CN112782676A - Optical fiber calibration system and method - Google Patents
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 115
- 238000000034 method Methods 0.000 title claims abstract description 53
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- 239000004973 liquid crystal related substance Substances 0.000 claims description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- 239000010453 quartz Substances 0.000 claims description 5
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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
- G01S7/497—Means for monitoring or calibrating
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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
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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
- G01S7/4818—Constructional features, e.g. arrangements of optical elements using optical fibres
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Abstract
The application is suitable for optical fiber calibration technical field, provides an optical fiber calibration system, includes: the optical fiber calibration system is provided with a transmitting module, an input optical fiber, an output optical fiber, an optical diffusion sheet, a receiving module and a calibration device; the transmitting module is used for transmitting the input light beam to the input optical fiber; the optical diffusion sheet is used for receiving the output light beams projected by the output optical fibers, converting the output light beams into uniform light spots and irradiating the uniform light spots to the receiving module; the receiving module is used for receiving the uniform light spots, generating optical signals and sending the optical signals to the calibration device; and the calibration device is used for receiving the optical signal and calculating calibration information according to the optical signal. An optical diffusion sheet is added in the optical fiber calibration system, so that the optical fiber signals can be subjected to light homogenizing treatment, and all calibration items related to the distance can be completed. Therefore, the method and the device can further improve the calibration efficiency, improve the optical fiber calibration process and improve the optical fiber calibration efficiency.
Description
Technical Field
The application belongs to the technical field of optical fiber calibration, and particularly relates to an optical fiber calibration system and method.
Background
During calibration, the TOF camera needs to calibrate parameters such as a distance error offset, a global error wiggling, a depth error FPPN, and the like. In the prior art, the global error wiggling of the TOF camera is calibrated by using optical fibers with different lengths. However, since the exit aperture of the optical fiber is small, the size of a light spot irradiated on the receiving end of the TOF camera is small, and the remaining most pixels cannot receive optical fiber signals, so that the depth error FPPN of the TOF camera cannot be calibrated by the method. The calibration of the depth error FPPN also needs to be performed on other calibration equipment.
By the TOF calibration method with multiple calibration devices, the whole TOF camera calibration efficiency is low, and the process is complicated.
Disclosure of Invention
The embodiment of the application provides an optical fiber calibration system and method, which can solve the problems of low calibration efficiency and complex process.
In a first aspect, an embodiment of the present application provides an optical fiber calibration system, where the system includes: the device comprises a transmitting module, an input optical fiber, an output optical fiber, an optical diffusion sheet, a receiving module and a calibration device;
the transmitting module is used for transmitting an input light beam to the input optical fiber;
the optical diffusion sheet is used for receiving the output light beams projected by the output optical fibers, converting the output light beams into uniform light spots and irradiating the uniform light spots to the receiving module;
the receiving module is used for receiving the uniform light spots, generating optical signals and sending the optical signals to the calibration device;
and the calibration device is used for receiving the optical signal and calculating calibration information according to the optical signal.
Further, the optical fiber includes a core; the core is a quartz core.
Further, the optical diffusion sheet is one or more of a microlens array, a diffuser, a liquid crystal adjusting element, and an optical super surface layer.
In a second aspect, an embodiment of the present application provides an optical fiber calibration method, which is applied to the calibration device in the optical fiber calibration system in the first aspect, and includes:
acquiring an optical signal acquired by a receiving module, and acquiring a target parameter of the optical signal;
and calculating error information according to the target parameters to obtain calibration information.
Further, acquiring a target parameter of the optical signal includes:
acquiring the flight time and the preset flight distance of an optical signal;
calculating error information according to the target parameters to obtain calibration information, wherein the method comprises the following steps:
calculating the actual flying distance of the optical signal according to the flying time of the optical signal;
and calculating distance cycle error information according to the actual flying distance and the preset flying distance.
Furthermore, the receiving module comprises a first phase detection window and a second phase detection window; the optical signal comprises a first optical signal detected by a first phase detection window and a second optical signal detected by a second phase detection window;
acquiring a time of flight of the optical signal, comprising:
and calculating the flight time of the optical signal according to the first optical signal, the second optical signal, the preset ambient light intensity and the modulation period.
Further, acquiring a time of flight of the optical signal comprises:
acquiring a single photon counting histogram of an optical signal;
and determining the flight time of the optical signal according to the single photon counting histogram.
Further, acquiring a target parameter of the optical signal includes:
acquiring an actual main point pixel measurement depth value and a preset main point pixel measurement depth value of the optical signal;
calculating error information according to the target parameters to obtain calibration information, wherein the error information calculation comprises the following steps:
and calculating global error information according to the measured depth value of the main point pixel and the preset measured depth value of the main point pixel.
Further, calculating error information according to the target parameter to obtain calibration information, including:
calculating according to the target parameters to obtain distance cycle error information and global error information;
calculating to obtain a corrected depth measurement value according to the distance cycle error information, the global error information and the uncorrected preset depth measurement value;
and calculating according to the corrected depth measurement value and the preset depth true value to obtain depth error information.
In a third aspect, an embodiment of the present application provides a calibration apparatus, including:
the acquisition unit is used for acquiring the optical signals acquired by the receiving module and acquiring target parameters of the optical signals;
and the calculating unit is used for calculating the error information according to the target parameters to obtain the calibration information.
Further, the obtaining unit is specifically configured to:
acquiring the flight time and the preset flight distance of an optical signal;
a computing unit, specifically configured to:
calculating the actual flying distance of the optical signal according to the flying time of the optical signal;
and calculating distance cycle error information according to the actual flying distance and the preset flying distance.
Furthermore, the receiving module comprises a first phase detection window and a second phase detection window; the optical signal comprises a first optical signal detected by a first phase detection window and a second optical signal detected by a second phase detection window;
an acquisition unit, specifically configured to:
and calculating the flight time of the optical signal according to the first optical signal, the second optical signal, the preset ambient light intensity and the modulation period.
Further, the obtaining unit is specifically configured to:
acquiring a single photon counting histogram of an optical signal;
and determining the flight time of the optical signal according to the single photon counting histogram.
Further, the obtaining unit is specifically configured to:
acquiring an actual main point pixel measurement depth value and a preset main point pixel measurement depth value of the optical signal;
a computing unit, specifically configured to:
and calculating global error information according to the measured depth value of the main point pixel and the preset measured depth value of the main point pixel.
Further, the computing unit is specifically configured to:
calculating according to the target parameters to obtain distance cycle error information and global error information;
calculating to obtain a corrected depth measurement value according to the distance cycle error information, the global error information and the uncorrected preset depth measurement value;
and calculating according to the corrected depth measurement value and the preset depth true value to obtain depth error information.
In a fourth aspect, an embodiment of the present application provides a calibration apparatus, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the optical fiber calibration method according to the second aspect is implemented.
In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, and the embodiment of the present application provides a computer-readable storage medium, where a computer program is stored, and when the computer program is executed by a processor, the method for calibrating an optical fiber according to the second aspect is implemented.
In the embodiment of the application, the optical fiber calibration system is provided with a transmitting module, an input optical fiber, an output optical fiber, an optical diffusion sheet, a receiving module and a calibration device; the transmitting module is used for transmitting the input light beam to the input optical fiber; the optical diffusion sheet is used for receiving the output light beams projected by the output optical fibers, converting the output light beams into uniform light spots and irradiating the uniform light spots to the receiving module; the receiving module is used for receiving the uniform light spots, generating optical signals and sending the optical signals to the calibration device; and the calibration device is used for receiving the optical signal and calculating calibration information according to the optical signal. An optical diffusion sheet is added in the optical fiber calibration system, so that the optical fiber signals can be subjected to light homogenizing treatment, and all calibration items related to the distance can be completed. Therefore, the method and the device can further improve the calibration efficiency, improve the optical fiber calibration process and improve the optical fiber calibration efficiency.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
FIG. 1 is a schematic diagram of an optical fiber calibration system according to a first embodiment of the present disclosure;
FIG. 2 is a schematic diagram of an optical fiber calibration system according to a first embodiment of the present disclosure;
FIG. 3 is a schematic diagram of a microlens array in an optical fiber calibration system according to a first embodiment of the present disclosure;
FIG. 4 is a schematic diagram of a diffuser in an optical fiber calibration system according to a first embodiment of the present disclosure;
FIG. 5 is a schematic diagram of a liquid crystal adjusting element in an optical fiber calibration system according to a first embodiment of the present application;
FIG. 6 is a schematic diagram of an optical super-surface layer in an optical fiber calibration system according to a first embodiment of the present disclosure;
FIG. 7 is a schematic flow chart diagram of a method for calibrating an optical fiber according to a second embodiment of the present application;
FIG. 8 is a schematic view of a calibration apparatus provided in a third embodiment of the present application;
fig. 9 is a schematic diagram of a calibration apparatus provided in a fourth embodiment of the present application.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It should also be understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.
As used in this specification and the appended claims, the term "if" may be interpreted contextually as "when", "upon" or "in response to" determining "or" in response to detecting ". Similarly, the phrase "if it is determined" or "if a [ described condition or event ] is detected" may be interpreted contextually to mean "upon determining" or "in response to determining" or "upon detecting [ described condition or event ]" or "in response to detecting [ described condition or event ]".
Furthermore, in the description of the present application and the appended claims, the terms "first," "second," "third," and the like are used for distinguishing between descriptions and not necessarily for describing or implying relative importance.
Reference throughout this specification to "one embodiment" or "some embodiments," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," or the like, in various places throughout this specification are not necessarily all referring to the same embodiment, but rather "one or more but not all embodiments" unless specifically stated otherwise. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless expressly specified otherwise.
Referring to fig. 1, fig. 1 is a schematic diagram of an optical fiber calibration system according to a first embodiment of the present application. The system comprises: the device comprises a transmitting module, an input optical fiber, an output optical fiber, an optical diffusion sheet, a receiving module and a calibration device.
And the transmitting module is used for transmitting the input light beam to the input optical fiber.
In one embodiment, as shown in fig. 2, a first optical path switch and a second optical path switch may be included in the fiber calibration system. The input optical fiber is connected with the first light path switch and used for transmitting the emission light beam to the first light path switch and selecting the optical fibers with different lengths through the first light path switch; one end of each optical fiber with different lengths is connected with the first light path switch, and the other end of each optical fiber is connected with the second light path switch and used for receiving the light beams transmitted by the first light path switch, wherein the light beams are totally reflected in the optical fibers and transmitted to the second light path switch; and the second light path switch is connected with the output optical fiber and used for controlling the light beams transmitted by the optical fibers with different lengths to sequentially pass through the output optical fiber and penetrate through the optical diffusion sheet.
In one embodiment, the emission module emits the light beam to be vertically incident to the input optical fiber, the input optical fiber is connected with the optical fibers with different lengths through the first optical path switch, and the optical fibers with different lengths are selected through the first optical path switch, so that the light beam emitted by the emission module has different optical paths.
It should be noted that the number of the first optical path switch and the second optical path switch corresponds to the number of the optical fibers one by one, and whether the optical fibers are conducted or not can be determined by switching the first optical path switch and the second optical path switch; the number and length of the optical fibers depend on the nominal number and distance required for the distance cyclic error information wiggling.
In one embodiment, the optical fiber is a light propagation carrier, which includes a core and a cladding surrounding the core, both of which are cylindrical. Preferably, the fiber core is a quartz fiber core, and quartz has high refractive index, high mechanical strength, good bending performance and is not easily influenced by external electromagnetic radiation, so the quartz fiber core has excellent optical transmission performance, and can form optical fibers with different lengths, so that light beams emitted by the emission module have different optical paths.
It should be understood that the refractive index of the cladding constituting the optical fiber should be smaller than that of the core; the cladding of the optical fiber may comprise multiple layers, but the refractive index should be gradually decreased from the core to the outermost cladding to ensure that the light beam can emit total reflection in the optical fiber and propagate to the second optical switch.
And the optical diffusion sheet is used for receiving the output light beams projected by the output optical fibers, converting the output light beams into uniform light spots and irradiating the uniform light spots to the receiving module.
In one embodiment, the distance between the optical diffuser and the receiving module is adjusted to make the uniform light spot cover each pixel point of the receiving module, i.e. fill the full view angle of the TOF camera.
In one embodiment, as shown in fig. 3, the optical diffusion sheet is a microlens array, the microlens array is composed of a plurality of microlens units, and the size of the microlens units in the microlens array is smaller than the size of the light spot of the output light beam of the output optical fiber, so that the output optical fiber corresponds to the plurality of microlens units, and the light spot with the small size output by the output optical fiber is converted into a uniform light spot, thereby avoiding the over-exposure phenomenon.
It should be understood that each microlens unit in the microlens array is configured to diverge the light beam, so that the light beam output by the output fiber can illuminate each pixel of the receiving module after passing through the microlens array.
In one embodiment, as shown in FIG. 4, the optical diffuser is a diffuser. The light beam output by the output optical fiber penetrates through the diffuser, the micro-nano structure is arranged on the surface of the diffuser, the size, the period and the shape of the micro-nano structure can be changed according to different requirements, the light spots of the output optical fiber output light beam are converted into uniform light spots, the field angle of the light beam is modulated, and the modulated light spots of the diffuser can cover each pixel of the receiving module.
In one embodiment, as shown in fig. 5, the optical diffusion sheet is a liquid crystal adjusting element, and under the control of different voltages, the liquid crystal can deflect at different angles, so as to convert the light spots of the output light beam of the output optical fiber into uniform light spots and control the divergence angle of the light beam, so that the light beam has different fields of view. It should be understood that the light beam modulated by the liquid crystal modulation element can be spread over the whole receiving module by selecting the liquid crystal modulation element with proper size and reasonably adjusting the distance between the liquid crystal modulation element and the receiving module.
In one embodiment, as shown in fig. 6, the optical diffusion sheet may also be an optical super-surface layer, in which a plurality of nano-antennas are included, and the nano-antennas belong to a sub-wavelength structure, and can modulate a light beam in multiple dimensions such as phase, amplitude, or polarization, so as to achieve a large field angle. More specifically, the structure of the nano-antenna is changed by applying a bias voltage to the optical super-surface layer, the dielectric constant of the nano-antenna is further changed, so that the light beam is modulated, the energy of the output light beam is concentrated, and the light spot with small size is converted into a uniform light spot and is irradiated to each pixel of the receiving module. It should be understood that the size, shape, and cancellation of the nanoantenna can be varied according to the requirements of the light beam, and is not limited thereto.
It should be noted that the optical diffuser can also be one or more combinations of optical devices, and is not limited herein.
And the receiving module is used for receiving the uniform light spots, generating optical signals and sending the optical signals to the calibration device.
And the calibration device is used for receiving the optical signal and calculating calibration information according to the optical signal.
In the embodiment of the application, the optical fiber calibration system is provided with a transmitting module, an input optical fiber, an output optical fiber, an optical diffusion sheet, a receiving module and a calibration device; the transmitting module is used for transmitting the input light beam to the input optical fiber; the optical diffusion sheet is used for receiving the output light beams projected by the output optical fibers, converting the output light beams into uniform light spots and irradiating the uniform light spots to the receiving module; the receiving module is used for receiving the uniform light spots, generating optical signals and sending the optical signals to the calibration device; and the calibration device is used for receiving the optical signal and calculating calibration information according to the optical signal. An optical diffusion sheet is added in the optical fiber calibration system, so that the optical fiber signals can be subjected to light homogenizing treatment, and all calibration items related to the distance can be completed. Therefore, the method and the device can further improve the calibration efficiency, improve the optical fiber calibration process and improve the optical fiber calibration efficiency.
Referring to fig. 7, fig. 7 is a schematic flowchart of an optical fiber calibration method according to a second embodiment of the present application. An execution subject of the optical fiber calibration method in this embodiment is the calibration device in the optical fiber calibration system in the first embodiment. The optical fiber calibration method shown in fig. 7 may include:
s101: and acquiring the optical signal acquired by the receiving module, and acquiring the target parameter of the optical signal.
The calibration device acquires the optical signal acquired by the receiving module and acquires the target parameter of the optical signal. The target parameter is a related parameter that can be calculated according to the optical signal, and may include a real-time parameter and a preset parameter. For example, the target parameters may include a time of flight and a preset distance of flight of the optical signal, and the like.
S102: and calculating error information according to the target parameters to obtain calibration information.
The calibration device can calculate error information according to the target parameters to obtain calibration information. The calibration information may include range cyclic error information wiggling, global error information offset, and depth error information FPPN.
In one embodiment, the calibration device obtains the flight time and the preset flight distance of the optical signal, and calculates the actual flight distance of the optical signal according to the flight time of the optical signal; and calculating distance cycle error information according to the actual flying distance and the preset flying distance.
Specifically, the calibration device calculates the flight time of the light beam according to the optical signal received by the receiving module, and calculates the actual flight distance L of the light beam based on the following formula:
L＝ct/2
where c is the speed of light and t is the time of flight of the light signal.
The actual flying distance L of the light beamwAnd a preset flying distance L'wCarrying out wiggling error calculation to obtain distance cyclic error information delta Lw＝L′w-Lw。
In one embodiment, the error curve may be fitted based on distance cycle error information for test flight distances for optical fibers of different lengths. Based on the optical fibers with different lengths, distance cycle error information of different flight distances is obtained, and curve fitting is carried out on the distance cycle error information under different flight distances through an interpolation method. It should be understood that the method of fitting the curve may also be a least squares method or other fitting function, and is not limited herein.
In one embodiment, the receiving module comprises a first phase detection window and a second phase detection window; the optical signal includes a first optical signal detected by the first phase detection window and a second optical signal detected by the second phase detection window. The calibration device can calculate the flight time of the optical signal according to the first optical signal, the second optical signal, the preset ambient light intensity and the modulation period.
In this implementationIn the embodiment, the receiving module is based on the principle of an indirect time-of-flight method, the received optical signal and the light beam emitted by the emitting module have certain phase delay, and when the receiving module comprises a first phase detection window and a second phase detection window, the flight time can be integrated by the first phase detection window and the second phase detection window to obtain a first optical signal QAAnd a second optical signal QBExpressed, the time of flight is:
wherein Q is0Is the intensity of the ambient light measured in the absence of incident light, and T is the modulation period.
In one embodiment, when the receiving module includes four phase detection windows, the modulation period of the line beam or the area array beam emitted from the emitting end is T, the reflected light signals detected by the four detection window signals are all continuous waves with a duty ratio of 50%, and the delays for the emitted light signals are 0 °, 90 °, 180 ° and 270 °, respectively, and the phase delay can be expressed by the following equation:
the ambient light is automatically eliminated in the equation, and based on the above equation, the time of flight can be further calculated as:
wherein f ismThe light source modulation frequency.
In one embodiment, the calibration means obtains a single photon count histogram of the optical signal; and determining the flight time of the optical signal according to the single photon counting histogram. In this embodiment, the receiving module is based on the principle of direct time-of-flight method, and is a Single Photon Avalanche Diode (SPAD) or SPAD array, and the receiving module further includes a Time Data Converter (TDC) circuit and a time-dependent single photon counting (TCSPC) circuit. When the emitting module emits a line beam or an area array beam which is modulated by pulses in time sequence, the optical signal detected by the receiving module is a single photon, a digital pulse is further generated, the TDC records the time when the digital pulse is generated, and adds an operation to the accumulated value of the single photon counting in a corresponding time interval, so that the flight time information of a plurality of groups of photons is output. After a number of repetitions of the same measurement, time data are recorded and accumulated in the same manner in the corresponding time interval, and a corresponding single photon counting histogram is obtained by the TCSPC circuit. And determining the time required by the photon to fly between the target and the system by performing peak judgment on the single photon counting histogram.
In one embodiment, the calibration device obtains an actual measured depth value of a principal point pixel and a preset measured depth value of the principal point pixel of the optical signal; and calculating global error information according to the measured depth value of the main point pixel and the preset measured depth value of the main point pixel.
Specifically, there is a fixed offset at each modulation frequency of the launch module due to the electrical delay caused by the launch module drive circuitry and the electro-optic conversion. Selecting any optical fiber to transmit a light beam to a receiving module, and calculating a measured depth value L of a pixel of a principal point of the light beam acquired by the receiving moduleoffsetAnd with the pixel true depth value L 'of the known principal point of the selected light-guiding fiber'offsetError calculation is carried out to obtain global error information of delta Loffset＝L′offset-Loffset。
In one embodiment, the calibration device obtains the distance cyclic error information and the global error information by calculation according to the target parameter, and the calculation method of the distance cyclic error information and the global error information is not limited in this embodiment. The calibration device calculates to obtain a corrected depth measurement value according to the distance cycle error information, the global error information and the uncorrected preset depth measurement value; and calculating according to the corrected depth measurement value and the preset depth true value to obtain depth error information.
Specifically, the light beam passing through the optical diffusion sheet may cover each pixel of the receiving module, that is, each pixel of the receiving module may generate an effective depth value, but due to design or production differences, there are slight differences between pixels, and thus it is necessary to correct an offset of each pixel, that is, depth error information, also called fixed phase offset (FPPN).
The depth measurement value of each pixel received by the receiving module after being corrected according to the distance cyclic error information and the global error information is LFPPN＝L+ΔLw+ΔLoffsetWherein L is an uncorrected predetermined depth measurement.
When the depth error information is calculated from the distance cycle error information and the global error information, the measurement value calculation should select the depth measurement value calculation performed by the light beam transmitted by the same optical fiber at the same pixel coordinate.
The calibrating device is used for calibrating the corrected depth measured value and the preset depth true value L'FPPNPerforming error calculation, i.e. obtaining depth error information Δ LFPPN＝L′FPPN-LFPPN。
The depth measurement value of the coordinate at a certain pixel coordinate point is L ═ L' - Δ LFPPNAnd obtaining the depth value corrected by the distance cycle error information, the global error information and the depth error information.
In this embodiment, the optical fiber calibration system includes a transmitting module, an input optical fiber, an output optical fiber, an optical diffuser, a receiving module, and a calibration device; the transmitting module is used for transmitting the input light beam to the input optical fiber; the optical diffusion sheet is used for receiving the output light beams projected by the output optical fibers, converting the output light beams into uniform light spots and irradiating the uniform light spots to the receiving module; the receiving module is used for receiving the uniform light spots, generating optical signals and sending the optical signals to the calibration device; and the calibration device is used for receiving the optical signal and calculating calibration information according to the optical signal. An optical diffusion sheet is added in the optical fiber calibration system, so that the optical fiber signal can be subjected to light homogenizing treatment, and all calibration items related to the distance can be completed only according to the optical signal. Therefore, the method and the device can further improve the calibration efficiency, improve the optical fiber calibration process and improve the optical fiber calibration efficiency.
It should be understood that, the sequence numbers of the steps in the foregoing embodiments do not imply an execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.
Referring to fig. 8, fig. 8 is a schematic view of a calibration device according to a third embodiment of the present application. The units are included for performing the steps in the corresponding embodiment of fig. 7. Please refer to fig. 7 for a related description of an embodiment. For convenience of explanation, only the portions related to the present embodiment are shown. Referring to fig. 8, the calibration device 8 includes:
the acquiring unit 810 is configured to acquire an optical signal acquired by the receiving module, and acquire a target parameter of the optical signal;
and a calculating unit 820, configured to perform error information calculation according to the target parameter to obtain calibration information.
Further, the obtaining unit 810 is specifically configured to:
acquiring the flight time and the preset flight distance of an optical signal;
the calculating unit 820 is specifically configured to:
calculating the actual flying distance of the optical signal according to the flying time of the optical signal;
and calculating distance cycle error information according to the actual flying distance and the preset flying distance.
Furthermore, the receiving module comprises a first phase detection window and a second phase detection window; the optical signal comprises a first optical signal detected by a first phase detection window and a second optical signal detected by a second phase detection window;
the obtaining unit 810 is specifically configured to:
and calculating the flight time of the optical signal according to the first optical signal, the second optical signal, the preset ambient light intensity and the modulation period.
Further, the obtaining unit 810 is specifically configured to:
acquiring a single photon counting histogram of an optical signal;
and determining the flight time of the optical signal according to the single photon counting histogram.
Further, the obtaining unit 810 is specifically configured to:
acquiring an actual main point pixel measurement depth value and a preset main point pixel measurement depth value of the optical signal;
the calculating unit 820 is specifically configured to:
and calculating global error information according to the measured depth value of the main point pixel and the preset measured depth value of the main point pixel.
Further, the calculating unit 820 is specifically configured to:
calculating according to the target parameters to obtain distance cycle error information and global error information;
calculating to obtain a corrected depth measurement value according to the distance cycle error information, the global error information and the uncorrected preset depth measurement value;
and calculating according to the corrected depth measurement value and the preset depth true value to obtain depth error information.
Fig. 9 is a schematic diagram of a calibration apparatus provided in a fourth embodiment of the present application. As shown in fig. 9, the calibration apparatus 9 of this embodiment includes: a processor 90, a memory 91, and a computer program 92, such as a fiber calibration program, stored in the memory 91 and executable on the processor 90. The processor 90, when executing the computer program 92, implements the steps in the above-described fiber calibration method embodiments, such as the steps 101 to 102 shown in fig. 7. Alternatively, the processor 90, when executing the computer program 92, implements the functions of the modules/units in the above-described device embodiments, such as the functions of the modules 810 to 820 shown in fig. 8.
Illustratively, the computer program 92 may be divided into one or more modules/units, which are stored in the memory 91 and executed by the processor 90 to accomplish the present application. One or more of the modules/units may be a series of computer program instruction segments capable of performing certain functions, which are used to describe the execution of the computer program 92 in the calibration apparatus 9. For example, the computer program 92 may be divided into an acquisition unit and a calculation unit, and the specific functions of each unit are as follows:
the acquisition unit is used for acquiring the optical signals acquired by the receiving module and acquiring target parameters of the optical signals;
and the calculating unit is used for calculating the error information according to the target parameters to obtain the calibration information.
The calibration device may include, but is not limited to, a processor 90, a memory 91. Those skilled in the art will appreciate that fig. 9 is only an example of the calibration apparatus 9, and does not constitute a limitation of the calibration apparatus 9, and may include more or less components than those shown, or some components in combination, or different components, for example, the calibration apparatus may further include an input-output device, a network access device, a bus, etc.
The Processor 90 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 91 may be an internal storage unit of the calibration apparatus 9, such as a hard disk or a memory of the calibration apparatus 9. The memory 91 may also be an external storage device of the calibration apparatus 9, such as a plug-in hard disk provided on the calibration apparatus 9, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), and the like. Further, the calibration apparatus 9 may also include both an internal storage unit of the calibration apparatus 9 and an external storage apparatus. The memory 91 is used for storing computer programs and other programs and data needed for the calibration device. The memory 91 may also be used to temporarily store data that has been output or is to be output.
It should be noted that, for the information interaction, execution process, and other contents between the above-mentioned devices/units, the specific functions and technical effects thereof are based on the same concept as those of the embodiment of the method of the present application, and specific reference may be made to the part of the embodiment of the method, which is not described herein again.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working processes of the units and modules in the system may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
An embodiment of the present application further provides a network device, where the network device includes: at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor, the processor implementing the steps of any of the various method embodiments described above when executing the computer program.
The embodiments of the present application further provide a computer-readable storage medium, where a computer program is stored, and when the computer program is executed by a processor, the computer program implements the steps that can be implemented in the above method embodiments.
The embodiments of the present application provide a computer program product, which when running on a mobile terminal, enables the mobile terminal to implement the steps in the above method embodiments when executed.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, all or part of the processes in the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium and can implement the steps of the embodiments of the methods described above when the computer program is executed by a processor. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer readable medium may include at least: any entity or device capable of carrying computer program code to a photographing apparatus/terminal apparatus, a recording medium, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), an electrical carrier signal, a telecommunications signal, and a software distribution medium. Such as a usb-disk, a removable hard disk, a magnetic or optical disk, etc. In certain jurisdictions, computer-readable media may not be an electrical carrier signal or a telecommunications signal in accordance with legislative and patent practice.
In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
In the embodiments provided in the present application, it should be understood that the disclosed apparatus/network device and method may be implemented in other ways. For example, the above-described apparatus/network device embodiments are merely illustrative, and for example, the division of the modules or units is only one logical division, and there may be other divisions when actually implementing, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not implemented. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.
Claims (10)
1. An optical fiber calibration system, the system comprising: the device comprises a transmitting module, an input optical fiber, an output optical fiber, an optical diffusion sheet, a receiving module and a calibration device;
the transmitting module is used for transmitting an input light beam to the input optical fiber;
the optical diffusion sheet is used for receiving the output light beams projected by the output optical fibers, converting the output light beams into uniform light spots and irradiating the uniform light spots to the receiving module;
the receiving module is used for receiving the uniform light spots, generating optical signals and sending the optical signals to the calibration device;
and the calibration device is used for receiving the optical signal and calculating calibration information according to the optical signal.
2. The fiber calibration system of claim 1, wherein the optical fiber comprises a core; the fiber core is a quartz fiber core.
3. The fiber calibration system of claim 1, wherein the optical diffuser is one or more of a micro lens array, a diffuser, a liquid crystal conditioning element, and an optical super surface layer.
4. An optical fiber calibration method applied to the calibration device in the optical fiber calibration system of any one of claims 1-3, the method comprising:
acquiring an optical signal acquired by a receiving module, and acquiring a target parameter of the optical signal;
and calculating error information according to the target parameters to obtain calibration information.
5. The method for calibrating optical fiber according to claim 4, wherein said obtaining the target parameter of the optical signal comprises:
acquiring the flight time and the preset flight distance of the optical signal;
the calculating of the error information according to the target parameter to obtain the calibration information comprises:
calculating the actual flying distance of the optical signal according to the flying time of the optical signal;
and calculating distance cycle error information according to the actual flying distance and the preset flying distance.
6. The method for calibrating optical fiber according to claim 5, wherein said receiving module comprises a first phase detection window and a second phase detection window; the optical signal comprises a first optical signal detected by the first phase detection window and a second optical signal detected by the second phase detection window;
the acquiring a time of flight of the optical signal includes:
and calculating the flight time of the optical signal according to the first optical signal, the second optical signal, the preset ambient light intensity and the modulation period.
7. An optical fiber calibration method according to claim 5, wherein said obtaining the time of flight of the optical signal comprises:
acquiring a single photon counting histogram of the optical signal;
and determining the flight time of the optical signal according to the single photon counting histogram.
8. The method for calibrating optical fiber according to claim 4, wherein said obtaining the target parameter of the optical signal comprises:
acquiring an actual main point pixel measurement depth value and a preset main point pixel measurement depth value of the optical signal;
the calculating of the error information according to the target parameter to obtain the calibration information comprises:
and calculating global error information according to the measured depth value of the main point pixel and the preset measured depth value of the main point pixel.
9. The method for calibrating optical fiber according to claim 4, wherein said calculating error information according to said target parameter to obtain calibration information comprises:
calculating to obtain distance cycle error information and global error information according to the target parameters;
calculating to obtain a corrected depth measurement value according to the distance cycle error information, the global error information and an uncorrected preset depth measurement value;
and calculating to obtain depth error information according to the corrected depth measurement value and the preset depth true value.
10. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the method according to any one of claims 4 to 9.
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