CN111147142A - Error correction system and method thereof - Google Patents

Error correction system and method thereof Download PDF

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Publication number
CN111147142A
CN111147142A CN201811298819.5A CN201811298819A CN111147142A CN 111147142 A CN111147142 A CN 111147142A CN 201811298819 A CN201811298819 A CN 201811298819A CN 111147142 A CN111147142 A CN 111147142A
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error correction
modulated light
detection device
distance detection
distance
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CN111147142B (en
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魏守德
陈韦志
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Lite On Technology Corp
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Lite On Technology Corp
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B10/00Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/40Transceivers
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S17/00Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06Systems determining position data of a target
    • G01S17/08Systems determining position data of a target for measuring distance only
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S7/00Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/497Means for monitoring or calibrating
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B10/00Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/50Transmitters
    • H04B10/516Details of coding or modulation

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  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Optical Radar Systems And Details Thereof (AREA)

Abstract

The invention discloses an error correction system and method based on flight time ranging. The error correction system comprises an L-shaped correction plate and a distance detection device. The L-shaped correction plate has a bottom plate with a plurality of target areas thereon and a side plate connected thereto. The distance detection device is disposed at a shooting position, and includes: the device comprises a modulated light transmitter, a modulated light receiver and a processor. The modulated light emitter is used for emitting modulated light according to the first signal, wherein the modulated light irradiates the bottom plate obliquely. The modulated light receiver is used for receiving the modulated light reflected by the target areas to generate a sensing signal. The processor is coupled to the modulated light receiver and generates a wobble error correction curve based on the sensed signal.

Description

Error correction system and method thereof
Technical Field
The present invention relates to an error correction system and method suitable for optical measurement technology, and more particularly, to an error correction system and method based on time-of-flight ranging.
Background
With the development of technology, optical three-dimensional measurement technology has become mature, wherein Time of flight (TOF) ranging is a common active depth sensing technology at present. The TOF ranging technique emits modulated light (e.g., infrared light), the modulated light reflects after encountering an object, and then converts the distance of the photographed object from the reflection time difference or phase difference of the modulated light reflected by the object to generate depth information.
However, TOF ranging techniques take into account a variety of error corrections, one source of which is periodic errors due to odd harmonics, known as wobble errors (wiggling error). The conventional swing error correction method is often complicated in steps, and the swing error is related to the distance of an object, so that a large space is required for erecting an error correction system in the measurement process or multiple measurements are performed for different distances, and time and labor are wasted. Therefore, how to provide a simple and effective error correction method is also one of the problems to be solved at present.
Disclosure of Invention
The invention provides an error correction system and method based on flight time ranging, which are beneficial to reducing the measurement times and the system volume and can simplify the error correction process.
The invention provides an error correction system based on time-of-flight ranging, which comprises an L-shaped correction plate and a distance detection device. The L-shaped correction plate has a bottom plate with a plurality of target areas thereon and a side plate connected thereto. The distance detection device is disposed at a shooting position, and includes: the device comprises a modulated light transmitter, a modulated light receiver and a processor. The modulated light emitter is used for emitting modulated light according to the first signal, wherein the modulated light irradiates the bottom plate obliquely. The modulated light receiver is used for receiving the modulated light reflected by the target areas to generate a sensing signal. The processor is coupled to the modulated light receiver and generates a wobble error correction curve based on the sensed signal.
The error correction method based on the time-of-flight ranging is suitable for an error correction system, wherein the error correction system comprises an L-shaped correction plate and a distance detection device, the distance detection device is arranged at a shooting position, and the L-shaped correction plate comprises a bottom plate and a side plate which are connected. The error correction method comprises the following steps: obtaining a plurality of actual distances from a plurality of target areas on a bottom plate of the L-shaped correction plate to a shooting position; emitting modulated light by the distance detection device to obliquely irradiate the bottom plate, and receiving the modulated light reflected by the target areas to generate sensing signals; calculating a plurality of measured distances of the target areas according to the sensing signals by a distance detection device; and comparing the measured distances with the actual distances by a distance detection device to generate a wobble error correction curve.
Based on the above, in the system and method for correcting errors based on time-of-flight ranging according to the embodiments of the present invention, the distance detection device emits the modulated light to obliquely irradiate the bottom plate of the L-shaped correction plate and receives the modulated light reflected by the target areas on the bottom plate to generate the sensing signals, and the distance detection device can calculate the distances to the target areas according to the sensing signals, thereby calculating the swing errors of the distance detection device at different distances at one time. Therefore, the embodiment of the invention can obtain a plurality of correction data corresponding to different distances in a limited system space at one time, and can greatly reduce the measurement times to quickly establish a swing error correction curve.
In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.
Drawings
FIG. 1 is a schematic block diagram of an error correction system based on time-of-flight ranging in accordance with an embodiment of the present invention.
Fig. 2A is a schematic diagram of an error correction system according to an embodiment of the invention.
Fig. 2B is a schematic diagram of a backplane according to an embodiment of the present invention.
Fig. 3A is a circuit schematic diagram of a modulated optical receiver according to an embodiment of the invention.
FIG. 3B is a signal waveform diagram of the embodiment of FIG. 3A according to the present invention.
FIG. 4 is a diagram illustrating a relationship between a reference phase and an equivalent flying distance according to an embodiment of the invention.
Fig. 5 is a schematic diagram of an error correction system according to another embodiment of the invention.
FIG. 6 is a block diagram of an error correction system according to another embodiment of the present invention.
FIG. 7 is a block diagram of an error correction system according to yet another embodiment of the present invention.
Fig. 8 is a flow chart of an error correction method in accordance with an embodiment of the present invention.
Detailed Description
FIG. 1 is a schematic block diagram of an error correction system based on time-of-flight ranging in accordance with an embodiment of the present invention. Referring to fig. 1, the error correction system 10 includes a distance detection device 100 and a correction plane TA. The distance detecting device 100 is used to measure the distance to the calibration plane TA. The distance detecting device 100 includes a modulated light emitter 110, a modulated light receiver 120, a processor 130, a signal processing unit 140 and a memory 150.
Signal processing unit 140 couples modulated optical transmitter 110 and modulated optical receiver 120. The signal processing unit 140 is configured to provide the first signal MS to the modulated light emitter 110. Modulated light emitter 110 emits modulated light EM in accordance with first signal MS. The modulated light EM is reflected by the collimating plane TA and the reflected modulated light REM is received by the modulated light receiver 120. The signal processing unit 140 also provides a control signal CS to the modulated optical receiver 120. The modulated light receiver 120 generates a sensing signal DS according to the control signal CS and the reflected modulated light REM. The processor 130 receives the sensing signal DS from the modulated light receiver 120 and performs error correction or distance measurement according to the sensing signal DS.
The modulated light emitter 110 is, for example, a laser diode, and the modulated light EM is, for example, infrared light, but not limited thereto. The modulated light receiver 120 is, for example, an image pickup device or a light source sensing device.
Embodiments of the time-of-flight ranging based error correction system and method will be described in detail below with reference to examples. Fig. 2A is a schematic diagram of an error correction system according to an embodiment of the present invention, and referring to fig. 1 and fig. 2A, the error correction system 20 includes a distance detection device 100 and an L-shaped correction plate 200.
In the embodiment of fig. 2A, the L-shaped correction plate 200 includes a bottom plate BB and a side plate SB connecting the bottom plate BB, wherein the bottom plate BB has a plurality of target areas P1, P2, P3 … PN thereon. The bottom plate BB or the side plate SB may be regarded as a correction plane TA in fig. 1 that reflects the modulated light EM. The distance detecting device 100 is disposed at the photographing position CP, and the modulated light emitter 110 emits modulated light EM to illuminate the L-shaped correction plate 200, particularly the oblique illumination bottom plate BB, according to the first signal MS, for example, the light ray R1 illuminates the target area P1, the light ray R2 illuminates the target area P2, and so on. The modulated light receiver 120 is used to receive the modulated light reflected by the target areas P1 PN. The processor 130 is coupled to the modulated optical receiver 120 and receives the sensing signal DS from the modulated optical receiver 120 to generate the wobble error correction curve.
Specifically, the bottom plate BB of the L-shaped correction plate 200 is disposed in the X direction, and the side plate SB is disposed in the Y direction. The bottom plate BB is the long side of the L-shaped correction plate 200, the side plate SB is the short side, and these target areas P1 to PN are arranged at different positions in the X direction so that the distances to obtain the modulated light receivers 120 are different. In another embodiment, the bottom plate BB and the side plate SB of the L-shaped correction plate 200 may not be perpendicular, and may have an acute angle or an obtuse angle therebetween. The shape and length of the correction plate are not limited by the present invention.
Specifically, the distances from the target areas P1 PN to the modulated light receiver 120 are preferably within the quasi-focus range of the modulated light receiver 120. For example, when the quasi-focal range of the modulated light receiver 120 is 30cm (centimeter) to infinity, the distance between the modulated light receiver 120 and the target area P1 is greater than or equal to 30 cm.
The imaging position CP of the distance detection apparatus 100 is located above the bottom plate BB (positive Y direction) and opposite to the side plate SB (direction away from the side plate SB), so that the side plate SB and the bottom plate BB can be simultaneously irradiated with the modulated light EM emitted from the distance detection apparatus 100.
Fig. 2B is a schematic diagram of a backplane according to an embodiment of the present invention. Referring to FIG. 2A with reference to FIG. 2B, in the embodiment of FIG. 2B, the substrate BB is a light-absorbing surface, the target areas P1-PN are pre-marked on the reflective area of the substrate BB, and the portions of the substrate BB except the target areas P1-PN are light-absorbing areas AB. As a result, only the light beams R1 RN impinging on the target areas P1 PN are reflected and received by the modulation light receiver 120. In another embodiment, the bottom plate BB may also have a checkerboard or other patterns, and the target areas P1 PN are characteristic points on the patterns, but the invention is not limited to the implementation pattern of the target areas.
The modulated light EM emitted by the modulated light emitter 110 is modulated light generated according to the first signal MS. For example, the first signal MS is a pulse signal, and the rising edge of the first signal MS corresponds to the trigger time of the modulated light EM. The signal processing unit 140 also outputs the control signal CS to the modulated light receiver 120, and the modulated light receiver 120 generates the sensing signal DS according to the control signal CS and the reflected modulated light REM.
Fig. 3A is a circuit diagram of a modulated optical receiver according to an embodiment of the invention, and fig. 3B is a signal waveform diagram of the embodiment of fig. 3A according to the invention. Referring to fig. 3A and 3B, the modulated light receiver 120 includes a photosensor 122, a capacitor CA, a capacitor CB, a switch SW1 and a switch SW 2. The photo sensor 122 is, for example, a photodiode (photodiode) or other component having the function of sensing the reflected modulated light REM. The photosensor 122 receives a common reference voltage, such as ground GND, at one end and couples the switch SW1 and one end of the switch SW2 at the other end. The other end of the switch SW1 is coupled to the capacitor CA via the node NA and controlled by the inverted signal CSB of the control signal CS. The other terminal of switch SW2 couples capacitor CB through node NB and is controlled by control signal CS. The modulated optical receiver 120 outputs a voltage (or current) signal VA on the node NA and a voltage (or current) signal VB on the node NB as the sensing signal DS. In another embodiment, the modulated optical receiver 120 can also select the difference between the output voltage signal VA and the output voltage signal VB as the sensing signal DS.
The embodiment of fig. 3A is merely exemplary, and the circuit architecture of the modulation optical receiver 120 is not limited thereto. The modulated light receiver 120 may have multiple photosensors 122, or more capacitors or switches. Those skilled in the art can make appropriate adjustments according to the common knowledge and actual requirements.
In the embodiment of FIG. 3B, when the inverted control signal CSB is low (e.g., logic 0), the switch SW1 is turned on, and the control signal CS is at high (e.g., logic 1), and the switch SW2 is turned off. Conversely, when the control signal CS is at a low level (e.g., logic 0), the switch SW2 is turned on, and the inverted control signal CSB is at a high level (e.g., logic 1), and the switch SW1 is turned off. In addition, when the photosensor 122 is turned on, it means that the reflected modulated light REM is received by the photosensor 120. When the photosensor 122 and the switch SW1 are both turned on, the capacitor CA is discharged (or charged), QA in fig. 3B indicates the amount of charge changed by the capacitor CA, and the voltage signal VA at the node NA is changed accordingly. When the photosensor 122 and the switch SW2 are both turned on, the capacitor CB is discharged (or charged), QB in fig. 3B indicates the amount of charge changed by the capacitor CB, and the voltage signal VB at the node NB changes accordingly. From the difference between the voltage signal VA and the voltage signal VB, the processor 130 can calculate the phase difference between the control signal CS and the reflected modulated light REM, which corresponds to the flight distance of the modulated light EM.
Specifically, in the embodiment of fig. 3B, the first signal MS is synchronized with the control signal CS, but the signal processing unit 140 may also make the first signal MS and the control signal CS not synchronized. That is, the control signal CS and the first signal MS may have a reference phase therebetween. The signal processing unit 140 delays or advances the phase of the first signal MS or the control signal CS according to different reference phases, so that the first signal MS and the control signal CS have a phase difference. The reference phases are, for example, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, 315 degrees, and 360 degrees, respectively. Here, the reference phases are equally spaced (but not limited), and the reference phases correspond to different flight distances. The number, size or spacing of the reference phases is not limited by the present invention. For example, the signal processing unit 140 may delay or advance the phase of the control signal CS by 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, 315 degrees, or 360 degrees compared to the phase of the first signal MS. The signal processing unit 140 may also delay or advance the phase of the first signal MS by 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, 315 degrees, or 360 degrees compared to the phase of the control signal CS. In other words, the signal processing unit 140 makes the first signal MS and the control signal CS have a phase difference therebetween, wherein the phase difference is one of a plurality of reference phases.
Specifically, since the first signal MS and the control signal CS have a phase difference equal to one of the reference phases, the phase difference calculated by the processor 130 according to the sensing signal DS includes the reference phase between the first signal MS and the control signal CS in addition to the phase difference between the modulated light REM generated by the modulated light EM traveling in the space and reflected by the plane. The error correction system 20 can equivalently increase the flight distance of the modulated light EM (or the modulated light REM) without increasing the system space by adding the reference phase between the first signal MS and the control signal CS, thereby achieving the effect of reducing the volume of the error correction system.
FIG. 4 is a diagram illustrating a relationship between a reference phase and an equivalent flying distance according to an embodiment of the invention. For example, in the embodiment of fig. 4, the reference phases are 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, 315 degrees, and 360 degrees.
When the modulation frequency of the modulated light EM is 75 mhz, it means that the flying distance of the modulated light EM within one period is 200cm (centimeter). The reference phases will correspond to different flight distances. Therefore, every time the phase difference between the first signal MS and the control signal CS changes by 45 degrees is equivalent to a change in the flying distance of 25cm (200cm divided by 8, the flying distance D is 25 cm). For example, when the phase difference between the first signal MS and the control signal CS is 90 degrees is equivalent to an increase in the flying distance by 50 cm. By analogy, the flight distance of the modulated light EM (or the modulated light REM) is equivalently increased by the phase difference between the first signal MS and the control signal CS.
The processor 130 calculates a plurality of measured distances of the target sections P1 PN from the sensing signal DS and compares the measured distances with actual distances from the target sections P1 PN to the photographing position CP measured by a corrected distance detecting means (not shown) to generate a wobble error correction curve. The corrected distance detection means refers to a distance detection means that has undergone error correction.
Referring to fig. 2A and fig. 4, taking the distance between the capturing position CP and the target area P1 as 20cm as an example, when the first signal MS is delayed by 45 degrees (equivalent to increasing the flying distance D (25cm)) compared to the control signal CS, it is equivalent to increasing the distance between the capturing position CP and the target area P1 by 25cm, as shown by the point MP1 in fig. 4. When the first signal MS is delayed by 90 degrees compared to the control signal CS, which corresponds to the shooting position CP being 70cm (20cm plus 50cm) away from the target area P1, refer to the point MP2 in fig. 4, and so on to the points MP3 to MP8 in fig. 4, wherein the points MP3 to 8 respectively represent the distances 95, 120, 145, 170, 195, and 220 cm.
It is worth mentioning that the positions of the target areas P1-PN are preferably arranged such that the distance between the shooting position CP and the target areas P1-PN can equally divide the flying distance D, thereby allowing the error correction data to be distributed more uniformly. Because the effect of equivalently increasing the flight distance is achieved by changing the phase difference between the first signal MS and the control signal CS, the error correction of the flight distance can be obtained in a shorter system length. In this way, the length of the bottom plate BB of the L-shaped correction plate 200 does not need to be as long as 200cm, thereby achieving the effect of reducing the volume of the error correction system.
The memory 150 is coupled to the processor 130 for storing the actual distances from the target areas P1 PN to the shooting position CP. The memory 150 may be any type of fixed or removable Random Access Memory (RAM), read-only memory (ROM), flash memory (flash memory), a hard disk or other similar device, an integrated circuit, or a combination thereof. The memory 150 also records a plurality of instructions that are executable by the processor 130, and the processor 130 can execute the instructions to perform the various functions described above.
In detail, the processor 130 may calculate a phase difference (or a time difference) according to the sensing signal DS (e.g., compare a difference of the voltage signal VA and the voltage signal VB) to further calculate a measured distance, and further compare the measured distance with an actual distance to obtain a plurality of first error correction data. For example, the first error correction data is an error value between the measured distance and the actual distance of the target areas P1 PN. In the present embodiment, the measurement operation of the distance detection apparatus 100 using one reference phase can obtain the first error correction data representing the plurality of target regions P1 PN at different distances at a time. The pixel coordinates of the target areas P1 PN are different from each other in the captured image, and therefore, the pixel offset error (phaseoffset) needs to be additionally considered. In particular, the pixel offset error is dependent only on position on the imaging plane and not on distance.
The light modulation receiver 120 performs a pre-calibration measurement to establish a lookup table LT, which is stored in the memory 150 and records each pixel coordinate and a corresponding pixel offset value in the image captured by the light modulation receiver 120. The processor 130 obtains the pixel offset values corresponding to the target areas P1 PN from the lookup table LT to calculate the wobble error correction curve. The processor 130 may calculate a wobble error correction curve based on the pixel offset values of the target areas P1 PN and the first error correction data.
In another embodiment, the target area pattern on the bottom plate BB of the error correction system 20, such as the circular reflection area of fig. 2B, may not be needed, but the processor 130 selects the pixel coordinates to determine the target area.
In an embodiment, the lookup table of the memory 130 additionally stores the pixel offset value of the corrected distance detection device in addition to the pixel offset value of the distance detection device 100. The memory 130 also stores camera parameters of the corrected distance detection device and the distance detection device 100. The processor 130 performs coordinate transformation to determine the coordinates of the target area to be used according to the camera parameters, the pixel offset value of the calibrated distance detection device, and the pixel offset value of the distance detection device 100. Therefore, after the distance detection apparatus 100 photographs the bottom panel BB or the side panel SB, the processor 130 can select which pixel coordinate base in the photographed image is used as the target area, and calculate the distance from the photographing position CP to the target area.
Fig. 5 is a schematic diagram of an error correction system according to another embodiment of the invention. The error correction system 40 is similar to the embodiment of the error correction system 20 of FIG. 2A, with the primary difference being that the L-shaped correction plate 400 of the error correction system 40 also has one more light absorbing spacer DB. The light absorbing barrier DB is disposed between the bottom plate BB and the side plate BS, and absorbs the modulated light reflected for the first time by the target areas P1 to PN. The influence due to the modulated light EM reflected multiple times can be reduced by providing the light absorbing barrier DB.
FIG. 6 is a block diagram of an error correction system according to another embodiment of the present invention. The error correction system 50 is similar to the embodiment of the error correction system 20 of FIG. 2A, and the main difference is that the bottom plate BB of the L-shaped correction plate 500 includes a plurality of triangular elements T1, T2, T3 … TN, and the target zones P1 PN are located on the slopes of the triangular elements T1 TN, respectively. The inclined surfaces of the triangular elements T1 to TN have inclination angles with respect to the extending direction (X direction) of the base plate BB and have different angles depending on the arrangement positions of the target areas P1 to PN. The slopes of the triangular elements T1-TN serve to reduce the incident angle of the modulated light RM. For example, the triangle element T1 may allow the light ray R1 to assume a state of normal incidence on the target area P1, the triangle element T2 may allow the light ray R2 to assume a state of normal incidence on the target area P2, and so on.
FIG. 7 is a block diagram of an error correction system according to yet another embodiment of the present invention. The embodiment of fig. 7 may be applied to the above-described embodiments. The modulated light EM emitted from the distance detection device 100 of the error correction system 60 has a Field of View FV (FOV). The farthest distance and the shortest distance of these target areas P1-PN with respect to the modulated light receiver 120 fall within the field of view of the modulated light receiver 120. The side plate SB also falls within the field of view, that is, the modulated light EM also strikes the side plate SB. The modulated light receiver 120 may receive the modulated light reflected by the side plate SB. The processor 130 generates the verification distance from the modulated light reflected by the side plate SB and further compares with the actual distance of the side plate to verify the accuracy of the distance detection apparatus 100. The above-mentioned side plate actual distance is the distance measured by the corrected distance detecting means. For the embodiments of how to measure the distance to the side plate SB and the target area on the side plate SB, reference is made to the above description of the embodiments, and those skilled in the art can obtain sufficient teaching and suggestions from the above description, and will not be further described herein.
It should be noted that the error correction system 60 of the present embodiment can have both error correction and verification functions. After calculating the swing error correction curve of the distance detection apparatus 100, the distance detection apparatus 100 may further perform a verification operation to determine the accuracy of the distance detection apparatus 100 after correction.
Fig. 8 is a flow chart of an error correction method in accordance with an embodiment of the present invention. The error correction method of fig. 8 can be applied to the embodiments of fig. 1 to 7. The following describes the flow of the error correction method with reference to the components of fig. 2A.
In step S710, a plurality of actual distances from the plurality of target areas P1-PN on the bottom plate BB of the L-shaped correction plate 200 to the shooting position CP are obtained. Specifically, the actual distance may be obtained by one corrected distance detecting device, which is a distance detecting device that has been error-corrected. The actual distance may also be obtained in other ways, and the invention is not limited to the means how the actual distance is obtained. These actual distances are stored in the memory of the distance detection means.
In step S720, the modulated light EM emitted by the distance detection device 100 obliquely irradiates the L-shaped correction plate 200 (e.g., the bottom plate BB), and receives the modulated light reflected by these target areas P1-PN to generate the sensing signal DS according to the control signal CS. Next, in step S730, a plurality of measured distances of the target areas P1 PN are calculated by the distance detection apparatus 100 according to the sensing signal DS, and in step S740, the measured distances are compared with the actual distances to generate a wobble error correction curve, wherein the measured distances refer to the distances from the target areas P1 PN to the photographing position CP.
The related component features and the specific implementation of the error correction method of the present embodiment can be obtained from the description of the embodiments of fig. 1 to 7, and therefore, the description thereof is omitted. In another embodiment, the order of obtaining the actual distance and measuring the distance may be switched, and the invention is not limited.
In summary, the time-of-flight ranging-based error correction system and method of the embodiments of the invention modulate light to be obliquely incident on a plurality of target areas on a bottom plate of an L-shaped correction plate, and generate a wobble error correction parameter according to a sensing signal DS, wherein the sensing signal DS can reflect a flight distance including a plurality of reference phases. More error correction data are obtained by arranging a plurality of target areas corresponding to different distances on the same bottom plate. Therefore, the error correction system and method of the embodiment of the invention can reduce the measurement times and reduce the chance of changing the configuration relationship of the architecture, so as to quickly and conveniently establish the swing error correction curve.
Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (18)

1. An error correction system based on time-of-flight ranging, comprising:
the L-shaped correction plate comprises a bottom plate and a side plate connected with the bottom plate, wherein the bottom plate is provided with a plurality of target areas; and
a distance detection device disposed at an imaging position, comprising:
a modulated light emitter for emitting modulated light according to a first signal, wherein the modulated light obliquely irradiates the substrate;
a modulated light receiver to receive the modulated light reflected by the plurality of target areas to generate a sensing signal; and
and the processor is coupled with the modulation light receiver and generates a swing error correction curve according to the sensing signal.
2. The error correction system of claim 1, wherein the distance detection device further comprises:
a memory coupled to the processor for storing actual distances from the target areas to the capture locations,
wherein the processor calculates a plurality of measured distances for the plurality of target zones from the sensing signals and compares the plurality of measured distances with the plurality of actual distances to generate the wobble error correction curve.
3. The system of claim 2, wherein the light modulation receiver is a camera or a light source sensor, wherein the light modulation receiver performs pre-calibration measurements to create a look-up table, the look-up table is stored in the memory and records pixel offset values corresponding to pixel coordinates of images captured by the light modulation receiver, and wherein the processor obtains the pixel offset values corresponding to the target areas from the look-up table to generate the wobble error correction curve.
4. The error correction system according to claim 3, characterized in that the plurality of actual distances are distances of the plurality of target areas to the shooting position measured by the corrected distance detection means.
5. The error correction system of claim 4, wherein the modulated light also illuminates the side panel, and the processor generates a verification distance based on the modulated light reflected by the side panel and further compares the verification distance with an actual side panel distance measured by the corrected distance detection device to verify the accuracy of the distance detection device.
6. The error correction system of claim 4, wherein the lookup table further comprises a plurality of pixel offset values of the corrected distance detection device, and the processor performs coordinate transformation to determine the plurality of target areas according to the plurality of pixel offset values of the corrected distance detection device and the plurality of pixel offset values of the distance detection device.
7. The error correction system of claim 1, wherein the distance detection device further comprises:
a signal processing unit coupled to the modulated optical transmitter to provide the first signal and coupled to the modulated optical receiver to provide a control signal, the signal processing unit causing the first signal and the control signal to have a phase difference, wherein the phase difference is one of a plurality of reference phases,
wherein the modulated light receiver generates the sensing signal according to the control signal and the reflected modulated light.
8. The error correction system of claim 1, wherein the plurality of target zones are a plurality of reflective zones and the base plate is a light absorbing surface.
9. The error correction system of claim 1, further comprising:
a light absorbing partition disposed between the bottom plate and the side plate to absorb the modulated light reflected by the plurality of target regions for the first time.
10. The system of claim 1, wherein the base plate includes a plurality of triangular elements thereon, the plurality of target areas being located on slopes of the plurality of triangular elements, respectively, the slopes of the plurality of triangular elements being configured to reduce an incident angle of the modulated light.
11. The error correction system of claim 1, wherein the modulated light receiver or light source sensing device is an image capture device, and the farthest distance and the shortest distance of the plurality of target areas relative to the modulated light receiver fall within a field of view of the modulated light receiver.
12. An error correction method based on time-of-flight ranging is applicable to an error correction system, and is characterized in that the error correction system comprises an L-shaped correction plate and a distance detection device, the distance detection device is configured at a shooting position, the L-shaped correction plate comprises a bottom plate and a side plate which is connected with the bottom plate, and the error correction method comprises the following steps:
obtaining a plurality of actual distances from a plurality of target areas on the bottom plate of the L-shaped correction plate to the shooting position;
emitting modulated light by the distance detection device to obliquely illuminate the base plate and receiving the modulated light reflected by the plurality of target areas to generate a sensing signal;
calculating, by the distance detection device, a plurality of measured distances for the plurality of target zones from the sensing signal; and
comparing, by the distance detection device, the plurality of measured distances with the plurality of actual distances to generate a swing error correction curve.
13. The error correction method of claim 12, wherein the step of generating the wobble error correction curve comprises:
pre-correcting and measuring the distance detection device to establish a lookup table, wherein the lookup table records a pixel offset value corresponding to a pixel coordinate of an image shot by the distance detection device; and
obtaining the plurality of pixel offset values corresponding to the plurality of target areas from the lookup table to generate the wobble error correction curve.
14. The error correction method of claim 13, further comprising:
measuring the side panel by a corrected distance detection device to generate a side panel actual distance;
the modulated light also illuminates the side panel; and
generating a verification distance by the distance detection device according to the modulated light reflected by the side plate, and further comparing with the actual distance of the side plate to verify the accuracy of the distance detection device.
15. The error correction method of claim 13, further comprising:
and performing coordinate conversion according to a plurality of pixel offset values of the corrected distance detection device and the plurality of pixel offset values of the distance detection device to determine the plurality of target areas.
16. The error correction method of claim 12, further comprising:
the distance detection device emits the modulated light according to a first signal; and
the first signal has a phase difference with a control signal, wherein the phase difference is one of a plurality of reference phases,
wherein the distance detection device generates the sensing signal according to the control signal and the reflected modulated light.
17. The method of claim 12, wherein the plurality of target areas are a plurality of reflective areas and the base plate is a light absorbing surface.
18. The error correction method of claim 12, further comprising:
absorbing the modulated light first reflected by the plurality of target regions by a light absorbing barrier disposed between the bottom plate and the side plate.
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106952309A (en) * 2016-01-07 2017-07-14 宁波舜宇光电信息有限公司 The device and method of Fast Calibration TOF depth camera many kinds of parameters
CN206460513U (en) * 2016-12-28 2017-09-01 上海兴芯微电子科技有限公司 Double shooting scaling boards
US20180106891A1 (en) * 2016-10-19 2018-04-19 Infineon Technologies Ag 3di sensor depth calibration concept using difference frequency approach
CN107967701A (en) * 2017-12-18 2018-04-27 信利光电股份有限公司 A kind of scaling method, device and the equipment of depth camera equipment
CN207802203U (en) * 2018-02-13 2018-08-31 技嘉科技股份有限公司 Calibration equipment
CN108700650A (en) * 2016-03-14 2018-10-23 Pmd技术股份公司 Device and method for calibrating light propagation time camera

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106952309A (en) * 2016-01-07 2017-07-14 宁波舜宇光电信息有限公司 The device and method of Fast Calibration TOF depth camera many kinds of parameters
CN108700650A (en) * 2016-03-14 2018-10-23 Pmd技术股份公司 Device and method for calibrating light propagation time camera
US20180106891A1 (en) * 2016-10-19 2018-04-19 Infineon Technologies Ag 3di sensor depth calibration concept using difference frequency approach
CN206460513U (en) * 2016-12-28 2017-09-01 上海兴芯微电子科技有限公司 Double shooting scaling boards
CN107967701A (en) * 2017-12-18 2018-04-27 信利光电股份有限公司 A kind of scaling method, device and the equipment of depth camera equipment
CN207802203U (en) * 2018-02-13 2018-08-31 技嘉科技股份有限公司 Calibration equipment

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
郭宁博 等: "基于飞行时间法的红外相机研究综述", 《兵器装备工程学报》 *

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