A ranging chip, device, and method based on Time-of-Flight (ToF)

Abstract

A ranging chip (201), device, and method based on Time-of-Flight (ToF) are disclosed, relating to the field of chip technology. This invention improves the accuracy of ToF ranging and effectively enhances the ranging distance of ToF. The ranging chip (201) includes: a first signal generator (301) for generating a first signal, the first signal comprising a plurality of first pulses, the width of which is a first width T, the first signal being used to control a light-emitting device to emit a light signal toward a target object; a second signal generator (302) for generating a second signal based on the first signal, the second signal comprising a plurality of first pulses in the first signal, and at least one second pulse delayed by a first width T from each of the plurality of first pulses; and a continuous wave processing circuit (303) for integrating the received light signal reflected from the target object based on the second signal to obtain a plurality of exposure values, the plurality of exposure values ​​being used to calculate the phase delay corresponding to the time of flight of the light signal between the testing chip (201) and the target object.

Description

Technical Field

[0001] This application relates to the field of chip technology, and in particular to a ranging chip, device and method based on Time-of-Flight (ToF). Background Technology

[0002] Time-of-Flight (ToF) ranging technology is currently widely used in numerous fields, such as autonomous driving, 3D imaging, facial recognition, and intelligent robotics. ToF ranging works by transmitting a light signal from a transmitter to a target object; the signal reflected by the target object is then received by a receiver. By measuring the round-trip time (time of flight) between the transmitter and the target object, the distance between them is calculated. This distance information can be used to generate 3D images of the target object and other information.

[0003] Time-of-Flight (ToF) ranging technology can employ continuous wave (CW) ToF modulation and pulse wave (P) ToF modulation. CW ToF calculates the phase difference between the emitted and received continuous light signals to determine the distance to the target object. However, CW ToF requires a long exposure time, which can lead to the reception of significant background light, resulting in a low signal-to-noise ratio and a large ranging error. P ToF, on the other hand, requires a standard square wave signal and calculates the distance to the target object by measuring the phase delay of the received square wave signal. However, P ToF requires precise square wave shape measurement, which is often imperfect, exhibiting distortion or glitches. Consequently, P ToF also has a larger ranging error and a shorter effective testing distance compared to CW ToF. Summary of the Invention

[0004] This application provides a ranging chip, device, and method based on Time-of-Flight (ToF) to improve the accuracy of ToF ranging.

[0005] In a first aspect, a time-of-flight (ToF) ranging chip is provided, comprising: a first signal generator for generating a first signal, the first signal including a plurality of first pulses, the width of the first pulses being a first width T, the first signal being used to control a light-emitting device to emit a light signal toward a target object; a second signal generator for generating a second signal based on the first signal, the second signal including the plurality of first pulses in the first signal, and at least one second pulse delayed by the first width T from each of the plurality of first pulses; and a continuous wave processing circuit for integrating the received light signal reflected from the target object based on the second signal to obtain a plurality of exposure values, the plurality of exposure values ​​being used to calculate the phase delay corresponding to the time of flight of the light signal between the chip and the target object.

[0006] In the above technical solution, by emitting pulsed light signals, the received pulsed light signals can be exposed for a short time, avoiding the noise signals caused by receiving a large amount of background light in CW ToF ranging, thereby improving the signal-to-noise ratio and ranging accuracy. At the same time, the emitted signal does not need to be a continuous wave or a standard square wave, but a discrete pulse wave, which can overcome the limitation of P ToF ranging chips on standard square wave waveforms.

[0007] In one possible implementation, the width of each of the at least one second pulse is a first width T. In the above possible implementations, the second pulses generated based on the first pulses are used to generate a demodulated signal for demodulating the received signal, thereby demodulating the received pulse signal according to the continuous wave ranging algorithm, which can improve the signal-to-noise ratio and increase the ranging distance.

[0008] In one possible implementation, the second pulse is a plurality of second pulses, and the interval between two adjacent second pulses in the plurality of second pulses is a first width T. In the above possible implementation, the plurality of second pulses generated based on the first pulse are used to generate a demodulated signal for demodulating the received signal, thereby demodulating the received pulse signal according to the continuous wave ranging algorithm, which can improve the signal-to-noise ratio and increase the ranging distance.

[0009] In one possible implementation, the continuous wave processing circuit specifically includes: a first delay unit for delaying the second signal to obtain multiple third signals with different phases; an image sensor array for exposing the light signal reflected from the target object received by the lens multiple times according to the multiple third signals with different phases to obtain multiple fourth signals; and an analog-to-digital converter for performing analog-to-digital conversion on the multiple fourth signals to obtain multiple digital image arrays, wherein the multiple digital image arrays include exposure values ​​corresponding to multiple pixels.

[0010] In one possible implementation, the interval between two adjacent first pulses in the plurality of first pulses is (N+1)*T, where N is a preset positive integer or a random positive integer. In the above possible implementation, when N in the emitted laser signal is a random signal, different pixels of the image sensor array expose the reflected signal after different phase delays, so that the modulation signals do not interfere with each other in the codeword dimension, time and frequency dimensions, thereby improving the anti-interference of the ranging results.

[0011] In one possible implementation, the delay unit is specifically used to: perform m delay processing on the second signal to obtain m third signals, wherein the m delay processing includes 0-phase delay processing, and the time difference between two adjacent delay processing in the m delay processing is 2T / m. In the above possible implementation, different third signals are generated by performing different phase delay processing on the second signal, so that the received pulse signal can be demodulated with the third signal according to the continuous wave ranging algorithm, thereby improving the ranging accuracy.

[0012] In one possible implementation, the ranging chip further includes: a second delay unit for generating a delayed signal of the first signal; and a light-emitting device for emitting a light signal toward the target object according to the delayed signal of the first signal. In the above possible implementations, the second delay unit enables the ToF ranging device to obtain multiple accurate exposure values ​​within a range from 0 meters to an ambiguous distance from the target object to the ToF ranging device.

[0013] In a second aspect, a ranging device is provided, comprising: a ranging chip as described in any one aspect, a light source driver, a light-emitting device, and a lens; the light source driver is used to drive the light-emitting device to emit a light signal according to a first signal generated by the ranging chip; the light-emitting device is used to emit a light signal toward a target object based on the drive of the first signal; and the lens is used to receive the light signal reflected by the target object and transmit the light signal to the ranging chip. In one possible embodiment, the light-emitting device is a direct-cavity surface-emitting laser (VCSEL).

[0014] Thirdly, an electronic device is provided, comprising a ranging device as described in any one of the first aspects, the electronic device further comprising: a calculation module, configured to calculate a phase delay corresponding to the time of flight of the light signal between the ranging device and the target object based on a plurality of exposure values ​​obtained by the ranging device.

[0015] Fourthly, a ranging method based on Time-of-Flight (ToF) is provided. The method includes: generating a first signal, the first signal comprising a plurality of first pulses, the width of each first pulse being a first width T, the first signal being used to emit an optical signal toward a target object; generating a second signal based on the first signal, the second signal comprising the plurality of first pulses in the first signal, and at least one second pulse delayed by the first width T from each of the plurality of first pulses; and integrating the received optical signal reflected from the target object based on the second signal to obtain a plurality of exposure values, the exposure values ​​being used to calculate the phase delay corresponding to the time-of-flight of the optical signal between the ranging chip and the target object.

[0016] In one possible implementation, the width of each of the at least one second pulse is a first width T.

[0017] In one possible implementation, the second pulse is a plurality of second pulses, and the interval between two adjacent second pulses in the plurality of second pulses is a first width T.

[0018] In one possible implementation, integrating the received light signal reflected by the target object based on the second signal to obtain multiple exposure values ​​includes: delaying the second signal to obtain multiple third signals with different phases; exposing the received light signal reflected by the target object multiple times based on the multiple third signals with different phases to obtain multiple fourth signals; and performing analog-to-digital conversion on the multiple fourth signals to obtain multiple digital image arrays, wherein the multiple digital image arrays include exposure values ​​corresponding to multiple pixels.

[0019] In one possible implementation, the interval between two adjacent first pulses in the plurality of first pulses is (N+1)*T, where N is a preset positive integer or a random positive integer.

[0020] In one possible implementation, delaying the second signal to obtain multiple third signals with different phases specifically includes: performing m delay processing on the second signal to obtain m third signals, wherein the m delay processing includes 0-phase delay processing, and the time difference between two adjacent delay processing in the m delay processing is 2T / m.

[0021] In one possible implementation, after generating the first signal, the ranging method further includes: emitting a light signal toward the target object based on the first signal.

[0022] In one possible implementation, after generating the first signal, the ranging method further includes: generating a delayed signal of the first signal; specifically, transmitting a light signal to the target object based on the first signal includes: transmitting a light signal to the target object based on the delayed signal of the first signal.

[0023] In one possible implementation, after integrating the received light signal reflected from the target object based on the second signal to obtain multiple exposure values, the ranging method further includes: calculating the phase delay corresponding to the flight time of the light signal between the ranging device and the target object based on the multiple exposure values.

[0024] Fifthly, an electronic device is provided, the electronic device including a processor coupled to a memory; the memory for storing computer programs or instructions; the processor for executing the computer programs or instructions stored in the memory, such that the electronic device can perform the method as described in any of the fourth aspects above.

[0025] In a sixth aspect, a computer-readable storage medium is provided for storing a program or instructions that, when executed by a processor of an electronic device, enable the electronic device to perform the method described in any of the fourth aspects above.

[0026] A seventh aspect provides a computer program product, including a program or instructions, which, when run on a computer, cause the computer to perform the method as described in any of the fourth aspects above.

[0027] The technical problems solved and the technical effects achieved by the above-mentioned Time-of-Flight (ToF) based ranging chips, devices, electronic devices, computer-readable storage media, and computer program products provided in this application can be referred to in any one of the first aspects above, and will not be repeated here.

[0028] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0029] Figure 1 A schematic diagram of the transmitted and reflected signals for ToF ranging;

[0030] Figure 2 A schematic diagram of the ToF ranging device provided in the embodiments of this application. Figure 1 ;

[0031] Figure 3 This is a schematic diagram of the ToF ranging chip provided in the embodiments of this application;

[0032] Figure 4(a) is a waveform diagram of the first signal provided in the embodiment of this application. Figure 1 ;

[0033] Figure 4(b) is a waveform diagram of the first signal provided in the embodiment of this application. Figure 2 ;

[0034] Figure 5(a) is a waveform diagram of the second signal provided in the embodiment of this application. Figure 1 ;

[0035] Figure 5(b) is a waveform diagram of the second signal provided in the embodiment of this application. Figure 2 ;

[0036] Figure 6 A schematic diagram of the ToF ranging device provided in the embodiments of this application. Figure 2 ;

[0037] Figure 7 This is a schematic diagram of the modulation waveform of a ToF ranging device provided in an embodiment of this application;

[0038] Figure 8 This is a schematic diagram of the modulation method of the ToF ranging device provided in the embodiments of this application;

[0039] Figure 9 A schematic diagram of the ToF ranging device provided in an embodiment of the present invention. Figure 3 ;

[0040] Figure 10 A schematic diagram of the modulation waveform of another ToF ranging device provided in the embodiments of this application;

[0041] Figure 11 A flowchart illustrating a ToF ranging method provided in an embodiment of this application;

[0042] Figure 12 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0043] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this embodiment, unless otherwise stated, "multiple" means two or more, and "at least one" means one or more.

[0044] It should be noted that, in this application, the terms "exemplary" or "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0045] This application provides a ranging method and device based on Time-of-Flight (ToF). The technical terms and their principles are briefly explained below.

[0046] LiDAR (Light Detection and Ranging) is a radar system that uses emitted laser beams to detect the position, velocity, and other characteristics of target objects. Its working principle involves emitting a laser detection signal towards the target object, then comparing the received signal reflected back from the target object with the emitted signal. Based on the comparison result, signal processing is performed to obtain information about the target object, such as the distance, azimuth, altitude, velocity, attitude, and even shape between the lidar and the target object. Furthermore, lidar possesses high measurement accuracy and fine temporal and spatial resolution, enabling it to perform functions such as distance measurement (range finding), target detection, imaging, tracking, and image recognition. Among these, range finding is the fundamental function of lidar.

[0047] Currently, lidar can measure the distance between the lidar and the target object using the time-of-flight principle of light. For example, the distance can be calculated using the formula: R = c × t / (2 × n), where n is the refractive index of the medium through which light propagates, and c is the speed of light, approximately 299792.458 km / s. This principle allows for detection distances ranging from a few meters to several kilometers.

[0048] The basic principle of the CW ToF measurement method is as follows: Figure 1 As shown, a Time-of-Flight (ToF) ranging device illuminates a target object by emitting a signal. When the modulated signal is reflected back to the surface of the ToF ranging device, a distance-related phase difference is generated. The ToF ranging device receives the reflected signal of the modulated signal, demodulates it to obtain the phase difference caused during flight, and then calculates the distance between the ToF ranging device and the target object based on known quantities such as the speed of light and the frequency of the modulated signal, according to the phase difference.

[0049] Furthermore, to obtain the three-dimensional coordinate information of the target object's distance from the lidar, and to reconstruct the shape of the target object's surface in the 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 phase difference between the lidar and corresponding points on the target object's surface, thereby obtaining the distance information of each corresponding point on the target object's surface. Finally, with each exposure of the ToF imaging system, the same number of distance information points as the sensor image pixels can be obtained, thus yielding a depth-distance image of the target object.

[0050] The following is a brief introduction to the ranging principle of CW ToF. For example... Figure 1As shown, the transmitted signal can be a cosine signal or a square wave signal. Let the transmitted signal s(t) be expressed as: s(t)=cos(ω·t), where t represents time and ω represents the frequency of the transmitted signal.

[0051] After the transmitted signal reaches the target object, the reflected signal will have a certain offset. Let the reflected signal g(t) be expressed as: Where 'a' represents the amplitude value, This represents the phase difference between the reflected signal and the transmitted signal.

[0052] By modulating the transmitted signal, the Time-of-Flight (ToF) ranging device receives and demodulates the reflected signal with phase difference from the target object, indirectly calculating the distance information between the ToF ranging device and the target object. The formula for calculating the distance information D is as follows: Where c represents the speed of light and f represents the frequency of the modulation signal.

[0053] The Time-of-Flight (ToF) ranging and demodulation process can be implemented using the correlation function method. The correlation function describes the degree of correlation between the values ​​of a reference signal at any two different times. Using the transmitted signal as the reference signal, the correlation function can be used to calculate the degree of correlation between the frequency-modulated transmitted signal and the reflected signal that produces a phase difference after illuminating the target object. The formula for calculating the correlation function is as follows:

[0054]

[0055] For example, four different delay values ​​τ can be selected: τ0 = 0°, τ1 = 90°, τ2 = 180°, and τ3 = 270°, and substituted into c(τ) for calculation. Since the reflected signal may contain reflected signals generated by background light, an offset K can be added to its correlation function. After superposition, the following values ​​C(τ0), C(τ1), C(τ2), and C(τ3) can be obtained.

[0056]

[0057]

[0058]

[0059]

[0060] The phase can be calculated using the above formula. Offset K and amplitude A. Phase delay. Representing the propagation delay of light during flight, it is proportional to the distance to the target when the modulation frequency is set to a fixed value. Offset K can be used to provide a general 2D intensity image, as well as indicate the amount of charge in an image sensor pixel. The amplitude value A represents the directly measurable depth resolution of the pixel. Wherein:

[0061]

[0062]

[0063]

[0064] Through phase delay Substitute into the above formula The distance D between the ToF ranging device and the target object can then be calculated.

[0065] Furthermore, since each pixel of the two-dimensional array image sensor can measure the distance information between the ToF ranging device and the target object's surface, the CW ToF ranging device actually obtains a depth distance image of the target object's surface relative to the ToF ranging device. The three-dimensional coordinate information of the target object's surface can be obtained through further data processing of the depth distance image data. This application does not provide a detailed description of the specific algorithm.

[0066] As described above, in the CW ToF measurement method, since both the transmitted and reflected signals are continuous waves, the exposure time is relatively long, and a large amount of background light is easily received during the exposure process, resulting in a low signal-to-noise ratio and a large ranging error. In contrast, the P ToF measurement method, which uses pulse waves, transmits a pulse wave instead of a continuous wave, and the transmitted light signal is a standard square wave signal. The distance between the transmitter and the target object is calculated by measuring the phase delay of the received square wave signal. However, the P ToF measurement method has very high requirements for the shape of the square wave waveform, while in reality, waveforms are often imperfect, exhibiting distortion or glitches. Therefore, the P ToF measurement method also has a larger ranging error, and its effective testing distance is shorter compared to CW ToF.

[0067] This application proposes a novel Time-of-Flight (ToF) ranging device and method by combining CW ToF and P ToF ranging technologies. When transmitting a signal, the ToF ranging device emits pulsed light signals in pulse mode, and during reception, it receives reflected pulsed light signals at intervals, similar to continuous-wave CW ToF. The ranging algorithm also uses a CW ToF ranging algorithm. By combining these two ranging technologies, the low signal-to-noise ratio problem caused by continuous reception of reflected light signals in CW ToF ranging is avoided, as is the requirement of P ToF for standard square waves, by using pulsed wave signals. This reduces the shortcomings of CW ToF ranging technology, effectively improves the ranging signal-to-noise ratio, and enables ToF ranging even when the waveform is not a standard square wave.

[0068] This application provides a Time-of-Flight (ToF) based ranging chip, which can be applied to devices such as 3D cameras, smart vehicles, or computers. For example,... Figure 2 As shown, this application embodiment uses a 3D ToF camera ranging device as an example for illustration. The ToF ranging device may include: a ranging chip 201, a lens 202, a light source driver 203, and a light-emitting device 204.

[0069] The ranging chip 201 can be used to generate a first signal, which can be used to control the light source driver 203 so that the light-emitting device 204 can emit a specified light signal towards the target object, such as emitting a pulsed light signal towards the target object. Here, the light signal is one of the aforementioned emitted signals, and the target object refers to an object to which the emitted light signal can reach and form a reflected light signal. In addition, the ranging chip 201 can also be used to receive the light signal reflected by the target object transmitted by the lens 202, and perform signal processing based on the first signal and the light signal reflected by the target object transmitted by the lens 202 to obtain the phase delay corresponding to the time of flight of the light signal between the ToF ranging device and the target object, thereby calculating the distance between the ToF ranging device and the target object.

[0070] Lens 202 is an optical device composed of one or more optical lenses, which can be used to receive the light signal reflected by the target object and transmit the light signal reflected by the target object to the ranging chip 201.

[0071] The light source driver 203 is used to drive the light-emitting device 204 to emit light signals according to the first signal generated by the ranging chip 201. For example, the light source driver 203 can be a laser driver.

[0072] The light-emitting device 204 is used to emit light signals toward the target object according to the indication signal from the light source driver 203. For example, a diode or laser is a device capable of emitting visible light signals or laser signals. Specifically, the light-emitting device can be a vertical-cavity surface-emitting laser (VCSEL) or a light-emitting diode (LED). Among them, a VCSEL is a special type of laser whose laser beam is emitted perpendicularly to its top surface, and its luminous power is strongly correlated with its operating mode, capable of stably emitting high-power pulses under certain conditions.

[0073] Combination Figure 2 ,like Figure 3 As shown, the ranging chip 201 provided in this application embodiment may specifically include: a first signal generator 301, a second signal generator 302, and a continuous wave processing circuit 303.

[0074] A signal generator is a device that can provide electrical signals of various frequencies, waveforms, and output levels; it is also called a signal source or oscillator. Various waveform curves are represented using trigonometric function equations. Signal generators can produce various waveforms, such as triangular waves, sawtooth waves, rectangular waves, or sine waves, including sine wave generators, low-frequency signal generators, high-frequency signal generators, pulse signal generators, or pseudo-random signal generators, etc. In the embodiments of this application, the signal generator is used to generate pulse signals; therefore, it can be a pulse signal generator or a pseudo-random signal generator capable of generating pulse signals.

[0075] A first signal generator 301 can be used to generate a first signal, which includes multiple first pulses, and the pulse width of each first pulse can be a first width. The first signal can be used by a light source driver 203 to drive a light-emitting device 204 to emit a light signal toward a target object based on the first signal. Additionally, the first signal can also be used by a second signal generator 302 to generate a second signal based on the first signal.

[0076] In one embodiment, the pulse width of the first pulse is a first width Tp, and the pulse interval can be N+1 times the first width. The pulse intervals of adjacent first pulses can be the same or different. That is, the interval between two adjacent first pulses in the first signal can be (N+1)*Tp, where N can be a preset positive integer or a random positive integer.

[0077] In the above embodiments, the signal generator can operate in a random or non-random state. If N is a random positive integer, different random positive integers can be used to generate pulse signals with different pulse intervals, which can avoid interference between multiple pulse signals at the same time and improve the anti-interference capability of the ranging results.

[0078] For example, the waveform of the first signal can be as shown in Figure 4(a) or Figure 4(b). As shown in Figure 4(b), N can be a random positive integer. When the ToF ranging device operates in a random state, the pseudo-random positive integer range can be set to (N1~N2). The first signal generator generates a first pulse signal based on the received Tp and the random positive integer range. The pulse width of the first pulse signal is Tp, and the interval between pulses is (N+1)*Tp, where N is a random positive integer generated by the pseudo-random number generator inside the first signal generator. For example, N can randomly take the value 1, 2, or 3, etc.

[0079] For example, the waveform of the first signal can also be as shown in Figure 4(a), where N can be a preset positive integer. When the ToF ranging device is operating in a non-random state, the first signal generator generates a first pulse signal with a pulse width of Tp and an interval of (n+1)*Tp between adjacent first pulses, where n is a preset positive integer and the pulse interval between adjacent pulses is the same.

[0080] The second signal generator 302 is configured to generate a second signal based on the first signal, the second signal including a first pulse from the first signal; the second signal also includes at least one second pulse spaced apart from each first pulse by a first width Tp.

[0081] In one possible implementation, the pulse width of the second pulse can be the first width Tp; if there are at least two second pulses, the pulse interval between the at least two adjacent second pulses can be the same as the first width Tp. The number of second pulses can be multiple, such as two or three, and the second pulses will not overlap with any of the first pulses.

[0082] For example, when the waveform of the first signal is as shown in Figure 4(a), the waveform of the second signal can be as shown in Figure 5(a). The second signal includes a first pulse with a pulse width of Tp, and also includes a plurality of second pulses spaced apart from each first pulse by a width of Tp, wherein the pulse width of the second pulse is also Tp.

[0083] When the waveform of the first signal is as shown in Figure 4(b) and the pulse interval is random, the waveform of the second signal can be as shown in Figure 5(b), and the pulse interval of the second signal is also random.

[0084] The continuous wave processing circuit 303 can be used to integrate the light signal reflected by the target object based on the input second signal to obtain multiple exposure values. The multiple exposure values ​​are used to calculate the phase delay corresponding to the time of flight of the light signal between the ranging chip 201 and the target object according to the ToF ranging algorithm of continuous wave CW.

[0085] In the embodiments described above, a first signal is generated by a first signal generator, and a second signal is generated based on the first signal. The second signal includes at least two pulse signals, and a cross-correlation operation is performed between the second signal and the reflected signal of the first signal. This allows for demodulation of the received reflected signal from the target object using the second signal. Since the maximum testable distance of the ToF ranging chip is positively correlated with the period of the modulation signal, a longer period of the modulation signal increases the maximum testable distance. Furthermore, compared to existing CW ToF ranging technology, by emitting pulsed light signals, the received pulsed light signals can be exposed for a short time, avoiding noise signals caused by a large amount of background light, thereby improving the signal-to-noise ratio and overcoming the limitation of PToF ranging chips on standard square wave waveforms.

[0086] In one implementation, such as Figure 6 As shown, the continuous wave processing circuit 303 described above may specifically include a delay unit 601, an image sensor array 602, and an analog-to-digital converter 603.

[0087] The delay unit 601 is used to delay the input second signal to obtain multiple third signals with different phases. These multiple third signals with different phases are input to the image sensor array 602 for multiple exposures of the light signal reflected from the target object received by the lens. The DLL delay value may vary between different ToF ranging devices.

[0088] In one implementation, the delay unit 601 can specifically be a delay-locked loop (DLL), also known as a delay line. A DLL is a component or device that precisely delays a signal for a certain period of time. For example, the DLL delay unit may include N delay modules, and the output signals of 0 to N delay modules are controlled by instructions to achieve a precise time delay between the output signal and the input signal. The delay value can be preset by the delay unit or input externally.

[0089] For example, such as Figure 7 As shown, the second signal can be delayed by 0 phase to obtain signal 1; delayed by 1 / 2 phase to obtain signal 2; delayed by 1 / 4 phase to obtain signal 3; and delayed by 3 / 4 phase to obtain signal 4.

[0090] The image sensor array 602 is used to perform multiple exposures on the signal reflected from the target object received by the lens, based on the input of multiple third signals with different phases. In other words, the reflected signal is superimposed on the multiple third signals with different phases, and through integration, multiple fourth signals are obtained. Each pixel of the image sensor array corresponds to one of the multiple fourth signals obtained from the multiple exposures. The image sensor array 602 inputs the multiple fourth signals to an analog-to-digital converter to generate a digital image array.

[0091] It should be noted that in practical applications, the exposure modulation process can be set to 1, 2, 3, 4 or more times, depending on the actual number of pixels, the accuracy of the ToF ranging chip and the application requirements (here, 1 time refers to a set of continuous waveforms, not a periodic waveform).

[0092] For example, in the above embodiments of this application, continuous wave exposure modulation is performed four times; alternatively, it can be set to continuous wave exposure modulation twice. Other exposure modulation times based on similar principles are also included within the scope of protection of this application. Furthermore, pixels can be spatially separated, meaning adjacent pixels can be exposed with different delay values; as long as the principle of exposure modulation is the same as that of this application, these are also included within the scope of protection of this application.

[0093] For example, adjacent pixels A and B are exposed with different delay values. Pixel A is exposed with 0-phase, denoted as A0; pixel B is exposed with 1 / 2-phase, denoted as B. 180 Then, as follows Figure 8 As shown, the image sensor array of the ToF ranging device can sequentially perform continuous wave A0B. 180 A 90 B 270 A 180 B0, A 270 B 90 Four exposures. Or perform low-frequency continuous wave A0B. 180 A 90 B 270 The two exposures mentioned above can be interchanged in practice.

[0094] The analog-to-digital converter 603 is used to digitize multiple input fourth signals according to an analog-to-digital signal conversion algorithm to obtain multiple digital image arrays.

[0095] In one implementation, such as Figure 9As shown, the ToF ranging device may further include a ranging module 901, used to calculate the distance between the ToF ranging device and the target object based on multiple digital image arrays obtained from the ToF ranging chip. This ranging module 901 can be implemented in hardware or software; this application does not specifically limit its implementation.

[0096] The embodiments described above combine CW ToF and P ToF ranging technologies. The transmitted signal uses P ToF ranging technology, sending pulse signals (first signal) at intervals. When the image sensor array receives the light, it exposes the received reflected light according to the second signal, and performs exposure using the four-phase delay method of the CW ToF ranging algorithm (two or four exposures). Compared to existing technologies, this effectively improves the ranging signal-to-noise ratio and allows ToF ranging even when the waveform is not a standard square wave. Furthermore, it effectively increases the maximum measurable distance, improving overall ranging performance. Simultaneously, when the emitted laser signal is random, different pixels in the image sensor array expose the reflected signal with different phase delays, ensuring that the modulated signals do not interfere with each other in the codeword, time, and frequency dimensions, thus improving ranging accuracy.

[0097] In another possible implementation, a delay unit, such as a second delay unit, can be added between the first signal generator 301 and the light source driver 203 to delay the first signal, so that the light source driver 203 can drive the light-emitting device to emit pulse light signals according to the signal generated after delaying the first signal.

[0098] For example, the waveform of the first signal can be as follows: Figure 10 As shown, the transmitted signal can be a pulsed light emitted after a 1 / 2 phase delay processing based on the first signal. Multiple third signals are generated from the first signal after different delay processing, and are used to perform four exposure modulations on the pulsed signal reflected by the target object. By calculating the phase difference between the transmitted and received signals, the distance information between the ToF ranging device and the target object is obtained. This embodiment enables the ToF ranging device to obtain multiple accurate exposure values ​​within a range from 0 meters to an ambiguous distance from the target object.

[0099] Next, the working process of the ToF ranging device provided in the embodiments of this application will be described. (Continued from the foregoing...) Figure 6 or Figure 7 As can be seen, the specific process of the ToF ranging device transmitting signals provided in this application embodiment can be as follows: Figure 11 S01-S03 are shown.

[0100] S01: Set the pulse duration width to Tp and input it to the first signal generator.

[0101] In one possible implementation, when the ranging device is operating in random mode, it is also necessary to set a random number range and generate random positive integers, which are then input to the first signal generator.

[0102] S02: The first signal generator generates the first signal.

[0103] The first signal generator can generate a first signal based on the received pulse width Tp, or the pulse width Tp and a random positive integer N. The first signal can include multiple first pulse signals, the pulse width of the first pulse signal is Tp, and the pulse interval between the multiple first pulses can be (N+1)*Tp.

[0104] S03: Issue a pulse signal based on the first signal.

[0105] The laser driver drives the light-emitting device according to the first signal or the delayed signal of the first signal, so that the light-emitting device emits a pulse light signal with corresponding brightness and darkness information.

[0106] Based on the foregoing, the specific process of the ToF ranging device provided in this application embodiment receiving and modulating the reflected signal can be as follows: Figure 11 S04-S08 are shown.

[0107] S04: The second signal generator generates a second signal based on the first signal.

[0108] The second signal includes all the first pulse signals in the first signal, and after the first pulse of the first signal, after an interval of Tp, one or more second pulse signals will be emitted. The pulse width of the second pulse signal can be Tp.

[0109] S05: Perform a time delay operation based on the second signal and output the delayed third signal.

[0110] The delay unit performs a time delay operation on the input second signal and outputs multiple third signals P1. For example, the first exposure is not delayed, the second exposure is delayed by 1 / 4 cycle, the third exposure is delayed by 1 / 2 cycle, and the fourth exposure is delayed by 3 / 4 cycle.

[0111] S06: Expose the reflected signal collected by the lens based on the third signal to obtain multiple fourth signals.

[0112] The image sensor array exposes the reflected signal P collected by the lens based on multiple third signals P1, resulting in an array of multiple fourth signals P2. Each pixel in the image sensor array outputs a different exposure value.

[0113] S07: Perform analog-to-digital conversion based on multiple fourth signals to obtain multiple digital image arrays.

[0114] The analog-to-digital converter performs analog-to-digital conversion on the P2 array signal to obtain the P3 array, which is then transmitted to the ranging module.

[0115] S08: Obtain the phase delay of the digital image array according to the ranging algorithm, and calculate the distance to the target object according to the frequency of the modulation signal.

[0116] After receiving the P3 array obtained by exposure of signals with different delays, the ranging module calculates the phase delay according to the above formula of the CW ToF ranging algorithm, and then calculates the distance information or image information of the corresponding pixel of the target object.

[0117] The above embodiments of this application, by combining CW ToF and P ToF ranging technologies, can effectively improve the ranging signal-to-noise ratio and can perform ToF ranging even when the waveform is not a perfect square wave.

[0118] This application also provides an electronic device, exemplarily, such as... Figure 12 As shown, the electronic device 1200 may include at least one processor 1201, a communication line 1202, and a memory 1203.

[0119] Processor 1201 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 programs according to the present disclosure.

[0120] Communication line 1202 may include a path for transmitting information between the aforementioned components, such as a bus.

[0121] The memory 1203 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or it may be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto. The memory may exist independently and be connected to the processor 1201 via communication line 1202. The memory 1203 may also be integrated with the processor 1201. The memory provided in the embodiments of this disclosure may generally be non-volatile. The memory 1203 stores computer execution instructions involved in the present disclosure and is controlled by the processor 1201. The processor 1201 executes the computer execution instructions stored in the memory 1203 to implement the method provided in the embodiments of the present disclosure.

[0122] Optionally, the computer execution instructions in this embodiment may also be referred to as application code, and this embodiment does not specifically limit this.

[0123] In a specific implementation, as one embodiment, the processor 1201 may include one or more CPUs, for example... Figure 12 CPU0 and CPU1 in the CPU.

[0124] In a specific implementation, as one example, the electronic device 1200 may include multiple processors, such as... Figure 12 Processors 1201 and 1207 are mentioned. Each processor can be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. Here, "processor" can refer to one or more devices, circuits, and / or processing cores used to process data (e.g., computer program instructions).

[0125] In a specific implementation, as one embodiment, the electronic device 1200 may also include a communication interface 1204. The communication interface 1204 uses any transceiver-like device for communicating with other devices or communication networks, such as an Ethernet interface, a radio access network (RAN) interface, a wireless local area network (WLAN) interface, etc.

[0126] In a specific implementation, as one embodiment, the electronic device 1200 may further include an output device 1205 and an input device 1206. The output device 1205 communicates with the processor 1201 and can display information in various ways. For example, the output device 1205 may be a liquid crystal display (LCD), a light-emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector, etc. The input device 1206 communicates with the processor 1201 and can receive user input in various ways. For example, the input device 1206 may be a mouse, keyboard, touchscreen device, or sensing device, etc.

[0127] In specific implementations, the electronic device 1200 can be a desktop computer, a portable computer, a network server, a handheld digital assistant (PDA), a mobile phone, a tablet computer, a wireless terminal device, an embedded device, or something similar. Figure 12 Devices with similar structures. This disclosure does not limit the type of electronic device 1200.

[0128] In some embodiments, Figure 12 The processor 1201 can call computer execution instructions stored in the memory 1203 to cause the device 1200 to execute the ToF ranging method in the above method embodiment.

[0129] In an exemplary embodiment, a storage medium including instructions is also provided, such as a memory 1203 including instructions, which can be executed by a processor 1201 of an electronic device 1200 to complete the above-described ToF ranging method.

[0130] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0131] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of circuits or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0132] The units described as separate components may or may not be physically separate. A component shown as a unit can be one or more physical units; that is, it can be located in one place or distributed in multiple different locations. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0133] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0134] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, essentially or in other words, the parts that contribute to the prior art, or all or part of the technical solutions, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0135] Finally, it should be noted that the above content is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A ranging chip based on Time-of-Flight (ToF), characterized in that, The ranging chip includes: A first signal generator is used to generate a first signal, the first signal including a plurality of first pulses, the width of the first pulse being a first width T, and the first signal being used to control a light-emitting device to emit a light signal toward a target object; A second signal generator is configured to generate a second signal based on the first signal, the second signal including the plurality of first pulses in the first signal, and at least one second pulse that is delayed by the first width T from each of the plurality of first pulses; A continuous wave processing circuit is used to integrate the received light signal reflected by the target object according to the second signal to obtain multiple exposure values, and the multiple exposure values ​​are used to calculate the phase delay corresponding to the time of flight of the light signal between the chip and the target object; The continuous wave processing circuit specifically includes: The first delay unit is used to delay the second signal to obtain multiple third signals with different phases. An image sensor array is used to expose the light signal reflected by the target object received by the lens multiple times based on the multiple third signals with different phases to obtain multiple fourth signals; An analog-to-digital converter is used to perform analog-to-digital conversion on the plurality of fourth signals to obtain a plurality of digital image arrays, wherein the plurality of digital image arrays include exposure values ​​corresponding to a plurality of pixels.

2. The ranging chip according to claim 1, characterized in that, The width of each of the at least one second pulse is the first width T.

3. The ranging chip according to claim 2, characterized in that, The second pulse is a plurality of second pulses, and the interval between two adjacent second pulses in the plurality of second pulses is the first width T.

4. The ranging chip according to any one of claims 1-3, characterized in that, The interval between two adjacent first pulses in the plurality of first pulses is (N+1)*T, where N is a preset positive integer or a random positive integer.

5. The ranging chip according to any one of claims 1-3, characterized in that, The first delay unit is specifically used for: The second signal is delayed m times to obtain m third signals. The m delay processes include 0-phase delay processing, and the time difference between two adjacent delay processes in the m delay processes is 2T / m.

6. The ranging chip according to any one of claims 1-3, characterized in that, The ranging chip also includes: The second delay unit is used to generate a delayed signal of the first signal; The light-emitting device is used to emit a light signal to the target object based on a delay signal of the first signal.

7. A ranging device based on Time-of-Flight (ToF), characterized in that, The ranging device includes: a ranging chip, a light source driver, a light-emitting device, and a lens as described in any one of claims 1-6; The light source driver is used to drive the light-emitting device to emit a light signal according to the first signal generated by the ranging chip. The light-emitting device is used to emit a light signal toward the target object based on the drive of the first signal; The lens is used to receive the light signal reflected by the target object and transmit the light signal to the ranging chip.

8. The ranging device according to claim 7, characterized in that, The light-emitting device is a direct-cavity surface-emitting laser (VCSEL).

9. An electronic device, characterized in that, The electronic device includes the ranging device as described in claim 7 or 8, and the electronic device further includes: The calculation module is used to calculate the phase delay corresponding to the time of flight of the light signal between the ranging device and the target object based on the multiple exposure values ​​obtained by the ranging device.

10. A ranging method based on Time-of-Flight (ToF), characterized in that, The method includes: A first signal is generated, the first signal including a plurality of first pulses, the width of the first pulses being a first width T, and the first signal being used to emit a light signal toward a target object; A second signal is generated based on the first signal, the second signal including the plurality of first pulses in the first signal, and at least one second pulse that is delayed by the first width T from each of the plurality of first pulses; The light signal reflected by the target object is integrated based on the second signal to obtain multiple exposure values. The exposure values ​​are used to calculate the phase delay corresponding to the flight time of the light signal between the ranging chip and the target object. The step of integrating the received light signal reflected by the target object based on the second signal to obtain multiple exposure values ​​includes: The second signal is delayed to obtain multiple third signals with different phases; Multiple fourth signals are obtained by exposing the light signal reflected from the target object multiple times based on the multiple third signals with different phases; The multiple fourth signals are subjected to analog-to-digital conversion to obtain multiple digital image arrays, each digital image array including exposure values ​​corresponding to multiple pixels.

11. The ranging method according to claim 10, characterized in that, The width of each of the at least one second pulse is the first width T.

12. The ranging method according to claim 11, characterized in that, The second pulse is a plurality of second pulses, and the interval between two adjacent second pulses in the plurality of second pulses is the first width T.

13. The ranging method according to any one of claims 10-12, characterized in that, The interval between two adjacent first pulses in the plurality of first pulses is (N+1)*T, where N is a preset positive integer or a random positive integer.

14. The ranging method according to any one of claims 10-12, characterized in that, The step of delaying the second signal to obtain multiple third signals with different phases specifically includes: The second signal is delayed m times to obtain m third signals. The m delay processes include 0-phase delay processing, and the time difference between two adjacent delay processes in the m delay processes is 2T / m.

15. The ranging method according to any one of claims 10-12, characterized in that, After generating the first signal, the ranging method further includes: A light signal is emitted toward the target object based on the first signal.

16. The ranging method according to claim 15, characterized in that, After generating the first signal, the ranging method further includes: A delayed signal for generating the first signal; The step of transmitting a light signal to the target object according to the first signal specifically includes: transmitting a light signal to the target object according to a delay signal of the first signal.

17. The ranging method according to any one of claims 10-12, characterized in that, After integrating the received light signal reflected by the target object based on the second signal to obtain multiple exposure values, the ranging method further includes: The phase delay corresponding to the flight time of the light signal between the ranging device and the target object is calculated based on the multiple exposure values.

18. An electronic device, characterized in that, Includes a processor, which is coupled to a memory; Memory is used to store computer programs or instructions; A processor for executing a computer program or instructions stored in the memory to enable an electronic device to perform the method as described in any one of claims 10 to 17.

19. A computer-readable storage medium, characterized in that, Used to store programs or instructions, which, when executed by a processor of an electronic device, enable the electronic device to perform the method as described in any one of claims 10 to 17.

20. A computer program product, characterized in that, Includes a program or instructions that, when the computer program product is run on a computer, cause the computer to perform the method as described in any one of claims 10 to 17.

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