Method and system for spatially distributed gating

Abstract

A light detection and ranging (lidar) device includes an emitter array including a plurality of emitter units configured to emit light signals in response to corresponding emitter control signals; a detector array including a plurality of detector pixels configured to be activated and deactivated for corresponding gating windows between pulses of the light signals; and a control circuit configured to provide a gating signal to activate a first subset of the detector pixels while leaving a second subset of the detector pixels inactive.

Description

[0001] Priority claim

[0002] This application claims priority to U.S. Provisional Application No. 62 / 769,736, filed on November 20, 2018, entitled “Spatially Distributed Strobing,” the entire contents and disclosure of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to light detection and ranging (LIDAR or lidar) systems, and more particularly, to methods and apparatus for reducing power consumption in time-of-flight LIDAR systems. Background Art

[0004] Time-of-flight (ToF)-based imaging is used for a variety of applications, including range finding, depth profiling, and 3D imaging (e.g., lidar). Direct time-of-flight measurements involve directly measuring the length of time between emitting radiation and sensing the radiation after reflection from an object or other target. From this, the distance to the target can be determined. Indirect time-of-flight measurements involve determining the distance to the target by phase modulating the amplitude of the signal emitted by the transmitter element of the lidar system and measuring the phase (e.g., with respect to delay or offset) of the return signal received by the detector element of the lidar system. These phases can be measured over a series of individual measurements or samples.

[0005] The emitter element can be controlled to emit radiation over the field of view for detection by the detector element. The emitter element for ToF measurement may include a pulsed light source, such as an LED or a laser. Examples of lasers that can be used include vertical cavity surface emitting lasers (VCSELs). Methods of configuring lasers for optical systems are discussed in U.S. Patent No. 10,244,181 to Warren, entitled "COMPACT MULTI-ZONE INFRARED LASER ILLUMINATOR."

[0006] In certain applications, single photon detector arrays, such as single photon avalanche diode (SPAD) arrays, can be used to sense reflected radiation from emitter elements in direct or indirect time-of-flight systems. SPAD arrays can be used as solid-state detectors in imaging applications where high sensitivity and temporal resolution are useful.

[0007] SPADs are based on a pn junction device that is biased beyond its breakdown region, for example, by or in response to a gating signal with a desired pulse width. The high reverse bias generates an electric field of sufficient magnitude so that a single charge carrier introduced into the depletion layer of the device causes a self-sustaining avalanche by impact ionization. The avalanche is actively or passively quenched by a quenching circuit to allow the device to "reset" to detect more photons. The starting charge carrier can be photoelectrically generated by a single incident photon striking the high field region. It is this property that gave rise to the name "single photon avalanche diode". This single photon detection mode of operation is often referred to as the "Geiger mode".

[0008] The power consumption of lidar systems is particularly problematic in certain applications, such as unmanned aerial vehicles (UAVs), automobiles, and industrial robots. For example, in automotive applications, the vehicle power supply must meet the increased transmit power requirements, which may add a considerable burden to the automaker. In addition, the heat generated by the higher transmit power may change the optical performance of the light-emitting array and / or may negatively affect reliability. Summary of the invention

[0009] According to some embodiments of the present disclosure, a light detection and ranging (lidar) device includes an emitter array, which includes a plurality of emitter units configured to emit light signals in response to corresponding emitter control signals; a detector array, which includes a plurality of detector pixels configured to be activated and deactivated for corresponding gating windows between pulses of the light signals; and a control circuit configured to provide a gating signal to activate a first subset of the detector pixels while keeping a second subset of the detector pixels inactive.

[0010] In some embodiments, the emitter array is further configured to emit light signals with emitter cycles between consecutive light signals, and the control circuit is further configured to provide a gating signal to activate a first subset of the detector pixels with a first time delay during the emitter cycle while a second subset is not activated.

[0011] In some embodiments, the strobe signal is a first strobe signal, and the control circuit is further configured to provide a second strobe signal to activate a second subset of the detector pixels with a second time delay during the emitter cycle while keeping the first subset of the detector pixels inactive.

[0012] In some embodiments, the first strobe signal is configured to be active for a first duration and the second strobe signal is configured to be active for a second duration different from the first duration.

[0013] In some embodiments, the second time delay is greater than the first time delay.

[0014] In some embodiments, the detector array comprises rows and columns, and the first subset of detector pixels comprises rows of the detector array or columns of the detector array.

[0015] In some embodiments, the first subset of detector pixels includes a first detector pixel and a second detector pixel, and the control circuit is further configured to activate the second detector pixel at a time offset after activating the first detector pixel.

[0016] In some embodiments, the detector array includes a first subarray of physically juxtaposed detector pixels and a second subarray of physically juxtaposed detector pixels, and the first subset of detector pixels includes first detector pixels of the first subarray and second detector pixels of the second subarray.

[0017] According to some embodiments of the present disclosure, a light detection and ranging (lidar) device includes an emitter configured to emit a first light signal and a second light signal with an emitter period between the first light signal and the second light signal; a detector array including a plurality of detector pixels configured to be activated and deactivated for corresponding gating windows during the emitter period; and a control circuit configured to apply a first gating window within the emitter period to a first subset of the plurality of detector pixels with a first time delay within the emitter period, and to apply a second gating window within the emitter period to a second subset of the plurality of detector pixels with a second time delay within the emitter period that is different from the first time delay.

[0018] In some embodiments, a first portion of the first gating window overlaps a second portion of the second gating window during a transmitter period.

[0019] In some embodiments, the detector array comprises rows and columns, and the first subset of detector pixels comprises rows of the detector array or columns of the detector array.

[0020] In some embodiments, the first subset of detector pixels includes a first detector pixel and a second detector pixel, and the control circuit is configured to activate the second detector pixel at a time offset after activation of the first detector pixel.

[0021] In some embodiments, the first time delay and the second time delay are configured to be programmatically controlled.

[0022] In some embodiments, a first duration of the first gating window is different from a second duration of the second gating window.

[0023] In some embodiments, the second time delay is greater than the first time delay, and a first duration of the first gating window is shorter than a second duration of the second gating window.

[0024] In some embodiments, the second time delay is greater than the first time delay, and a first duration of the first gating window is longer than a second duration of the second gating window.

[0025] In some embodiments, the detector array includes a first subarray of physically juxtaposed detector pixels and a second subarray of physically juxtaposed detector pixels, and the first subset of detector pixels includes first detector pixels of the first subarray and second detector pixels of the second subarray.

[0026] According to some embodiments of the present disclosure, a light detection and ranging (lidar) device includes an emitter configured to emit a first light signal and a second light signal with an emitter period between the first light signal and the second light signal; a detector array including a plurality of detector pixels configured to be activated and deactivated for corresponding gating windows during the emitter period; and a control circuit configured to provide a gating signal to activate a first subset of the plurality of detector pixels and a second subset of the plurality of detector pixels with different corresponding time delays relative to the first light signal within the emitter period.

[0027] In some embodiments, the control circuit is further configured to provide a gating signal to activate the first subset during a first gating window within the transmitter cycle, and the control circuit is further configured to provide a gating signal to activate the second subset during a second gating window within the transmitter cycle.

[0028] In some embodiments, a first portion of the first gating window overlaps a second portion of the second gating window.

[0029] In some embodiments, a first duration of the first gating window is different from a second duration of the second gating window.

[0030] In some embodiments, the detector array comprises rows and columns, and the first subset of detector pixels comprises rows of the detector array or columns of the detector array.

[0031] In some embodiments, the first subset of detector pixels includes a first detector pixel and a second detector pixel, and the control circuit is configured to activate the second detector pixel at a time offset after activation of the first detector pixel.

[0032] In some embodiments, the different respective time delays are configured to be programmatically controlled.

[0033] In some embodiments, a first corresponding time delay of the first gating window is shorter than a second corresponding time delay of the second gating window, and a first duration of the first gating window is shorter than a second duration of the second gating window.

[0034] In some embodiments, a first corresponding time delay of the first gating window is shorter than a second corresponding time delay of the second gating window, and a first duration of the first gating window is longer than a second duration of the second gating window. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1A is an example lidar system according to some embodiments described herein.

[0036] Figure 1B is an example of a control circuit that generates an emitter control signal and / or a detector control signal according to some embodiments described herein.

[0037] Figure 2A and Figure 2B shows the global gating distribution according to some embodiments described herein ( Figure 2A ) and a comparison between the spatially gated distribution.

[0038] Figure 3 , Figure 4 and Figure 5 An example spatial gating distribution is shown according to some embodiments described herein.

[0039] Figure 6 An example digital pixel configuration is shown according to some embodiments described herein.

[0040] Figure 7 Another example of a column strobe distribution according to some embodiments described herein is shown.

[0041] Figure 8 Another example of overlapping gating windows is shown according to some embodiments described herein.

[0042] Fig. 9 Examples of using gating windows of different durations are shown according to some embodiments described herein.

[0043] Fig.10 Examples of pseudo-random gating period durations are shown according to some embodiments described herein.

[0044] Fig.11 An example of a constantly active strobe is shown according to some embodiments described herein.

[0045] Fig.12 An example of a sub-array constant activity gating distribution (raster) is shown according to some embodiments described herein.

[0046] Fig.13 An example of a constant sliding gating window is shown according to some embodiments described herein.

[0047] Fig.14 An example implementation of an embodiment of a circuit configured to generate a 2 ns gating window delay according to some embodiments described herein is shown.

[0048] Fig.15 A non-limiting example implementation of an embodiment of a gate decoder according to some embodiments described herein is shown.

[0049] Fig.16 An example of a global 4-bit Gray code strobe counter is shown according to some embodiments described herein.

[0050] Fig.17 An example of a 4-bit non-linear Gray code gate counter is shown according to some embodiments described herein.

[0051] Fig.18 A non-limiting example implementation of a gate decoder according to some embodiments described herein is shown.

[0052] Fig.19 A non-limiting example implementation of a gate decoder according to some embodiments described herein is shown.

[0053] Fig. 20 A non-limiting example implementation of a programmable gating block according to some embodiments described herein is shown.

[0054] Fig.21 Shows Fig.15 An example embodiment of the operation of a gate decoder. DETAILED DESCRIPTION

[0055] A lidar system may include an array of emitters and an array of detectors, or a system with a single array of emitters and detectors, or a system with an array of emitters and a single detector. As described herein, one or more emitters may define an emitter unit, and one or more detectors may define a detector pixel. A flash lidar system may acquire a three-dimensional perspective view (e.g., a point cloud) of one or more targets by emitting light from an array of emitters or a subset of an array for a short duration (pulse) over a field of view (FoV) or scene and detecting an echo signal reflected from a target in the FoV at one or more detectors. A non-flash or scanning lidar system may generate an image frame by raster scanning the light emission (continuously) over a field of view or scene, for example, using a point scan or line scan to emit the power required for each point, and scanning sequentially to reconstruct the complete field of view.

[0056] An example of a lidar system 100 or circuit 100 according to an embodiment of the present disclosure is shown in FIG. Figure 1A. The lidar system 100 includes a control circuit 105, a timing circuit 106, an emitter array 115 including a plurality of emitters 115e, and a detector array 110 including a plurality of detectors 110d. The detector 110d includes a time-of-flight sensor (e.g., a single-photon detector array, such as a SPAD). One or more emitter elements 115e of the emitter array 115 may define an emitter unit that emits radiation pulses or continuous wave signals (e.g., through a diffuser or filter 114) at a time and frequency controlled by a timing generator or driver circuit 116, respectively. In a particular embodiment, the emitter 115e may be a pulsed light source, such as an LED or a laser (e.g., a vertical cavity surface emitting laser (VCSEL)). The radiation is reflected back from the target 150 and sensed by the detector pixels defined by one or more detector elements 110d of the detector array 110. The control circuit 105 implements a pixel processor that measures and / or calculates the flight time of an illumination pulse in its journey from the emitter array 115 to the target 150 and back to the detector 110 d of the detector array 110 using direct or indirect ToF measurement techniques.

[0057] In some embodiments, the emitter module 115 or emitter circuit 115 may include an array of emitter elements 115e (e.g., VCSELs), corresponding optical element arrays 113 and 114 coupled to one or more emitter elements (e.g., lenses 113 (e.g., microlenses) and / or diffusers 114), and / or driver electronics 116. The optical elements 113 and 114 may be optional and may be configured to provide a sufficiently low beam divergence of light output from the emitter elements 115e to ensure that the illumination fields of a single emitter element 115e or groups of emitter elements 115e do not significantly overlap, and also to provide a sufficiently large beam divergence of light output from the emitter elements 115e to provide eye safety for an observer.

[0058] The driver electronics 116 may each correspond to one or more emitter elements and may each operate in response to a timing control signal referenced to a master clock and / or a power control signal that controls the peak power of light output by the emitter element 115e. In some embodiments, each emitter element 115e in the emitter array 115 is connected to and controlled by a corresponding driver circuit 116. In other embodiments, groups of emitter elements 115e in the emitter array 115 (e.g., emitter elements 115e that are spatially close to each other) may be connected to the same driver circuit 116. The driver circuit or circuit system 116 may include one or more drive transistors configured to control the modulation frequency, timing, and amplitude of the light emission signal output from the emitter 115e.

[0059] The emission of light signals from multiple emitters 115e provides a single image frame for the flash lidar system 100. The maximum light power output of the emitters 115e can be selected to generate a signal-to-noise ratio for the return signal from the most distant, least reflective target under the brightest background illumination conditions that can be detected according to the embodiments described herein. Optional filters for controlling the emission wavelength of light and diffusers 114 for enhancing the illumination field of the emitter array 115 are shown by way of example.

[0060] Light emitted from one or more emitters 115e is incident on and reflected from one or more targets 150, and the reflected light is detected by one or more detectors 110d (e.g., via receiving optics 112) as light signals (also referred to herein as return signals, echo signals, or echoes), converted into electrical signal representations (referred to herein as detection signals), and processed (e.g., based on time of flight) to define a 3-D point cloud representation 170 of a field of view 190. Operations of a lidar system according to embodiments of the present disclosure described herein may be performed by one or more processors or controllers, such as a processor or controllers. Figure 1A The control circuit 105.

[0061] In some embodiments, the receiver module / detector module or circuit 110 includes an array of detector pixels (each detector pixel includes one or more detectors 110d, such as SPADs), receiving optics 112 (e.g., one or more lenses to collect light on the FoV 190), and receiving electronics (including timing circuits 106) configured to power, enable, and disable, and provide timing signals to all or part of the detector array 110. The detector pixels can be activated or deactivated with at least nanosecond accuracy and can be individually addressable, addressable in groups, and / or globally addressable. The receiving optics 112 may include a macro lens configured to collect light from the maximum FoV that can be imaged by the lidar system, a micro lens for improving the collection efficiency of the detection pixel, and / or an anti-reflection coating for reducing or preventing stray light detection. In some embodiments, a spectral filter 111 can be provided to pass "signal" light (i.e., light having a wavelength corresponding to the wavelength of the optical signal output from the transmitter) or allow "signal" light to pass, but substantially reject or block non-signal light (i.e., light having a wavelength different from the optical signal output from the transmitter) from passing.

[0062] The detectors 110d of the detector array 110 are connected to the timing circuit 106. The timing circuit 106 can be phase locked to the driver circuit 116 of the emitter array 115. The sensitivity of each detector 110d or group of detectors can be controlled. For example, when the detector elements include reverse biased photodiodes, avalanche photodiodes (APDs), PIN diodes, and / or Geiger mode avalanche diodes (SPADs), the reverse bias can be adjusted, whereby the higher the over bias, the higher the sensitivity.

[0063] In some embodiments, the control circuit 105, such as a microcontroller or a microprocessor, provides different transmitter control signals to the driver circuits 116 of different transmitters 115e and / or provides different signals (e.g., selection signals) to the timing circuits 106 of different detectors 110d to enable / disable different detectors 110d to detect echo signals from the target 150.

[0064] An example of a control circuit 105 that generates an emitter control signal and / or a detector control signal is Figure 1B Shown in. Figure 1B The control circuitry 105 may represent one or more control circuits, for example, an emitter control circuit configured to provide an emitter control signal to the emitter array 115 and / or a detector control circuit configured to provide a gating signal to the detector array 110 as described herein. In addition, the control circuitry 105 may include a sequencer circuit configured to coordinate the operation of the emitters 115e and the detectors 110d. More generally, the control circuitry 105 may include one or more circuits configured to generate respective detector signals that control the timing of activation of the detectors 110d and / or the duration of activation of the detectors 110d, and / or to generate respective emitter control signals that control the output of light signals from the emitters 115e.

[0065] In some lidar embodiments, different imaging distance ranges can be achieved by using different emitters 115e. For example, an emitter 115e configured to illuminate a target 150 at a distance range of up to 200 meters (m) may be operated to emit four times the power per solid angle as an emitter 115e configured to image a distance range of up to 100m. In some embodiments, the same emitter 115e may be configured to use different power levels depending on the distance being imaged. For example, if the lidar system 100 is configured to illuminate a target 150 at a distance of, for example, 200 meters from the emitter array 115, the emitter 115e may be driven at a first power level. If the lidar system 100 is switched or otherwise configured (e.g., dynamically) to illuminate a target 150 at a distance of, for example, 100 meters from the emitter array 115, the emitter 115e may be driven at a second power level less than the first power level.

[0066] As used herein, gating may refer to the generation of a detector control signal (also referred to herein as a gating signal or "gating") to control the timing of activation and / or the duration of activation (also referred to herein as a gating window) of one or more detectors 110d of the lidar system 100. That is, some embodiments described herein may utilize range gating (i.e., biasing the SPAD with a variable delay relative to the emission of an emitter (e.g., a laser) to be activated and deactivated within a duration or time window within an emitter cycle, thereby capturing reflected signal photons corresponding to a specific range of distances in each window / frame) to limit the number of ambient photons acquired in each emitter cycle. An emitter cycle (e.g., a laser cycle) refers to the time between emitter pulses. In some embodiments, the emitter cycle time is set to the time required for an emitted light pulse to travel to the farthest allowed target and back or is otherwise based on the time required for an emitted light pulse to travel to the farthest allowed target and back, i.e., based on the desired range of distances. To cover targets within a desired range of about 200 meters, in some embodiments the laser may be operated at a frequency of up to 750 kHz (ie, emitting a laser pulse approximately every 1.3 microseconds or more).

[0067] Range-gated flash lidars (e.g., having gating windows corresponding to various ranges of distance) may use gating for a variety of reasons. For example, in some embodiments, detector elements may be grouped into pixels and the detector elements and / or detector pixels may be selectively activated after emission of a light signal to detect an echo signal from a target during a particular gating window. The detected echo signal may be used to generate a histogram of detected "counts" of photons incident on the detector from the echo signal. Examples of methods for detecting target distances based on histograms are discussed, for example, in U.S. patent application Ser. No. 16 / 273,783, filed on Feb. 12, 2019, entitled "METHODS AND SYSTEMS FOR HIGH-RESOLUTION LONG-RANGE FLASH LIDAR," the contents of which are incorporated herein by reference.

[0068] The detectors (eg, SPADs) may be biased so that they are inactive during the firing of the lidar transmitter and for a period of time corresponding to the minimum range of the lidar system. In some embodiments, a capacitor array may be provided in the lidar system to allow for charge distribution and rapid recharging of the detector array.

[0069] In some embodiments, detection can begin with a timing signal (e.g., a start signal) shortly after the emitter (e.g., a laser) fires and can end with the earlier of an avalanche trigger or the end of an active time window (e.g., an end signal). In some embodiments, detection can begin with or in response to an avalanche, if one occurs, and can end just prior to the firing of a subsequent laser pulse. In some embodiments, the timing signals (e.g., the start signal and the end signal) are not the start of a laser cycle or the end of a laser cycle, but rather are signals timed between the start and end of a cycle. In some embodiments, the timing of the start and end signals is not the same during all cycles, for example, to allow for range gating.

[0070] In some embodiments, the recharging scheme is passive, and once an avalanche occurs, the SPAD device is recharged immediately and quickly. In some embodiments, the recharging circuit is active, and the recharging time is electrically controlled. In some embodiments, the active recharging circuit biases the SPAD beyond breakdown for a time associated with the firing of the laser pulse. In some embodiments, the recharging circuit biases the SPAD within a portion of the time required for the light pulse to pass through the farthest target and return (e.g., a "gating window"), and the gating window is changed to gate the range of the lidar. In some embodiments, the active recharging circuit holds the SPAD in its recharged state long enough to release a sufficiently large percentage of the trapped charge (e.g., 1ns, 2ns, 3ns, 5ns, 7ns, 10ns, 50ns, or 100ns), and then quickly charges the SPAD.

[0071] In a detector array utilizing SPADs, the entire array can receive the same gating window at the same time. This technique may be referred to as global gating distribution. As used herein, a gating window may be the duration (e.g., pulse width) of a gating signal in which the SPAD is biased to determine whether the SPAD has detected a photon. For example, in a SPAD array of 600×300 SPAD pixels, all 180K pixels may receive the same gating window. The gating window may be repeated multiple times within a subframe. At the end of the cycle, the subframe may be read out, for example, to count the number of detected photons. Subsequently, the process may be started again by exposing the next gating window and repeating the operation. In some embodiments, individual SPADs may be "reset" between gating windows and / or subframes.

[0072] However, such techniques may result in a large SPAD capacitance to recharge multiple SPADs and / or all SPADs simultaneously. For example, in some embodiments, each pixel may include two SPAD microcells, each approximately 10 μm×10 μm, each SPAD microcell having a capacitance of approximately 100 fF. In such an embodiment, if there are 180k pixels, each with a capacitance of 100 fF, the total capacitance associated with the recharging operation may be 180k×100 fF×2=~40 nF.

[0073] Additionally, for short-range planar targets (e.g., the side of a white truck 10m away), there may be large coincident pixel peak powers. For example, such a target may cause all SPADs to activate, which may result in increased power consumption. For example, 180k pixels × 100μA × 1.1V = 18W of power.

[0074] A different technique that can avoid and / or reduce these issues is to use spatial gating distribution. Spatial gating distribution can distribute gating spatially across the pixel array so that subsets of pixels are simultaneously active for planar targets. Spatial gating distribution can result in a lower SPAD recharge peak current and be distributed over multiple gating windows in the lasing cycle. Spatial gating distribution can also result in a lower pixel active peak power and be distributed over multiple gating windows in the lasing cycle.

[0075] Figure 2A and Figure 2B shows the global gating distribution according to some embodiments described herein ( Figure 2A ) and spatial gating distribution ( Figure 2B ). Figure 2A and 2B As shown, an example laser cycle can be divided into n gating windows. For example, the laser cycle time (e.g., the time between laser shots) can be 1.3 μs. The laser cycle can be divided into n gating windows, such as sixteen gating windows. In such an example, the gating windows can be distributed at 81 ns intervals within the 1.3 μs laser cycle. Figure 2A and Figure 2B The timing between the laser pulses discussed is only one example. Other timings are possible without departing from the invention.

[0076] Figure 2A Figure 1 shows an example of a global gating distribution. In particular, Figure 2AThe diagram illustrates a timing sequence of a series of n gating windows with respect to a laser pulse of a lidar system, wherein each gating window 1 to n defines the duration of activation of a detector (e.g., a SPAD) of the lidar system at a different corresponding delay relative to the laser pulse, in response to a respective gating signal Strobe#0 to Strobe#n. In some embodiments, the duration of each gating window may be the same, such as Figure 2A As shown. An image subframe may include multiple laser pulses with multiple gating windows between each laser pulse. For example, there may be about 1000 laser cycles in each subframe. Each subframe may also represent data collected for a corresponding gating window. A gating window readout operation may be performed at the end of each subframe, and multiple subframes (corresponding to respective gating windows) constitute each image frame (for example, 20 subframes in each frame).

[0077] For detection purposes, some lidar systems activate a specific gating for a given detector only once for a specific laser pulse. In other words, the detector (e.g., a SPAD and / or a collection of SPADs in a SPAD pixel) may only be active for a single gating window (with a corresponding distance sub-range) for a specific laser cycle. Figure 2A An example of the timing of Strobe #0 to Strobe #n in relation to their respective laser pulses is shown. For example, Figure 2A It is shown that a particular gating window (e.g., a particular activation time of a detector corresponding to a particular distance range) can be used for multiple laser cycles. For example, a first gating window (e.g., Strobe #0) can be used for multiple laser cycles for all detectors (e.g., LASER #0 to LASER #(X-1)). A second gating window (e.g., Strobe #1) corresponding to a different distance sub-range can be used for a second multiple laser cycles (e.g., LASER #X to LASER #(Y-1)). This progression can continue through subsequent gating windows corresponding to different distance sub-ranges until each distance sub-range has been sampled (e.g., n gating windows) and multiple laser cycles are used for each distance sub-range. Although Figure 2A The use of lasers as optical transmitters is described, but it should be understood that other types of optical signals may be used without departing from the scope and spirit of the present invention.

[0078] The time between pulses of the optical signal (and / or the corresponding gating window) can correspond to a distance range (e.g., the time required for a photon to propagate from the emitter to a target within the distance range and back to the detector), and the corresponding gating window can therefore correspond to a sub-range of the distance range. For example, to image a distance range of 200 meters (m), ten corresponding gating windows can be defined to cover a distance sub-range of 1m-20m, a distance sub-range of 20m-40m, a distance sub-range of 40m-60m, ..., and a distance sub-range of 180m-200m. Although ten gating windows are used as an example to make the distance sub-range clearer, it can be understood that a different number of gating windows (e.g., sixteen gating windows) can be used to make corresponding changes to the covered distance sub-range.

[0079] As described above, in a global gating distribution, a corresponding gating window for a particular laser cycle can be globally applied to multiple and / or all detectors of a lidar system. Thus, during a given laser cycle, all detectors of the lidar system can each sample a specific range of photons. The lidar system can collect all counts of photons detected by the detectors to generate a point cloud.

[0080] Figure 2B 2 shows an arrangement of gating windows for spatial gating distribution according to some embodiments described herein. Figure 2B As shown, in the case of a spatial gating distribution, more than one gating window may be activated during a particular laser cycle. Rather than globally providing the same gating window (and associated distance sub-range) to all detectors of the lidar system, different gating windows may be applied to different detectors of the detector array, depending on the spatial distribution scheme used. Thus, during a given laser cycle, at a first time delay (associated with a particular distance sub-range) after the emission of a laser pulse, a first gating window (e.g., Strobe #0) may be applied to a first detector (e.g., a SPAD and / or SPAD pixel) and / or a first subset of detectors. During the same laser cycle, at a second time delay (associated with a second distance sub-range) after the emission of a laser pulse, a second gating window (e.g., Strobe #n) may be applied to a second detector (e.g., a SPAD and / or SPAD pixel) and / or a second subset of detectors. In this way, different detectors of the detector array may be activated at different times during a laser cycle.

[0081] Various spatial arrangements of gating within a pixel array are possible. An example of a spatial distribution may include an arrangement of sub-arrays between pixel arrays. A sub-array may include multiple detectors (e.g., pixels) that are physically juxtaposed. For example, a square arrangement of detectors within a pixel array may be grouped into sub-arrays. The sub-array arrangement may facilitate signal routing. An embodiment of a spatial distribution may include a single or group of columns and / or rows in a pixel array, which may similarly provide easier routing.

[0082] Figure 3 An example of a subarray spatial distribution for 16 SPADs within a pixel and / or an example subarray of a pixel according to some embodiments of the present invention is shown. As used herein, a pixel may refer to a single detector (e.g., a SPAD) and a group of detectors. For example, a pixel may include a 4×4 arrangement of detectors (e.g., SPADs). Figure 3 An example of a pixel array 310 of 16 pixels forming a sub-array of pixels of a lidar system is shown, where each pixel is labeled as pixel C, pixel R, where C represents a column of pixels in the pixel array and R represents a row of pixels in the pixel array. A lidar system, such as a lidar system, may include a plurality of such pixel arrays 310. That is, the detector array 110 (see FIG. 1 ) of the lidar system 100 may include one or more pixel arrays 310. Figure 3 Also shown is a specific gating window configuration 320 of n gating windows, where n is an integer. The gating window configuration 320 shows the ordering of gating windows applied to a specific pixel position of the pixel array 310 during a given laser cycle. Figure 3 3, gating window configuration 320 is intended to illustrate how a gating window is applied to pixel array 310. For example, a Strb#0 designation in a particular cell of gating window configuration 320 is intended to indicate that a corresponding pixel (e.g., PIXEL 0,0) in pixel array 310 is to be activated during Strobe#0 (e.g., Strobe#0 is to be applied to PIXEL 0,0). A Strb#1 designation in another cell of gating window configuration 320 is intended to indicate that a corresponding pixel (e.g., PIXEL0,1) in pixel array 310 is to be activated during Strobe#1, which is the subsequent gating window after Strobe#0, and so on.

[0083] Figure 3 The sub-array spatial distribution is shown where specific pixels are selected during each gating window. Figure 3 This is merely an example of one embodiment of a sub-array gating distribution (eg, grating distribution) and is not intended to be limiting. Figure 3As shown, the subarray gating distribution 320 can process pixels sequentially (e.g., from left to right) based on the position of the pixels in a row. When a particular row is completed, the next gating window can continue the next row in the opposite direction (e.g., from right to left). Those of ordinary skill in the art will recognize that other subarray-based processing configurations can be used without departing from the inventive concept.

[0084] For example, Figure 4 A "spiral" subarray gating distribution 420 is shown according to some embodiments of the present invention. Figure 4 In the embodiment, the spiral distribution 420 is applied to Figure 3 A similar pixel array 310 is shown in FIG. Figure 4 As shown, gating during a particular laser cycle may occur along a particular row, then along a particular column, alternating in a spiral pattern toward the center of pixel array 310 .

[0085] Figure 5 Another example of a random subarray gating distribution 520 according to some embodiments of the present invention is shown. Figure 5 As shown, gating during a particular laser cycle can be performed randomly within the pixel array 310, and pixels are not repeatedly selected during laser cycles without a particular pattern. In some embodiments, the random subarray gating distribution 520 can be different in different laser cycles. For example, the random subarray gating distribution 520 can be reconfigured in each laser cycle, but the present invention is not limited to this. In some embodiments, the random subarray gating distribution 520 can be reconfigured after a specific duration. The examples of subarray processing described herein are intended to be illustrative only and not limiting of the embodiments described herein.

[0086] Figure 6 An example digital pixel configuration is shown according to some embodiments described herein. Figure 6A digital pixel implementation in conjunction with a pixel subarray 605 is shown, wherein a digital pixel strobe generator may use a normally-on voltage controlled oscillator (VCO) 610 shared at the center of the subarray 605. A signal from the VCO 610 may be cyclically distributed to each pixel counter when and if the correlator triggers. The correlators may be configured to output respective correlation signals representing detection by the detector of one or more photons, the respective arrival times of the photons being within a predetermined correlation time relative to at least one other detected photon. Correlator circuits are discussed, for example, in U.S. patent application serial number 16 / 273,783, filed on February 12, 2019, entitled “METHODS AND SYSTEMS FOR HIGH-RESOLUTION LONG-RANGE FLASH LIDAR.” In Figure 6 In some embodiments, the VCO frequency may be lower (eg, <2 GHz) because accurate time stamp digitization of laser pulses having a duration of a few (eg, less than 10) nanoseconds may be less important. In some embodiments, a clock synchronization signal 620 may be provided to the VCO 610 .

[0087] Figure 7 Another example of column gating distribution according to some embodiments described herein is shown. Figure 7 As shown, during each gating window, one or more columns of pixels of the pixel array may be simultaneously gated. For example, if 16 gating windows are defined, the 0th column, the 16th column, the 32nd column, etc. (e.g., every sixteenth column) may be gated during the first window, the 1st column, the 17th column, the 33rd column, etc. may be gated during the second window, and so on. Figure 7 The examples of column processing in are intended to be illustrative only and not limiting of the embodiments described herein. Row processing may be performed with Figure 7 is performed similarly to what is described in , but the processing elements are rows of the pixel array rather than columns.

[0088] In addition to the gating distribution changes discussed herein, additional improvements can be obtained by using various configurations of gating window timing. In some embodiments, improvements can be achieved by overlapping the gating windows, for example, by a fraction of the gating window width to account for scenarios where the laser return from the target is distributed over two adjacent gating windows. This fraction can be, for example, 1 / 20, 1 / 10, 1 / 5, 1 / 4, 1 / 3, 1 / 2, etc. of the gating window. Figure 8 This embodiment is shown. Gating overlap may result in a slight increase in gate length. The use of gating overlap can be used in conjunction with the gating distribution schemes discussed herein (e.g., pixel sub-array, row-based, column-based, etc.).

[0089] In some embodiments, improvements can be achieved by having gating with different durations. For example, to equalize the signal to background ratio (SBR), it may be advantageous for the short-range gating window (e.g., the gating window associated with the closer range sub-range) to be longer or shorter in duration than the long-range gating window. The duration may be adjusted by approximately 1 / r 2 distribution, where r is the distance from the transmitter. Fig. 9 An example of using gating windows of different durations according to some embodiments described herein is shown. This scheme provides a shorter acquisition window for fainter targets that are farther away, thereby allowing fewer ambient photons to arrive, thereby achieving a higher signal-to-background ratio when calculating the average arrival time compared to a uniform gating window scenario. Although Fig. 9 An example is shown in which the acquisition of a more distant target is shorter, but it will be appreciated that other configurations are possible. Fig. 9 The configuration may be reversed and the duration of a short-range gating window (eg, a gating window associated with a closer range sub-range) may be shorter than a long-range gating window (eg, the gating window duration may increase as the distance range increases).

[0090] In some embodiments, a pseudo-random cycle duration may be used. In some implementations, problems may arise related to interference between multiple lidar systems. One solution may include making the signal of one lidar system appear as random as possible to the outside world (i.e., another lidar system), but synchronized with the original lidar. Spatial sampling of different distance subranges in different pixels in different subframes may have a certain jitter effect on the interfering lidar system, because the lidar system according to the example embodiments described herein may sample a given distance subrange in a given pixel at different subframe sequences. Fig.10 Examples of pseudo-random gating period durations are shown according to some embodiments described herein. Fig.10 The sequence shown may not be repeated.

[0091] In some embodiments, a constantly active strobe may be used. Fig.11 An example of a constantly active strobe according to some embodiments described herein is shown. For example, one way to spatially distribute the strobes is to have more strobes of the same duration slightly time offset from each other by a constant delay interval. Using the example of sixteen strobes discussed previously, four equally delayed strobe gates can be used. Fig.11As shown, a first strobe (e.g., Strobe #0) can be applied to four different detectors with corresponding time delays between the applications of the various strobe windows. For example, Strobe #0 applications are shown as Strobe #0 D0 (Strobe #0 applied to detector 0), Strobe #0 D1 (Strobe #0 applied to detector 1), Strobe #0 D2 (Strobe #0 applied to detector 2), and Strobe #0 D3 (Strobe #0 applied to detector 3). This pattern is repeated for Strobe #1, Strobe #2, and Strobe #3, and so on. In some embodiments, D0 and D1 can be adjacent detectors in the pixel array (see, e.g., the discussion below). Fig.12 ) and can be enabled sequentially. For example, Strobe #0D0, Strobe #0D1, Strobe #0D2, Strobe #0D3 can activate detectors in adjacent pixel arrays at a time point offset by a portion (e.g., 1 / 4) of the strobe period. Fig.11 It is shown that Strobe #0, Strobe #1, Strobe #2 and Strobe #3 are all applied to, for example, detector 0 (D0), it should be understood that different detectors can be activated for different gating windows. Fig.11 Only four detectors (e.g., D0, D1, D2, D3) are shown, but it should be understood that this is for illustrative purposes only, and that lidar systems according to embodiments described herein may include additional detectors. Thus, additional gating windows may be provided that extend across all or most of the laser cycles.

[0092] This delay between corresponding gating windows can be implemented, for example, in a circuit using a delay locked loop (DLL). In such an example, there might be four groups of sixteen strobes offset from each other by 20.25ns (81ns / 4). The SPAD charging current would be distributed at intervals of 64×20.25ns instead of 16×81ns. This may disrupt the temporal midpoints of the window intervals. In some embodiments, this can result in easier external error correction. In some embodiments using a constantly active strobe, an external system can subtract the spatial-temporal offset from each pixel laser return estimate. Fig.11 In the example shown, only 4 of the 16 gating windows are shown.

[0093] In some embodiments, a pixel subarray gating profile may be combined with a constant activity gating profile. Fig.12 An example of a sub-array constant activity gating profile (grating) 1220 is shown in accordance with some embodiments described herein.

[0094] In some embodiments, processing of one subpixel array may be performed slightly offset from another subpixel array. Fig.12 Four sub-arrays 1210_a, 1210_b, 1210_c and 1210_d are shown in FIG. Figure 3 The gating windows may be applied to corresponding subarrays in the four subarrays 1210_a, 1210_b, 1210_c, and 1210_d in the manner described above. A first gating window (e.g., Strobe #0) applied to a first detector of a first subarray 1210_a (e.g., STRB #0D0) may be offset in time from a first gating window applied to a first detector of a second subarray 1210_b (e.g., STRB #0D1), which may be offset from a first gating window applied to a first detector of a third subarray 1210_c (e.g., STRB #0D2), and so on. A second gating window (e.g., Strobe #1) may be applied to the next of the various subarrays in the gating distribution with a similar offset. Although the delay subarrays are in Fig.12 , but it should be understood that this is only an example. As will be appreciated by those skilled in the art, many other patterns are possible as the number of delay groups increases. For example, the offset gating window may also be applied to Figure 4 The gate distribution of 420 and Figure 5 The gating distribution 520 or any other gating distribution described herein.

[0095] In some embodiments, a constant sliding gating window scheme may be used. Fig.13 An example of a constant sliding gating window according to some embodiments described herein is shown. The scheme distributes the gating windows in a column format for ease of generation and reduced wiring. For example, for the 600th column, 600 separate gatings may be generated. For example, in a 600×300 array, a column of 300 SPADs may be recharged every 2ns. This mechanism may result in low average current consumption (e.g., 100mA for a 3V excess estimate). In some embodiments, when one side of the lidar's detector (e.g., the left side) observes a close distance (e.g., using a gating window associated with a closer distance sub-range), the other side of the detector (e.g., the right side) may observe a long distance (e.g., using a gating window associated with a farther distance sub-range). In one embodiment, a cyclic wave of gating distances may continuously move from left to right. In some embodiments, an external system may compensate (e.g., subtract) to offset the pixel time estimate (e.g., 2ns×column index).

[0096] In some embodiments, a gating window (e.g., 81 ns duration) with a time delay (e.g., 2 ns) can be generated to provide a substantially constant SPAD recharge power across the SPAD array. For example, if there are 600 columns, 600 gating windows multiplied by the offset time between gating windows of 2 ns results in 1.3 μs. In such an embodiment, 1 / 600 of the SPAD capacitance th (40nF for example) might recharge 3V every 2ns, which might give 100mA.

[0097] Fig.14 An example implementation of an embodiment of a circuit configured to generate a 2ns gating window delay according to some embodiments described herein is shown. Fig.14 In FIG. 1 , a 600×300 SPAD array 1410 is provided as an example, in which corresponding columns among 600 columns are activated based on delay.

[0098] Reference Fig.14 , the phase-locked loop PLL may include a phase detector 1420, a charge pump 1425, and a filter 1427. The PLL may generate a phase clock signal provided to a delay locked loop DLL. The DLL may include a phase detector 1440 and a charge pump 1445. The signal output from the charge pump 1445 may be provided to a series of delay elements 1447, which may be used to generate delayed gating windows (illustrated as column 1 gating window, column 2 gating window, etc.) from the phase clock signal that may be provided to each column of the pixel array 1410. It should be understood that Fig.14 Configuration can also be implemented based on rows instead of columns.

[0099] Fig.15 A non-limiting example implementation of an embodiment of a gate decoder according to some embodiments described herein is shown. The gate decoder may be configured to decode pixel x, pixel y (where x is a column of pixels and y is a row of pixels). Fig.15 In StrobeState<3:0> <y>is a column-based signal, StrobeCounter<3:0> is global to the entire pixel array, IntState<3:0><x,y> It's pixels<x,y> Internal signals in SelStrobe<x,y> It is the selection signal used to select SPAD and pixel activity inside pixel x and pixel y.

[0100] Decoding pixel x and pixel y may occur in two stages. First, the decoder can write the column signal <x>Second, the decoder can select the correct pulse from the globally distributed StrobeCounter<3:0>.

[0101] In some embodiments, the spatial gating pattern in the pixel array may be hardwired and cannot (or may be difficult to) change after chip fabrication. In some embodiments, the word on StrobeState<3:0> may be written to the internal pixel state IntState<3:0> by an external system (see, for example, Fig.15 ) to establish a spatial gating pattern in a programmable manner (e.g., programmatically controlled). For example, at sensor chip startup, the controller can load an initial pattern of StrobeState<3:0> values ​​into the pixel array. This can be done, for example, by rolling write pulses Write for each row of the pixel array. <x>and loads StrobeState<3:0> from the column-based register <y>IntState<3:0> may select a globally distributed (eg, Gray code) strobe count StrobeCounter<3:0>, which may cycle from 0 to 15 at a repetition rate corresponding to the maximum distance of the lidar system (eg, 1.3 μs).

[0102] Gray code is an ordering of the binary number system so that two consecutive values ​​differ by only one bit (binary digit) (eg, there is only one signal transition at any given point). Fig.16 An example of a global 4-bit Gray code strobe counter is shown according to some embodiments described herein. Fig.17 An example of a 4-bit non-linear Gray code gate counter according to some embodiments described herein is shown. Figure 7 In the code, different signals represent different code bits. Fig.17 As shown, at the transition point (such as Fig.17 The code is changed at a point (as indicated by the dotted line in FIG. 1 ), and in some embodiments, the transition point can be changed according to a synchronous clock signal.

[0103] After decoding, a nonlinear Gray code may produce a longer strobe at close distances and a shorter strobe at long distances. This may result in a reduction in background noise and may improve the centroid at long distances. Conversely, a longer strobe may accept more background noise at short distances where the signal is larger. It should be understood that Fig.16 and 17 The codes shown in are examples only and are not intended to limit the present disclosure. Other bit configurations, including those that do not use Gray codes, may be used without departing from the present invention.

[0104] Fig.21 Shows Fig.15 An example embodiment of the operation of a gate decoder. Fig.21 In , a series of gating windows can be programmed when the sensor is powered on. For example, different pixels can be assigned different IntState values. Fig.21 In the example of FIG. 1 , hexadecimal value 0xA is assigned to Pixel #0, hexadecimal value 0x5 is assigned to Pixel #1, hexadecimal value 0x8 is assigned to Pixel #2, and so on, up to Pixel #15, which is assigned hexadecimal value 0xD. These assignments are examples only and are not intended to limit the embodiments described herein. Fig.21 As shown, a code (eg, two's complement) for a strobe counter may be used in conjunction with a strobe decoder to programmatically (eg, through operation of a circuit and / or processor) distribute the strobe windows among pixels.

[0105] In some embodiments, the subframe can be read out by scanning rows with an ADC or digital readout according to a rolling shutter scheme. When reading out the pixel data of row y, the IntState<3:0> of row y can also be read out from the pixel, incremented, and then written back to the same pixel by the column parallel digital circuit.

[0106] Although a method of gating update has been described, the embodiments described herein are not limited thereto. Other gating update sequences are also feasible without departing from the concepts of the present invention. For example, if the target is viewed as being oriented toward the system by an on-chip (column-based) controller or an off-chip controller, the pixel's IntState<3:0> can be decremented. As another example, a linear feedback shift register (LFSR) sequence can be used for non-continuous but cyclic gating hopping. As another example, if the target is viewed as being acquired by an on-chip (column-based) controller or an off-chip controller, the gating can remain unchanged and the same gating subframe can be read out at a higher frame rate. This can be accomplished by comparing the photon counting signal to a threshold (associated with the gating).

[0107] Fig.18 0046 shows a non-limiting example implementation of a gate decoder according to some embodiments described herein. Fig.18 As shown, a strobe signal (eg, SelStrobe) for activating a detector (eg, SPADS) in a pixel array may be generated based on a strobe state signal (StrobeState) and a strobe counter (StrobeCounter) signal.<x,y> ). As discussed herein, the StrobeState signal can be a column-based signal and the StrobeCounter signal can be global for the entire pixel array. In the first stage of decoding, the column signal Write <x>The local strobe count is latched under the control of . In the second stage of decoding, the SelStrobe signal can be decoded based on the output of the first stage (e.g., IntState) and the StrobeCounter signal. The system can be reset under the control of the SysRst signal. In some embodiments, Fig.18 The D-type flip-flop 1810 shown may be implemented as a latch or SRAM to reduce area.

[0108] Fig.19 0046 shows a non-limiting example implementation of a gate decoder according to some embodiments described herein. Fig.19 As shown, the strobe decoder can also be implemented as a 16-to-1 multiplexer 1910, which is controlled by IntState<3:0>, which receives the input of the StrobeState<15:0> global strobe signal. In this case, the strobes can be generated separately, so that overlapping strobes can be distributed. In some embodiments, using more lines and multiplexers can occupy more silicon area. The input of multiplexer 1910 can be controlled by Fig.18 A D-type flip-flop 1810 similar to that discussed is provided.

[0109] Fig. 20 2000 according to some embodiments described herein. Fig. 20 In the block diagram of FIG, only the blocks related to the spatial gating distribution (not the main lidar operation) are illustrated. Fig. 20 , a pixel array 2010 may be provided. The pixel array 2010 may have M rows and N columns. The configuration of the gating windows provided to the pixel array 2010 may be adjusted and / or controlled by a gating system controller circuit 2015. The gating system controller circuit 2015 may be, for example, part of a control circuit such as the control circuit 105 of FIG. 1 . Figure 15-19 As discussed above, programmable gating distribution can be based on signals such as StrobeCounter, StrobeState, and Write. In other words, a particular gating window can be controlled for a given pixel (e.g., Pixel 2) based on a given state of the StrobeCounter signal, the StrobeState signal, and the Write signal.<x,y> The StrobeState signal may be provided by the StrobeState update control circuit 2025 based on the communication between the strobe system controller circuit 2015 and the StrobeState shift register circuit 2020. The StrobeState shift register circuit 2020 may be under the further control of the strobe system controller circuit 2015.

[0110] The StrobeCounter signal may be provided by the StrobeCounter clock distribution circuit 2030 based on communication between the gate system controller circuit 2015 and the gate generator circuit 2035. The gate generator circuit 2035 may receive an input signal from the phase locked loop 2040 under the control of the gate system controller circuit 2015.

[0111] Under the control of the strobe system controller circuit 2015 , a Write signal may be provided by the row addressing circuit 2017 . Fig. 20 An example implementation for generating a StrobeState signal, a StrobeCounter signal, and a Write signal is shown, and it should be understood that other circuit configurations are feasible without departing from the concept of the present invention. Fig. 20 As shown, the peripheral circuits can be configured to write in the strobed state, allowing other circuits to apply a global strobed counter signal. As a result, customization of the spatial sampling and temporal sampling of the detector can be done programmatically. The customization can be done at device power-up and can be done relatively slowly through the serial chain and / or modified when needed.

[0112] It should be understood that the various gating allocation schemes discussed herein (e.g., pixel subarray, row-based, column-based) may be used with the various gating timing schemes discussed herein (e.g., overlapping gating, non-linear gating, random gating, constant activity gating, constant sliding gating) without departing from the present invention.

[0113] Various embodiments have been described herein with reference to the accompanying drawings showing example embodiments. However, these embodiments may be embodied in different forms and should not be construed as being limited to the embodiments set forth herein. Instead, these embodiments are provided to make this disclosure thorough and complete and to fully convey the inventive concept to those skilled in the art. Various modifications to the example embodiments and the general principles and features described herein will be apparent. In the accompanying drawings, the sizes and relative sizes of layers and regions are not shown to scale and may be exaggerated in some cases for clarity.

[0114] The example embodiments are mainly described in terms of specific methods and devices provided in a specific implementation. However, these methods and devices can be effectively operated in other implementations. Phrases such as "example embodiments", "one embodiment" and "another embodiment" can refer to the same or different embodiments and multiple embodiments. The embodiments will be described with respect to a system and / or device with certain components. However, the system and / or device may include fewer or more components than those shown, and the arrangement and type of components may be changed without departing from the scope of the inventive concept. The example embodiments will also be described in the context of a specific method with specific steps or operations. However, these methods and devices can be effectively used for other methods with different and / or additional steps / operations and steps / operations in different orders inconsistent with the exemplary embodiments. Therefore, the inventive concept is not intended to be limited to the illustrated embodiments, but is in accordance with the widest scope consistent with the principles and features described herein.

[0115] As will be appreciated by those skilled in the art, aspects of the present disclosure may be illustrated and described herein as any of a plurality of patentable classes or any new and useful process, machine, manufacture, or composition of matter included in the context, or any new and useful improvement thereof. Thus, aspects of the present disclosure may be implemented entirely in hardware, entirely in software (including firmware, resident software, microcode, etc.), or in a combination of software and hardware, which are collectively referred to herein as "circuits," "modules," "components," or "systems." In addition, aspects of the present disclosure may take the form of a computer program product contained in one or more computer-readable media having computer-readable program code contained thereon.

[0116] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments. As used herein, the singular forms "a", "an", and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "include" or "comprises" as used herein are open-ended and include one or more stated elements, steps, and / or functions, but do not exclude one or more unstated elements, steps, and / or functions. The term "and / or" includes any and all combinations of one or more of the relevant listed items.

[0117] It should be understood that although the terms first, second, etc. can be used to describe various elements in this article, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Therefore, without departing from the scope of the present invention, the first element discussed below can be referred to as the second element.

[0118] It should also be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there can be intermediate elements. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intermediate elements.

[0119] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those of ordinary skill in the art to which the inventive concept belongs. It should be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0120] In conjunction with the above description and the accompanying drawings, many different embodiments are disclosed herein. It should be understood that it would be excessively repetitive and confusing to describe and illustrate verbatim every combination and subcombination of these embodiments. Therefore, this specification, including the accompanying drawings, should be interpreted as constituting a complete written description of all combinations and subcombinations of the embodiments described herein, as well as the manner and process of making and using them, and should support claims to any such combination or subcombination.

[0121] In the drawings and specification, embodiments of the present disclosure have been disclosed, and although specific terms are used, they are used in a generic and descriptive sense only and not for purposes of limitation. The following claims are provided to ensure that this application satisfies all legal requirements as a priority application in all jurisdictions, and should not be construed as setting forth the scope of the invention.< / x> < / y> < / x> < / x> < / y>

Claims

1. A flash light detection and ranging lidar device, comprising: an emitter array comprising a plurality of emitter units configured to emit optical signals in response to respective emitter control signals; a detector array comprising a plurality of detector pixels configured to be activated and deactivated for corresponding gating windows between pulses of the light signal; as well as a control circuit configured to provide a gating signal to activate a first subset of the detector pixels while leaving a second subset of the detector pixels inactive; The emitter array is further configured to emit the optical signal, with an emitter period between consecutive optical signals, and Wherein the control circuit is further configured to provide the strobe signal to activate a first subset of the detector pixels with a first time delay during the emitter cycle, while the second subset is not activated.

2. The lidar device according to claim 1, wherein: The strobe signal is a first strobe signal, and Wherein the control circuit is further configured to provide a second strobe signal to activate a second subset of the detector pixels with a second time delay during the emitter cycle while keeping the first subset of the detector pixels inactive.

3. The lidar device according to claim 2, wherein: The first strobe signal is configured to be active for a first duration, and Wherein, the second selection signal is configured to be active for a second duration different from the first duration.

4. The lidar device according to claim 2 or 3, wherein: The second time delay is greater than the first time delay.

5. The lidar device according to any one of claims 1 to 3, wherein: The detector array comprises rows and columns, and Therein, the first subset of detector pixels includes rows of the detector array or columns of the detector array.

6. The lidar device according to any one of claims 1 to 3, wherein: The first subset of detector pixels includes a first detector pixel and a second detector pixel, and Wherein the control circuit is further configured to activate the second detector pixel at a time offset after activating the first detector pixel.

7. The lidar device according to any one of claims 1 to 3, wherein: The detector array comprises a first subarray of physically parallel detector pixels and a second subarray of physically parallel detector pixels, and The first subset of detector pixels includes first detector pixels of the first subarray and second detector pixels of the second subarray.

8. A flash light detection and ranging lidar device, comprising: a transmitter configured to transmit a first optical signal and a second optical signal with a transmitter period between the first optical signal and the second optical signal; a detector array comprising a plurality of detector pixels configured to be activated and deactivated for respective gating windows during the emitter cycle; as well as and a control circuit configured to apply a first gating window within the emitter cycle to a first subset of the plurality of detector pixels with a first time delay within the emitter cycle and to apply a second gating window within the emitter cycle to a second subset of the plurality of detector pixels with a second time delay within the emitter cycle that is different from the first time delay.

9. The lidar device according to claim 8, wherein: A first portion of the first gating window overlaps a second portion of the second gating window during a transmitter period.

10. The lidar device according to claim 8 or 9, wherein: The detector array comprises rows and columns, and Therein, the first subset of detector pixels includes rows of the detector array or columns of the detector array.

11. The lidar device according to claim 8 or 9, wherein: The first subset of detector pixels includes a first detector pixel and a second detector pixel, and Wherein the control circuit is configured to activate the second detector pixel at a time offset after the activation of the first detector pixel.

12. The lidar device according to claim 8 or 9, wherein: The first time delay and the second time delay are configured to be programmatically controlled.

13. The lidar device according to claim 8 or 9, wherein: A first duration of the first gating window is different from a second duration of the second gating window.

14. The lidar device according to claim 8 or 9, wherein: The second time delay is greater than the first time delay, and The first duration of the first gating window is shorter than the second duration of the second gating window.

15. The lidar device according to claim 8 or 9, wherein: The second time delay is greater than the first time delay, and Wherein, a first duration of the first gating window is longer than a second duration of the second gating window.

16. The lidar device according to claim 8 or 9, wherein: The detector array comprises a first subarray of physically parallel detector pixels and a second subarray of physically parallel detector pixels, and The first subset of detector pixels includes first detector pixels of the first subarray and second detector pixels of the second subarray.

17. A flash light detection and ranging lidar device, comprising: a transmitter configured to transmit a first optical signal and a second optical signal with a transmitter period between the first optical signal and the second optical signal; a detector array comprising a plurality of detector pixels configured to be activated and deactivated for respective gating windows during the emitter cycle; as well as A control circuit is configured to provide a gating signal to activate a first subset of the plurality of detector pixels and a second subset of the plurality of detector pixels at different respective time delays relative to the first light signal during the emitter cycle.

18. The lidar device of claim 17, wherein: The control circuit is further configured to provide the gating signal to activate the first subset during a first gating window within the transmitter cycle, and Wherein, the control circuit is further configured to provide the gating signal to activate the second subset during a second gating window within the transmitter cycle.

19. The lidar device of claim 18, wherein: A first portion of the first gating window overlaps a second portion of the second gating window.

20. The lidar device according to claim 18 or 19, wherein: A first duration of the first gating window is different from a second duration of the second gating window.

21. The lidar device according to any one of claims 17 to 19, wherein: The detector array comprises rows and columns, and Therein, the first subset of detector pixels includes rows of the detector array or columns of the detector array.

22. The lidar device according to any one of claims 17 to 19, wherein: The first subset of detector pixels includes a first detector pixel and a second detector pixel, and Wherein the control circuit is configured to activate the second detector pixel at a time offset after the activation of the first detector pixel.

23. The lidar device according to any one of claims 17 to 19, wherein: The different respective time delays are configured to be programmatically controlled.

24. The lidar device of claim 18 or 19, wherein: A first corresponding time delay of the first gating window is shorter than a second corresponding time delay of the second gating window, and The first duration of the first gating window is shorter than the second duration of the second gating window.

25. The lidar device of claim 18 or 19, wherein: A first corresponding time delay of the first gating window is shorter than a second corresponding time delay of the second gating window, and Wherein, a first duration of the first gating window is longer than a second duration of the second gating window.

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