WO2024050902A1

WO2024050902A1 - Itof camera, calibration method, and related device

Info

Publication number: WO2024050902A1
Application number: PCT/CN2022/123163
Authority: WO
Inventors: 孙瑞; 刘欣; 焦健楠; 陶郅; 王飞
Original assignee: 奥比中光科技集团股份有限公司; 深圳奥芯微视科技有限公司
Priority date: 2022-09-05
Filing date: 2022-09-30
Publication date: 2024-03-14
Also published as: CN115469331A

Abstract

The present application discloses an ITOF camera, an intelligent terminal, a calibration method, and a computer readable storage medium. An ITOF camera 10 comprises an emitter 100, a collector 200, a light guide structure communicated with the emitter 100 and the collector 200, and a control and processing unit 300. The control and processing unit 300 is configured to control a first light source to emit a first optical signal and to control a measurement photosensitive unit to collect a reflected first optical signal to calculate the distance of a target object; the control and processing unit 300 is further configured to control a second light source to emit a second optical signal to the light guide structure, to control a reference photosensitive unit to collect the second optical signal transmitted by the light guide structure so as to calculate a corresponding first optical transmission measurement distance, to calculate an error between the first optical transmission measurement distance and an actual optical transmission distance as a second global error, and to correct the distance of the target object according to the second global error. Therefore, the ITOF camera in the present application can not only realize a distance measurement function, but also calibrate a global error of the ITOF camera in real time.

Description

ITOF cameras, calibration methods and related equipment

This application claims priority to the Chinese patent application submitted to the China Patent Office on September 5, 2022, with the application number 202211077959.6 and the invention name "ITOF camera, calibration method and related equipment", the entire content of which is incorporated into this application by reference. middle.

Technical field

This application relates to the field of camera technology, and in particular to an ITOF camera, an intelligent terminal, a calibration method and a computer-readable storage medium.

Background technique

ITOF cameras need to calibrate the global error (offset) before leaving the factory. The offset includes the electronic signal delay of the ITOF camera itself and the electronic signal delay of the printed circuit board (PCB) circuit. The signal delays of different cameras and different PCBs are different, that is, The offset is different, so each camera needs to be calibrated separately. However, during long-term use of an ITOF camera that has been successfully calibrated, due to the aging of electronic components, the signal delay of electronic transmission changes, and the offset will also change, and the offset needs to be recalibrated. Currently, in order to ensure measurement accuracy, ITOF cameras that have been used for a long time usually need to be returned to the factory for recalibration of offset, which increases the cost of after-sales maintenance.

Therefore, in view of the above-mentioned defects, the existing technology still needs to be improved and developed.

Technical solutions

The main purpose of this application is to provide an ITOF camera, a smart terminal, a calibration method and a computer-readable storage medium, aiming to solve the problem in the prior art that ITOF cameras need to be returned to the factory to recalibrate the offset after long-term use, which increases the cost of after-sales maintenance. .

In order to achieve the above purpose, the first aspect of the present application provides an ITOF camera, including an emitter, a collector, a light guide structure connecting the emitter and the collector, and a control and processor, wherein the emitter includes a first light source and a second light source. Light source; the collector includes a measurement photosensitive unit and a reference photosensitive unit; the control and processor are used to control the first light source to emit a first optical signal to the target object, and control the measurement photosensitive unit to collect the first optical signal reflected by the target object and generate a first electrical signal, and process the first electrical signal to calculate the distance of the target object; the control and processor are also used to control the second light source to emit a second optical signal to the light guide structure, and control the reference photosensitive unit to collect the second light signal transmitted through the light guide structure. optical signal and generate a second electrical signal, and process the second electrical signal to calculate the corresponding first optical transmission measurement distance, and calculate the error between the first optical transmission measurement distance and the actual optical transmission distance as the second global error; the control and The processor is also configured to correct the distance of the target object according to the second global error.

In some embodiments, the emitter further includes: an optical diffusion sheet. The optical diffusion sheet includes a microstructure area and a non-microstructure area, wherein the microstructure area is disposed on the transmission light path of the first light source for emitting light to the first light source. The light beam is modulated to project a flood light beam to the target object; the non-microstructure area is set between the microstructure area and the light guide structure to prevent the light beam emitted by the first light source from being incident into the light guide structure, and the light guide structure is an optical fiber or The inner wall is a cavity with a realm.

A second aspect of this application provides an intelligent terminal, including a processor, a memory and an ITOF camera as described above, wherein: the processor is used to initiate a calibration signal to the ITOF camera; and the control and processor in the ITOF camera are used to control the emission of the second light source. The second optical signal of the preset frequency is incident on the reference photosensitive unit through the light guide structure, and generates a third electrical signal; the control and processor are also used to calculate the corresponding second optical transmission measurement distance based on the third electrical signal, and calculate the third optical signal. The distance error between the second optical transmission measurement distance and the actual optical transmission distance of the second optical signal is calculated, and the signal delay of the pre-stored second global error and the distance error is calculated, and the third step is performed based on the signal delay and the pre-stored first global error. Global error calculation to correct the distance of the target object measured by the ITOF camera using the third global error.

A third aspect of the present application provides a calibration method, which includes: controlling a second light source to emit a second optical signal of a preset frequency through a light guide structure and incident on a reference photosensitive unit to generate a third electrical signal; and calculating a corresponding signal based on the third electrical signal. The second optical transmission measurement distance; calculate the distance error between the second optical transmission measurement distance and the actual optical transmission distance; calculate the pre-stored second global error and the distance error to perform signal delay; according to the signal delay and the pre-stored first global error A third global error calculation is performed to correct the distance of the target object measured by the ITOF camera using the third global error.

A fourth aspect of the present application provides a computer-readable storage medium. A calibration program is stored on the computer-readable storage medium. When the calibration program is executed by a processor, the steps of the above-mentioned calibration method are implemented.

beneficial effects

In this embodiment, the control and processor can not only control the first light source to emit a first optical signal to the target object, and then reflect it to the measurement photosensitive unit for distance measurement, but also control the second light source to emit a second optical signal to the light guide. The light guide structure is incident on the reference photosensitive unit for second global error calculation, and the distance of the target object is corrected according to the second global error. Therefore, the ITOF camera in this application can not only realize the ranging function, but also calibrate the global error of the ITOF camera in real time, without requiring the terminal manufacturer to perform global error calibration on the production line, which solves the problem that the product needs to be returned to the factory for re-installation after long-term use. Offset calibration is performed to ensure accuracy, thereby reducing after-sales maintenance costs.

Description of the 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 description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only for the purpose of the present application. For some embodiments, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a system block diagram of an intelligent terminal according to the embodiment of the present application;

Figure 2 is a system block diagram of the ITOF camera according to the embodiment of the present application;

Figure 3 is a schematic flow chart of the calibration method according to the embodiment of the present application;

Figure 4 is a schematic flow chart of a calibration method according to another embodiment of the present application;

Figure 5 is a schematic flow chart of a calibration method according to another embodiment of the present application.

Embodiments of the invention

In the following description, for the purpose of explanation rather than limitation, specific details such as specific system structures and technologies are provided to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be practiced in other embodiments without 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, when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and/or components but does not exclude one or more other features , the presence or addition of a whole, a step, an operation, an element, a component, and/or a collection thereof.

It should also be understood that the terminology used in the specification of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this specification and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly dictates otherwise.

It will be further 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 as "when" or "once" or "in response to determining" or "in response to detecting" depending on the context. Similarly, the phrase "if determined" or "if [the described condition or event] is detected" may be interpreted, depending on the context, to mean "once determined" or "in response to a determination" or "once the [described condition or event] is detected" event]” or “in response to detection of [the described condition or event]”.

The technical solutions in the embodiments of the present application are clearly and completely described below with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

Many specific details are set forth in the following description to fully understand the present application. However, the present application can also be implemented in other ways different from those described here. Those skilled in the art can do so without violating the connotation of the present application. Similar generalizations are made, and therefore the present application is not limited to the specific embodiments disclosed below.

Figure 1 shows a system block diagram of a smart terminal, including a processor 20, a memory 30 and an ITOF camera 10 connected thereto. As one of the mainstream three-dimensional visual perception technologies, ITOF technology is widely used in smart terminal devices such as mobile phones, tablets, sweeping robots, and mobile robots. For example, an ITOF camera is installed in a sweeping robot. The ITOF camera collects three-dimensional information about the surrounding environment of the mobile robot and transmits the three-dimensional information to the processor in the sweeping robot. The processor performs obstacle scene recognition, positioning perception and other processing based on the three-dimensional information. , based on the processing results, the robot is controlled to perform obstacle avoidance, path planning, etc. Among them, the ITOF camera 10 includes a transmitter 100, a collector 200, and a control and processor 300. The transmitter 100 is used to transmit modulated light signals toward multiple target points in the target scene, and the collector 200 is used to collect the target. The reflected light signal generates an electrical signal, the control and processor 300 is connected to the transmitter 100 and the collector 200 and controls the synchronous activation of the transmitter 100 and the collector 200, and processes the electrical signal output by the collector 200 to calculate the optical signal to and from the target. The flight time of the point is further calculated to calculate the distance to the target point. Those skilled in the art can understand that the principle block diagram shown in Figure 1 is only a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the ITOF camera 10 to which the solution of the present application is applied. Specifically, the ITOF Camera 10 may include more or fewer components than shown in the figures, or combine certain components, or have a different arrangement of components.

It should be noted that the control and processor 300 may be the processor 20 in the smart terminal, that is, the processor 20, the transmitter 100 and the collector 200 implement the ranging and calibration functions, or the control and processor 300 may be a separate A single processor, the transmitter 100 and the collector 200 constitute the ITOF camera 10 of the present application.

Currently, ITOF cameras need to calibrate system errors before leaving the factory. The main calibration contents include temperature drift, depth error (FPPN), distance measurement error (wiggling) and global error (offset). Among them, offset is mainly caused by the electronic signal delay of the ITOF camera itself and the electronic signal delay of the printed circuit board (PCB) circuit. Different cameras and different PCB test boards have different signal delays, that is, different offsets, so each camera needs to be calibrated separately. However, after a successfully calibrated ITOF camera is matched to a different test board, the test board will produce additional offset delays. For example, when assembling an ITOF camera into a smart terminal product, the entire machine needs to be re-calibrated for offset, and this calibration process is basically completed on the production line of the terminal manufacturer. This increases the development costs for terminal manufacturers using ITOF cameras, reduces the user experience, and is not conducive to the promotion and use of ITOF cameras. Moreover, during long-term use of an ITOF camera that has been successfully calibrated, due to the aging of electronic components, the signal delay of electronic transmission changes, and the offset will also change, and the offset needs to be recalibrated. Currently, in order to ensure measurement accuracy, ITOF cameras that have been used for a long time usually need to be returned to the factory for recalibration of offset, which increases the cost of after-sales maintenance.

In order to solve the above problems, this application provides an ITOF camera with a calibration system and a calibration method for installing the ITOF camera in an intelligent terminal device. The offset of the ITOF camera can be calibrated in real time without the need for the terminal manufacturer to calibrate the camera in production. At the same time, this ITOF can solve the problem of the product needing to be returned to the factory for re-offset calibration to ensure accuracy after long-term use, thus reducing after-sales maintenance costs.

Figure 2 shows an ITOF camera provided by the present application. The ITOF camera 10 includes an emitter 100, a collector 200, a control and processor 300, and a light guide structure 400 connecting the emitter 100 and the collector 200. The emitter 100 includes a first light source 101 and a second light source 102. The collector 200 includes a reference photosensitive unit 201 and a measurement photosensitive unit 202. The control and processor 300 is used to control the first light source 101 to emit a first light signal to the target object, and The measurement photosensitive unit 202 is controlled to collect the first optical signal reflected by the target object and generate a first electrical signal, and process the first electrical signal to calculate the distance of the target object; the control and processor 300 is also used to control the second light source 102 to emit a second The optical signal is transmitted to the light guide structure 400, and the reference photosensitive unit 201 is controlled to collect the second optical signal transmitted through the light guide structure 400 and generate a second electrical signal, and process the second electrical signal to calculate the first light of the second optical signal. Transmit the measured distance, calculate the error between the first optical transmission measurement distance and the actual optical transmission distance as the second global error, and correct the distance of the target object according to the second global error, thereby realizing the ranging of the ITOF camera 10 function and offset calibration function.

In some embodiments, the first light source 101 and the second light source 102 can be a light source such as a light emitting diode (LED), an edge emitting laser (EEL), a vertical cavity surface emitting laser (VCSEL), or a light source composed of multiple light sources. Array, the emitted light beam has the same modulation frequency and wavelength, and the emitted light beam can be visible light, infrared light, ultraviolet light, etc. In one embodiment, the first light source 101 is a light source array composed of multiple vertical cavity surface emitting lasers for emitting a spot pattern beam toward a target object. The second light source 102 is a single point light source, which can be an LED, an EEL, or a VCSEL. Either one, preferably, the second light source 102 is a single-point VCSEL, used to emit a spot beam with a very small divergence angle to be incident on the light guide structure. In one embodiment, the emitter 100 includes a light source array composed of a plurality of light sources, and is configured with zone control of the light source array to form a first light source 101 and a second light source 102, wherein the number of light sources in the first light source 101 is greater than that of the second light source. The number of light sources in the light source 102, the field of view angle of the light beam emitted by the first light source 101 is greater than the field of view angle of the light beam emitted by the second light source 102. It should be noted that the working modes of the first light source 101 and the second light source 102 can be adjusted according to actual applications, that is, the first light source 101 and the second light source 102 can work independently at different times, which is not limited here.

In some embodiments, as shown in FIG. 2 , the emitter 100 further includes an optical diffusion sheet 500 . The optical diffusion sheet 500 includes a microstructure area and a non-microstructure area, wherein the microstructure area is disposed in the transmission light direction of the first light source 101 . On the way, it is used to modulate the light beam emitted by the first light source 101 to project a flood light beam to the target object. The non-microstructure area is correspondingly arranged between the microstructure area and the light guide structure to prevent the light beam emitted by the first light source 101 from being incident into the light guide structure. Specifically, the optical diffusion sheet may be a diffuser or a soft mirror.

In some embodiments, the collector 200 includes an image sensor composed of a plurality of pixels, which may be a charge coupled device (CCD), a complementary metal oxide semiconductor (CMOS), an avalanche diode (AD), a single photon avalanche diode (SPAD) The array size represents the resolution of the depth camera, such as 320x240, etc. Generally, the image sensor 121 is also connected to a readout circuit composed of one or more of a signal amplifier, a time-to-digital converter (TDC), an analog-to-digital converter (ADC), and other devices (not shown in the figure). ). Generally, the image sensor 121 includes at least one pixel, and each pixel includes a plurality of taps (for storing and reading or discharging charge signals generated by incident photons under the control of corresponding electrodes), such as including 3 taps. , used to read the charge signal data.

In one embodiment, the image sensor in the collector 200 is divided into two areas, including the measurement photosensitive unit 202 and the reference photosensitive unit 201. For example, a row, a column or several pixels can be selected as the reference photosensitive unit 201, and the image sensor The remaining pixels are the measurement photosensitive units 202. The reference photosensitive unit 201 corresponds to the light guide structure and is used to receive the second optical signal transmitted through the light guide structure and generate a second electrical signal for calibration. In some embodiments, the collector 200 also includes a receiving lens 600 and a filter 700. Preferably, the filter 700 is adapted to the measurement photosensitive unit 202. For example, the filter 700 can be attached to the measurement photosensitive unit 202. Surface, the optical signal reflected back by the target object is incident on the measurement photosensitive unit 202 through the receiving lens 600 to generate a first electrical signal for distance measurement. The filter 600 needs to select a narrow-band filter that matches the wavelength of the second light source. , used to suppress ambient light in other bands and avoid interference from ambient light.

In some embodiments, the light guide structure 400 is an optical fiber or a cavity with an inner wall. Specifically, the light pipe may be a single-mode optical fiber, a multi-mode optical fiber, or a specular reflector.

In some embodiments, the control and processor 300 can be an independent dedicated circuit, such as a dedicated SOC chip, FPGA chip, ASIC chip, etc. composed of a CPU, memory, bus, etc., or it can also include a general processing circuit, such as the After the ITOF camera is integrated into the smart terminal, the processor in the smart terminal can serve as at least part of the control and processor 300 . For ease of description, the two are described separately below, but this does not limit the scope of protection of the present application.

In one embodiment, the control and processor 300 processes the first electrical signal to calculate a phase delay of the reflected first optical signal relative to the emitted first optical signal.

further according to the phase delay

Calculate the distance D ₁ corresponding to the target, that is:

f ₁ is the modulation frequency of the first optical signal, and C is the speed of light.

The ITOF camera provided in this application has a calibration system itself, and offset calibration needs to be performed before leaving the factory. Specifically, a _real calibration plate is provided at a fixed distance D from the ITOF camera. The control and processor 300 controls the first light source 101 to emit a first optical signal to the calibration plate at a preset distance. The first optical signal reflected by the calibration plate is incident on the calibration plate. Measure the photosensitive unit 202 and generate a first electrical signal. The control and processor 300 is also used to process the first electrical signal to calculate the distance D _measurement of the calibration plate. The calculated distance D _measurement is the measurement distance of the calibration plate. Due to the electronic signal delay As a result, there is a deviation between the measurement distance D of the calibration plate and _{the real distance D. The calculated error is: D error = D measurement} _- _D _real _. D _error is the offset value that needs to be calibrated during conventional offset calibration, that is, the data is stored in In the camera, as the pre-stored first global error, when actually measuring the target distance, the calibration offset value is used to correct the measurement value of the target object to obtain a more accurate measurement distance value of the target.

In some embodiments, the control and processor 300 processes the second electrical signal to calculate the phase delay of the second optical signal received by the reference photosensitive unit 201 relative to the emitted second optical signal.

further according to the phase delay

Calculate the flight distance d ₂ corresponding to the second optical signal, that is:

f ₂ is the modulation frequency of the second optical signal.

Secondly, before leaving the factory, the control and processor 300 controls the second light source 102 to emit a second optical signal to the light guide structure 400. The second optical signal transmitted through the light guide structure 400 is incident on the reference photosensitive unit 201 to generate a second electrical signal. The control and processor 300 is also used to process the second electrical signal to calculate the corresponding first optical transmission measurement distance d _measurement . Due to the delay of the electronic signal, the measurement distance d _{measurement is} different from the actual optical transmission distance d (d=L ₁ + L ₂ + There is a deviation in L ₃ ), and the calculated error is: d _error = d _measurement - d, where L ₁ represents the distance from the second light source 102 to the light guide structure 400 , L ₂ represents the length of the light guide structure 400 , and L ₃ represents The distance between the light guide structure 400 and the reference photosensitive unit 201; d _error is the offset value that needs to be calibrated during conventional offset calibration, that is, the data is stored in the camera as the pre-stored second global error. When the ITOF camera actually measures the target distance, the calibration offset value is used to correct the measurement value of the target object to obtain a more accurate measurement distance value of the target. It can be understood that when the ITOF camera measures distance, you can choose to use the first global error or the second global error to correct the distance value. And because the calibration system is set up inside the ITOF camera, in the application, the camera can be calibrated in real time. Calibrate the offset, or perform an offset calibration on the camera after using it for a period of time to reduce new errors caused by the aging of electronic components. In order to solve the different delay problems caused by different circuits used in terminals, this application proposes a calibrated ITOF camera, which also requires secondary calibration.

An intelligent terminal provided by this application includes an ITOF camera 10, a processor 20 and a memory 30. After the ITOF camera 10 is integrated into a smart terminal, the PCB board in the terminal equipment will also bring additional optical signal delay error, that is, offset error. At this time, the entire machine needs to be calibrated for offset. At this time, since the ITOF camera 10 comes with its own calibration system, no additional calibration equipment or calibration environment is required. It can be completed only through online software and algorithms. Specifically, on the terminal device, the processor 20 starts the calibration signal to the ITOF camera 10, and the control and processor 300 in the ITOF camera 10 controls the second light source 102 to emit a second optical signal of a preset frequency through the light guide structure 400. The reference photosensitive unit 201 generates a third electrical signal, calculates the corresponding second light transmission measurement distance d′ according to the third electrical signal, and compares the second light transmission measurement distance d′ with the actual light transmission distance d (d=L ₁ + L ₂ + L ₃ ) to calculate the distance error: Δd=d′-d. In addition, due to the additional signal delay caused by the electronic circuit on the PCB of the whole machine, the control and processor 300 is also used to calculate the signal delay using the pre-stored second global error d _error and the distance error Δd: Δdd=Δd-d _error . In order to realize the calibration of the global error, the control and processor 300 is also used to calculate the global error using the pre-stored first global error D _error and the signal delay Δdd: ΔD = D _error + Δdd, as the third global error, and store the final The offset value ΔD is used to calibrate the real-time global error, that is, the third global error is stored in the camera. When the target distance is actually measured, this value is used to correct the measurement value to obtain a more accurate measurement distance value of the target.

In summary, in this embodiment, the control and processor 300 can not only control the first light source 101 to emit the first light signal to the target object, and then reflect it to the measurement photosensitive unit 202 for ranging, but also control the second light source 102 to emit the first light signal. The second optical signal goes to the light guide structure 400 and is incident on the reference photosensitive unit 201 for global error calibration. Therefore, the ITOF camera in this application can not only achieve the ranging function, but also perform real-time calibration of the global error of the ITOF camera. Calibration does not require the terminal manufacturer to perform global error calibration on the production line, which solves the problem of the product needing to be returned to the factory for re-offset calibration to ensure accuracy after long-term use, thus reducing after-sales maintenance costs.

As shown in Figure 3, this application also provides a calibration method. When the ITOF camera is integrated into a smart terminal, the global error of the ITOF camera 10 in the above embodiment is calibrated through the calibration method.

The calibration method is executed by the control and processor 300 in the ITOF camera or the smart terminal with the ITOF camera 10. The calibration method includes the following steps:

In step S301, the second light source 102 is controlled to emit a second optical signal of a preset frequency through the light guide structure 400 and incident on the reference photosensitive unit 201 to generate a third electrical signal.

Step S302: Calculate the corresponding second optical transmission measurement distance according to the third electrical signal.

Step S303, calculate the distance error between the second optical transmission measurement distance d′ and the actual optical transmission distance d, and calculate Δd=d′-d, where the actual optical transmission distance d=L ₁ +L ₂ +L ₃ , where, L ₁ represents the distance from the second light source 102 to the light guide structure 400 , L ₂ represents the length of the light guide structure 400 , and L ₃ represents the distance from the light guide structure 400 to the reference photosensitive unit 201 .

Step S304: Calculate the signal delay meter of the pre-stored second global error d _error and distance error Δd, and calculate Δdd=Δd-d _error .

Step S305, perform a third global error calculation based on the signal delay Δdd and the pre-stored first global error D _error , and calculate ΔD = D _error + Δdd to use the third global error to correct the distance of the target object measured by the ITOF camera. .

In some embodiments, the control and processor 300, or the smart terminal with the ITOF camera 10 performs the following steps to obtain the pre-stored first global error, as shown in Figure 4, including:

In step S401, the first light source 101 is controlled to emit a first optical signal to a calibration plate at a preset measurement distance. The first optical signal reflected by the calibration plate is incident on the measurement photosensitive unit 202 to generate a first electrical signal.

Step S402, calculate the measurement distance of the calibration plate according to the first electrical signal, that is, the control and processor 300 processes the first electrical signal to calculate the phase delay of the reflected first optical signal relative to the emitted first optical signal.

further according to the phase delay

Calculate the distance D ₁ corresponding to the target, that is:

f ₁ is the modulation frequency of the first optical signal.

Step S403: Calculate the error between the preset distance and the measured distance of the calibration plate, and store Derro as the pre-stored first global _error .

In some embodiments, the control and processor 300, or the smart terminal with the ITOF camera 10 performs the following steps to obtain the pre-stored second global error, as shown in Figure 5, including:

Step S501, control the second light source 102 to emit a second optical signal to the light guide structure 400, and then enter the reference photosensitive unit 201 through the light guide structure 400 to generate a second electrical signal.

Step S502, calculate the corresponding first optical transmission measurement distance according to the second electrical signal, that is, the control and processor 300 processes the second electrical signal to calculate the relative distance between the second optical signal received by the reference photosensitive unit 201 and the second light emitted. signal phase delay

further according to the phase delay

f ₂ is the modulation frequency of the second optical signal.

Step S503, calculate the error between the first optical transmission measurement distance and the actual optical transmission distance, and store d _error as the pre-stored second global error, where the actual optical transmission distance d (d=L ₁ +L ₂ +L ₃ ), Wherein, L ₁ represents the distance from the second light source 102 to the light guide structure 400 , L ₂ represents the length of the light guide structure 400 , and L ₃ represents the distance from the light guide structure 400 to the reference photosensitive unit 201 .

In summary, in this calibration method, the second light source 102 is controlled to emit a second optical signal of a preset frequency to the light guide structure 400, and is incident on the reference photosensitive unit 201 through the light guide structure 400 to generate a third electrical signal; according to the third electrical signal Calculate the corresponding second optical transmission measurement distance based on the signal, calculate the distance error between the second optical transmission measurement distance and the actual optical transmission distance; perform signal delay calculation using the pre-stored second global error and distance error; compare the signal delay and the pre-stored optical transmission distance. The first global error is stored and the third global error is calculated to use the third global error to correct the distance measured by the ITOF camera. Therefore, the global error of the ITOF camera can be calibrated in real time through the above calibration method without Terminal manufacturers are required to perform global error calibration on the production line, which solves the problem of products needing to be returned to the factory for re-offset calibration to ensure accuracy after long-term use, thus reducing after-sales maintenance costs.

Based on the above embodiments, the memory 30 of the smart terminal stores a calibration program that can be run on the processor 20 . The calibration program can be executed by the processor 20 to implement the steps of the above calibration method.

In some embodiments, when the calibration program is executed by the processor 20, the following operation instructions are performed: control the second light source 102 to emit a second optical signal through the light guide structure 400 and enter the reference photosensitive unit 201 to generate a second electrical signal; process the second Calculate the corresponding second optical transmission measurement distance from the electrical signal; calculate the distance error between the second optical transmission measurement distance and the actual optical transmission distance; calculate the signal delay between the pre-stored second global error and the distance error; according to the signal delay and the pre-stored The third global error is calculated using the first global error to correct the distance measured by the ITOF camera using the third global error.

Embodiments of the present application also provide a computer-readable storage medium. A calibration program is stored on the computer-readable storage medium. When the calibration program is executed by a processor, the steps of the above-mentioned calibration method are implemented.

It should be understood that the sequence number of each step in the above embodiment does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above functional units and modules is used as an example. In actual applications, the above functions can be allocated to different functional units and modules according to needs. Module completion means dividing the internal structure of the above device into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be hardware-based. It can also be implemented in the form of software functional units. In addition, the specific names of each functional unit and module are only for the convenience of distinguishing each other and are not used to limit the scope of protection of the present application. For the specific working processes of the units and modules in the above system, please refer to the corresponding processes in the foregoing method embodiments, and will not be described again here.

In the above embodiments, each embodiment is described with its own emphasis. For parts that are not detailed or documented in a certain embodiment, please refer to the relevant descriptions of other embodiments.

Those of ordinary skill in the art can appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented with electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each specific application, but such implementations should not be considered beyond the scope of this application.

In the embodiments provided in this application, it should be understood that the disclosed apparatus/terminal equipment and methods can be implemented in other ways. For example, the apparatus/terminal equipment embodiments described above are only illustrative. For example, the division of the above modules or units is only a logical function division. In actual implementation, it can be divided in other ways, such as multiple units or units. Components may be combined or may be integrated into another system, or some features may be ignored, or not implemented.

If the above-mentioned integrated modules/units are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the present application can implement all or part of the processes in the methods of the above embodiments by instructing relevant hardware through a computer program. The above computer program can be stored in a computer-readable storage medium. The computer program can be stored in a computer-readable storage medium. When executed by the processor, the steps of each of the above method embodiments can be implemented. Wherein, the above-mentioned computer program includes computer program code, and the above-mentioned computer program code may be in the form of source code, object code, executable file or some intermediate form, etc. The above-mentioned computer-readable media may include: any entity or device capable of carrying the above-mentioned computer program code, recording media, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random accessory Access memory (RAM, Random Access Memory), electrical carrier signals, telecommunications signals, and software distribution media, etc. It should be noted that the content contained in the above computer-readable storage media can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction.

The above-described embodiments are only used to illustrate the technical solutions of the present application, but not to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art will understand that they can still implement the above-mentioned implementations. The technical solutions described in the examples are modified, or some of the technical features are equivalently replaced; however, these modifications or substitutions do not mean that the essence of the corresponding technical solutions deviates from the spirit and scope of the technical solutions in the embodiments of this application, and they should all be included in this application. within the scope of protection applied for.

Claims

An ITOF camera, characterized in that it includes an emitter, a collector, a light guide structure connecting the emitter and the collector, and a control and processor, wherein;

The emitter includes a first light source and a second light source;

The collector includes a measurement photosensitive unit and a reference photosensitive unit;

The control and processor are used to control the first light source to emit a first optical signal to a target object, and control the measurement photosensitive unit to collect the first optical signal reflected by the target object and generate a first electrical signal, and processing the first electrical signal to calculate a distance of the target object;

The control and processor are also used to control the second light source to emit a second optical signal to the light guide structure, and control the reference photosensitive unit to collect the second optical signal transmitted through the light guide structure and Generate a second electrical signal, process the second electrical signal to calculate the corresponding first optical transmission measurement distance, and calculate the error between the first optical transmission measurement distance and the actual optical transmission distance as the second global error;

The control and processor are further configured to correct the distance of the target object according to the second global error.
The ITOF camera according to claim 1, wherein the emitter further includes an optical diffusion sheet, the optical diffusion sheet includes a microstructure area and a non-microstructure area, wherein the microstructure area is disposed on the The transmission optical path of the first light source is used to modulate the light beam emitted by the first light source to project a flood light beam to the target object; the non-microstructure area is provided between the microstructure area and the light guide between structures to prevent the light beam emitted by the first light source from being incident into the light guide structure.
The ITOF camera according to claim 1, wherein the light guide structure is an optical fiber or a cavity with an inner wall.
The ITOF camera according to claim 1, wherein the control and processor are further configured to process the first electrical signal to calculate the reflected first optical signal relative to the emitted first light signal. The phase delay of the signal; the control and processor is also used to calculate the distance of the target object based on the phase delay.
The ITOF camera according to claim 1, wherein the control and processor are further used to control the first light source to emit the first light signal to a calibration plate at a preset distance, and the first light signal is reflected by the calibration plate. The first optical signal is incident on the measurement photosensitive unit to generate the first electrical signal, the first electrical signal is processed to calculate the measurement distance of the calibration plate, and the preset distance and the distance of the calibration plate are calculated. The error in the measured distance is taken as the first global error.
An intelligent terminal, characterized by comprising a processor, a memory and an ITOF camera as claimed in claims 1-5, wherein;

The processor is used to initiate a calibration signal to the ITOF camera;

The control and processor are used to control the second light source to emit a second optical signal of a preset frequency through the light guide structure and incident on the reference photosensitive unit, and generate a third electrical signal;

The control and processor are further configured to calculate the corresponding second optical transmission measurement distance according to the third electrical signal, and calculate the distance error between the second optical transmission measurement distance and the actual optical transmission distance, and calculate the predetermined optical transmission distance. The stored second global error and the signal delay of the distance error, and performing a third global error calculation based on the signal delay and the pre-stored first global error to use the third global error to measure the ITOF camera The distance to the target object is corrected.
A calibration method based on the ITOF camera according to any one of claims 1 to 5, the calibration method is applied to the smart terminal according to claim 6, characterized in that the calibration method includes:

Controlling the second light source to emit a second optical signal of a preset frequency through the light guide structure and incident on the reference photosensitive unit to generate a third electrical signal;

Calculate the corresponding second optical transmission measurement distance according to the third electrical signal;

Calculate the distance error between the second optical transmission measurement distance and the actual optical transmission distance;

Calculate the signal delay between the pre-stored second global error and the distance error;

A third global error calculation is performed according to the signal delay and the pre-stored first global error, so as to use the third global error to correct the distance of the target object measured by the ITOF camera.
The calibration method according to claim 7, characterized in that the calibration method further includes:

Control the first light source to emit a first optical signal to a calibration plate at a preset distance, and the first optical signal reflected by the calibration plate is incident on the measurement photosensitive unit to generate a first electrical signal;

Calculate the measurement distance of the calibration plate according to the first electrical signal;

The error between the preset distance and the measured distance of the calibration plate is calculated as a pre-stored first global error.
The calibration method according to claim 7, characterized in that the calibration method further includes:

Controlling the second light source to emit a second optical signal to the light guide structure, and incident on the reference photosensitive unit through the light guide structure to generate a second electrical signal;

Calculate the corresponding first optical transmission measurement distance according to the second electrical signal;

The error between the first optical transmission measurement distance and the actual optical transmission distance is calculated as a pre-stored second global error.
A computer-readable storage medium, characterized in that a calibration program is stored on the computer-readable storage medium, and when the calibration program is executed by a processor, the calibration method according to any one of claims 7-9 is implemented. step.