 is a flowchart illustrating an operation example of the distance measuring device according to Embodiment 8.
- FIG. FIG. 34 is a flow chart showing an example of the fourth flare determination process in FIG.
- FIG. 35 is a diagram for explaining an example of a specific operation of the fourth flare determination process in FIG. 33;
- FIG. 36 is a schematic diagram for explaining disturbance light with respect to the distance measuring device.
- FIG. 36 is a schematic diagram for explaining disturbance light with respect to the distance measuring device.
- the illumination light and the reflected light between the distance measuring device 90 and the objects 95, 96 and 97 are schematically shown.
- a rangefinder 90 includes a light source 91 , an image sensor 92 and an optical system 94 .
- Light source 91 emits illumination light to object 95 .
- the image sensor 92 has multiple pixels 93 .
- the optical system 94 includes one lens or a plurality of lenses, and guides the reflected light from the object with respect to the illumination light to the image sensor 92 .
- a dark gray pixel among the plurality of pixels 93 is a pixel of interest PX for explaining ambient light.
- Solid lines in the figure indicate the light emitted from the light source 91 and the directly reflected light.
- the dashed lines in the figure indicate the indirectly reflected light that constitutes the multipath.
- a dotted line in the figure indicates stray light caused by reflection on the light receiving surface of the image sensor 92 and reflection on the lens surface of the optical system 94 .
- the target pixel PX receives direct reflected light R0 from the object 95, stray light R1 from the object 96, and indirect reflected light R2 from the object 97.
- the directly reflected light R0 is reflected light that is reflected by the object 95 from the light source 91 and directly reaches the distance measuring device 90 .
- the stray light R1 is incident light that causes flare, and strong directly reflected light 98 is repeatedly reflected between the surface of the image sensor 92 and the surface of the lens and enters the pixel of interest PX.
- the stray light R1 is generated in the following cases. That is, when an object 96 is present at a close distance to the distance measuring device 90 and has a high reflectance, strong direct reflected light 98 from the object 96 enters the distance measuring device 90 .
- a strong direct reflected light 98 is reflected between the surface of the image sensor 92 and the surface of the lens and reaches the target pixel PX. If the optical system 94 includes multiple lenses, reflections between the lenses may also occur.
- the stray light R1 causes a virtual image called flare in the luminance image, and causes an error in the distance value in the distance image.
- the indirect reflected light R2 is incident light that has been reflected twice or more.
- the indirect reflected light R2 is light that is emitted from the light source 91 and is reflected by the object 97 and further reflected by the target object 95 to enter the target pixel PX.
- the indirect reflected light R2 is likely to occur when the reflectance of the object 97 is high.
- the indirect reflected light R2 and the directly reflected light R0 form multipaths (multiple propagation paths).
- the indirectly reflected light R2 causes a virtual image called a ghost in the luminance image, and causes an error in the distance value in the distance image.
- the distance value of the target pixel PX calculated by the image sensor 92 may have an error due to the influence of ambient light.
- a distance measuring device includes a light source that emits irradiation light, and a plurality of light sources that hold signal charges generated at a plurality of different exposure timings with respect to the irradiation light. and a signal processing circuit for calculating a distance value based on the plurality of packets, wherein the signal processing circuit converts the plurality of packets corresponding to one pixel to If it is determined that there is no ambient light, the distance value of the pixel is calculated by the first process, and if it is determined that there is ambient light, the second process different from the first process is performed. Calculate the distance value of the pixel.
- a distance measurement method is a distance measurement method using a light source that emits irradiation light and a solid-state imaging device, wherein signal charges generated at a plurality of different exposure timings for the irradiation light are A plurality of packets to be held are generated for each pixel, the presence or absence of disturbance light is determined using the plurality of packets corresponding to one pixel, and when it is determined that there is no disturbance light, the distance value of the pixel is obtained by a first process. is calculated, and when it is determined that there is ambient light, the distance value of the pixel is calculated by a second process different from the first process.
- FIG. 1 is a block diagram showing a configuration example of a distance measuring device 1 according to Embodiment 1 of the present disclosure.
- a distance measuring device 1 includes a light source 2, an optical system 3, a solid-state imaging device 4, a control circuit 5 and a signal processing circuit 6.
- FIG. 1 is a block diagram showing a configuration example of a distance measuring device 1 according to Embodiment 1 of the present disclosure.
- a distance measuring device 1 includes a light source 2, an optical system 3, a solid-state imaging device 4, a control circuit 5 and a signal processing circuit 6.
- FIG. 1 is a block diagram showing a configuration example of a distance measuring device 1 according to Embodiment 1 of the present disclosure.
- a distance measuring device 1 includes a light source 2, an optical system 3, a solid-state imaging device 4, a control circuit 5 and a signal processing circuit 6.
- FIG. 1 is a block diagram showing a configuration example of a distance measuring device 1 according to Embodiment 1 of the present disclosure.
- the light source 2 emits irradiation light to the object to be distance-measured according to the light emission control signal from the control circuit 5 .
- the illuminating light is infrared light, for example pulsed light or a continuous wave with varying amplitude.
- the irradiation light is assumed to be pulsed light.
- the optical system 3 includes one lens or multiple lenses, and guides reflected light from the subject to the light receiving surface of the solid-state imaging device 4 .
- the solid-state imaging device 4 has a plurality of pixels arranged two-dimensionally.
- FIG. 2 is a block diagram showing a configuration example of the distance measuring device 1 in FIG.
- the solid-state imaging device 4 in FIG. 2 is a CCD (Charge Coupled Device) type solid-state imaging device, and includes a plurality of pixels 12, a plurality of pixels 13, and a plurality of VCCDs (Vertical Charge Coupled Device) 14.
- CCD Charge Coupled Device
- VCCDs Very Charge Coupled Device
- the plurality of pixels 12 and the plurality of pixels 13 are arranged in a matrix.
- the plurality of pixels 12 are pixels for generating a distance image, are mainly sensitive to infrared light, and generate signal charges according to the amount of incident infrared light.
- a distance image is an image having pixel values that indicate distance.
- FIG. 2 shows an example in which a plurality of pixels 12 labeled "IR" are arranged in odd rows.
- Each of the plurality of pixels 12 generates a plurality of types of signal charges corresponding to a plurality of different exposure timings with respect to irradiation light.
- the signal charges are held in packets formed in the VCCD 14 .
- the plurality of pixels 13 are pixels for generating black-and-white images, are mainly sensitive to visible light, and generate signal charges according to the amount of incident visible light.
- a black and white image is an image that has pixel values that indicate brightness.
- a plurality of pixels 13 are labeled "W" in FIG. 2 and are arranged in even rows. Each of the plurality of pixels 13 generates signal charges according to the amount of incident visible light.
- the plurality of VCCDs 14 are provided in the same number as the columns, and hold and vertically transfer the signal charges generated by the plurality of pixels 12 as packets. Therefore, each of the plurality of VCCDs 14 is covered with a plurality of types of vertical transfer electrodes.
- each VCCD 14 is covered with ten kinds of vertical transfer electrodes V1 to V10.
- the above packet is a potential well formed in the VCCD 14 by 10 types of vertical transfer control voltages applied to the vertical transfer electrodes V1 to V10.
- the vertical transfer electrodes V1 to V10 function as transfer electrodes for packet formation and transfer.
- the vertical transfer electrode V4 functions as a transfer electrode and also as a readout electrode for reading signal charges from the pixels 12 to the VCCD14.
- FIG. 3 is an explanatory diagram showing an example of a plurality of types of packets formed during ranging operation.
- FIG. 3 shows an example in which six packets P1 to P6 are generated per pixel 12.
- the pixels 13 for monochrome images may be omitted.
- the VCCD 14 shows a configuration example in which the signal charges from the two pixels 12 on both sides of the VCCD 14 are simultaneously read out and mixed, but a configuration in which they are not mixed is also possible.
- the solid-state imaging device 4 may be of a CCD type or a MOS type as long as it can generate a plurality of packets with different exposure timings per pixel 12 .
- the control circuit 5 controls the light emission of the light source 2 and the exposure of the solid-state imaging device 4 according to the light emission control signal and the exposure control signal. With this control, the solid-state imaging device 4 generates, for each pixel 12, a plurality of packets holding signal charges generated at a plurality of different exposure timings with respect to the irradiation light.
- FIG. 4A shows a specific example of an exposure operation using a light emission control signal and an exposure control signal for generating a plurality of packets for each pixel 12.
- FIG. FIG. 4A is a time chart showing an operation example of generating packets P1 to P6 shown in FIG.
- L0 in FIG. 4A indicates a light emission pulse included in the light emission control signal output from the control circuit 5 to the light source 2.
- the light emission pulse is of positive logic, and instructs light emission at high level and non-light emission at low level. That is, the light source 2 emits light during the high level period of the light emission pulse L0 and turns off during the low level period.
- E1 indicates an exposure pulse included in the exposure control signal output from the control circuit 5 to the solid-state imaging device 4.
- the exposure pulse E1 is of negative logic, and indicates exposure at a low level and non-exposure at a high level.
- the pulse width of the exposure pulse E1 is the same as that of the light emission pulse L0. Note that the pulse width of the exposure pulse E1 may be different from that of the light emission pulse L0.
- “E2" to “E6” are the same as the exposure pulse E1. However, the exposure pulses E1 to E6 instruct exposure at different timings with respect to the light emission pulse L0.
- FIG. 4A six different types of exposure operations are collectively shown in one time chart for convenience.
- the six types of exposure operations are exposure operations by a set (L0, E1) of light emission pulse L0 and exposure pulse E1, (L0, E2), (L0, E3), (L0, E4), (L0, E5), ( L0, E6), which are actually performed separately.
- the control circuit 5 controls the light source 2 and the solid-state imaging device 4 to perform these six types of exposure operations.
- the signal charge generated by the exposure operation by (L0, E1) is transferred to packet P1.
- the signal charges generated by the exposure operations of (L0, E2), (L0, E3), (L0, E4), (L0, E5), and (L0, E6) are transferred to packets P2 to P6, respectively. be done.
- the time difference between the light emission pulse L0 and the exposure pulse is (L0, E1), (L0, E2), (L0, E3), (L0, E4), (L0, E5), (L0, E6 ) is the largest.
- the exposure pulses E1 to E6 correspond to six distance intervals obtained by dividing the distance range of the distance measuring device 1.
- the signal processing circuit 6 uses a plurality of packets corresponding to one pixel 12 to determine the presence or absence of disturbance light. Furthermore, when the signal processing circuit 6 determines that there is no disturbance light, the signal processing circuit 6 calculates the distance value of the pixel 12 by the first processing. Further, when the signal processing circuit 6 determines that there is ambient light, the signal processing circuit 6 calculates the distance value of the pixel 12 by a second process different from the first process.
- a gray frame represents an example of the timing at which the pixel 12 can receive the directly reflected light R0 from the object. An example of the timing at which the pixel 12 can receive the stray light R1 that causes flare is indicated by a hatched frame. Furthermore, in FIG.
- the signal processing circuit 6 determines the presence/absence of one or both of the stray light R1 and the indirect reflected light R2 as ambient light.
- the second processing in the signal processing circuit 6 may be, for example, invalidation of the pixels 12 that set the distance value to an invalid value. As a result, inaccurate distance values including errors due to ambient light can be eliminated, so the influence of ambient light can be suppressed.
- the second process may calculate the distance value by excluding packets corresponding to ambient light. As a result, since the distance value is calculated while suppressing the error due to the ambient light, the influence of the ambient light can be suppressed.
- FIG. 5 is a flow chart showing an operation example of the distance measuring device 1 according to the first embodiment. This figure is a flow chart showing the distance measurement method of the present disclosure.
- the ranging device 1 first performs packet generation and preprocessing (S50). For example, the rangefinder 1 performs the six types of exposure operations shown in FIG. 4A once or multiple times to generate packets P1 to P6. Furthermore, as preprocessing, the signal processing circuit 6 subtracts the signal amount indicating the magnitude of the background light from the signal amount of the packets P1 to P6.
- the signal processing circuit 6 performs processing of loop 1 (S51 to S56) for each of the plurality of pixels 12.
- the signal processing circuit 6 performs ambient light determination processing on the pixel 12 (S52).
- the ambient light determination process is a process of determining presence/absence of ambient light using a plurality of packets P1 to P6 generated from the pixel 12 concerned.
- the signal processing circuit 6 determines that there is no disturbance light (no in S53), it performs the first process (S54). Processing is performed (S55).
- the first process is a process of selecting, from among the plurality of packets P1 to P6, the packet exposed to the light reflected directly from the object. This process is called selection process A.
- the packet with the maximum signal amount is selected as the first packet from the packets P1 to P6, and the second packet is selected from the packets adjacent to the first packet in terms of distance. Adjacent in distance means that two distance intervals corresponding to two packets are adjacent. In the example of FIG.
- the signal processing circuit 6 After loop 1 is completed for all of the plurality of pixels 12, the signal processing circuit 6 performs distance calculation for each of the plurality of pixels 12 to calculate the distance value z (S57). However, in the distance calculation in step S57, the signal processing circuit 6 sets an invalid value as the distance value for the pixel 12 set as an invalid pixel in step S55.
- the distance value z is calculated, for example, by Equation 1 using the signal amounts of the two packets selected in the first process of step S54.
- c is a constant that indicates the speed of light.
- i indicates the number of the packet with the smaller time difference from the illuminating light among the two packets selected in step S54 (“3” in packet 3 in FIG. 4A). In other words, i indicates the packet number corresponding to the closer one of the two distance intervals from the distance measuring device 1 to which the two packets selected in step S54 correspond (packet 3 in FIG. 4A). '3').
- Tp is the pulse width of the pulsed light and also the pulse width of the exposure pulse.
- S0 indicates the signal amount of the packet with the smaller time difference from the illuminating light out of the two selected packets.
- S1 indicates the signal amount of the packet with the larger time difference from the illuminating light out of the two selected packets.
- BG0 indicates the background light component of the packet with the smaller time difference from the illuminating light among the two selected packets.
- BG1 indicates the background light component of the one of the two selected packets that has a larger
- the pixels 12 that are determined to have ambient light invalidate the pixels 12 that include ambient light, so that the influence of ambient light can be suppressed.
- FIG. 6 is a flowchart showing an example of ambient light determination processing performed for each pixel 12 in FIG. 7A and 7D are explanatory diagrams showing examples of packet signal amounts when there is no ambient light.
- 7B and 7C are explanatory diagrams showing examples of signal amounts of packets when there is ambient light.
- A1 indicates the signal amount after preprocessing of the packet P1 in FIG. 4A or 4B, that is, the signal amount from which the background light component is removed. The same is true for A2 to A6.
- the signal amounts A1 to A6 correspond to the packets P1 to P6 in ascending order of the time difference between the irradiation light and the exposure timing, in other words, in descending order of the distance between the distance measuring device 1 and the reflecting object.
- the signal processing circuit 6 first compares the signal amount of each of a plurality of packets corresponding to the pixel 12 with a first reference value, and counts the number of packets exceeding the first reference value (S61).
- the first reference value may be, for example, a value obtained by adding background light and noise components that may occur in the environment of the distance measuring device 1 .
- This first reference value may be a predetermined value, or may be a value dynamically determined based on actual measurements.
- the signal processing circuit 6 determines that there is ambient light (S62).
- the threshold value N1 is a number that depends on the number of packets used to calculate the distance value z. According to step S62, it is determined that there is ambient light in the example of FIG. 7B.
- the signal processing circuit 6 selects the N2 highest signal amounts among the plurality of packet signals corresponding to the pixel 12 (N2 is an integer equal to or greater than 2, and N2 is 2 in FIG. 6). is selected (S63), and it is determined whether or not the exposure timings of the selected N2 packets are in a predetermined adjacent relationship (S64). It is determined (S66), and if there is an adjacent relationship (yes in S64), it is determined that there is no ambient light (S65).
- the predetermined adjacency relationship means that two distance sections corresponding to two exposure pulses are adjacent. According to step S64, it is determined that there is disturbance light in the example of FIG. 7C.
- the examples of FIGS. 7A and 7D are determined to have no ambient light.
- the presence or absence of ambient light such as indirect reflected light and stray light can be determined for each pixel 12 .
- step S52 when it is determined that there is ambient light in step S52, the distance measuring device 1 notifies the higher system of the ranging device 1 or the user of the ranging device 1 that there is ambient light. may be warned.
- the distance measuring device 1 includes a light source that emits irradiation light and a plurality of packets that hold signal charges generated at a plurality of different exposure timings for the irradiation light. and a signal processing circuit that calculates a distance value based on the plurality of packets. The presence or absence of light is determined, and if it is determined that there is no ambient light, the distance value of the pixel is calculated by the first process, and if it is determined that there is ambient light, the distance of the pixel is determined by the second process that is different from the first process. Calculate the value.
- the first process or the second process is selectively performed according to the determination result indicating the presence or absence of disturbance light, so it is possible to reduce the influence of disturbance light.
- the presence or absence of stray light that causes flare and indirectly reflected light in multipath can be determined as disturbance light.
- the signal processing circuit compares the signal amount of each of the plurality of corresponding packets with a first reference value for each pixel, and counts the number of packets whose signal amount exceeds the first reference value. , when the counted number exceeds the threshold value, it may be determined that there is ambient light.
- the presence or absence of disturbance light can be determined for each pixel by comparing a plurality of packets with the first reference value and determining the threshold value.
- the signal processing circuit selects the top N packets (N is an integer equal to or greater than 2) having a large signal amount among the corresponding plurality of packets for each pixel, and selects the selected N packets. It may be determined whether or not the exposure timings are in a predetermined adjacency relationship, and if there is no adjacency relationship, it may be determined that there is a disturbance.
- the presence or absence of disturbance light can be determined for each pixel based on the signal amounts of a plurality of packets and the adjacency relationship of the top N packets.
- the irradiation light is pulsed light
- the signal processing circuit compares each of the plurality of packets corresponding to one pixel with a first reference value, and determines the number of packets exceeding the first reference value. If the counted number exceeds a threshold value, it is determined that there is disturbance light, and among the plurality of packets, the top N packets (N is an integer equal to or greater than 2) having a large signal amount are selected and selected. It may be determined whether or not the exposure timings of the obtained N packets are in a predetermined adjacency relationship, and if there is no adjacency relationship, it may be determined that there is a disturbance.
- the presence or absence of disturbance light can be determined for each pixel by comparing a plurality of packets with the first reference value, threshold determination, and the adjacency relationship of the top N packets.
- the threshold value may be determined depending on the number of packets used for calculating the distance value among the plurality of packets.
- an appropriate threshold can be determined according to the number of packets used to calculate the distance value.
- the threshold may be 2 and the N may be 2.
- a distance measuring device that calculates a distance value based on the ratio of two packets.
- the signal processing circuit may invalidate the pixel in the second processing.
- the effect of the ambient light can be suppressed by disabling the pixel.
- a distance measurement method is a distance measurement method using a light source that emits irradiation light and a solid-state imaging device, and holds signal charges generated at a plurality of different exposure timings with respect to the irradiation light. For each pixel, the presence or absence of disturbance light is determined using the corresponding plurality of packets, and when it is determined that there is no disturbance light, the distance value of the pixel is calculated by the first process. When it is determined that there is ambient light, the distance value of the pixel is calculated by a second process different from the first process.
- the first process or the second process is selectively performed according to the determination result indicating the presence or absence of disturbance light, so it is possible to reduce the influence of disturbance light.
- the presence or absence of stray light that causes flare and indirectly reflected light in multipath can be determined as disturbance light.
- Embodiment 2 In the first embodiment, an example of invalidating the pixels 12 determined to have ambient light has been described. In contrast, in a second embodiment, a configuration example of a distance measuring device that calculates a distance value by excluding packets corresponding to ambient light without invalidating pixels 12 determined to have ambient light will be described. .
- the configuration of the distance measuring device 1 according to Embodiment 2 may be the same as in FIGS. However, the processing of the signal processing circuit 6 is partially different. In the following, the description will focus on the different points to avoid duplication of description.
- FIG. 8 is a flow chart showing an operation example of the distance measuring device according to the second embodiment. The flowchart of the figure differs from that of FIG. 5 in that steps S81, S82, and S84 are newly added, and that step S83 is provided instead of step S55.
- step S81 When it is determined in step S53 that there is ambient light, the signal processing circuit 6 further performs level determination processing (S81).
- This level determination process is a process for determining the presence or absence of flare, that is, the presence or absence of ambient light that causes flare. If the signal processing circuit 6 determines that there is no flare as a result of the level determination processing (no in S82), it performs the first processing (S54), and if it determines that there is flare (yes in S82), it performs the second processing (S83). ).
- the second process in step S83 does not invalidate the pixels 12, but performs a process of excluding packets corresponding to ambient light and selecting packets to be used for distance calculation. This second process is called a first level cut coefficient method.
- the signal processing circuit 6 performs a correction process on the packet selection result by the second process of step S83 after completing the loop 1 (S84). After correction processing, the signal processing circuit 6 calculates a distance value for each pixel 12 by distance calculation. Since there are no invalid pixels 12 in the distance calculation in step S57, all pixels 12 are calculated.
- FIG. 9 is a flowchart showing an example of level determination processing in FIG.
- FIGS. 10A and 10C are diagrams showing examples of packet signal amounts when flare occurs.
- FIG. 10B is a diagram showing an example of the signal amount of a packet when flare does not occur.
- the signal processing circuit 6 acquires M packets from the front for the pixels 12 determined to have ambient light in step S53 (S91).
- the M packets from the near side refer to the M packets corresponding to the M distance intervals from the distance measuring device 1 .
- the signal processing circuit 6 compares each of the acquired M packets with the second reference value (S92).
- the second reference value indicates the amount of signal that can cause flare, and is set individually for each packet, for example, as indicated by the dashed lines in FIGS. 10A to 10C.
- the second reference value may be a value common to M packets.
- the second reference value is set individually for each packet so that the distance section closer to the distance measuring device 1 is larger, as indicated by the dashed lines in FIGS. 10A to 10C. .
- the signal processing circuit 6 determines that there is no disturbance light that causes flare (S93). If one or more exceeds the second reference value (yes in S92), it is estimated that there is a possibility that flare will occur, and the process proceeds to step S94.
- step S94 the signal processing circuit 6 acquires the remaining packets excluding the preceding M packets (S94), and if none of the remaining packets exceeds the second reference value (no in S95), no flare (S93), and if one or more of the remaining packets exceed the second reference value (yes in S95), it is determined that there is flare (S96).
- the example of FIG. 10A is determined to have flare, and the second process is applied. Also, in the example of FIG. 10B and the example of FIG. 10C, it is determined that there is no flare, and the first process is applied. In the example of FIG. 10C, even though there is actually flare, it is determined that there is no flare at step S95. Since the signal amount of all packets of the directly reflected light is smaller than the second reference value and can be ignored, it is excluded from the second processing (first level cut coefficient method). Also, in the example of FIG. 10C, the distance value of the corresponding pixel 12 may be set to an invalid value.
- FIG. 11 is a flow chart showing an example of the second processing by the first level cut coefficient method in FIG.
- FIG. 12 is an explanatory diagram schematically showing an example of multiple packets to which the second process of FIG. 11 is applied.
- the signal processing circuit 6 compares each of the plurality of packets corresponding to the target pixel with the third reference value (S110), and determines that the signal amount of the packet below the third reference value among the plurality of packets. is set to 0 (S111).
- the third reference value indicates the amount of signal that can occur due to flare or multipath, and is a value that is individually set for each packet, as indicated by broken lines in (a) and (b) of FIG. or a value common to all packets.
- the third reference value may be the same as the second reference value in FIGS. 10A to 10C. Here, it is assumed that the third reference value is the same as the second reference value.
- packets A2, A5, and A6 are below the third reference value.
- the signal amounts of packets A2, A5, and A6 are set to zero. As a result, it is possible to eliminate packets containing noise that could not be eliminated in the preprocessing of step S50.
- the signal processing circuit 6 multiplies each non-zero packet among the plurality of packets by a coefficient (S112).
- the coefficient here is determined so that a packet corresponding to a distance section farther from the range finder 1 has a larger value for each packet.
- the coefficient is set to a larger value for a packet corresponding to a distance section in which the amount of attenuation of irradiated light and reflected light is greater.
- FIG. 12(c) shows the packet after multiplication.
- the signal processing circuit 6 selects the largest packet as the first packet among the packets multiplied by the coefficients (S113). In (d) of FIG. 12, packet A3 is selected as the first packet.
- the signal processing circuit 6 acquires two packets that are adjacent to the first packet in terms of distance (S114), and selects the one with the larger signal amount as the second packet (S116). or S117). In (e) of FIG. 12, packet A4 is selected as the second packet.
- either before or after coefficient multiplication may be selected as the amount of signal used to select the second packet.
- the two adjacent packets do not include the preceding M packets (no in S115)
- the one with the larger signal amount before coefficient multiplication is selected as the second packet (S116)
- the two adjacent packets include the preceding M packets (yes in S115)
- the larger signal amount after multiplication by the coefficient is selected as the second packet (S117).
- the second processing of the first level cut coefficient method of FIG. 11 packets containing ambient light are excluded and the first and second packets used for distance calculation are selected, so the influence of ambient light is suppressed. It is possible to In addition, since the difference in attenuation for each distance interval corresponding to a plurality of packets is converted into an equivalent attenuation by multiplying the coefficient, the signal amounts of packets with different distance intervals can be directly compared. Furthermore, since the signal amount used to select the second packet selects either before or after the coefficient multiplication depending on the situation, it is possible to more appropriately select the two packets used for the distance calculation.
- FIG. 13 is a flowchart showing an example of correction processing in FIG. 14A is an explanatory diagram schematically showing the correction processing in FIG. 8.
- FIG. 14B is an explanatory diagram of indexes corresponding to selection results in the first process and the second process.
- FIG. 13 shows correction processing performed for each pixel 12 that is the target of the second processing. Assume that this correction process is not applied to the pixel 12 that is the target of the first process.
- the signal processing circuit 6 acquires the indices of peripheral pixels around the target pixel of correction processing (S131).
- FIG. 14A nine pixels 12 are shown.
- a black pixel 12 in the center indicates a target pixel on which the second processing is performed.
- the eight gray pixels 12 surrounding the target pixel indicate the surrounding pixels.
- the numerical value of each pixel 12 indicates an index.
- the index takes a value from 1 to 5 and indicates two packets used for distance calculation selected in the first process and the second process.
- index 1 indicates that packets P1 and P2 were selected for the distance calculation.
- index 2 indicates packets P2 and P3.
- Indexes 3 through 5 are similarly as shown in FIG. 14B.
- the signal processing circuit 6 counts the number K of peripheral pixels having the same index value among the eight peripheral pixels (S132).
- K is the number of indices included most among the eight peripheral pixels.
- the count number K for index "2" is seven.
- the signal processing circuit 6 determines whether or not the count number K is equal to or greater than L (S133).
- L is a constant constant, for example 7. Note that L may be 6, 5, or any other number.
- the signal processing circuit 6 determines that K is not equal to or greater than L, the signal processing circuit 6 terminates the correction process. It is determined whether or not they are different (S134). Further, the signal processing circuit 6 ends the correction process if it determines that it does not differ (no in S134), and if it determines that it differs (yes in S134), it converts the index of the target pixel to K neighboring pixels. is corrected to the same value as the index of (S135). In the example of FIG. 14A, the index "1" of the target pixel is corrected to the same value "2" as the indices of the K neighboring pixels.
- the index of the target pixel is corrected to the same value as the indices of the surrounding pixels.
- correction process of FIG. 13 may also be applied to the pixel 12 that is the target of the first process.
- peripheral pixels in the correction process of FIG. 13 are not limited to FIG. 14A, and may correspond to FIGS. 15 and 16.
- a black pixel P21 indicates a target pixel for correction processing.
- Eight gray pixels P01, P10, P11, P20, P22, P30, P31, and P41 around the target pixel P21 indicate peripheral pixels.
- a black pixel P31 indicates a target pixel for correction processing.
- Eight gray pixels P11, P21, P22, P30, P32, P41, P42, and P51 around the target pixel P31 indicate peripheral pixels.
- the relative positions of the surrounding pixels are the same even when pixels other than the pixels P21 and P31 are the target pixels.
- Each pixel in FIGS. 15 and 16 corresponds to the position of the center of gravity of the two pixels 12 for mixing signal charges in FIGS.
- the signal processing circuit processes M packets corresponding to M distance intervals from the one closest to the range finder among the plurality of packets. is compared with a second reference value, and when one or more of the M packets exceeds the second reference value, it is determined that there is ambient light.
- the signal processing circuit compares each of the plurality of packets with a second reference value, and selects, among the plurality of packets, the highest order corresponding to M distance sections from the one closest to the range finder. when one or more of the M packets exceed the second reference value, and one or more of the plurality of packets other than the M packets exceed the second reference value If it exceeds, it may be determined that there is ambient light.
- the second reference value may be determined for each of the plurality of packets.
- the signal processing circuit compares each of the plurality of packets with a third reference value, and sets the signal amount of a packet smaller than the third reference value among the plurality of packets to zero.
- each of the plurality of packets that is not 0 is multiplied by a coefficient having a large value corresponding to the order of distance from the distance measuring device for each packet, and among the packets after multiplication, the largest packet is selected as the first packet, the larger one of the packets adjacent to the first packet in terms of distance is selected as the second packet, and the distance value is calculated from the first packet and the second packet.
- the signal processing circuit determines whether or not at least one of the packets adjacent to the first packet in distance is included in the N packets in order of distance from the distance measuring device. If it is determined to be included, the larger one of the multiplied packets adjacent to the first packet in terms of distance is selected as the second packet, and if it is determined not to be included, the A larger one of the packets before multiplication that are adjacent to the first packet in terms of distance may be selected as the second packet.
- the signal processing circuit selects, for each pixel, at least two packets used for calculating a distance value from the plurality of packets in the first processing and the second processing, and selects the packets selected in the second processing.
- the selection results of at least two packets may be corrected based on the selection results of pixels surrounding the pixel.
- CW indirect TOF rangefinder 1 In the third embodiment, a CW indirect TOF rangefinder 1 will be described. In the CW-type indirect TOF method, not pulsed light but continuous wave (CW) is used as irradiation light.
- CW continuous wave
- the configuration of the distance measuring device 1 according to Embodiment 3 may be the same as in FIGS. However, the main differences are that the light emitted from the light source 2 is continuous wave instead of pulsed light, and that a plurality of packets corresponding to different timings are based on the phase of the continuous wave. In the following, the different points will be mainly described.
- 17A and 17B are explanatory diagrams showing an example of irradiation light and a plurality of packets generated from one pixel 12 in the distance measuring device according to the third embodiment.
- the upper part of the figure shows the light emitted from the light source 2.
- This illuminating light is a continuous wave with a periodically varying amplitude.
- the illuminating light is a sine wave whose amplitude (ie, brightness) varies between minimum and maximum values. The minimum value can be 0.
- the frequency of the sine wave is fmod.
- One period of a sine wave is 1/fmod.
- the lower part of the figure shows an example of the waveform of reflected light received by the solid-state imaging device 4 .
- the reflected light has a time difference of phase delay ⁇ with respect to the illuminating light.
- the solid-state imaging device 4 generates four packets A0 to A3 with different exposure timings for each pixel 12 .
- the exposure timing of the packet A0 is the timing of the phase difference ⁇ 0 with respect to the irradiation light.
- the exposure timing of packet A1 is the timing of the phase difference ( ⁇ 0+ ⁇ /2) with respect to the irradiation light.
- the exposure timing of packet A2 is the timing of the phase difference ( ⁇ 0+ ⁇ ) with respect to the irradiation light.
- the exposure timing of packet A3 is the timing of the phase difference ( ⁇ 0+3 ⁇ /2) with respect to the irradiation light.
- the signal processing circuit 6 calculates the phase delay ⁇ for each pixel 12 by Equation 2 using the four packets A0 to A3, and calculates the distance value z for each pixel 12 by Equation 3.
- the operation of the distance measuring device 1 in Embodiment 3 may be the same as in FIG. However, the processing contents of steps S50, S52, S54, and S57 are different. The different points will be mainly described below.
- step S50 the control circuit 5 controls the light source 2 to emit the irradiation light shown in FIG.
- the solid-state imaging device 4 is controlled to generate A3 from A0.
- step S52 the signal processing circuit 6 performs ambient light determination processing shown in FIG. 18, for example.
- FIG. 19 shows an explanatory diagram of the ambient light determination process of FIG.
- the ambient light determination process of FIG. 18 differs from that of FIG. 6 in that steps S63 and S64 are deleted and the first reference value and threshold are different.
- the first reference value should be determined based on the waveform of the sine wave, the amount of background light, and the amount of noise so that at least one of the four packets A0 to A3 does not exceed it.
- the threshold depends on the number of packets used for distance calculation, and may be 3 in FIG. That is, the threshold is used to determine whether all four packets A0 to A3 have exceeded the first reference value.
- the upper part of FIG. 19 shows the sine wave of the irradiation light.
- the middle part of FIG. 19 shows the reflected light when there is no ambient light. In this case, at least one of the four packets A0 to A3 does not exceed the first reference value.
- the lower part of FIG. 19 shows reflected light when there is ambient light.
- the thick black line in the figure indicates the reflected light, and the double line indicates the sum of the reflected light and the ambient light.
- the signal amount of packets A0 to A3 is the sum of reflected light and disturbance light. In this case, since all four packets A0 to A3 exceed the first reference value, it is determined that disturbance light is present.
- the ambient light determination process of FIG. 18 can determine the presence or absence of ambient light even in the CW indirect TOF rangefinder 1 .
- the irradiation light is a continuous wave having an amplitude that changes periodically, and the threshold is 3.
- Embodiment 4 describes the range finder 1 according to Embodiment 4 in which a part of the operation performed by the range finder 1 according to Embodiment 2 is changed.
- the configuration of the distance measuring device 1 according to Embodiment 4 is the same as that of the distance measuring device 1 according to Embodiment 2. However, part of the processing performed by the signal processing circuit 6 according to the fourth embodiment differs from the processing performed by the signal processing circuit 6 according to the second embodiment. In the following, the description will focus on the different points to avoid duplication of description.
- FIG. 20 is a flow chart showing an operation example of the distance measuring device 1 according to the fourth embodiment.
- the flowchart of FIG. 20 differs from that of FIG. 8 in that the process of step S83 is changed to the process of step S83A. That is, the range finder 1 according to Embodiment 2 performs the second processing by the first level cut coefficient method, whereas the range finder 1 according to Embodiment 4 uses the second level cut coefficient The difference is that the second process is performed according to the method.
- FIG. 21 is a flow chart showing an example of the second processing by the second level cut coefficient method in FIG.
- FIG. 22 is an explanatory diagram schematically showing an example of multiple packets to which the second process of FIG. 21 is applied.
- the flowchart of FIG. 21 differs from that of FIG. 11 in that the processing of steps S114 to S117 is changed to the processing of steps S124 to S127.
- the signal processing circuit 6 compares each of the plurality of packets corresponding to the target pixel with the third reference value (S110), and determines the signal amount of the packet below the third reference value among the plurality of packets. is set to 0 (S111).
- packets A1, A5, and A6 are below the third reference value.
- the signal amounts of packets A1, A5, and A6 are set to zero. As a result, it is possible to eliminate packets containing noise that could not be eliminated in the preprocessing of step S50.
- the signal processing circuit 6 multiplies each non-zero packet among the plurality of packets by a coefficient (S112).
- the coefficient here is determined to have a larger value for each packet corresponding to a distance section farther from the distance measuring device.
- the coefficient is set to a larger value for a packet corresponding to a distance section in which the amount of attenuation of irradiated light and reflected light is greater.
- FIG. 22(c) shows the packet after multiplication.
- the signal processing circuit 6 selects the largest packet as the first packet among the packets multiplied by the coefficients (S113). In (d) of FIG. 22, packet A3 is selected as the first packet.
- the signal processing circuit 6 determines whether or not the first packet is the predetermined packet from the distance measuring device 1 (S124).
- step S124 if the first packet is the predetermined number packet from the distance measuring device 1 (yes in S124), the signal processing circuit 6 determines that the packet before multiplication that is adjacent to the first packet in terms of distance is It is determined whether both of them exceed the third reference value (S125).
- step S125 if both the packets before multiplication that are adjacent to the first packet in distance exceed the third reference value (yes in S125), that is, the coefficient multiplication of the packet that is adjacent to the first packet in distance If both previous signal amounts exceed the third reference value, the signal processing circuit 6 selects the packet farther from the distance measuring device 1 from among the packets adjacent to the first packet in terms of distance as the second packet (S127). ). In (e) of FIG. 22, packet A4 is selected as the second packet.
- step S124 if the first packet is not the predetermined packet from the distance measuring device 1 (no in S124), and in the process of step S125, the packet before multiplication that is adjacent to the first packet in terms of distance does not exceed the third reference value (no in S125), the signal processing circuit 6 selects the larger one of the packets adjacent to the first packet in terms of distance before multiplication, that is, Of the packets that are adjacent to the first packet in terms of distance, the packet with the larger signal amount before coefficient multiplication is selected as the second packet (S126).
- the first packet is selected as the predetermined number of packets
- both packets exceed the third reference value
- the one farther from the distance measuring device 1 is selected as the second packet from among the packets adjacent to the first packet in terms of distance, and the closer one, that is, the flare is generated. Do not select a packet with a high probability as the second packet. Therefore, two packets to be used for distance calculation can be more appropriately selected.
- the signal processing circuit compares each of the plurality of packets with a third reference value, changing the signal amount of packets smaller than the third reference value among the packets to 0, and assigning a larger value to each of the packets that are not 0 among the plurality of packets in order of distance from the distance measuring device for each packet; multiplying the coefficients, selecting the largest packet from among the multiplied packets as the first packet, determining whether the first packet is a predetermined number of packets in order from the distance measuring device, When it is determined that the packet is the predetermined number of packets and the packets before multiplication that are adjacent to the first packet in distance both exceed the third reference value, the packet is adjacent to the first packet in distance. A packet farther from the distance measuring device is selected as a second packet, and a distance value is calculated from the first packet and the second packet.
- Embodiment 5 describes the range finder 1 according to Embodiment 5 in which part of the operation performed by the range finder 1 according to Embodiment 2 is changed.
- the configuration of the distance measuring device 1 according to Embodiment 5 is the same as that of the distance measuring device 1 according to Embodiment 2. However, part of the processing performed by the signal processing circuit 6 according to the fifth embodiment differs from the processing performed by the signal processing circuit 6 according to the second embodiment. In the following, the description will focus on the different points to avoid duplication of description.
- the distance measuring device 1 determines whether or not flare occurs in the region of the plurality of pixels 12 arranged in a matrix at a stage prior to performing ambient light determination processing on each pixel 12. is determined, and when it is determined that no flare has occurred, an operation of performing the first processing without performing the disturbance determination processing is performed for each pixel 12 .
- FIG. 23 is a flow chart showing an operation example of the distance measuring device 1 according to the fifth embodiment. 23 differs from FIG. 8 in that the process of step S50 is divided into the process of step S210 and the process of step S230, and the process of step S220 is added between them. The difference is that the process of step S240 is added between the process and the process of step S52, and the process of step S81 and the process of step S82 are deleted.
- the distance measuring device 1 first performs the six types of exposure operations shown in FIG. 4A once or multiple times to generate packets P1 to P6 (step S210).
- the signal processing circuit 6 When the packet is generated, the signal processing circuit 6 performs first flare determination processing for determining whether or not flare occurs in the region of the pixels 12 based on the packet of the pixels 12 (step S220). Here, it is assumed that the signal processing circuit 6 sets a flare determination flag (substitutes 1 for the flare determination flag whose initial value is 0) when determining that flare is occurring.
- the signal processing circuit 6 After performing the first flare determination process, the signal processing circuit 6 performs preprocessing (step S230).
- the signal processing circuit 6 performs processing of loop 1 (S51 to S56) for each of the plurality of pixels 12.
- the signal processing circuit 6 checks whether or not it has been determined that flare has occurred in the area of a plurality of pixels 12 (S240). That is, it is checked whether the flare determination flag is 1 or 0.
- the signal processing circuit 6 performs the first 1 processing is performed (S54), and if it is determined that flare has occurred in the region of a plurality of pixels 12 (yes in S240), that is, if the flare determination flag is 1, the disturbance is applied to the pixel 12. Light determination processing is performed (S52).
- the signal processing circuit 6 determines that there is no ambient light (no in S53), it performs the first process on the pixel 12 (S54), and if it determines that there is ambient light (yes in S53), Second processing is performed on pixel 12 by the first level cut coefficient method (S83).
- FIG. 24 is a flow chart showing an example of the first flare determination process in FIG.
- FIG. 25 is a diagram for explaining an example of a specific operation of the first flare determination process, and shows pixels 12 whose signal amount exceeds the fourth reference value in each of packets P1 to P6. It is a schematic diagram.
- target packets are not necessarily limited to all packets.
- target packets may be limited to predetermined packets.
- each square arranged in a matrix indicates each of the plurality of pixels 12 arranged in a matrix.
- a pixel 12 is shown.
- a pixel 12 located third from the left in the horizontal direction (third column) and second from the top in the vertical direction (second row).
- the first number in parentheses indicates the position of the column in the plurality of pixels 12 arranged in a matrix
- the second number indicates the position of the row.
- P6 packet the signal amount exceeds the fourth reference value.
- the signal processing circuit 6 first performs the processing of loop 1 (S221 to S225) for each of a plurality of pixels 12.
- the signal processing circuit 6 first compares the signal amount of each of the plurality of packets corresponding to the pixel 12 with a fourth reference value, and counts the number of packets exceeding the fourth reference value (S222).
- the fourth reference value may be, for example, a value corresponding to the amount of signal that causes flare. This fourth reference value may be a predetermined value, or may be a value dynamically determined based on actual measurements.
- This first reference number may be a predetermined value. In this case, for example, it may be determined based on the amount of signal of the pixels 12 that satisfies a predetermined condition related to the occurrence of flare, which is obtained by performing experiments, simulations, or the like in advance.
- pixel 12 (7-6), pixel 12 (8-6), pixel 12 (9-6), pixel 12 (7-7), and pixel 12 (8-7). are determined as high signal amount pixels.
- step S224 when the process of step S224 is completed, and when the number counted in the process of step S222 does not exceed the first reference number (no in S223), the process of loop 1 of the pixel 12 is performed.
- the loop processing 1 of the next pixel 12 is started, or the loop processing 1 of all the pixels 12 is completed, the processing of the loop 1 is terminated and the processing proceeds to step S226.
- the signal processing circuit 6 After completing the loop 1 processing for all of the plurality of pixels 12, the signal processing circuit 6 checks whether the number of high signal amount pixels exceeds the second reference number (S226).
- This second reference number may be a predetermined value. In this case, for example, it may be determined based on the number of high-signal amount pixels counted when flare occurs, which is obtained by performing experiments, simulations, or the like in advance.
- step S226 if the number of high-signal amount pixels exceeds the second reference number (yes in S226), the signal processing circuit 6 determines that there is flare (S227), and the number of high-signal amount pixels is If the second reference number is not exceeded (no in S226), the signal processing circuit 6 determines that there is no flare (S228).
- the signal processing circuit 6 determines that there is no flare because nine pixels 12 are high signal amount pixels as described above.
- the signal processing circuit further determines the presence or absence of flare. If it is determined that there is no flare, the distance value of the pixel is calculated by the first processing for each pixel.
- the first process or the second process is selectively performed for each of a plurality of pixels according to the determination of the presence or absence of flare, so that the influence of disturbance light can be further reduced.
- the irradiating light is pulsed light
- the signal processing circuit determines whether the number of packets whose signal amount exceeds the fourth reference value exceeds the first reference number in the determination of the presence or absence of flare. In the case of pixels, it may be determined that there is flare when the number of high-signal amount pixels exceeds the second reference number.
- the presence or absence of flare can be determined by comparing the number of high-signal amount pixels with the second reference number.
- the number of packets exceeding the fourth reference value is counted in the processing of step S222 of the first flare determination processing shown in FIG.
- the number of consecutive packets in the distance interval exceeding the value may be counted.
- Embodiment 6 is related to Embodiment 6 in which a part of the configuration of the distance measuring device 1 according to Embodiment 5 and a part of the operation performed by the distance measuring device 1 according to Embodiment 5 are changed. The distance measuring device 1 will be explained.
- the configuration of the distance measuring device 1 according to the sixth embodiment differs from the distance measuring device 1 according to the fifth embodiment in that the solid-state imaging device 4 has a plurality of pixels 12 and a plurality of pixels 13 arranged in a matrix.
- the surrounding area is modified to include a plurality of optical black pixels 15 (hereinafter, the "optical black pixels” are also referred to as "OB pixels").
- the OB pixel 15 has the same pixel structure as the pixel 12, but is a pixel that is prevented from directly entering light from the outside by a light shielding film. However, when flare occurs, external light may indirectly enter the OB pixels 15 .
- the OB pixels 15 are mainly used for extracting dark current components.
- FIG. 26 schematically shows how the solid-state imaging device 4 according to Embodiment 6 includes a plurality of OB pixels 15 in a region surrounding a plurality of pixels 12 and a plurality of pixels 13 arranged in a matrix. It is a top view.
- a plurality of OB pixels 15 are provided in the solid-state imaging device 4 according to Embodiment 6, in an OB pixel region surrounding an effective pixel region in which a plurality of pixels 12 and a plurality of pixels 13 arranged in a matrix are arranged.
- FIG. 26 shows as if a gap is generated between the effective pixel area and the OB pixel area, it is not necessarily limited to a configuration in which a gap is generated between the effective pixel area and the OB pixel area.
- the configuration may be such that there is no gap between the effective pixel area and the OB pixel area.
- part of the processing performed by the signal processing circuit 6 according to the sixth embodiment is the same as the processing performed by the signal processing circuit 6 according to the fifth embodiment. different. To avoid duplication of explanation, different points will be mainly explained below.
- FIG. 27 is a flow chart showing an operation example of the distance measuring device 1 according to the sixth embodiment.
- the flowchart of FIG. 27 differs from that of FIG. 23 in that the process of step S220 is changed to the process of step S320. That is, the distance measuring device 1 according to Embodiment 5 performs the first flare determination process to determine whether or not flare occurs in the region of the plurality of pixels 12 arranged in a matrix. On the other hand, the distance measuring device 1 according to Embodiment 6 performs the second flare determination process to determine whether or not flare occurs in the region of the plurality of pixels 12 arranged in a matrix. The difference is that judgment is made.
- FIG. 28 is a flow chart showing an example of the second flare determination process in FIG.
- FIGS. 29A and 29B are diagrams for explaining an example of a specific operation of the second flare determination process, and are for OB pixels 15 whose signal amount in a predetermined packet (to be described later) exceeds a fifth reference value. It is a schematic diagram showing.
- each linearly arranged square in the OB pixel region indicates each of the plurality of linearly arranged OB pixels 15, and hatched squares represent signal OB pixels 15 whose amount exceeds the fifth reference value are shown.
- the signal processing circuit 6 first counts the number of OB pixels 15 whose signal amount exceeds the fifth reference value in a predetermined packet (S321).
- This predetermined packet may be a predetermined packet. In this case, for example, an experiment, a simulation, or the like may be performed in advance, and the number of OB pixels 15 whose signal amount exceeds the fifth reference value, which is counted when flare occurs, may be determined.
- This predetermined packet is, for example, a P1 packet.
- the fifth reference value may be a predetermined value, or may change dynamically.
- the dark current component of the OB pixels 15 varies depending on the environment (especially temperature) in which the distance measuring device 1 is used. In this case, the dark current component of only the specific OB pixel 15 does not change, and the dark current components of all the OB pixels 15 interlock and change in the same manner. For this reason, for example, in an environment where the dark current component of the OB pixel 15 is relatively small, the fifth reference value is made small, and in an environment where the dark current component of the OB pixel 15 is relatively large, the fifth reference value is made relatively large. , the fifth reference value may be dynamically changed. This makes it possible to more accurately determine the presence or absence of flare.
- the signal processing circuit 6 determines that there is flare (S323), and the counted number is the third reference number. If it is less than the number or exceeds the fourth reference number (no in S322), it is determined that there is no flare (S324).
- the third reference number and the fourth reference number may be predetermined values.
- the third reference number may be determined, for example, based on the number of OB pixels 15 whose signal amount locally increases when flare occurs, which is obtained by conducting experiments, simulations, or the like in advance.
- the fourth reference number is obtained by, for example, conducting experiments, simulations, etc. in advance. Even though flare does not occur, the environmental factors in which the distance measuring apparatus 1 is used may cause the overall OB pixels to reach 15 pixels. may be determined based on how the signal amount of is increased or decreased.
- the signal processing circuit 6 determines that there is flare. On the other hand, in case 2 shown in FIG. The signal processing circuit 6 determines that there is no flare.
- the signal processing circuit further determines the presence or absence of flare. If it is determined that there is no flare, the distance value of the pixel is calculated by the first processing for each pixel.
- the first process or the second process is selectively performed for each of a plurality of pixels according to the determination of the presence or absence of flare, so that the influence of disturbance light can be further reduced.
- the irradiation light is pulsed light
- the signal processing circuit determines the presence or absence of flare by determining that the number of optical black pixels in a predetermined packet whose signal amount exceeds a fifth reference value is a third reference number. It may be determined that there is a flare if the above conditions are met and the fourth reference number is larger than the third reference number and equal to or less than the fourth reference number.
- the presence or absence of flare can be determined based on the number of optical black pixels whose signal amount exceeds the fifth reference value in a predetermined packet.
- the fifth reference value may dynamically change.
- the presence or absence of flare can be determined more accurately.
- Embodiment 7 describes the range finder 1 according to Embodiment 7 in which a part of the operation performed by the range finder 1 according to Embodiment 5 is changed.
- the distance measuring device 1 according to Embodiment 5 determines whether or not flare occurs in the region of the plurality of pixels 12 arranged in a matrix at a stage prior to performing ambient light determination processing on each pixel 12. This is an example of determining (determining the presence or absence of flare).
- the distance measuring device 1 according to Embodiment 7 determines whether or not flare has occurred for each of the plurality of pixels 12 before performing ambient light determination processing for each pixel 12 . This is an example of determining the presence or absence of flare.
- the configuration of the distance measuring device 1 according to Embodiment 7 is the same as that of the distance measuring device 1 according to Embodiment 5. However, part of the processing performed by the signal processing circuit 6 according to the seventh embodiment differs from the processing performed by the signal processing circuit 6 according to the fifth embodiment. In the following, the description will focus on the different points to avoid duplication of description.
- FIG. 30 is a flow chart showing an operation example of the distance measuring device 1 according to the seventh embodiment.
- the flowchart of FIG. 30 differs from that of FIG. 23 in that the process of step S220 is changed to the process of step S420 and the process of step S240 is changed to the process of step S440. That is, the distance measuring device 1 according to Embodiment 5 performs the first flare determination process to determine whether or not flare occurs in the region of the plurality of pixels 12 arranged in a matrix.
- the distance measuring device 1 according to Embodiment 7 performs third flare determination processing to determine whether or not flare has occurred for each of the plurality of pixels 12, and
- the distance measuring apparatus 1 according to the fifth embodiment examines in loop 1 whether or not it is determined that flare has occurred in the area of the plurality of pixels 12, whereas the distance measuring apparatus 1 according to the seventh embodiment The difference is that the apparatus 1 checks whether or not it is determined that the pixel 12 is flared.
- FIG. 31 is a flow chart showing an example of the third flare determination process in FIG.
- 32A to 32C are diagrams for explaining an example of a specific operation of the third flare determination process.
- each square arranged in a matrix represents each of the plurality of pixels 12 arranged in a matrix, and in FIG. 32A, hatched squares indicate high signal amount
- diagonally hatched squares represent pixels 12 that constitute a high-signal pixel group composed of a predetermined number or more (here, for example, 5 or more) of high-signal amount pixels that are adjacent to each other.
- 32C lightly hatched squares are within a predetermined range (here, as an example, within a range of one pixel) from a high-signal amount pixel group (a group of darkly hatched squares).
- target packets are not necessarily limited to all packets.
- target packets may be limited to predetermined packets.
- the flowchart of FIG. 31 differs from that of FIG. 24 in that the processing of steps S226 to S228 is changed to the processing of steps S426 to S432. That is, the processing after loop 1 is different.
- the signal processing circuit 6 identifies a high signal amount pixel group consisting of a predetermined number or more of high signal amount pixels adjacent to each other (S426). ).
- the predetermined number may be a predetermined value.
- the predetermined number is determined, for example, based on the number of high-signal amount pixels in a group of adjacent high-signal amount pixels that can occur when flare occurs, which is obtained by conducting experiments, simulations, etc. in advance. good too.
- pixel 12(8-5), pixel 12(6-6), pixel 12(7-6), pixel 12(8-6), pixel 12(9-6), pixel 12(7-7) , and pixels 12(8-7), which are adjacent to each other, are identified as a high signal amount pixel group.
- the signal processing circuit 6 performs loop 2 (S427 to S432) processing for each of the plurality of pixels 12. In FIG. 31, when a high-signal amount pixel group is specified, the signal processing circuit 6 performs loop 2 (S427 to S432) processing for each of the plurality of pixels 12. In FIG. 31,
- the signal processing circuit 6 first determines whether the pixel 12 belongs to the high signal amount pixel group (S428).
- the signal processing circuit 6 determines that the pixel 12 belongs to the high signal amount pixel group (yes in S428), it determines that the pixel 12 has flare (S430).
- the signal processing circuit 6 does not determine that the pixel 12 belongs to the high signal amount pixel group (no in S428), the pixel 12 is located within a predetermined range from the high signal amount pixel group. (S429).
- the signal processing circuit 6 determines that the pixel 12 is located within a predetermined range from the high signal amount pixel group (yes in S429), it determines that the pixel 12 has flare (S430).
- pixel 12(7-5), pixel 12(8-5), pixel 12(6-6), pixel 12(7-6), pixel 12(8-6), pixel 12(9-6), pixel 12(7-7), and pixel 12(8-7) are the pixels 12 constituting the high signal amount pixel group, the predetermined range is 1 When it is within the range of pixel 12, as shown in FIG. 32B, pixel 12(7-5), pixel 12(8-5), pixel 12(6-6), pixel 12(7-6), pixel 12(8-6), pixel 12(9-6), pixel 12(7-7), and pixel 12(8-7) are the pixels 12 constituting the high signal amount pixel group, the predetermined range is 1 When it is within the range of pixel 12, as shown in FIG.
- pixels 12 (9-8) are judged to have flare.
- the signal processing circuit 6 determines that the pixel 12 is not located within a predetermined range from the high signal amount pixel group (no in S429), it determines that the pixel 12 has no flare (S431).
- step S430 when the process of step S430 is finished and when the process of step S431 is finished, the process of loop 2 for the pixel 12 is finished, and the loop process 2 for the next pixel 12 is started.
- the loop processing 2 for all the pixels 12 has been completed, the processing of the loop 2 is exited and the third flare processing is completed.
- the signal processing circuit further determines the presence or absence of flare for each pixel, and targets the pixels determined to have flare.
- the presence/absence of disturbance light is determined in step 1, and the distance value of each pixel is calculated by the first processing for pixels determined to be free of flare.
- the first process or the second process is selectively performed for each of a plurality of pixels according to the determination of the presence or absence of flare, so that the influence of disturbance light can be further reduced.
- the irradiation light is pulsed light
- the signal processing circuit configures a high-signal-amount pixel group made up of a predetermined number or more of high-signal-amount pixels adjacent to each other in the determination of the presence or absence of flare performed for each pixel. and pixels located within a predetermined range from the high-signal-amount pixel group are determined to have flare, and the high-signal-amount pixels have the first number of packets whose signal amount exceeds the fourth reference value. The number of pixels may exceed the reference number.
- the presence or absence of flare can be determined based on the pixels forming the high-signal amount pixel group.
- the distance measuring apparatus 1 according to Embodiment 6 determines whether or not flare occurs in the region of the plurality of pixels 12 arranged in a matrix at a stage prior to performing ambient light determination processing on each pixel 12. This is an example of judging (judging the presence or absence of flare).
- the distance measuring apparatus 1 according to the eighth embodiment determines whether or not flare has occurred for each of the plurality of pixels 12 at a stage prior to performing ambient light determination processing for each pixel 12. This is an example of determining the presence or absence of flare.
- the configuration of the distance measuring device 1 according to the eighth embodiment is the same as that of the distance measuring device 1 according to the sixth embodiment. However, part of the processing performed by the signal processing circuit 6 according to the eighth embodiment differs from the processing performed by the signal processing circuit 6 according to the sixth embodiment. In the following, the description will focus on the different points to avoid duplication of description.
- FIG. 33 is a flow chart showing an operation example of the distance measuring device 1 according to the eighth embodiment.
- the flowchart of FIG. 33 differs from that of FIG. 27 in that the process of step S320 is changed to the process of step S520 and the process of step S240 is changed to the process of step S540. That is, the range finder 1 according to Embodiment 6 performs the second flare determination process to determine whether or not flare occurs in the region of the plurality of pixels 12 arranged in a matrix.
- the distance measuring device 1 according to the eighth embodiment performs the fourth flare determination process to determine whether or not flare has occurred for each of the plurality of pixels 12, and
- the distance measuring apparatus 1 according to the sixth embodiment examines in loop 1 whether or not it is determined that flare has occurred in the area of the plurality of pixels 12, whereas the distance measuring apparatus 1 according to the eighth embodiment The difference is that the apparatus 1 checks whether or not it is determined that the pixel 12 is flared.
- FIG. 34 is a flow chart showing an example of the fourth flare determination process in FIG.
- FIG. 35 is a diagram for explaining an example of a specific operation of the fourth flare determination process.
- each of the linearly arranged squares in the OB pixel area indicates each of the plurality of linearly arranged OB pixels 15. OB pixels 15 exceeding the 5 reference value are shown.
- each square arranged in a matrix in the effective pixel area indicates each of the plurality of pixels 12 arranged in a matrix, and the squares hatched with light oblique lines represent the signal amount. shows a pixel 12 having a predetermined positional relationship with respect to an OB pixel 15 having a value exceeding the fifth reference value.
- the signal processing circuit 6 first identifies OB pixels 15 whose signal amount in a predetermined packet exceeds the fifth reference value (S521).
- This predetermined packet may be a predetermined packet. In this case, for example, an experiment, a simulation, or the like may be performed in advance, and the number of OB pixels 15 whose signal amount exceeds the fifth reference value, which is counted when flare occurs, may be determined.
- This predetermined packet is, for example, a P1 packet.
- the signal processing circuit 6 identifies a total of seven OB pixels 15 hunted with oblique lines in the OB pixel area as OB pixels 15 whose signal amount exceeds the fifth reference value.
- the signal processing circuit 6 performs processing of loop 1 (S522 to S526) for each of the plurality of pixels 12.
- the signal processing circuit 6 first determines whether the pixel 12 has a predetermined positional relationship with respect to one or more OB pixels 15 whose signal amount exceeds the fifth reference value (S523). .
- the signal processing circuit 6 determines that the pixel 12 has a predetermined positional relationship with respect to one or more OB pixels 15 whose signal amount exceeds the fifth reference value (yes in S523), the pixel 12 (S524).
- the signal processing circuit 6 has a predetermined positional relationship with respect to one or more OB pixels 15 whose signal amount exceeds the fifth reference value, pixel 12 (1-1), pixel 12 (2-1), pixel 12(1-2), pixel 12(2-2), pixel 12(1-3), pixel 12(2-3), pixel 12(1-4), pixel 12(2 -4), pixel 12(1-5), pixel 12(2-5), pixel 12(1-6), and pixel 12(2-6).
- step S524 When the process of step S524 is completed and when the process of step S525 is completed, the process of loop 1 for the pixel 12 is terminated and the loop process 1 for the next pixel 12 is started, or all pixels If the loop process 1 of 12 has been completed, the process of the loop 1 is exited and the fourth flare process is completed.
- the signal processing circuit further determines the presence or absence of flare for each pixel, and targets the pixels determined to have flare.
- the presence/absence of disturbance light is determined in step 1, and the distance value of each pixel is calculated by the first processing for pixels determined to be free of flare.
- the first process or the second process is selectively performed for each of a plurality of pixels according to the determination of the presence or absence of flare, so that the influence of disturbance light can be further reduced.
- the irradiation light is pulsed light
- the signal processing circuit determines whether or not there is a flare in each pixel, for one or more optical black pixels whose signal amount in a predetermined packet exceeds a fifth reference value. On the other hand, it may be determined that there is flare for pixels having a predetermined positional relationship.
- the presence or absence of flare can be determined based on one or more optical black pixels whose signal amount exceeds the fifth reference value.
- each component may be implemented by dedicated hardware or by executing a software program suitable for each component.
- Each component may be realized by reading and executing a software program recorded in a recording medium such as a hard disk or a semiconductor memory by a program execution unit such as a CPU or processor.
- the software that realizes the range finder and the like of each of the above embodiments is the following program. That is, this program causes the computer to execute the processes shown in the flowcharts of FIGS.
- the present disclosure is not limited to these embodiments. As long as it does not deviate from the spirit of the present disclosure, various modifications that a person skilled in the art can think of are applied to the present embodiment, and a form constructed by combining the components of different embodiments may also be one or more of the present disclosure. may be included within the scope of the embodiments.
- the present disclosure can be used for rangefinders that generate range images.
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Abstract
Description
本発明者は、「背景技術」の欄において記載した、測距装置に関し、外乱光の影響の問題が生じることを見出した。
[1.1 構成]
図1は、本開示の実施の形態1における測距装置1の構成例を示すブロック図である。同図において測距装置1は、光源2、光学系3、固体撮像装置4、制御回路5および信号処理回路6を備える。
次に、本実施の形態における測距装置1の動作例について詳細に説明する。
次に、図5のステップS53における外乱光判定処理の詳細な例について説明する。
実施の形態1では、外乱光ありと判定された画素12を無効化する例を説明した。これに対して、実施の形態2では、外乱光ありと判定された画素12を無効化しないで、外乱光に対応するパケットを除外して距離値を算出する測距装置の構成例について説明する。
図8は、実施の形態2に係る測距装置の動作例を示すフローチャートである。同図のフローチャートは、図5と比べて、新たにステップS81、S82、S84が追加された点と、ステップS55の代わりにS83を有する点とが異なっている。
次に、図8のステップS81のレベル判定処理の詳細な例について説明する。
次に、図8のステップS84の補正処理の詳細な例について説明する。
実施の形態3では、CW型の間接TOF方式の測距装置1について説明する。CW型の間接TOF方式では、照射光としてパルス光ではなく連続波(CW:Continuous Wave)を用いる。
図17は、実施の形態3に係る測距装置における照射光と1画素12から生成される複数のパケットの例とを示す説明図である。
実施の形態4では、実施の形態2に係る測距装置1が行う動作の一部が変更された実施の形態4に係る測距装置1について説明する。
実施の形態5では、実施の形態2に係る測距装置1が行う動作の一部が変更された実施の形態5に係る測距装置1について説明する。
実施の形態6では、実施の形態5に係る測距装置1の構成の一部、および、実施の形態5に係る測距装置1が行う動作の一部が変更された実施の形態6に係る測距装置1について説明する。
実施の形態7では、実施の形態5に係る測距装置1が行う動作の一部が変更された実施の形態7に係る測距装置1について説明する。
実施の形態8では、実施の形態6に係る測距装置1が行う動作の一部が変更された実施の形態8に係る測距装置1について説明する。
2、91 光源
3 光学系
4 固体撮像装置
5 制御回路
6 信号処理回路
12、13、93、P00、P01、P02、P03、P04、P10、P11、P12、P13、P20、P21、P22、P23、P24、P30、P31、P32、P33、P40、P41、P42、P43、P44、P50、P51、P52、P53 画素
14 VCCD
15 オプティカルブラック画素(OB画素)
92 イメージセンサ
94 光学系
95 対象物
96、97 物体
98 強い直接反射光
A0~A6 パケット
E1~E6 露光パルス
L0 発光パルス
P1~P6 パケット
PX 注目画素
R0 直接反射光
R1 迷光
R2 間接反射光
Claims (23)
- 照射光を発する光源と、
前記照射光に対して異なる複数の露光タイミングで生成された信号電荷を保持する複数のパケットを画素毎に生成する固体撮像装置と、
前記複数のパケットに基づいて距離値を算出する信号処理回路と、を備え、
前記信号処理回路は、
画素毎に、対応する前記複数のパケットを用いて外乱光の有無を判定し、
外乱光なしと判定した場合、第1処理により当該画素の距離値を算出し、
外乱光ありと判定した場合、前記第1処理と異なる第2処理により当該画素の距離値を算出する
測距装置。 - 前記信号処理回路は、
画素毎に、対応する前記複数のパケットのそれぞれの信号量と第1基準値とを比較し、
信号量が前記第1基準値を超えるパケットの数をカウントし、
カウントした数がしきい値を超える場合、外乱光ありと判定する
請求項1に記載の測距装置。 - 前記信号処理回路は、
画素毎に、対応する前記複数のパケットのうち、信号量が大きい上位N個(Nは2以上の整数)のパケットを選択し、
選択したN個のパケットの露光タイミングが所定に隣接関係にあるか否かを判定し、
隣接関係にない場合、外乱ありと判定する
請求項1に記載の測距装置。 - 前記照射光はパルス光であり、
前記信号処理回路は、
1画素に対応する前記複数のパケットのそれぞれの信号量と第1基準値とを比較し、
前記第1基準値を超えるパケットの数をカウントし、
カウントした数がしきい値を超える場合、外乱光ありと判定し、
前記複数のパケットのうち、信号量が大きい上位N個(Nは2以上の整数)のパケットを選択し、
選択したN個のパケットの露光タイミングが所定に隣接関係にあるか否かを判定し、
隣接関係にない場合、外乱ありと判定する
請求項1に記載の測距装置。 - 前記しきい値は、前記複数のパケットのうち、距離値の算出に用いられるパケットの数に依存して定められる
請求項2または4に記載の測距装置。 - 前記しきい値は2であり、前記Nは2である
請求項4に記載の測距装置。 - 前記信号処理回路は、
前記複数のパケットのうち、前記測距装置に近い方からM個の距離区間に対応するM個のパケットのそれぞれと、第2基準値とを比較し、
M個のパケットのうちの1つ以上が前記第2基準値を超える場合に外乱光ありと判定する
請求項4から6のいずれか1項に記載の測距装置。 - 前記信号処理回路は、
前記複数のパケットのそれぞれと第2基準値とを比較し、
前記複数のパケットのうち、前記測距装置に近い方からM個の距離区間に対応する上位のM個のパケットのうちの1つ以上が前記第2基準値を超える場合で、かつ、前記複数のパケットのうち前記M個のパケット以外のパケットのうちの1つ以上が前記第2基準値を超える場合に、外乱光ありと判定する
請求項4から6のいずれか1項に記載の測距装置。 - 前記第2基準値は、前記複数のパケット毎に定められる
請求項7または8に記載の測距装置。 - 前記信号処理回路は、
前記第2処理において、前記複数のパケットのそれぞれと第3基準値とを比較し、
前記複数のパケットのうち前記第3基準値より小さいパケットの信号量を0に変更し、
前記複数のパケットのうち0でないパケットのそれぞれに、パケット毎に前記測距装置から遠い距離順に対応して大きい値をもつ係数を乗算し、
乗算後のパケットのうち、最大のパケットを第1パケットとして選択し、
前記第1パケットに距離的に隣接するパケットのうち大きい方を第2パケットとして選択し、
前記第1パケットおよび前記第2パケットから距離値を算出する
請求項1から9のいずれか1項に記載の測距装置。 - 前記信号処理回路は、前記第2処理において、
前記第1パケットに距離的に隣接するパケットの少なくとも一方が、前記測距装置から近い距離順でN個のパケットに含まれるか否かを判定し、
含まれると判定した場合には、前記第1パケットに距離的に隣接する乗算後のパケットのうち大きい方を第2パケットとして選択し、
含まれないと判定した場合には、前記第1パケットに距離的に隣接する乗算前のパケットのうち大きい方を第2パケットとして選択する
請求項10に記載の測距装置。 - 前記信号処理回路は、
前記第2処理において、前記複数のパケットのそれぞれと第3基準値とを比較し、
前記複数のパケットのうち前記第3基準値より小さいパケットの信号量を0に変更し、
前記複数のパケットのうち0でないパケットのそれぞれに、パケット毎に前記測距装置から遠い距離順に対応して大きい値をもつ係数を乗算し、
乗算後のパケットのうち、最大のパケットを第1パケットとして選択し、
前記第1パケットが、前記測距装置から近い順で所定個目のパケットか否かを判定し、
前記所定個目のパケットであると判定した場合において、前記第1パケットに距離的に隣接する乗算前のパケットがともに前記第3基準値を超えるときには、前記第1パケットに距離的に隣接するパケットのうち、前記測距装置から遠い方を第2パケットとして選択し、
前記第1パケットおよび前記第2パケットから距離値を算出する
請求項1から9のいずれか1項に記載の測距装置。 - 前記照射光は、周期的に変化する振幅を有する連続波であり、
前記しきい値は、3である
請求項2に記載の測距装置。 - 前記信号処理回路は、前記第2処理において当該画素を無効にする
請求項1から9および13のいずれか1項に記載の測距装置。 - 前記信号処理回路は、
前記第1処理および前記第2処理において前記複数のパケットから距離値の算出に用いる少なくとも2つのパケットを画素毎に選択し、
前記第2処理で選択された前記少なくとも2つのパケットの選択結果を、当該画素の周囲の画素の選択結果に基づいて補正する
請求項1から13のいずれか1項に記載の測距装置。 - 前記信号処理回路は、
さらに、フレアの有無を判定し、
フレアありと判定した場合、前記画素毎に行う外乱光の有無の判定を行い、
フレアなしと判定した場合、さらに、画素毎に、前記第1処理により当該画素の距離値を算出する
請求項1に記載の測距装置。 - 前記照射光はパルス光であり、
前記信号処理回路は、前記フレアの有無の判定では、信号量が第4基準値を超えるパケットの数が第1基準数を超える画素を高信号量画素とする場合に、当該高信号量画素の数が第2基準数を超える場合に、フレアありと判定する
請求項16に記載の測距装置。 - 前記照射光はパルス光であり、
前記信号処理回路は、前記フレアの有無の判定では、所定のパケットにおける信号量が第5基準値を超えるオプティカルブラック画素の数が、第3基準数以上であり、かつ、前記第3基準数より大きい第4基準数以下である場合に、フレアありと判定する
請求項16に記載の測距装置。 - 前記第5基準値は、動的に変化する
請求項18に記載の測距装置。 - 前記信号処理回路は、
さらに、画素毎にフレアの有無を判定し、
フレアありと判定した画素を対象として、前記画素毎に行う外乱光の有無の判定を行い、
フレアなしと判定した画素を対象として、さらに、画素毎に、前記第1処理により当該画素の距離値を算出する
請求項1に記載の測距装置。 - 前記照射光はパルス光であり、
前記信号処理回路は、前記画素毎に行うフレアの有無の判定では、互いに隣接する所定数以上の高信号量画素からなる高信号量画素集団を構成する画素、および、当該高信号量画素集団から所定の範囲内に位置する画素に対しフレアありと判定し、
前記高信号量画素は、信号量が第4基準値を超えるパケットの数が第1基準数を超える画素である
請求項20に記載の測距装置。 - 前記照射光はパルス光であり、
前記信号処理回路は、前記画素毎に行うフレアの有無の判定では、所定のパケットにおける信号量が第5基準値を超える1以上のオプティカルブラック画素に対して所定の位置関係にある画素に対しフレアありと判定する
請求項20に記載の測距装置。 - 照射光を発する光源および固体撮像装置を用いる測距方法であって、
前記照射光に対して異なる複数の露光タイミングで生成された信号電荷を保持する複数のパケットを画素毎に生成し、
画素毎に、対応する前記複数のパケットを用いて外乱光の有無を判定し、
外乱光なしと判定した場合、第1処理により当該画素の距離値を算出し、
外乱光ありと判定した場合、前記第1処理と異なる第2処理により当該画素の距離値を算出する
測距方法。
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Publication number | Priority date | Publication date | Assignee | Title |
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JPH10227857A (ja) * | 1997-02-14 | 1998-08-25 | Nikon Corp | 光波測距装置 |
WO2017013857A1 (ja) * | 2015-07-22 | 2017-01-26 | パナソニックIpマネジメント株式会社 | 測距装置 |
WO2019181518A1 (ja) * | 2018-03-20 | 2019-09-26 | パナソニックIpマネジメント株式会社 | 距離測定装置、距離測定システム、距離測定方法、及びプログラム |
JP6676866B2 (ja) | 2015-05-28 | 2020-04-08 | パナソニック株式会社 | 測距撮像装置及び固体撮像素子 |
WO2021095382A1 (ja) * | 2019-11-15 | 2021-05-20 | パナソニックIpマネジメント株式会社 | センシングデバイスおよび情報処理装置 |
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Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10227857A (ja) * | 1997-02-14 | 1998-08-25 | Nikon Corp | 光波測距装置 |
JP6676866B2 (ja) | 2015-05-28 | 2020-04-08 | パナソニック株式会社 | 測距撮像装置及び固体撮像素子 |
WO2017013857A1 (ja) * | 2015-07-22 | 2017-01-26 | パナソニックIpマネジメント株式会社 | 測距装置 |
WO2019181518A1 (ja) * | 2018-03-20 | 2019-09-26 | パナソニックIpマネジメント株式会社 | 距離測定装置、距離測定システム、距離測定方法、及びプログラム |
WO2021095382A1 (ja) * | 2019-11-15 | 2021-05-20 | パナソニックIpマネジメント株式会社 | センシングデバイスおよび情報処理装置 |
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