Anti-interference ranging device and method

Abstract

An anti-interference distance measurement device and method, the device comprising a pulse position modulator (1011) and a phase shift keying modulator (1012) connected to the pulse position modulator (1011); the pulse position modulator (1011) is used to generate a baseband signal according to a random number signal; each random number in the random number signal corresponds to a pulse position of the baseband signal; when there are multiple consecutive identical random numbers in the random number signal, there are M time intervals between the pulse positions corresponding to the multiple consecutive identical random numbers in the baseband signal; the phase of the random number signal and the baseband signal are synchronized; the phase shift keying modulator (1012) is used to modulate a carrier signal and a baseband signal to generate a first signal; the first signal is used to drive a light emitter (103) to generate a first pulse light to illuminate an object to be measured. The anti-interference distance measurement device and method can improve the anti-interference ability of the distance measurement signal.

Description

Technical Field

[0001] The present application relates to the field of distance measurement technology, and in particular to an anti-interference distance measurement device and method. Background Art

[0002] Time of flight (TOF) imaging is an active imaging method in which a camera system emits laser light toward a target and calculates its distance by measuring the time it takes for the sensor to receive the reflected light. To achieve higher measurement accuracy and resolution using actively modulated light, it's crucial to minimize the effects of noise and interference on the output.

[0003] When using TOF cameras, it's inevitable that multiple cameras will be simultaneously photographing the same object, or multiple cameras will be photographing each other. Without any processing, the calculated distance will rarely be equal to the actual distance. Because TOF applications often involve multiple cameras working together, traditional continuous wave or pulse wave modulation is susceptible to interference from multiple cameras operating at the same frequency, leading to erroneous distance measurements.

[0004] Currently, Code Division Multiplexing (CDM) and Binary Phase Shift Keying (BPSK) technologies are used to generate square wave signals with random phase jumps. Pixel modulated signals are sent in groups, and the waveform frequency between each group is fixed, but the phase is only 0 degrees and 180 degrees, and there is no gap time. The phase of the random jump is controlled by any pseudo-random number or binary random number generated by a random number generator (for example, binary 0 corresponds to a phase of 0 degrees, and binary 1 corresponds to a phase of 180 degrees). However, when the exposure time is constant and the operating frequency is too high, the random number sequence may be too long, and there will be long continuous 0s or continuous 1s in the long random number sequence. The possibility of interference from such a long continuous signal will greatly increase, affecting the anti-interference effect.

[0005] Therefore, how to improve the anti-interference ability of imaging when multiple TOF cameras are measuring distance is an urgent problem to be solved. Summary of the Invention

[0006] The embodiments of the present application provide an anti-interference ranging device and method, which can improve the anti-interference capability of TOF cameras when multiple TOF cameras are measuring distance.

[0007] In a first aspect, an embodiment of the present application provides an anti-interference ranging device, which may include:

[0008] A pulse position modulator and a phase shift keying modulator connected to the pulse position modulator (in the embodiment of the present application, a binary phase shift keying BPSK modulator is used as an example for description, and types of phase shift keying modulators include but are not limited to binary phase shift keying modulators);

[0009] The pulse position modulator is configured to generate a baseband signal based on a random number signal; wherein the random number signal includes one or more random numbers, each of the one or more random numbers corresponding to a pulse position of the baseband signal; when the random number signal includes multiple consecutive identical random numbers, there are M time intervals between the pulse positions corresponding to the multiple consecutive identical random numbers in the baseband signal, where M is an integer greater than 0; and the random number signal and the baseband signal are phase synchronized;

[0010] The phase-shift keying modulator is used to modulate the carrier signal and the baseband signal to generate a first signal; wherein the first signal is used to drive the light emitter to generate a first pulse light, and the first pulse light is used to illuminate the object to be measured.

[0011] The embodiment of the present application mainly reduces the impact of the anti-interference ability of the signal caused by the continuous consistency of the phase in the signal caused by continuous identical random numbers by adding a pulse position modulator (i.e., PPM modulator) to the anti-interference ranging device (such as a ranging chip). Specifically, the PPM modulator receives a random number signal containing one or more random numbers, wherein each of the one or more random numbers corresponds to the pulse position of a baseband signal. The PPM modulator makes the corresponding position of the modulated output baseband signal appear in accordance with the relevant parameters of the pulse position corresponding to the random number, and makes a certain number of time intervals between the two pulse positions; the mapping relationship between the random number and the pulse position provided by the PPM modulator in different cameras can be set to be different, so that the number of intervals between the two pulse positions in the baseband signal generated in each camera is different, thereby improving the anti-interference performance of the pulse light wave finally output, so that the camera can effectively identify the pulse light wave emitted by itself and filter the pulse light waves emitted by other cameras. The embodiment of the present application does not limit the method of determining the correspondence between random numbers and pulse positions. Different from the prior art, the random number is directly sent to the phase shift keying modulator; when there are continuous 0s or continuous 1s, the phases between each group of signal waves in the first signal output by the phase shift keying modulator may be continuously the same. By modulating the order, when there are multiple consecutive identical random numbers that may appear in the random number signal, the phases of consecutive groups of baseband signals in the output baseband signal will not be continuously the same, thereby improving the anti-interference ability of the signal. The embodiment of the present application randomizes the waveform and uses the randomized waveform for emission and pixel cross-correlation reception. Because random numbers have good autocorrelation and cross-correlation characteristics, only the signal emitted by the local machine will be amplified and output during pixel cross-correlation reception, and other signals will be randomly processed, so that there will be no large errors in the ranging results.

[0012] In one possible implementation, the apparatus further includes a phase-locked loop circuit connected to the phase-shift keying modulator; the phase-locked loop circuit is configured to generate the carrier signal according to a preset period, wherein the carrier signal is phase-synchronized with the random number signal. In this embodiment of the present application, the phase-locked loop circuit is connected to the phase-shift keying modulator, and the phase-locked loop circuit generates a carrier signal for input into the phase-shift keying modulator to modulate the signal, thereby outputting a first signal that meets the requirements.

[0013] In one possible implementation, the apparatus further includes: a delay line circuit connected to the phase-shift keying modulator; the delay line circuit is configured to perform multiple phase delay operations on the first signal according to a preset phase delay value to generate multiple pixel-internal integrated switching signals; each of the multiple phase delay operations corresponds to a pixel-internal integrated switching signal. In this embodiment of the present application, the delay line circuit DLL performs multiple signal phase delays on the first signal output by phase-shift keying modulation, which is then integrated with subsequently received reflected light to calculate the distance between the object under test and the camera.

[0014] In one possible implementation, the device further includes: a pixel array connected to the delay line circuit, and an optical lens connected to the pixel array; the optical lens is used to receive a second pulse of light, which is the pulse of light reflected by the object to be measured; each pixel in the pixel array is used to determine the multiple exposure signals corresponding to each pixel based on the internal integrated switching signals of the multiple pixels and the second pulse of light. In an embodiment of the present application, a plurality of delayed switching signals and the received second pulse of light (i.e., the reflected first signal) are exposed by a pixel array connected to the delay line circuit to obtain multiple exposure signals. The reflected second pulse of light is received by the optical lens to further calculate the distance between the camera and the object.

[0015] In one possible implementation, the device further includes an analog-to-digital converter (ADC) connected to the pixel array; the ADC is configured to convert the multiple exposure signals corresponding to each pixel into corresponding multiple digital signals. In this embodiment of the present application, the analog-to-digital converter connected to the pixel array converts the exposure signals (i.e., analog signals) into multiple digital signals, facilitating computational processing by a related processing module on the digital signals to determine a distance value.

[0016] In one possible implementation, the random number signal includes multiple random numbers that last for a preset duration; the device also includes a random number generator connected to the pulse position modulator; the random number generator is configured to generate the multiple random numbers that last for the preset duration based on a random number generation period, where the preset duration is the same as the random number generation period. In this embodiment of the present application, the random number generator generates multiple random numbers that are used to change the phase of each group of signal waves in the first signal, thereby enhancing the first signal's anti-interference capability.

[0017] In one possible implementation, the random number signal includes multiple pseudorandom numbers that last for a preset duration; the device also includes a pseudorandom number generator connected to the pulse position modulator; the pseudorandom number generator is configured to generate multiple pseudorandom numbers that last for a preset duration based on a pseudorandom number generation period, a pseudorandom number cycle, and a preset initial pseudorandom number; the preset duration is the same as the value of the pseudorandom number generation period. In an embodiment of the present application, multiple pseudorandom numbers are generated using a pseudorandom number generator and preset related generation parameters (such as a pseudorandom number cycle period, etc.), which are used to change the phase of each group of signal waves in the first signal, thereby enhancing the anti-interference capability of the first signal.

[0018] In one possible implementation, the phases of the carrier signal and the baseband signal are synchronized. In the embodiment of the present application, by controlling the phase synchronization of the carrier signal and the baseband signal, the two are integrated in the BPSK modulator to generate a first signal that meets the requirements.

[0019] In one possible implementation, the pulse position modulator is specifically configured to modulate the random number signal into the baseband signal according to the pulse position corresponding to each random number in the random number signal in a first mapping table, wherein the first mapping table belongs to one of multiple mapping tables corresponding to a first modulation order; the first modulation order is one of multiple preset modulation orders; each mapping table in the multiple mapping tables includes a mapping relationship between each random number and the pulse position of the baseband signal; and the multiple mapping tables correspond one-to-one to the multiple preset modulation orders. In the embodiment of the present application, the mapping relationship between the random number and the baseband signal pulse position is determined by the first modulation order (such as 2nd order, 4th order); in the case of consecutive identical random numbers, it is beneficial to generate a time interval before the same pulse position in the baseband signal, rather than continuously repeating. For example, the PPM modulator receives the random number signal and the pulse position of the baseband signal corresponding to the random number determined in the first mapping table (corresponding to the first modulation order), and then outputs the modulated baseband signal. The first mapping table can be determined from multiple mapping tables based on the first modulation order; the mapping table and the modulation order can both be pre-stored data; or the required first mapping table can be further determined based on the known first modulation order. Different mapping tables correspond to different modulation orders, and each mapping table includes the form of the random numbers and the pulse position corresponding to each random number.

[0020] In a second aspect, an embodiment of the present application provides an anti-interference ranging method, including:

[0021] generating a baseband signal according to a random number signal; wherein the random number signal includes one or more random numbers, each of the one or more random numbers corresponding to a pulse position of the baseband signal; when the random number signal includes multiple consecutive identical random numbers, M time intervals exist between the pulse positions corresponding to the multiple consecutive identical random numbers in the baseband signal, where M is an integer greater than 0; and the random number signal and the baseband signal are phase synchronized;

[0022] The carrier signal and the baseband signal are modulated to generate a first signal; wherein the first signal is used to drive the light emitter to generate a first pulse light, and the first pulse light is used to illuminate the object to be measured. Optionally, the first signal can include multiple groups of pulse waves (such as multiple groups of square waves).

[0023] In a possible implementation, the method further includes: controlling the light emitter to emit the first pulse light according to the first signal.

[0024] In a possible implementation, the method further includes: generating the carrier signal according to a preset period, wherein the phase of the carrier signal is synchronized with the phase of the random number signal.

[0025] In a possible implementation, the method further includes: performing multiple phase delay operations on the first signal according to a preset phase delay value to generate multiple pixel internal integral switch signals; each operation of the multiple phase delay operations corresponds to a pixel internal integral switch signal.

[0026] In one possible implementation, the method further includes: receiving a second pulse of light, where the second pulse of light is pulse of light reflected by the object to be measured; and determining a plurality of exposure signals corresponding to each pixel based on the internal integrated switch signals of the plurality of pixels and the second pulse of light.

[0027] In a possible implementation, the method further includes: converting the multiple exposure signals corresponding to each pixel into corresponding multiple digital signals.

[0028] In one possible implementation, the method further includes: receiving the corresponding multiple digital signals; obtaining the phase delay of the second pulse light according to a ranging algorithm, and calculating the distance between the object to be measured and the anti-interference ranging device according to the frequency of the second pulse light.

[0029] In one possible implementation, the method further includes: generating multiple pseudo-random numbers that last for a preset time period based on a pseudo-random number generation period, a pseudo-random number period, and a preset initial pseudo-random number; the preset time period is the same as the value of the pseudo-random number generation period.

[0030] In a possible implementation manner, the phases of the carrier signal and the baseband signal are synchronized.

[0031] In one possible implementation, generating a baseband signal based on a random number signal includes: modulating the random number signal into the baseband signal based on the pulse position corresponding to each random number in the random number signal in a first mapping relationship table, wherein the first mapping relationship table belongs to one of multiple mapping relationship tables corresponding to a first modulation order; the first modulation order is one of multiple preset modulation orders; each mapping relationship table in the multiple mapping relationship tables includes a mapping relationship between each random number and the pulse position of the baseband signal; and the multiple mapping relationship tables correspond one-to-one to the multiple preset modulation orders.

[0032] In a third aspect, an embodiment of the present application provides an anti-interference ranging system, characterized by comprising:

[0033] A pulse position modulator, a phase shift keying modulator connected to the pulse position modulator, a phase locked loop circuit connected to the phase shift keying modulator, a delay line circuit connected to the phase shift keying modulator, a pixel array connected to the delay line circuit, an analog to digital converter (ADC) connected to the pixel array, and a pseudo random number generator connected to the pulse position modulator;

[0034] The pulse position modulator is configured to generate a baseband signal based on a random number signal; wherein the random number signal includes one or more random numbers, each of the one or more random numbers corresponding to a pulse position of the baseband signal; when the random number signal includes multiple consecutive identical random numbers, there are M time intervals between the pulse positions corresponding to the multiple consecutive identical random numbers in the baseband signal, where M is an integer greater than 0; and the random number signal and the baseband signal are phase synchronized;

[0035] The phase-shift keying modulator is used to modulate the carrier signal and the baseband signal to generate a first signal; wherein the first signal is used to drive the light emitter to generate a first pulse light, and the first pulse light is used to illuminate the object to be measured;

[0036] The phase-locked loop circuit is used to generate a carrier signal according to a preset period, and the phase of the carrier signal is synchronized with the phase of the random number signal;

[0037] The pseudo-random number generator is configured to generate a plurality of random numbers of a preset duration based on a pseudo-random number generation period, a pseudo-random number period, and a preset initial pseudo-random number; the preset duration is the same as the value of the random number generation period;

[0038] The delay line circuit is configured to perform multiple phase delay operations on the first signal according to a preset phase delay value to generate multiple pixel internal integration switch signals; each of the multiple phase delay operations corresponds to one pixel internal integration switch signal;

[0039] Each pixel in the pixel array is configured to determine a plurality of exposure signals corresponding to each pixel according to the plurality of internal integrated switch signals of the pixels and the second pulse light;

[0040] The ADC is used to convert the multiple exposure signals corresponding to each pixel into corresponding multiple digital signals.

[0041] In one possible implementation, the system further includes a light source driver and a light emitter connected to the phase-shift keying modulator, wherein the light emitter is connected to the light source driver; the light source driver is configured to control the light emitter to emit the first pulsed light according to the first signal. In an embodiment of the present application, by connecting the light source driver and the light emitter to the phase-shift keying modulator, the light emitter is driven by the first signal to emit pulsed light with corresponding brightness information, thereby illuminating a target object and measuring the distance between the camera and the target object.

[0042] In one possible implementation, the system further includes a ranging circuit connected to the ADC; the ranging circuit is configured to receive the corresponding multiple digital signals; obtain the phase delay of the second pulse light according to a ranging algorithm; and calculate the distance between the object to be measured and the anti-interference ranging device based on the frequency of the second pulse light. In this embodiment of the present application, the ranging circuit connected to the ADC calculates the received digital signals to obtain the distance between the camera and the object to be measured.

[0043] In one possible implementation, the light emitter is a light emitting diode (LED) or a vertical cavity surface emitting laser (VCSEL). In the embodiment of the present application, under the control of the first signal, an optical device such as an LED or VCSEL emits pulsed light of varying brightness to facilitate measuring the distance of an object.

[0044] In a possible implementation, the system further includes: an optical lens connected to the pixel array; the optical lens is configured to receive the second pulsed light, where the second pulsed light is the pulsed light reflected by the object to be measured.

[0045] In one possible implementation, generating a baseband signal based on a random number signal includes: modulating the random number signal into the baseband signal based on the pulse position corresponding to each random number in the random number signal in a first mapping relationship table, wherein the first mapping relationship table belongs to one of multiple mapping relationship tables corresponding to a first modulation order; the first modulation order is one of multiple preset modulation orders; each mapping relationship table in the multiple mapping relationship tables includes a mapping relationship between each random number and the pulse position of the baseband signal; and the multiple mapping relationship tables correspond one-to-one to the multiple preset modulation orders.

[0046] In a fourth aspect, an embodiment of the present application provides an electronic device, which may include: the anti-interference ranging device as described in the first aspect or the second aspect above, and a discrete device coupled to the outside of the anti-interference ranging device.

[0047] In a fifth aspect, an embodiment of the present application provides a terminal, comprising a processor configured to support the terminal in executing corresponding functions of the anti-interference ranging method provided in the third aspect. The terminal may also include a memory coupled to the processor and storing necessary program instructions and data for the terminal. The terminal may also include a communication interface for communicating with other devices or a communication network.

[0048] In a sixth aspect, embodiments of the present application provide a radar, which may include the apparatus described in the first aspect or the system described in the third aspect, configured to implement the anti-interference ranging function provided by the apparatus or system. The radar may also include a memory coupled to the apparatus or system for storing program instructions and data necessary for the radar; the radar may also include an external power supply coupled to the apparatus or system for supplying power to the radar.

[0049] In a seventh aspect, an embodiment of the present application provides a vehicle equipped with the apparatus described in the first aspect or the system described in the third aspect, configured to implement the anti-interference ranging function provided by the apparatus or system. The vehicle may also include an autonomous driving system configured to control the vehicle's travel based on road conditions. The vehicle may also include an external discrete device coupled to the apparatus or system.

[0050] In an eighth aspect, embodiments of the present application provide a method for modulating continuous wave exposure four times; this method may include exposing a phase of 0°, a phase of 180°, a phase of 90°, and a phase of 270° in a continuous wave. Specifically, continuous wave exposures of 0° and 180°, 90° and 270°, 180° and 0°, and 270° and 90° are sequentially performed.

[0051] In a ninth aspect, embodiments of the present application provide a method for modulating continuous wave exposure twice; the method may include exposing a phase of 0°, exposing a phase of 180°, exposing a phase of 270°, and exposing a phase of 0°, 180°, 90°, and 270°, respectively, in the continuous wave. Specifically, the continuous wave is sequentially exposed at phases 0° and 180°, and then at phases 90° and 270°.

[0052] In a tenth aspect, embodiments of the present application provide a method for performing two-step pulse wave exposure modulation. This method may include, within the pulse wave, modulating exposure at a phase of 180° and a phase of 0°. Specifically, the continuous wave is sequentially exposed at phases 0° and 180°, and then at phases 180° and 0°.

[0053] In an eleventh aspect, embodiments of the present application provide a method for single-shot pulse wave exposure modulation. This method may include exposing phases 0° and 180°, respectively, within the pulse wave. Specifically, exposing phases 0° and 180° in an exposure sequence. Optionally, exposing phases 180° and 0° in another exposure sequence. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments.

[0055] Figure 1 This is a schematic diagram of a TOF application scenario provided by an embodiment of the present application;

[0056] Figure 2 This is a schematic diagram of another TOF application scenario provided by an embodiment of the present application;

[0057] Figure 3 This is another TOF application scenario diagram provided by an embodiment of the present application;

[0058] Figure 4 This embodiment of the present application provides a method based on Figure 3 Schematic diagram of multi-camera ranging scene;

[0059] Figure 5 This is a schematic diagram of a multi-camera ranging system architecture provided by an embodiment of the present application;

[0060] Figure 6 This is a schematic diagram of the architecture of an anti-interference ranging device provided in an embodiment of the present application;

[0061] Figure 7 This is a schematic structural diagram of an anti-interference ranging device provided in an embodiment of the present application;

[0062] Figure 8This is a flow chart of a transmitter provided in an embodiment of the present application;

[0063] Figure 9 This is a signal diagram of a binary random number provided in an embodiment of the present application;

[0064] Figure 10 Schematic diagram of a random number signal and a carrier signal provided in an embodiment of the present application;

[0065] Figure 11 This is a PPM modulation schematic diagram provided in an embodiment of the present application;

[0066] Figure 12 This is a waveform diagram of a BPSK modulator provided in an embodiment of the present application;

[0067] Figure 13 This is a schematic structural diagram of another anti-interference ranging device provided in an embodiment of the present application;

[0068] Figure 14 This is a flowchart of a receiving end provided in an embodiment of the present application;

[0069] Figure 15 This is a signal diagram of a first pulse light and a second pulse light provided in an embodiment of the present application;

[0070] Figure 16 This is a signal diagram provided by an embodiment of the present application, taking a square wave signal as an example;

[0071] Figure 17 This is a schematic diagram of a DLL structure provided by an embodiment of the present application;

[0072] Figure 18 1 is another TOF ranging principle schematic diagram provided in an embodiment of the present application;

[0073] Figure 19 This is a schematic diagram of a continuous wave exposure modulated four times provided in an embodiment of the present application;

[0074] Figure 20 This is a schematic diagram of a continuous wave exposure modulated twice provided in an embodiment of the present application;

[0075] Figure 21 This is a schematic diagram of a pulse wave exposure modulated twice provided in an embodiment of the present application;

[0076] Figure 22 This is a schematic diagram of a pulse wave exposure modulation method provided by an embodiment of the present application;

[0077] Figure 23 is a schematic diagram of an anti-interference ranging method provided in an embodiment of the present application;

[0078] Figure 24 is a schematic diagram of an anti-interference ranging method provided in an embodiment of the present application;

[0079] Figure 25 It is a structural diagram of a device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0080] The embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0081] The terms "first", "second", "third" and "fourth" in the specification and claims of this application and the accompanying drawings are used to distinguish different objects rather than to describe a specific order; and the objects described by the terms "first", "second", "third" and "fourth" may also be the same objects, or have inclusion or other relationships with each other. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0082] Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0083] As used in this specification, the terms "component," "module," "system," and the like are used to refer to computer-related entities, hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, and / or a computer. By way of illustration, both an application running on a computing device and a computing device can be a component. One or more components can reside in a process and / or an execution thread, and a component can be located on a computer and / or distributed between two or more computers. In addition, these components can be executed from various computer-readable media having various data structures stored thereon. Components can communicate, for example, through local and / or remote processes based on signals having one or more data packets (e.g., data from two components interacting with another component across a local system, a distributed system, and / or a network, such as the Internet interacting with other systems via signals).

[0084] First, some terms in this application are explained to facilitate understanding by those skilled in the art.

[0085] (1) Binary Phase Shift Keying (BPSK) is a method for converting analog signals into data values. It uses a combination of complex waves with phase shifts to represent information. BPSK uses a reference sine wave and a phase-inverted wave, making one 0 and the other 1, allowing two values ​​(1 bit) of information to be transmitted and received simultaneously.

[0086] (2) Pulse Position Modulation (PPM) modulates the signal so that only the time at which each pulse in the carrier pulse series is generated changes without changing its shape and amplitude. The change in the time at which each pulse is generated is proportional to the amplitude of the modulation signal voltage and is independent of the frequency of the modulation signal.

[0087] (3) Vertical-Cavity Surface-Emitting Laser (VCSEL) is a semiconductor whose laser is emitted perpendicular to the top surface. It is different from the edge-emitting laser that is generally manufactured by cutting independent chips and emits laser light from the edge.

[0088] (4) Random numbers are the result of a special random experiment. The most important characteristic of random numbers is that the subsequent number it generates has nothing to do with the previous number.

[0089] (5) Pseudo-random numbers are random numbers from a uniform distribution between [0, 1] calculated using a deterministic algorithm. They are not truly random, but have statistical characteristics similar to random numbers, such as uniformity and independence.

[0090] (6) Baseband signal is the original electrical signal emitted by the information source without modulation (spectrum shifting and transformation). Its characteristics are low frequency, signal spectrum starting from near zero frequency, and low-pass form.

[0091] (7) Carrier, or carrier signal, refers to the waveform that is modulated to transmit a signal. The frequency band of the baseband signal is very wide (theoretically infinite), but due to bandpass, there is almost no transmission medium with infinite bandwidth. Therefore, the baseband signal cannot be transmitted over long distances on ordinary media. Otherwise, inter-symbol interference and attenuation will make it impossible to recover the signal. Therefore, the baseband signal is modulated with a carrier to reduce the bandwidth, which can ensure reliable signal transmission and reduce attenuation. The receiving end then demodulates and restores the original digital signal.

[0092] (8) Delay-locked loop (DLL) technology is widely used in the field of timing. It is a delay line with controllable delay. A delay line is a component or device used to delay an electrical signal for a period of time. The delay line should have a flat amplitude-frequency characteristic and a certain phase shift characteristic (or delay-frequency characteristic) within the passband, with appropriate matching impedance and low attenuation.

[0093] (9) Analogue-to-digital conversion (ADC), also known as A / D converter, is an electronic component that converts analog signals into digital signals. A typical analog-to-digital converter converts an input voltage signal into an output digital signal. Since the digital signal itself has no practical meaning and only represents a relative size, any analog-to-digital converter requires a reference analog quantity as a conversion standard. The most common reference standard is the maximum convertible signal size. The output digital quantity represents the size of the input signal relative to the reference signal.

[0094] (10) The pseudorandom number period refers to the number of non-repeating pseudorandom numbers in a periodic pseudorandom number sequence, or the number of numbers contained in one cycle of the iterative process of generating pseudorandom numbers. Pseudorandom numbers are generated using a recursive formula according to a certain procedure, generally starting from a certain initial value to generate a pseudorandom number sequence x1, x2, ...; if there exists m such that for any n, xn+m=xn (n=1, 2, ...), then the minimum m that satisfies the above relationship is called the pseudorandom number period.

[0095] (11) Binary On-Off Keying (OOK), also known as binary amplitude keying, uses a unipolar non-return-to-zero code sequence to control the on and off of a sinusoidal carrier.

[0096] (12) Among multiple phase-shift keying (MPSK), the most commonly used is quadrature phase-shift keying, or QPSK. This modulation scheme is used when transmitting digital television signals over satellite channels. It can be considered to consist of two 2PSK modulators. The input serial binary information sequence is serial-to-parallel converted and divided into two sequences with half the rate. The level converter generates bipolar two-level signals, I(t) and Q(t), respectively. These signals then modulate the carriers Acos2πfct and Asin2πfct, and the QPSK signal is obtained by adding them together.

[0097] (13) Three-dimensional (3D) refers to the three axes of the coordinate system, namely the x-axis, y-axis, and z-axis, where x represents left and right space, y represents up and down space, and z represents front and back space. However, in practical applications, the x-axis is generally used to describe left and right movement, the z-axis is used to describe up and down movement, and the y-axis is used to describe front and back movement, forming a sense of three-dimensionality in human vision.

[0098] (14) Phase is the position of a wave at a specific moment in its cycle, i.e., a measure of whether it is at a peak, a trough, or somewhere in between. Phase describes the measurement of the change in a signal waveform and is usually measured in degrees (angles), also known as the phase angle. When a signal waveform changes in a cyclical manner, one cycle of the waveform is 360°.

[0099] (15) The time of flight (ToF) ranging method belongs to a two-way ranging technology, which mainly uses the flight time of the signal between two asynchronous transceivers (or reflected surfaces) to measure the distance between nodes. Traditional ranging technologies are divided into two-way ranging technology and one-way ranging technology. When the signal level is well modulated or in a non-line-of-sight environment, the estimation results based on the RSSI (Received Signal Strength Indication) ranging method are relatively ideal. In a line-of-sight environment, the ToF distance estimation method can make up for the shortcomings of the RSSI distance estimation method. However, the ToF ranging method has two key constraints: one is that the sending device and the receiving device must always be synchronized; the other is the length of the signal transmission time provided by the receiving device. In order to achieve clock synchronization, the ToF ranging method uses clock offset to solve the clock synchronization problem.

[0100] To facilitate understanding of TOF camera imaging, some common application scenarios are listed below, which can include the following three scenarios.

[0101] Scenario 1: Applied to vehicles and related systems.

[0102] In automotive applications, TOF can be used for autonomous driving, collision avoidance, and automatic braking. Using the Time of Flight (TOF) principle, vehicle-mounted systems can precisely detect the driver's body and head position, even capturing blinks even when wearing glasses or sunglasses, to determine whether the driver is paying attention or experiencing fatigue, thereby initiating appropriate countermeasures. For example, this can be achieved through seat vibration or a warning sound. The less focused the driver, the more alert the car will be. To respond quickly and accurately, assistance systems and emergency braking can be automatically activated before a potential emergency occurs. Furthermore, this technology can control the in-car entertainment system or air conditioning system based on hand movements or body gestures, and even enable new assistance and safety features outside the vehicle, such as door opening assistance systems, which prevent car doors from opening and colliding with other cars, walls, or ceilings in parking lots or home basements.

[0103] Specifically, see Figure 1 , Figure 1 This is a schematic diagram of a TOF application scenario provided by an embodiment of the present application; Figure 1 As shown, a vehicle equipped with a TOF system (or TOF camera) can use this technology to measure the distance D to the preceding vehicle. When the distance D is less than a preset safety distance, the vehicle is slowed down or stopped. The TOF-equipped vehicle can be a self-driving car.

[0104] Scenario 2: Application in the field of human-computer interaction.

[0105] TOF provides a real-time distant image, so it can be used to record human movements very simply. This has enabled many consumer electronics products (such as TVs) to have a completely new way of interaction. By equipping a TOF sensor, the depth data of the target object can be obtained. Specifically, the infrared projector continuously emits infrared pulses, and the phase delay of the infrared pulse light reflected from objects at different distances is inconsistent. The infrared sensor is then used to receive feedback messages, and pulse light with different phase delays will output different phase values ​​on the infrared sensor through four-phase reception. This determines the depth information of the object captured by each pixel and distinguishes objects at different depths. The application of this technology can realize human-computer interaction and has more extensive applications in gaming.

[0106] Specifically, see Figure 2 , Figure 2 This is another TOF application scenario diagram provided by the embodiment of the present application; Figure 2 As shown in the figure, a display equipped with a TOF system can identify changes in human body movements. When the display is running a game that requires controlling a character based on human movements, the TOF camera can identify changes in human body movements to achieve corresponding control of the character in the game.

[0107] Scenario 3: Application in machine vision.

[0108] In industrial machine vision applications, robots use TOF cameras to classify objects and accurately locate and place them. In addition, TOF has an irreplaceable position in robotics, face recognition, and earth topography mapping. Figure 3 , Figure 3 This is another schematic diagram of a TOF application scenario provided by an embodiment of the present application. In the illustrated 3D scenario, a TOF system transmits electromagnetic waves toward a seat, and a receiver receives the feedback signal from these electromagnetic waves. The TOF system uses a timer to calculate the time. Based on this information, the distance between the seat and the TOF camera is calculated.

[0109] When multiple TOF cameras are measuring the distance to a target object, it is necessary to consider improving the anti-interference capability of the signals between TOF cameras. Figure 4 , Figure 4 This embodiment of the present application provides a method based on Figure 3 Schematic diagram of multi-camera ranging scene; Figure 4 As shown, camera 1 emits signal 1 for distance measurement toward a target object (a bicycle is used as an example in the figure), and the distance between camera 1 and the target object is measured based on the reflected signal 1'. Simultaneously, camera 2 sends signal 2 to the target object, and the distance between camera 2 and the target object is measured based on the received signal 2'. However, since two cameras are measuring distance simultaneously, camera 1 may receive feedback signal 2' of signal 2 sent by camera 2, resulting in deviations in distance measurement. For example, when there are multiple TOF cameras (i.e., TOF modules) in a scene, the active light emitted by TOF module 1 is likely to be received by another TOF module (e.g., module 2). If module 2 happens to receive the pulse light wave emitted by module 1 during exposure, the distance measurement result will be incorrect.

[0110] It is understandable that Figure 1-Figure 4 The application scenario shown is only an exemplary scenario in the embodiment of the present application. The application scenarios in the embodiment of the present application include but are not limited to the above application scenarios.

[0111] The above introduces several application scenarios of TOF ranging. Figure 4 For an application scenario, a system architecture based on which the present application embodiment is based is described, see Figure 5 , Figure 5 Schematic diagram of a multi-camera ranging system architecture provided by an embodiment of the present application; Figure 5As shown, the system architecture includes a ranging module 1 (i.e., a TOF module, which is applied to a depth camera, i.e., a TOF camera) and a ranging module 2. The embodiment of the present application is applied to a ranging system with multiple TOF cameras. In order to solve the problem of mutual interference when multiple cameras are working, the embodiment of the present application makes the pixel reference waveforms emitted by each camera during ranging to be orthogonal to each other, so that the camera will not be affected by interference signals when performing TOF exposure (correlated reception).

[0112] Among them, the structural composition of ranging module 1 and ranging module 2 is the same. The embodiment of the present application takes one of the ranging modules (such as ranging module 1) as an example for explanation. The ranging module includes a light emitter, a light source driver, a ranging chip and a lens. Specifically, ranging module 1 includes a light emitter 1, a light source driver 1, a ranging chip 1 and a lens 1. Optionally, the multi-camera ranging system architecture can also include multiple other ranging modules, Figure 5 Two ranging modules are used as an example for explanation.

[0113] Specifically, the ranging chip may also include a controller, a pixel array, and an analog-to-digital converter. Taking ranging chip 1 as an example, controller 1 sends a drive signal to laser driver (or light source driver) 1, which controls laser 1 to emit pulsed light containing brightness information (i.e., corresponding to the drive signal). After the pulsed light irradiates the target object and reflects, the reflected pulsed light is received by lens 1. At this point, pixel array 1 calculates the signal results based on the delayed drive signal generated by controller 1 and the received reflected pulsed light, and outputs an analog signal. This analog signal is converted into a digital signal by analog-to-digital converter 1 for the next step of distance calculation.

[0114] It is understandable that Figure 5 The system architecture in the embodiment of the present application is only an exemplary implementation. The system architecture in the embodiment of the present application includes but is not limited to the above system architecture.

[0115] The following describes a specific architecture of the ranging module involved in the embodiment of the present application. Figure 6 , Figure 6 Schematic diagram of the architecture of an anti-interference ranging device provided in an embodiment of the present application; Figure 6 As shown, the system architecture is described by taking the ranging module 1 as an example, which includes the ranging module 10 (corresponding to Figure 5 The ranging module 1) and the ranging circuit (or ranging module) 20; Specifically, the ranging module 10 may include a ranging chip 101 (corresponding to Figure 5 Distance measurement chip 1), light source driver 102 (corresponding to Figure 5 Light source driver 1), light emitter 103 (corresponding to Figure 5The light emitter 1) and the lens (corresponding to Figure 5 The distance measurement module 1 in the general lens may include a filter) 104. Among them,

[0116] The ranging chip 1 (101) may include: a random / pseudo-random number generator 1010, a PPM modulator (i.e., a pulse position modulator or pulse position modulator) 1011, a BPSK modulator (i.e., a binary phase shift keying modulator) 1012, a phase-locked loop circuit 1013, a delay line circuit DLL 1014, a pixel array 1015, and an analog-to-digital converter 1016. Specifically, the TOF ranging principle is first described. The phase-locked loop circuit 1013 within the TOF system generates a square wave of a certain frequency (e.g., 20 MHz). This waveform drives the light source 1 (103, such as a VCSEL / LED) to emit light through the light source driver 1 (102). The reflected light is focused onto pixel array 1 (1015) through lens 1 (104). Pixel array 1 (1015) can use a switching circuit with the same frequency (e.g., 20 MHz) but with phase delay (0 degrees, 90 degrees, 180 degrees, 270 degrees) to integrate the received light signal and output the corresponding value. The phase delay caused by the flight time can be calculated through phase calculation. Among them, the random / pseudo-random number generator 1010 is used to generate a random number for the phase of the control signal; taking the random number generator as an example, the random number generator is used to generate a random number of 0 or 1.

[0117] The pulse position modulator 1011 (hereinafter referred to as the PPM modulator) is used to generate a baseband signal with strong anti-interference ability based on a random number signal. When continuous identical random numbers (such as continuous "0" or continuous "01") appear in the random number signal, in the baseband signal, the phase in the signal band synchronized with the continuous identical random number phase will not be continuously repeated (for example, the phases corresponding to 0, 0, 0 are all 0 degrees, but due to the effect of the PPM modulator 1011, there will be a certain time interval between the 0-degree phase and the next 0-degree phase). When there are no multiple continuous identical random numbers in the random number signal, the pulse position corresponding to the random number can also be determined according to the pulse position mapping table of the random number. For example, if a certain random number in the random number signal is "01011001", it can still be modulated by the PPM modulator 1011. It can be understood that "0", "00" and "001" can all be considered as a type of random number, and the embodiments of the present application are not limited to this. ; and when a long series of 0s or 1s appears in the random number signal, the phase difference between the pulse lights sent by each ranging camera is increased by adding the PPM modulator 1011. Even if this camera receives the pulse lights irradiated on the object by other cameras, it can be effectively filtered and shielded by the algorithm.

[0118] In one possible implementation, the random number signal is modulated into a baseband signal based on the pulse position corresponding to each random number in a first mapping table. The first mapping table is one of multiple mapping tables corresponding to a first modulation order; the first modulation order is one of multiple preset modulation orders; each of the multiple mapping tables includes a mapping between each random number and a pulse position of the baseband signal; and the multiple mapping tables correspond one-to-one with the multiple preset modulation orders. For example, a PPM modulator receives a random number signal and analyzes each random number in the random number signal. Based on the first mapping table in the PPM modulator, the pulse position of the baseband signal corresponding to each random number in the random number signal is determined; and the random number signal is modulated into a baseband signal. The first mapping table is related to the modulation order of the PPM modulator. For example, an 8th-order modulation order corresponds to an 8th-order mapping table, and a 16th-order modulation order corresponds to a 16th-order mapping table. Optionally, the PPM modulator may store only one modulation order and its corresponding mapping table; or it may store multiple modulation orders and a mapping table corresponding to each of the multiple modulation orders. Furthermore, the PPM modulator may store only a few modulation orders; when a user selects a modulation order, the corresponding mapping table is generated. This embodiment of the present application is not limited to this.

[0119] Phase shift keying modulator 1012 (i.e., binary phase shift keying modulator) is used to modulate the carrier signal and the baseband signal to generate the first signal. Optionally, phase shift keying modulator 1012 may include a binary phase shift keying modulator (this embodiment of the present application uses this as an example), a quaternary phase shift keying modulator, an octal phase shift keying modulator, a hexadecimal phase shift keying modulator, or a decadecimal phase shift keying modulator.

[0120] As you can understand, PSK modulation appends the modulating signal's information to the carrier's phase. For example, a carrier phase of 0° represents a modulating signal level of "1," while a phase of 180° represents a modulating signal level of "0." If the carrier's phase is further subdivided into m different phases, typically m = 2N, where N is a positive integer. Common values ​​for m = 4, 8, 16, and 32 are known as 4PSK, 8PSK, and so on, respectively. Thus, each carrier with a specific phase represents N bits of information.

[0121] The phase-locked loop circuit 1013 is used to generate a carrier signal with a certain fixed period. For example, the pulse period of the square wave generated by the phase-locked loop circuit 1013 is Tp.

[0122] The delay line circuit DLL1014 is configured to perform multiple phase delay operations on the first signal according to a preset phase delay value to generate multiple pixel internal integration switch signals; each of the multiple phase delay operations corresponds to one pixel internal integration switch signal.

[0123] Pixel array 1 (1015) is used to perform an integration operation on the delayed first signal and the first signal reflected by the target object, and output various simulation parameters for calculating the distance.

[0124] The analog-to-digital converter 1 (1016) is used to convert various analog parameters into digital parameters.

[0125] The ranging circuit 20 is used to determine the distance between the ranging camera and the target object based on digital parameters and a preset ranging algorithm or formula. Optionally, when the ranging circuit is implemented in hardware, a specific circuit structure calculates the input signal and outputs the distance result. Alternatively, when the corresponding ranging function is implemented in software, a preset computer program or code uses the input signal as a calculation parameter and then outputs the corresponding distance result.

[0126] It is understandable that Figure 6 The system architecture in the embodiment is only an exemplary implementation in the embodiment of the present application. The application scenarios in the embodiment of the present application include but are not limited to the above application scenarios.

[0127] The following combines the above Figure 6 The system architecture shown is used to specifically analyze and solve the technical problems raised in this application.

[0128] See Figure 7 , Figure 7 This is a schematic diagram of the structure of an anti-interference ranging device provided by an embodiment of the present application; the anti-interference ranging device can be applied to the transmitting end of the anti-interference ranging device. The anti-interference ranging device includes a random / pseudo-random number generator 1010, a pulse position modulator 1011 (i.e., a PPM modulator), a binary phase shift keying modulator 1012 (i.e., a BPSK modulator), a phase-locked loop circuit 1013, a laser driver 102, and a light emitter 103. The connection method of each circuit or module can be as follows: Figure 7 Optionally, the device may include a random / pseudo-random number generator 1010 , a phase-locked loop circuit 1013 , a laser driver 102 and a light emitter 103 .

[0129] See Figure 8 , Figure 8 This is a flow chart of a transmitter provided in an embodiment of the present application; Figure 8 As shown in the reference Figure 7Based on the structural relationship shown, the following steps can be included:

[0130] Step 1: Set the random number generation period (Tr), pseudo-random number period (N), phase-locked loop pulse generation period (Tp), and PPM modulation order (M).

[0131] Step 2: The random number generator 1010 generates a random number R according to Tr, or the pseudo-random number generator 1010 generates a pseudo-random number R according to Tr, the pseudo-random number period N, and a preset initial state. Simultaneously, the parallel phase-locked loop circuit 1013 generates a square wave L with a pulse period of Tp according to Tp (for the BPSK modulator 1012, L is the carrier), and L is phase-synchronized with R.

[0132] Step 3: The PPM modulator 1011 outputs a modulated PPM signal P (for the BPSK modulator 1012, P is a baseband signal) according to the set modulation order M and the input signal R. P is phase-synchronized with L.

[0133] Step 4: The BPSK modulator 1012 performs BPSK modulation on the carrier L and the baseband signal P, and outputs a modulated signal P1 (the P1 signal is a pulse sequence of digital 0 or 1).

[0134] Step 5: The P1 signal passes through the light source driver 102 to enable the light emitter 103 (such as VCSEL or LED) to emit pulse light with corresponding brightness information.

[0135] The random / pseudo-random number generator 1010 is specifically used to generate a binary random number; the binary random number controls the phase change of the baseband signal, and ultimately controls the phase of the waveform sent by the light emitter. For example, binary 0 corresponds to a phase of 0 degrees, and binary 1 corresponds to a phase of 180 degrees. It is understood that continuous binary random numbers can be regarded as random number signals, see Figure 9 , Figure 9 : is a signal diagram of a binary random number provided in an embodiment of the present application; Figure 9 As shown, a high level 1 represents a binary number 1, and a low level 0 represents a binary number 0. Figure 9 Three random number signals are listed, including random number signal 1, random number signal 2, and random number signal 3. Each random number signal is only a segment of a random number signal, used to illustrate random numbers by way of example, and does not represent a specific pattern. The occurrence of 0 and 1 is random. The embodiments of this application do not limit the random number in the random number signal.

[0136] In one possible implementation, the apparatus further includes a phase-locked loop circuit connected to the BPSK modulator; the phase-locked loop circuit is configured to generate a carrier signal according to a preset period, wherein the carrier signal has the same phase as the random number signal. In one possible implementation, the phases of the carrier signal and the baseband signal are synchronized. For example, the parallel phase-locked loop circuit 1013 is configured to generate a square wave L with a pulse period of Tp according to Tp (for the BPSK modulator, L is the carrier), and L is phase-synchronized with R (i.e., the duration of a set of waveforms in L is the same as the duration of a random number in the random number signal, and the generation time and end time are the same). For example, see Figure 10 , Figure 10 Schematic diagram of a random number signal and a carrier signal provided in an embodiment of the present application; Figure 10 As shown, each random number corresponds to a group of waveforms in the square wave L (generally, a group of waveforms includes the entire high and low levels). The square wave L is an unmodulated signal. Figure 10 The random number signal in Figure 9 The following description will be made using a random number segment in the random number signal 1 as an example.

[0137] A pulse position modulator 1011 is configured to generate a baseband signal based on a random number signal, wherein two consecutive groups of signals in the baseband signal have different phases. Optionally, the baseband signal is generated by comparing the random number signal with a first mapping relationship table. The random number signal includes one or more random numbers, each of which corresponds to a phase of the baseband signal. A PPM modulator is used to ensure that consecutive identical random numbers in the random number signal correspond to multiple discontinuous repetitions of the phase of the baseband signal. The phases of the random number signal and the baseband signal are synchronized. Specifically, the random number signal is modulated into the baseband signal based on the pulse position corresponding to each random number in the random number signal in the first mapping relationship table. The first mapping relationship table includes a mapping relationship between each random number and the pulse position of the baseband signal. The first mapping relationship table corresponds to a preset modulation order. The random number signal is modulated into the baseband signal based on the pulse position corresponding to each random number in the random number signal in the first mapping relationship table. For example, the first mapping relationship table is a fourth-order mapping relationship table. Then, based on the modulation order 4, the fourth-order mapping relationship table among the multiple mapping relationship tables is determined to be the first mapping relationship table. Optionally, the modulation order may include multiple orders, for example, 2nd order, 4th order, 8th order, etc.

[0138] Optionally, the random number signal is modulated into the baseband signal based on the pulse position corresponding to each random number in the random number signal in a first mapping table, wherein the first mapping table is one of multiple mapping tables corresponding to a first modulation order; the first modulation order is one of multiple preset modulation orders; each of the multiple mapping tables includes a mapping between each random number and the pulse position of the baseband signal; and the multiple mapping tables have a one-to-one correspondence with the multiple preset modulation orders. For example, the baseband signal is generated based on a known modulation order and a mapping table, combined with the random number signal. The device may pre-store multiple mapping tables and modulation orders corresponding to the multiple mapping tables. After the modulation order is determined, the corresponding mapping table can be obtained for further modulating the random number signal. Optionally, the PPM modulator stores multiple modulation orders and mapping tables corresponding to the multiple modulation orders.

[0139] For example, please refer to Table 1, which is a mapping table of 2PPM modulation orders provided by an embodiment of the present application; as shown in Table 1, for example, the random number 0 corresponds to 10 under the mapping relationship of 2PPM; the random number 1 corresponds to 01 under the mapping relationship of 2PPM. When the random number generator generates multiple consecutive random numbers 0, the multiple consecutive random numbers 0 are mapped to multiple consecutive 10s according to the mapping relationship provided in Table 1. Then, for example, the modulated random number signal corresponding to the continuous "000" is "101010", which can prevent 1 and 0 from appearing continuously, so as to affect the phase discontinuity of the final signal. Please refer to Figure 11 , Figure 11 This is a PPM modulation diagram provided by an embodiment of the present application; Figure 11 As shown, the random number signal 4 is "110001". After PPM modulation, the baseband signal (i.e., the pulse position modulation signal in the figure, i.e., the PPM signal, corresponding to the aforementioned signal P) is "010110101001", where "11" corresponds to "0101", so that 1 is not repeated multiple times continuously, and "000" corresponds to "101010", so that multiple 0s are not repeated multiple times continuously. To a certain extent, the occurrence of consecutive 1s or consecutive 0s is reduced. More specifically, a certain random number segment is "00". According to the mapping rules in Table 1, the resulting number sequence is "1010".

[0140] OOK 2PPM 0 10 1 01

[0141] Table 2 is a mapping table of a 4PPM modulation order provided by an embodiment of the present application. The specific mapping relationship is shown in Table 2. Please refer to the corresponding description of Table 1, which will not be repeated here. The embodiment of the present application does not limit the modulation order, and the modulation order can also include 8PPM.

[0142] Table 2

[0143]

[0144]

[0145] It can be understood that both Table 1 and Table 2 above are mapping tables corresponding to the modulation order; the embodiments of the present application do not limit how to determine the mapping table. Optionally, the modulation order (e.g., 2nd order) and the corresponding mapping table are preset in the PPM modulator; then, during the baseband signal modulation process of the PPM modulator, the input random number signal is generated into a baseband signal according to the random number and the known 2nd order mapping table. Optionally, the modulation order (e.g., 4th order) is preset in the PPM modulator, but the corresponding mapping table is not preset; then, during the operation of the PPM modulator, the 4th order mapping table is first determined according to the 4th order modulation order. The 4th order mapping table can be one of the multiple mapping tables stored in the memory of the ranging device (i.e., the first mapping table); or the ranging device obtains the mapping table corresponding to the 4th order modulation order through a network or a related algorithm. Then, according to the random number signal and the 4th order mapping table, the random number signal is modulated into the required baseband signal.

[0146] The binary phase shift keying modulator (hereinafter referred to as BPSK modulator) is used to modulate the carrier signal (i.e., square wave L) and the aforementioned baseband signal (i.e., signal P) to generate a first signal (P1) comprising multiple groups of pulse waves; wherein the phases of two consecutive groups of pulse waves in the aforementioned multiple groups of pulse waves are different. Figure 12 , Figure 12 is a waveform diagram of a BPSK modulator provided in an embodiment of the present application; Figure 12 As shown, the square wave L, the pulse position modulation signal P and the first signal P1 are all exemplary waveforms; wherein, the random number signal shown is a segment of the random number signal, such as "00"; according to the aforementioned mapping rule, the pulse position modulation signal corresponding to "00" is "1010"; the square wave L shown is the carrier signal, and the pulse signal P1 is generated according to the carrier signal and the pulse position modulation signal. Figure 12 In the example, 0 represents no change in the phase of square wave L, and 1 represents a pseudo-180° change in the phase of square wave L. Therefore, the phase of the waveform corresponding to 1 in pulse signal P1 becomes 180°. It is understood that a single pulse signal P period may correspond to many square wave pulses; the multiple pulses shown in the figure are used as an example for illustration in this embodiment.

[0147] See Figure 13 , Figure 131 is a schematic structural diagram of another anti-interference ranging device provided in an embodiment of the present application; the anti-interference ranging device can be applied to the receiving end of the anti-interference ranging device. The anti-interference ranging device may include a pulse position modulator (i.e., PPM modulator) 1011, a binary phase shift keying (BPSK) modulator 1012 connected to the pulse position modulator 1011, a delay line circuit DLL 1014, a pixel array 1015, and a ranging circuit 20. Optionally, the device may also include a pseudo-constant current generator connected to the PPM modulator 1011, a phase-locked loop circuit 1013 connected to the BPSK modulator, a lens 104, and an analog-to-digital converter 1016.

[0148] Combine Figure 12 The following is an analysis of the ranging process involved in the receiving end of the embodiment of the present application. Figure 14 , Figure 14 This is a flow chart of a receiving end provided in an embodiment of the present application; Figure 14 As shown, the following steps may be included:

[0149] Step 1: Set the random number generation period (Tr), pseudo-random number period (N), phase-locked loop pulse generation period (Tp), and PPM modulation order (M).

[0150] Step 2: The random number generator 1010 generates a random number R according to Tr, or the pseudo-random number generator generates a pseudo-random number R according to Tr, the pseudo-random number period N, and a preset initial state. Simultaneously, the phase-locked loop circuit 1013, connected to the BPSK modulator 1012, is configured to generate a carrier signal according to a preset period. The carrier signal has the same phase as the random number signal. For example, the parallel phase-locked loop circuit 1013 generates a square wave L with a pulse period of Tp according to Tp (for the BPSK modulator 1012, L is the carrier wave). L and R are phase-synchronized.

[0151] Step 3: The PPM modulator 1011 outputs a modulated PPM signal P (for the BPSK modulator 1012, P is a baseband signal) according to the set modulation order M and the input signal R. P is phase-synchronized with L.

[0152] Step 4: The BPSK modulator 1012 performs BPSK modulation on the carrier L and the baseband signal P, and outputs a modulated signal P1 (the P1 signal is a pulse sequence of digital 0 or 1).

[0153] Step 5: Delay line circuit 1014 delays input P1 and outputs P2. (The DLL delay value varies between different TOF systems; for example, the first exposure has no delay, the second exposure has a delay of 1 / 4 cycle, the third exposure has a delay of 1 / 2 cycle, and the fourth exposure has a delay of 3 / 4 cycle. The delay value can be preset or externally entered.)

[0154] Step 6: The pixel array 1015 exposes the reflected light P1 ′ collected by the lens according to the P2 (01 sequence) signal, and each pixel outputs an exposure value (P3 array).

[0155] Step 7: The analog-to-digital converter 1016 performs a digitization operation on the P3 array signal to obtain the P4 array, which is then transmitted to the ranging circuit 20 .

[0156] Step 8: After receiving the P4 arrays exposed under different DLL delays, the ranging circuit uses the ranging algorithm to obtain the phase delay and calculates the distance to the object based on the operating frequency.

[0157] See Figure 15 , Figure 15 : is a signal diagram of a first pulse light and a second pulse light provided in an embodiment of the present application; Figure 15 As shown, assuming that the infrared continuous light signal emitted by the light emitter 103 (corresponding to the emission signal in the figure, i.e., the first pulse light) is a modulated cosine or square wave signal, the signal can be expressed by formula (1). The signal reflected from the target object will produce an offset, which is partly due to the illumination of the background light; and a modulated cosine signal containing a phase delay, which is caused by the emission signal illuminating the target scene and reflecting back to the sensor at a medium distance; the reflected signal (corresponding to the received signal in the figure, i.e., the second pulse light) can be expressed by formula (2).

[0158] s(t)=cos(wt) (1)

[0159]

[0160] By modulating the transmitted signal, the sensor receives and demodulates the signal with phase delay information reflected from the target scene to indirectly calculate the distance information. The distance calculation is shown in formula (3).

[0161]

[0162] In a possible implementation, the schematic diagram of the laser emission source, the echo signal (ie, the reflected signal) and the pixel modulation signal can be seen in FIG. Figure 16 , Figure 16 : is a signal diagram provided in an embodiment of the present application, taking a square wave signal as an example; Figure 16 The following figure shows the waveforms of three signals: the laser emission source (i.e., the first pulse of light), the echo signal (i.e., the second pulse of light), and the pixel modulation signal (the processed signal input to the pixel array). The waveform of the laser emission source is consistent with the waveform and phase of the pixel modulation signal, while the echo signal has a certain delay.

[0163] In one possible implementation, the device further includes a pixel array 1015 connected to the delay line circuit 1014; each pixel in the pixel array 1015 is configured to determine a plurality of exposure signals corresponding to each pixel based on the integrated switching signals within the plurality of pixels and the aforementioned second pulse light. The structure of the delay line circuit DLL1014 is described in detail in the accompanying drawings. Figure 17 , Figure 17 This is a schematic diagram of a DLL structure provided in an embodiment of the present application; the DDL 1014 is used to delay the output of a signal by changing the phase, where each τ corresponds to a delay; the numerical value and number of delays are not limited in the embodiment of the present application; after a pulse is input, the input pulse is delayed according to a preset delay numerical value and number, and one or more delayed signals are output. For example, the TOF ranging demodulation process uses a correlation function method, with the transmitted signal as the reference signal. By calculating the correlation function between the frequency-modulated transmitted signal and the phase-shifted reflected signal after irradiating the target, the solution is calculated as shown in Equation (4).

[0164]

[0165] In one possible implementation, the device further includes a delay line circuit 1014 connected to the BPSK modulator 1012. The delay line circuit 1014 is configured to perform a phase delay operation on the first signal according to a preset phase delay value, thereby generating multiple pixel-internal integrated switching signals. For example, by deriving Equation 4, the expression for the correlation function c(τ) can be obtained. Four different delay values ​​of τ are selected: τ0 = 0°, τ1 = 90°, τ2 = 180°, and τ3 = 270°, and these are substituted into s(t) to calculate the corresponding values. The emitted light is a square wave of a certain frequency, and the reflected light has the same waveform as the emitted light, but delayed by a flight time. The reference signals within the pixel are modulated waveforms C1 to C4. These four reference signals are cross-correlated and integrated with the reflected light, respectively, to produce the output results Q1 to Q4 (Q1 corresponds to Equation 5, Q2 corresponds to Equation 7, Q3 corresponds to Equation 6, and Q4 corresponds to Equation 8). To account for the possibility that the reflected signal may contain background light, an offset K is added. After the superposition process, the final expressions can be expressed as the following formulas (5) to (8).

[0166]

[0167]

[0168]

[0169]

[0170] Using formulas (5) to (8) we can calculate the phase Offset B and amplitude A. Phase delay represents the propagation delay of light during flight and is proportional to the distance to the target when the modulation frequency is set to a fixed value. The offset B can be used to provide a conventional 2D intensity image and indicate the amount of charge in the image sensor pixel. The amplitude A represents the achievable depth resolution of direct measurement. The formulas obtained by conversion are shown in Equations (9) to (11).

[0171]

[0172]

[0173]

[0174] The phase obtained by the above calculation can be used to calculate the distance D between the camera and the target object according to formula (3). Since each pixel of the two-dimensional array image sensor can measure the distance information corresponding to the target scene surface, what is actually obtained is the depth distance image of the target scene surface. In order to reconstruct the three-dimensional information in the real scene, the data needs to be further processed. The method adopted in this paper is to first use the camera calibration method to obtain the camera parameters, and then combine the obtained two-dimensional distance map based on the pinhole imaging principle to finally calculate the three-dimensional coordinates. The obtained formulas can be expressed by formulas (12) to (14).

[0175]

[0176]

[0177] Z w =D (14)

[0178] In one possible implementation, the device further includes an analog-to-digital converter (ADC) 1016 connected to the pixel array 1015; the ADC is configured to convert the multiple exposure signals into corresponding digital signals. Optionally, the device further includes a distance measurement circuit 20 connected to the ADC; the distance measurement circuit 20 is configured to receive the corresponding digital signals; obtain the phase delay of the second pulse of light according to a distance measurement algorithm, and calculate the distance between the object to be measured and the anti-interference distance measurement device based on the frequency of the second pulse of light. For example, when measuring an object in a target scene, a high-frequency infrared modulated signal is emitted from the LED modulated light source of the TOF imaging system to illuminate the target scene. The modulated signal then reflects back to the sensor surface, generating a phase difference related to the distance. The sensor receives and demodulates the phase difference caused during the flight process and then calculates the distance between the TOF sensor and the target object based on known quantities such as the light flight velocity and the modulation frequency. Optionally, to obtain complete three-dimensional information about the target scene and reconstruct the surface shape of the object in the target scene using a two-dimensional TOF image sensor array, each pixel in the TOF image sensor array must be able to independently receive and demodulate the distance information or phase difference to each corresponding point on the object surface. Ultimately, each exposure of the TOF imaging system yields the same amount of distance information as the sensor's image pixel resolution, namely, a depth-range image and a grayscale image of the target scene. It's understandable that the range is related to the frequency of the transmitted signal. The maximum measurable distance is often referred to as the fuzzy distance D, where D = c / (f*2), where c is the speed of light and f is the frequency. For example, for a 10MHz system, the fuzzy distance is 15 meters.

[0179] In a possible implementation, the aforementioned device further includes an optical lens (ie, lens 104 ) connected to the aforementioned pixel array 1015 ; the aforementioned optical lens 104 is used to receive the aforementioned second pulsed light.

[0180] The embodiment of the present application mainly reduces the impact of the signal's anti-interference ability caused by the continuous consistency of the phase in the signal caused by continuous identical random numbers by adding a pulse position modulator (i.e., PPM modulator) to the ranging chip. Specifically, the PPM modulator receives a random number signal and a modulation order, and outputs a modulated baseband signal. The modulation order ensures that when multiple consecutive identical random numbers may appear in the random number signal, the phases of consecutive groups of baseband signals in the output baseband signal will not be continuously the same, thereby improving the signal's anti-interference ability. The embodiment of the present application randomizes the waveform and uses a randomized waveform to transmit and pixel cross-correlate reception. Because random numbers have good autocorrelation and cross-correlation characteristics, only the signal transmitted by the local machine will be amplified and output during pixel cross-correlation reception, and other signals will be randomized, which will not cause errors in ranging.

[0181] See Figure 18 , Figure 18 This is another TOF ranging principle diagram provided by the embodiment of the present application; in addition to the continuous wave measurement principle, there is also a measurement method based on pulse modulation. Figure 18 As shown in the figure, an echo signal is generated after the pulsed light source is irradiated. The pulsed light source is irradiated for a short period of time (Δt), and two inverted windows PH1 and PH2 are used at each pixel to sample the reflected energy at the same time interval (Δt). The charges Q1 and Q2 accumulated during the sampling process are measured, and the distance is calculated using the following formula:

[0182]

[0183] During the exposure modulation process, according to the actual pixels, system and application requirements, in order to obtain depth of field information, the exposure modulation can be divided into 1 time, 2 times, 3 times, 4 times or more (1 time here refers to a group of continuous waveforms, not a periodic waveform). Several typical combinations are listed below: 1. Continuous wave exposure modulation 4 times; 2. Continuous wave exposure modulation 2 times; 3. Pulse wave exposure modulation 2 times; 4. Pulse wave exposure modulation 1 time. The embodiments of the present application do not limit the number of exposure modulations based on other similar principles. It is understandable that separating pixels in space, that is, exposing adjacent pixels at different phases, is also included in the protection scope of the embodiments of the present application as long as the principle is the same.

[0184] See Figure 19 , Figure 19 Schematic diagram of a continuous wave exposure modulated four times provided in an embodiment of the present application; Figure 19 As shown, A0 represents the exposure at phase 0°, A 180 Indicates exposure at a phase of 180°. Similarly, A 90 Indicates exposure at a phase of 90°, A 270 Indicates exposure at phase 270°. A0A 180 Indicates that TapA and TapB are exposed at phases 0° and 180° respectively. 180 A0 means that TapA and TapB are exposed at phases of 180° and 0° respectively. 180 , A 90 A 270 , A 180 A0, A 270 A 90 and low frequency continuous wave A0A 180 , A 90 A 270 In the embodiment of the present application, the exposure of A0A is performed during the modulation. 180 and A 180The reversed exposure order of A0 is mainly because the charge collection capacitor may be different for each TAP, which will affect the system accuracy. The chopping technology can eliminate the mismatch caused by factors such as the capacitor (gain error) at the charge collection point during reception, the set voltage and background light, thereby improving the accuracy of the depth information.

[0185] See Figure 20 , Figure 20 is a schematic diagram of a continuous wave exposure modulated twice provided in an embodiment of the present application; Figure 20 As shown, A0 represents the exposure at phase 0°, A 180 Indicates exposure at a phase of 180°. Similarly, A 90 Indicates exposure at a phase of 90°, A 270 Indicates exposure with a phase of 270°. In actual operation, the exposure modulation order can be interchanged. A0A 180 Indicates that TapA and TapB perform exposure modulation with phases of 0° and 180° respectively. 180 A0 means that TapA and TapB are modulated with phases of 180° and 0° respectively. 180 , A 90 A 270 The exposure sequence can be interchanged in actual operation. 180 and A 90 A 270 Exposure is mainly to reduce power consumption and increase frame rate, but because the number of exposures is relatively small Figure 19 The method shown in Figure 2 reduces the number of exposures by two, and the received signal strength is halved. Therefore, this exposure method results in higher ranging errors. Furthermore, this example does not use chopping technology to eliminate misalignments caused by process, device, and environmental factors, which reduces depth information accuracy. In practice, the pulse modulation phases of TapA and TapB can be swapped.

[0186] See Figure 21 , Figure 21 Schematic diagram of a pulse wave exposure modulated twice provided in an embodiment of the present application; Figure 21 As shown, A0 represents the exposure at phase 0°, A 180 Indicates exposure with a phase of 180°. A0A 180 Indicates that TapA and TapB perform exposure modulation with phases of 0° and 180° respectively. 180 A0 means that TapA and TapB are modulated with exposure of 180° and 0° phases respectively. In actual operation, the order can be interchanged. 180 and A 180The reversed exposure order of A0 is mainly because the charge collection capacitor may be different for each TAP, which will affect the system accuracy. The chopping technology can eliminate the mismatch caused by factors such as the capacitor (gain error) at the charge collection point during reception, the set voltage and background light, thereby improving the accuracy of the depth information.

[0187] See Figure 22 , Figure 22 Schematic diagram of a pulse wave exposure modulation provided by an embodiment of the present application; Figure 22 As shown, A0 represents the exposure at phase 0°, A 180 Indicates exposure at a phase of 180°. In this embodiment, chopping technology is not used to eliminate misalignments caused by process, device, and environmental factors. This reduces the accuracy of depth information, but also reduces power consumption. In practice, the pulse modulation phases of TapA and TapB can be swapped.

[0188] The above describes a specific anti-interference ranging device and application scenarios. The following describes the method embodiments involved in this application.

[0189] See Figure 23 , Figure 23 This is a schematic diagram of an anti-interference ranging method provided by an embodiment of the present application; the anti-interference ranging method is applied to an anti-interference ranging device (including the above-mentioned system architecture). Figure 23 Describing from a single side of the transmitting end, the method may include the following steps S2301 to S2305.

[0190] Step S2301: Generate a carrier signal according to a preset period.

[0191] Specifically, a fixed-frequency carrier signal is generated according to a preset carrier generation period and sent to a phase-shift keying modulator. The carrier signal is phase-synchronized with the random number signal, so that the carrier signal and the baseband signal generated by the random number signal are processed and the final light source drive signal is output, which is used to ultimately drive the light emitter to emit pulsed light.

[0192] Step S2302: Generate multiple pseudo-random numbers with a preset duration according to the pseudo-random number generation period, the pseudo-random number period and the preset initial pseudo-random number.

[0193] Specifically, concurrently with the aforementioned steps, a plurality of random numbers (or pseudo-random numbers) that last for a preset duration are generated based on a pseudo-random number generation cycle, a pseudo-random number period, and a preset initial pseudo-random number. The aforementioned preset duration is the same as the value of the aforementioned pseudo-random number generation cycle. In one possible implementation, the aforementioned random number signal includes a plurality of pseudo-random numbers that last for a preset duration; the aforementioned method further includes: generating, by a pseudo-random number generator, a plurality of pseudo-random numbers that last for a preset duration based on the pseudo-random number generation cycle, a pseudo-random number period, and a preset initial pseudo-random number; the aforementioned preset duration is the same as the value of the aforementioned pseudo-random number generation cycle.

[0194] Step S2303: Generate a baseband signal according to the random number signal.

[0195] Specifically, a first mapping table corresponding to a first modulation order among multiple modulation orders is determined; then, based on the mapping relationship of each random number in the random number signal in the first mapping table, the pulse position of the baseband signal corresponding to each random number is determined, thereby modulating the entire random number signal into a baseband signal. The phases of two consecutive groups of signals in the aforementioned baseband signal are different; wherein the aforementioned random number signal includes one or more random numbers, each random number in the aforementioned random number signal corresponds to a phase of the aforementioned baseband signal, and the aforementioned modulation order is used to control the phase of the aforementioned baseband signal corresponding to consecutive identical random numbers in the aforementioned random number signal to be discontinuously repeated multiple times; the phases of the aforementioned random number signal and the aforementioned baseband signal are synchronized. For example, based on a preset modulation order, a mapping relationship between each random number and the pulse position of the baseband signal is determined; the pulse position of the baseband signal corresponding to each random number in the random number signal in the mapping relationship is determined, thereby modulating the baseband signal. Optionally, the random numbers in the random number signal are determined by pseudorandom numbers. The functions of random numbers or pseudo-random numbers in the embodiments of the present application are the same, and can be considered to be different only in name, which does not affect the application of the embodiments of the present application.

[0196] Optionally, the first modulation order is one of a plurality of preset modulation orders.

[0197] Step S2304: modulate the carrier signal and the baseband signal to generate a first signal.

[0198] Specifically, the system receives a baseband signal from a PPM modulator and a carrier signal from a phase-locked loop circuit, processes the two synchronized signals, and generates a first signal (i.e., a pulse signal that meets ranging requirements). Two consecutive pulse waves within the plurality of pulse waves have different phases. The first signal is used to generate a first pulse of light, which is used to illuminate the object under test.

[0199] In a possible implementation, the light emitter is controlled to emit the first pulse light according to the first signal.

[0200] Step S2305: Control the light emitter to emit a first pulse light according to the first signal.

[0201] Specifically, the light source driver receives a first signal; driven by the first signal, the light source driver causes the light emitter to emit a first pulse light.

[0202] The embodiment of the present application mainly reduces the impact of the anti-interference ability of the signal caused by the continuous consistency of the phase in the signal caused by continuous identical random numbers by adding a pulse position modulator (i.e., PPM modulator) to the anti-interference ranging device (such as a ranging chip). Specifically, the PPM modulator receives a random number signal containing one or more random numbers, wherein each of the one or more random numbers corresponds to the pulse position of a baseband signal. The PPM modulator makes the corresponding position of the modulated output baseband signal appear in accordance with the relevant parameters of the pulse position corresponding to the random number, and makes a certain number of time intervals between the two pulse positions; the mapping relationship between the random number and the pulse position provided by the PPM modulator in different cameras can be set to be different, so that the number of intervals between the two pulse positions in the baseband signal generated in each camera is different, thereby improving the anti-interference performance of the pulse light wave finally output, so that the camera can effectively identify the pulse light wave emitted by itself and filter the pulse light waves emitted by other cameras. The embodiment of the present application does not limit the method of determining the correspondence between random numbers and pulse positions. Different from the prior art, the random number is directly sent to the phase shift keying modulator; when there are continuous 0s or continuous 1s, the phases between each group of signal waves in the first signal output by the phase shift keying modulator may be continuously the same. By modulating the order, when there are multiple consecutive identical random numbers that may appear in the random number signal, the phases of consecutive groups of baseband signals in the output baseband signal will not be continuously the same, thereby improving the anti-interference ability of the signal. The embodiment of the present application randomizes the waveform and uses the randomized waveform for emission and pixel cross-correlation reception. Because random numbers have good autocorrelation and cross-correlation characteristics, only the signal emitted by the local machine will be amplified and output during pixel cross-correlation reception, and other signals will be randomly processed, so that there will be no large errors in the ranging results.

[0203] It should be noted that the anti-interference ranging method described in the embodiments of the present application can refer to the relevant description of the anti-interference ranging device (transmitting end) in the aforementioned device embodiment, and will not be repeated here.

[0204] See Figure 24 , Figure 24This is a schematic diagram of an anti-interference ranging method provided by an embodiment of the present application; the anti-interference ranging method is applied to an anti-interference ranging device (including the above-mentioned system architecture). Figure 24 Describing from the single side of the receiving end, the method may include the following steps S2401 to S2408.

[0205] Step S2401: Generate a carrier signal according to a preset period.

[0206] Specifically, a fixed-frequency carrier signal is generated according to a preset carrier generation period and sent to a phase-shift keying modulator. The carrier signal is phase-synchronized with the random number signal, so that the carrier signal and the baseband signal generated by modulating the random number signal are processed and a final light source drive signal is output, which is used to ultimately drive the light emitter to emit pulsed light. The phase of the carrier signal and the random number signal are the same.

[0207] Step S2402: Generate multiple pseudo-random numbers with a preset duration according to the pseudo-random number generation period, the pseudo-random number period and the preset initial pseudo-random number.

[0208] Specifically, concurrently with the aforementioned steps, multiple random numbers or pseudo-random numbers are generated for a preset duration based on a pseudo-random number generation cycle, a pseudo-random number period, and a preset initial pseudo-random number. The aforementioned preset duration is the same as the value of the aforementioned pseudo-random number generation cycle. In one possible implementation, the aforementioned random number signal includes multiple pseudo-random numbers that last for a preset duration; the aforementioned method further includes: generating, by a pseudo-random number generator, multiple pseudo-random numbers that last for a preset duration based on the pseudo-random number generation cycle, the pseudo-random number period, and a preset initial pseudo-random number; the aforementioned preset duration is the same as the value of the aforementioned pseudo-random number generation cycle.

[0209] Step S2403: Generate a baseband signal according to the random number signal.

[0210] Specifically, a first mapping relationship table corresponding to the first modulation order is determined based on a first modulation order among multiple modulation orders; then, based on the mapping relationship of each random number in the random number signal in the first mapping relationship table, the pulse position of the baseband signal corresponding to each random number is determined, so as to modulate the entire random number signal into a baseband signal. The phases of two consecutive groups of signals in the aforementioned baseband signal are different; wherein the aforementioned random number signal includes one or more random numbers, each random number in the aforementioned random number signal corresponds to a phase of the aforementioned baseband signal, and the aforementioned modulation order is used to control the phase of the aforementioned baseband signal corresponding to consecutive identical random numbers in the aforementioned random number signal to be discontinuously repeated multiple times; the phases of the aforementioned random number signal and the aforementioned baseband signal are synchronized. For example, based on a preset modulation order, a mapping relationship between each random number and the pulse position of the baseband signal is determined; and the pulse position of the baseband signal corresponding to each random number in the random number signal in the mapping relationship is determined, so as to modulate the baseband signal. A detailed description can be found in the aforementioned step S2303 and will not be repeated here.

[0211] Step S2404: modulate the carrier signal and the baseband signal to generate a first signal.

[0212] Specifically, the system receives a baseband signal from a PPM modulator and a carrier signal from a phase-locked loop circuit, processes the two synchronized signals, and generates a first signal (i.e., a pulse signal that meets ranging requirements). Two consecutive pulse waves within the plurality of pulse waves have different phases. The first signal is used to generate a first pulse of light, which is used to illuminate the object under test.

[0213] Step S2405: performing multiple phase delay operations on the first signal according to a preset phase delay value to generate multiple pixel internal integration switch signals.

[0214] Specifically, each of the aforementioned multiple phase delay operations corresponds to an internal integrated switch signal of a pixel.

[0215] In a possible implementation, multiple phase delay operations are performed on the first signal according to a preset phase delay value to generate multiple pixel internal integration switch signals; each of the multiple phase delay operations corresponds to one pixel internal integration switch signal.

[0216] Step S2406: Determine a plurality of exposure signals corresponding to each pixel according to the internal integrated switch signals of the plurality of pixels and the second pulse light.

[0217] Specifically, after receiving the second pulse light (the second pulse light is the pulse light reflected by the object to be measured), the multiple exposure signals corresponding to each pixel are determined according to the internal integrated switch signals of the multiple pixels and the second pulse light.

[0218] Step S2407: converting the multiple exposure signals into corresponding multiple digital signals.

[0219] Specifically, according to the exposure signal input of each pixel, the multiple exposure signals of each pixel can be converted into corresponding multiple digital signals through the analog-to-digital converter ADC; and then each digital signal is calculated and processed according to a corresponding calculation method.

[0220] Step S2408: After receiving multiple digital signals corresponding to the multiple exposure signals, obtain the phase delay of the second pulse light according to the ranging algorithm, and calculate the distance between the object to be measured and the anti-interference ranging device according to the frequency of the second pulse light.

[0221] Specifically, after receiving the corresponding multiple digital signals, the phase of the second pulse light received by the lens is delayed according to a preset ranging algorithm; then the distance between the target object (i.e., the object to be measured) and the anti-interference ranging device is calculated based on the relevant frequency of the second pulse light.

[0222] Alternatively, by calculating the distance information at each pixel, a depth image of the object to be measured is obtained. Combined with images from other dimensions, the distance between the object and the camera in three-dimensional space can be restored, or a three-dimensional image of the object can be restored.

[0223] In a possible implementation, the method further includes: receiving the second pulse light through an optical lens.

[0224] In a possible implementation, the aforementioned light emitter is a light emitting diode (LED) or a vertical cavity surface emitting laser (VCSEL).

[0225] In a possible implementation, the phases of the carrier signal and the baseband signal are synchronized.

[0226] In a possible implementation, generating a baseband signal according to the random number signal and the first modulation order includes:

[0227] According to the pulse position corresponding to each random number in the random number signal in the first mapping relationship table, the random number signal is modulated into the baseband signal, wherein the first mapping relationship table belongs to one of multiple mapping relationship tables corresponding to the first modulation order; the first modulation order is one of multiple preset modulation orders; each of the multiple mapping relationship tables includes the mapping relationship between each random number and the pulse position of the baseband signal; the multiple mapping relationship tables correspond one-to-one to the multiple preset modulation orders.

[0228] The embodiment of the present application mainly reduces the impact of the anti-interference ability of the signal caused by the continuous consistency of the phase in the signal caused by continuous identical random numbers by adding a pulse position modulator (i.e., PPM modulator) to the anti-interference ranging device (such as a ranging chip). Specifically, the PPM modulator receives a random number signal containing one or more random numbers, wherein each of the one or more random numbers corresponds to the pulse position of a baseband signal. The PPM modulator makes the corresponding position of the modulated output baseband signal appear in accordance with the relevant parameters of the pulse position corresponding to the random number, and makes a certain number of time intervals between the two pulse positions; the mapping relationship between the random number and the pulse position provided by the PPM modulator in different cameras can be set to be different, so that the number of intervals between the two pulse positions in the baseband signal generated in each camera is different, thereby improving the anti-interference performance of the pulse light wave finally output, so that the camera can effectively identify the pulse light wave emitted by itself and filter the pulse light waves emitted by other cameras. The embodiment of the present application does not limit the method of determining the correspondence between random numbers and pulse positions. Different from the prior art, the random number is directly sent to the phase shift keying modulator; when there are continuous 0s or continuous 1s, the phases between each group of signal waves in the first signal output by the phase shift keying modulator may be continuously the same. By modulating the order, when there are multiple consecutive identical random numbers that may appear in the random number signal, the phases of consecutive groups of baseband signals in the output baseband signal will not be continuously the same, thereby improving the anti-interference ability of the signal. The embodiment of the present application randomizes the waveform and uses the randomized waveform for emission and pixel cross-correlation reception. Because random numbers have good autocorrelation and cross-correlation characteristics, only the signal emitted by the local machine will be amplified and output during pixel cross-correlation reception, and other signals will be randomly processed, so that there will be no large errors in the ranging results.

[0229] It should be noted that the anti-interference ranging method described in the embodiments of the present application can refer to the relevant description of the anti-interference ranging device (receiving end) in the aforementioned device embodiment, and will not be repeated here.

[0230] like Figure 25 As shown, Figure 25 This is a schematic diagram of the structure of a device provided in an embodiment of the present application. Figure 25 The device 25 includes at least one processor 2501 and at least one memory 2502. In addition, the device may also include common components such as a power supply, which will not be described in detail here.

[0231] The processor 2501 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the above program.

[0232] The memory 2502 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory may exist independently and be connected to the processor via a bus. The memory may also be integrated with the processor.

[0233] The memory 2502 is used to store application code for executing the above solution, and the execution is controlled by the processor 2501. The processor 2501 is used to execute the application code stored in the memory 2502.

[0234] Figure 25 When the device shown is an anti-interference ranging device, the code stored in the memory 2502 can execute the above Figure 23 or Figure 24 Provided anti-interference ranging method.

[0235] It should be noted that the functions of the device 25 described in the embodiment of the present application can be found in the relevant description in the aforementioned device embodiment, and will not be repeated here.

[0236] An embodiment of the present application provides an electronic device, which may include the aforementioned anti-interference ranging device and a discrete device coupled to the outside of the aforementioned anti-interference ranging device.

[0237] An embodiment of the present application provides a terminal, comprising a processor configured to support the terminal in executing the corresponding functions of the aforementioned anti-interference ranging method. The terminal may also include a memory coupled to the processor and storing necessary program instructions and data for the terminal. The terminal may also include a communication interface for communicating with other devices or a communication network.

[0238] The present application also provides a radar, which may include the aforementioned anti-interference ranging device or the aforementioned anti-interference ranging system, configured to implement the anti-interference ranging function provided by the aforementioned device or system. The radar may also include a memory coupled to the aforementioned device or system, configured to store program instructions and data necessary for the radar; and an external power supply coupled to the aforementioned device or system, configured to supply power to the radar.

[0239] An embodiment of the present application provides a vehicle equipped with the aforementioned anti-interference ranging device or the aforementioned anti-interference ranging system, configured to implement the anti-interference ranging function provided by the aforementioned device or system. The aforementioned vehicle may also include an autonomous driving system configured to control the vehicle's travel based on road conditions. The aforementioned vehicle may also include an external discrete device coupled to the aforementioned device or system.

[0240] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0241] It should be noted that for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that this application is not limited by the order of the actions described, because according to this application, certain steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily required by this application.

[0242] In the several embodiments provided in this application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the above-mentioned units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0243] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0244] In addition, the functional units in the embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0245] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server or a network device, etc., specifically a processor in a computer device) to execute all or part of the steps of the above-mentioned methods of each embodiment of the present application. Among them, the aforementioned storage medium may include: U disk, mobile hard disk, magnetic disk, optical disk, read-only memory (Read-Only Memory, abbreviated: ROM) or random access memory (Random Access Memory, abbreviated: RAM) and other media that can store program codes.

[0246] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An anti-interference ranging device, characterized in that: include: A pulse position modulator, and a phase shift keying modulator connected to the pulse position modulator; The pulse position modulator is used to generate a baseband signal according to a random number signal; wherein the random number signal includes one or more random numbers, each of the one or more random numbers corresponds to a pulse position of the baseband signal; when there are multiple consecutive identical random numbers in the random number signal, there are M time intervals between the pulse positions corresponding to the multiple consecutive identical random numbers in the baseband signal, where M is an integer greater than 0; the phase of the random number signal and the baseband signal are synchronized; The phase-shift keying modulator is used to modulate the carrier signal and the baseband signal to generate a first signal; wherein the first signal is used to drive the light emitter to generate a first pulse light, and the first pulse light is used to irradiate the object to be tested.

2. The device according to claim 1, characterized in that The pulse position modulator is specifically used to: modulate the random number signal into the baseband signal according to the pulse position corresponding to each random number in the random number signal in the first mapping relationship table, wherein the first mapping relationship table belongs to one of multiple mapping relationship tables corresponding to the first modulation order; the first modulation order is one of multiple preset modulation orders; each of the multiple mapping relationship tables includes the mapping relationship between each random number and the pulse position of the baseband signal; the multiple mapping relationship tables correspond one-to-one to the multiple preset modulation orders.

3. The device according to claim 1 or 2, characterized in that: The device also includes a phase-locked loop circuit connected to the phase-shift keying modulator; The phase-locked loop circuit is used to generate the carrier signal according to a preset period, and the phase of the carrier signal is synchronized with the random number signal.

4. The device according to any one of claims 1 to 3, characterized in that: The device further comprises: a delay line circuit connected to the phase shift keying modulator; The delay line circuit is used to perform multiple phase delay operations on the first signal according to a preset phase delay value to generate multiple pixel internal integrated switch signals; each operation of the multiple phase delay operations corresponds to a pixel internal integrated switch signal.

5. The device according to claim 4, characterized in that The device further comprises: a pixel array connected to the delay line circuit; Each pixel in the pixel array is used to determine a plurality of exposure signals corresponding to each pixel according to the internal integrated switch signals of the plurality of pixels and the second pulse light.

6. The device according to claim 5, characterized in that The device also includes an analog-to-digital converter ADC connected to the pixel array; the ADC is used to convert the multiple exposure signals corresponding to each pixel into corresponding multiple digital signals.

7. The device according to any one of claims 1 to 6, characterized in that: The device also includes a pseudo-random number generator connected to the pulse position modulator; The pseudo-random number generator is used to generate a plurality of random numbers of a preset duration according to a pseudo-random number generation cycle, a pseudo-random number period and a preset initial pseudo-random number; the preset duration is the same as the value of the random number generation cycle.

8. The device according to any one of claims 1 to 7, characterized in that: The phases of the carrier signal and the baseband signal are synchronized.

9. An anti-interference ranging method, characterized in that: include: Generate a baseband signal according to a random number signal; wherein the random number signal includes one or more random numbers, each of the one or more random numbers corresponds to a pulse position of the baseband signal; when there are multiple consecutive identical random numbers in the random number signal, there are M time intervals between the pulse positions corresponding to the multiple consecutive identical random numbers in the baseband signal, where M is an integer greater than 0; the phase of the random number signal and the baseband signal are synchronized; The carrier signal and the baseband signal are modulated to generate a first signal; wherein the first signal is used to drive the light emitter to generate a first pulse light, and the first pulse light is used to irradiate the object to be measured.

10. The method according to claim 9, characterized in that The method further includes: controlling the light emitter to emit the first pulse light according to the first signal.

11. The method according to claim 9 or 10, characterized in that: The method further comprises: The carrier signal is generated according to a preset period, and the phase of the carrier signal is synchronized with the random number signal.

12. The method according to any one of claims 9 to 11, characterized in that: The method further comprises: According to a preset phase delay value, multiple phase delay operations are performed on the first signal to generate multiple pixel internal integrated switch signals; each operation of the multiple phase delay operations corresponds to a pixel internal integrated switch signal.

13. The method according to claim 12, characterized in that The method further comprises: receiving a second pulse of light, where the second pulse of light is a pulse of light reflected by the object to be detected; A plurality of exposure signals corresponding to each pixel are determined according to the internal integrated switch signals of the plurality of pixels and the second pulse light.

14. The method according to claim 13, characterized in that The method further comprises: The multiple exposure signals corresponding to each pixel are converted into corresponding multiple digital signals.

15. The method according to claim 14, characterized in that The method further comprises: receiving the corresponding plurality of digital signals; The phase delay of the second pulse light is obtained according to the distance measurement algorithm, and the distance between the object to be measured and the anti-interference distance measurement device is calculated according to the frequency of the second pulse light.

16. The method according to any one of claims 9 to 15, characterized in that: The method further comprises: According to the pseudo-random number generation cycle, the pseudo-random number period and the preset initial pseudo-random number, a plurality of pseudo-random numbers lasting for a preset time length are generated; the preset time length is the same as the value of the pseudo-random number generation cycle.

17. The method according to any one of claims 9 to 16, characterized in that: The phases of the carrier signal and the baseband signal are synchronized.

18. The method according to any one of claims 9 to 17, characterized in that: The generating of a baseband signal according to a random number signal comprises: According to the pulse position corresponding to each random number in the random number signal in the first mapping relationship table, the random number signal is modulated into the baseband signal, wherein the first mapping relationship table belongs to one of multiple mapping relationship tables corresponding to the first modulation order; the first modulation order is one of multiple preset modulation orders; each of the multiple mapping relationship tables includes the mapping relationship between each random number and the pulse position of the baseband signal; the multiple mapping relationship tables correspond one-to-one to the multiple preset modulation orders.

19. An anti-interference ranging system, characterized in that: include: A light source driver, a light emitter connected to the light source driver, and a device according to any one of claims 1 to 8; The light source driver is used to control the light emitter to emit the first pulse light according to the first signal.

20. The system according to claim 19, characterized in that The system further comprises an optical lens; the optical lens is used to receive a second pulse light, where the second pulse light is the pulse light reflected by the object to be detected.

21. The system according to claim 19 or 20, characterized in that The system further includes a distance measuring circuit; the distance measuring circuit is used for: receiving a corresponding plurality of digital signals, wherein the corresponding plurality of digital signals are signals converted from a plurality of exposure signals corresponding to each pixel; The phase delay of the second pulse light is obtained according to the distance measurement algorithm, and the distance between the object to be measured and the anti-interference distance measurement device is calculated according to the frequency of the second pulse light, wherein the second pulse light is the pulse light reflected by the object to be measured.

22. The system according to any one of claims 19 to 21, characterized in that: The light emitter is a light emitting diode (LED) or a vertical cavity surface emitting laser (VCSEL).

23. A radar, characterized in that: The radar includes the device as described in claims 1-8 or the system as described in claims 19-21, which is used to implement the anti-interference ranging function provided by the device or the system; the radar also includes a memory coupled to the device or the system, which is used to store program instructions and data necessary for the radar; the radar also includes an external power supply coupled to the device or the system, and the external power supply is used to power the radar.

24. A vehicle, characterized in that: The vehicle includes the device described in claims 1-8 or the system described in claims 19-21, which is used to implement the anti-interference ranging function provided by the device or the system; the vehicle also includes an automatic driving system, which is used to control the driving of the vehicle according to road conditions; the vehicle also includes an external discrete device coupled to the device or the system.

25. A terminal, characterized in that: The terminal includes a processor, which is configured to support the terminal to perform the corresponding functions of the anti-interference ranging method as described in any one of claims 9 to 18; the terminal also includes a memory, which is coupled to the processor and is used to store program instructions and data necessary for the terminal; the terminal also includes a communication interface for communicating through a communication network.

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