IMAGING DEVICE PIXEL SYSTEM, PIXEL, AND METHOD - Patent application

Abstract

To provide improved pixel detection and pixel systems.SOLUTION: A pixel system 200 for an imaging device includes: one or more pixels 201 comprising a pulse trigger assembly 203 configured to detect a pulse at one or more threshold voltages; and a timer system 205 forming part of and / or connected to the one or more pixels, the timer system comprising one or more trigger switches 207a, 207b. The pulse trigger assembly activates the one or more trigger switches in response to detecting the pulse at the one or more threshold values. The pixel system includes a time-of-flight (TOF) module 209 operatively connected to the one or more pixels and / or the timer system to determine a TOF based on an output from the timer system while simultaneously performing one or both of passive imaging and asynchronous laser pulse detection.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to pixels, and in particular to pixel detection and pixel systems. [Background technology]

[0002] Certain pixel designs may be made to detect passive illumination as well as active illumination, e.g., laser pulses. Conventional designs can only detect that a pulse has occurred, but cannot properly detect time-of-flight and therefore cannot accurately measure distance. Summary of the Invention [Problem to be solved by the invention]

[0003] Such conventional methods and systems have generally been considered satisfactory for their intended purposes. However, there remains a need in the art for improved pixel detection and pixel systems. The present disclosure provides a solution to this need. [Means for solving the problem]

[0004] In accordance with at least one aspect of the present disclosure, a pixel system for an imaging device may include one or more pixels including a pulse trigger assembly configured to detect a pulse at one or more threshold voltages, and a timer system forming part of and / or connected to the one or more pixels, the timer system including one or more trigger switches. The pulse trigger assembly may be configured to actuate the one or more trigger switches in response to detecting a pulse at the one or more thresholds. The pixel system may include a time-of-flight (TOF) module operably connected to the one or more pixels and / or timer system to determine a time-of-flight (TOF) based on an output from the timer system.

[0005] The timer system may include at least one voltage ramp configured to enable the TOF module to determine a TOF of the signal based on voltage values ​​of the at least one voltage ramp that vary over time. The timer system may include one or more analog-to-digital converters (ADCs), the one or more ADCs configured to receive voltage values ​​from the at least one voltage ramp when the one or more trigger switches are actuated by a pulse.

[0006] The one or more pixels may include a voltage buffer connected to the at least one voltage ramp, a column buffer connected to each of the one or more ADCs, and a ramp capacitor connected to the column buffer. One or more trigger switches may be arranged between each column buffer and the voltage buffer connected to the at least one voltage ramp.

[0007] The pulse trigger assembly may include a diode, an amplifier connected to the diode to receive a voltage therefrom, one or more high pass filters connected to the amplifier, a comparator for each of the one or more threshold voltages, and a voltage threshold trigger line connecting each comparator to a respective one of the one or more trigger switches. The pulse trigger assembly may include one or more TOF mode switches configured to selectively enable the one or more trigger switches to operate.

[0008] The one or more trigger switches may include a first trigger switch and a second trigger switch connected to the first comparator and the second comparator, respectively, and configured to be actuated at a first threshold voltage of the pulse and a second threshold voltage of the pulse, respectively. The one or more TOF mode switches may include a first TOF switch and a second TOF switch. In the first TOF mode, the first TOF switch may be actuated to be capable of actuating the first trigger switch. In the second TOF mode, the second TOF switch may be actuated to be capable of actuating the second trigger switch.

[0009] The pulse trigger assembly may include an asynchronous laser pulse detection (ALPD) system selectively connected to a first threshold trigger voltage line via an ALPD mode switch. The ALPD system may be connected between a first comparator and a first TOF mode switch. The first TOF mode switch may be between the first comparator and the first trigger switch. A second TOF mode switch may be connected between the amplifier and the second comparator.

[0010] The pixel may include a passive imaging system connected to the diode. The passive imaging system includes at least one passive imaging mode switch configured to enable a passive imaging signal to be output from the diode to at least one of the one or more ADCs in a passive imaging mode. The pixel may be configured such that the passive imaging mode can be operated in the first TOF mode but not in the second TOF mode, and the ALPD mode can be operated in the passive imaging mode.

[0011] The one or more pixels are configured such that the first TOF mode and the second TOF mode are operable together to provide a multi-threshold readout that enables the TOF module to reduce or eliminate one or more errors. In certain embodiments, the one or more high pass filters may include a single high pass filter operatively connected to each comparator. A voltage ramp may be connected to the passive imaging line by a ramp switch in front of the voltage buffer.

[0012] In accordance with at least one aspect of the present disclosure, the pixel may include any suitable embodiment of a pixel disclosed herein (e.g., as described above). For example, the pixel may include a pulse trigger assembly configured to detect a pulse at one or more threshold voltages, and a timer system connected to the pulse trigger assembly, the timer system including one or more trigger switches. The pulse trigger assembly may be configured to actuate the one or more trigger switches in response to detecting the pulse at the one or more thresholds. The timer system may include a voltage buffer configured to connect to at least one voltage ramp, one or more column buffers configured to connect to one or more respective analog-to-digital converters (ADCs), the one or more trigger switches being disposed between each column buffer and the voltage buffer, and one or more ramp capacitors connected to each column buffer for receiving a voltage from the voltage ramp. The pulse trigger assembly may include a diode, an amplifier connected to the diode to receive a voltage therefrom, one or more high pass filters connected to the amplifier, a comparator for each of the one or more threshold voltages, a voltage threshold trigger line connecting each comparator to a respective one of the one or more trigger switches, and one or more TOF mode switches configured to selectively enable the one or more trigger switches to operate. The one or more trigger switches may include a first trigger switch and a second trigger switch connected to the first comparator and the second comparator, respectively, and configured to be activated at a first threshold voltage of the pulse and a second threshold voltage of the pulse, respectively.

[0013] In accordance with at least one aspect of the present disclosure, the method may include determining a time-of-flight (TOF) of the output signal by first determining that a pulse is received at a pixel at two or more threshold voltages to determine a single time value at which the pulse is received. The method may then include using a voltage ramp to compare an initial voltage to a ramp voltage at the single time value at which the pulse is received to determine a voltage difference, and then correlating the voltage difference with the TOF based on the correlation data. The method may further include selecting between a multi-threshold mode of operation of the TOF and a different mode of operation. The method may include any other suitable method(s) and / or portion(s) thereof.

[0014] These and other features of the subject disclosed systems and methods will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments taken in conjunction with the drawings.

[0015] Preferred embodiments thereof are described in detail herein with reference to certain drawing figures so that those skilled in the art to which the subject disclosure pertains can readily understand, without undue experimentation, how to make and use the devices and methods of the subject disclosure. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic diagram of an embodiment of an imaging system according to the present disclosure. [Diagram 2] 1 is a schematic diagram of an embodiment of a system according to the present disclosure. [Figure 3A] FIG. 3 is a schematic diagram of the embodiment of FIG. 2 shown with passive imaging mode and asynchronous laser pulse detection (ALPD) mode enabled simultaneously. [Figure 3B] FIG. 3 is a schematic diagram of the embodiment of FIG. 2 shown with a first time-of-flight (TOF) mode and a passive imaging mode enabled simultaneously. [Figure 3C]FIG. 3 is a schematic diagram of the embodiment of FIG. 2 shown with the first and second TOF modes enabled simultaneously, while the passive imaging and ALPD modes are disabled. [Figure 4] 1 is a schematic diagram of an embodiment of a system according to the present disclosure. [Figure 5A] FIG. 5 is a schematic diagram of the embodiment of FIG. 4 shown with passive imaging mode and ALPD mode enabled, and TOF mode disabled. [Figure 5B] FIG. 5 is a schematic diagram of the embodiment of FIG. 4 shown with passive imaging mode enabled. [Figure 5C] FIG. 5 is a schematic diagram of the embodiment of FIG. 4 shown with the first TOF mode, the second TOF mode, and the ALPD mode enabled, and with the passive imaging mode disabled. [Figure 6] FIG. 1 is a schematic diagram showing a single threshold TOF measurement. [Figure 7] 1 is a series of figures showing the difference between a single threshold TOF measurement and a multi-threshold (eg, two-times) TOF measurement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Reference is now made to the drawings, in which like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, an exemplary diagram of an embodiment of a system according to the disclosure is shown in FIG. 1 and generally designated by reference numeral 100. Other embodiments and / or aspects of the present disclosure are shown in FIGS. 2-7. Certain embodiments described herein may be used to provide accurate time-of-flight (TOF) measurements (e.g., relative to a laser pulse), pulse detection, passive imaging, and / or any other suitable use.

[0018] 1, an embodiment of a system 100 may include one or more laser sources 101 (e.g., providing a Gaussian shaped pulse) connected to one or more optics 103 to output laser pulses 104 (e.g., through air) to a target 103 having a particular reflectivity and distance from the laser source 101. The system 100 may include an imaging device 105 connected to one or more optics 107 for receiving reflected laser pulses 106. In certain embodiments, the system 100 may be configured to operate with a target at any suitable distance and at any suitable resolution.

[0019] In accordance with at least one aspect of the present disclosure, and with reference to FIGS. 2 and 4, a pixel system 200, 400 for an imaging device (e.g., imaging device 105) may include one or more threshold voltages (e.g., V th1 and / or V th2 ) the pixel system 200, 400 may include one or more pixels 201, 401 including a pulse trigger assembly 203, 403 configured to detect a pulse at one or more thresholds. The pixel system 200, 400 may include a timer system 205, 405 forming part of and / or connected to the one or more pixels 201, 401. The timer system 205, 405 may include one or more trigger switches 207a, 207b, 407a, 407b. The pulse trigger assembly 203, 403 may be configured to actuate the one or more trigger switches 207a,b, 407a,b in response to detecting a pulse at one or more thresholds.

[0020] The pixel system 100 may include a time-of-flight (TOF) module 209, 409 operatively connected to one or more pixels 203, 403 and / or timer systems 205, 405 to determine a time-of-flight (TOF) based on an output from the timer system 205, 405. The TOF module 209, 409 may include any suitable computer hardware and / or software configured to perform any suitable functions (e.g., as disclosed herein).

[0021] The timer system 205, 405 may include at least one voltage ramp 211, 411 configured to enable the TOF module 209 to determine the TOF of the signal based on voltage values ​​of the at least one voltage ramp 211 that change over time. The timer system 205, 405 may include one or more analog-to-digital converters (ADCs) 213a, 213b, 413a, 413b. The one or more ADCs 213a,b, 413a,b may be configured to receive voltage values ​​from the at least one voltage ramp 211 when the one or more trigger switches 207a,b, 407a,b are actuated by a pulse.

[0022] For example, in certain embodiments, one or more pixels 203, 403 may include a voltage buffer 215, 415 connected to at least one voltage ramp 211, 411, a column buffer 217a, 217b, 417a, 417b connected to each of the one or more ADCs 213a, b, 413a, b, and a ramp capacitor 219a, 219b, 419a, 419b connected to the column buffer 217a, b, 417a, 417b. In this regard, the one or more ADCs 213a, b, 413a, 413b can read out the voltage on each ramp capacitor 219a, b, 419a, b and can provide a ramp voltage to the TOF module 209, 409. This allows the TOF module 209, 409 to determine the TOF as a function of the voltage difference between the starting voltage of one or more voltage ramps 211, 411 and the voltage on the ramp capacitors 219a,b, 419a,b, which indicates the amount of time that has elapsed. In certain embodiments, a dedicated clock mechanism is not required. In certain embodiments, the system 200, 400 may include multiple pixels 203, 403 and may, for example, utilize a single voltage ramp 211 and / or ADC (or group of ADCs) that is common to all of the pixels 203, 403.

[0023] One or more trigger switches 207a,b, 407a,b may be located, for example, between each column buffer 217a,b, 417a,b and a voltage buffer 215, 415 connected to at least one voltage ramp 211, 411. Any other suitable locations are contemplated herein.

[0024] The pulse trigger assembly 203, 403 may include a diode 219, 419 and an amplifier 221, 421 connected to the diode 219, 419 to receive a voltage therefrom. The diode 219, 419 may be biased with a cathode voltage as would be recognized by one of ordinary skill in the art. The pulse trigger assembly 203, 403 may include one or more high pass filters 223a, 223b, 423 connected to the amplifier 221, 421, a comparator 225a, 225b, 425a, 425b for each of the one or more threshold voltages, and a voltage threshold trigger line 227a, 227b, 427a, 427b connecting the respective comparator 225a, b, 425a, b to a respective trigger switch 207a, b, 407a, b of the one or more trigger switches 207a, b, 407a, b. As shown in Figure 2, the high pass filters 223a,b may be common components with the comparators 225a,b. In certain embodiments, the high pass filters 423 may be separate from the comparators 425a,b, as shown, for example, in Figure 4. Any suitable delineation of the components is contemplated herein. The one or more trigger switches 207a,b may be any suitable type of switch configured to be controlled, for example, by a control voltage applied to its gate.

[0025] As shown in Figure 2, the pulse trigger assembly 203, 403 may include one or more TOF mode switches 229a, 229b configured to selectively enable one or more trigger switches 207a, b to operate. As shown in Figure 4, a single TOF mode switch 429 may be used to selectively enable a ramp voltage to one or more trigger switches 407a, b.

[0026] As shown in FIGS. 2 and 4, one or more trigger switches 207a,b, 407a,b are connected to a first comparator 225a, 425a and a second comparator 225b, 425b, respectively, to trigger a first threshold voltage (e.g., V th1 ) and a second threshold voltage of the pulse (e.g., V th2 For example, the trigger switch 207 may include a first trigger switch 207a, 407a and a second trigger switch 207b, 407b configured to be actuated at each of the diodes 219, 419 when the received voltage from the diode 219, 419 exceeds a first threshold, e.g., V th1 When the first comparator 225a, 425a is at or above the threshold voltage Vcc, the first comparator 225a, 425a may output a signal on a line 227a, 427a proximal to the first trigger switch 207a, 407a. The second trigger switch 207b, 407b, and / or any other suitable number of trigger switches may operate in a similar manner.

[0027] 2, the one or more TOF mode switches 229a, 229b may include a first TOF switch 229a and a second TOF switch 229b. In a first TOF mode (e.g., as shown in FIG. 3B), the first TOF switch 229a may be actuated to actuate the first trigger switch 207a. In a second TOF mode (e.g., as shown in FIG. 3C), the second TOF switch 229b may be actuated to actuate the second trigger switch 207b.

[0028] The pulse trigger assembly 203, 403 and / or the pixel 201, 401 may include an asynchronous laser pulse detection (ALPD) system 231, 431 selectively connected to the first threshold trigger voltage line 227a, 427a, for example, via an ALPD mode switch 233 as shown in FIG. 2, or without a switch as shown in FIG. 4. The ALPD system 231 may be connected, for example, between the first comparator 225a, 425a and the first TOF mode switch 229a (for example, as shown in FIG. 2). As shown in FIG. 4, it is contemplated that the ALPD system 231 may be in parallel with the threshold trigger voltage line 427a, for example, without a switch therebetween, as in FIG. 2. Any other suitable location is contemplated herein.

[0029] As shown in FIG. 2, the first TOF mode switch 229a may be between the first comparator 225a and the first trigger switch 207a. In certain embodiments, the second TOF mode switch may be connected between the amplifier 221 and the second comparator 225b. Any other suitable location is contemplated herein. In certain embodiments, the ALPD system 231, 431 may include suitable components that output a signal to a control module (e.g., the TOF module 209) indicating that a pulse has been received, but are not capable of providing data indicative of the TOF. For example, the ALPD system 231 may include a voltage V dd The column buffer 231c may include a pulse switch 231a that is actuated by the voltage from the first comparator 225a to allow the voltage in the capacitor 231b to operate on V dd The pulse may be connected to a suitable ADC (not shown) which may be connected to the control module to read out when the pulse is at . The control module may then determine that a pulse has occurred, for example, without determining the TOF.

[0030] In certain embodiments, the pixel 201, 401 may include a passive imaging system 233, 433 connected to the diode 219, 419. The passive imaging system 433 may include at least one passive imaging mode switch 235, 435 configured to enable a passive imaging signal to be output from the diode 219, 419 to at least one of the one or more ADCs (e.g., the second ADC 213b, 413b) in a passive imaging mode (e.g., as shown in Figs. 3A, 5A, and 5B). The pixel 201 may be configured to be able to operate the passive imaging mode with the first TOF mode (e.g., as shown in Fig. 3B), but not the second TOF mode (e.g., as shown in Figs. 3C and 5C). As shown in Figs. 3A and 5A, the ALPD mode may be operated with the passive imaging mode, or the passive imaging mode may be separate (e.g., Fig. 5B).

[0031] 3C and 5C, one or more pixels 201 may be configured to be operable in both a first TOF mode and a second TOF mode to provide a multi-threshold readout that enables the TOF module to reduce or eliminate one or more errors. Any other suitable combinations of modes are contemplated herein.

[0032] The embodiments of Figures 2 and 4 may be configured to function similarly. The embodiment of Figure 4 may include a different arrangement of parts, for example, to reduce part count, as compared to the embodiment of Figure 2. For example, in certain embodiments, the one or more high pass filters may include a single high pass filter 423 operably connected to each comparator 425a,b. The voltage ramp 411 may be connected to the passive imaging line 437 by a ramp switch (e.g., TOF mode switch 429) before the voltage buffer 415. In certain embodiments, for example, as shown in Figure 4, the voltage ramp may be buffered to the pixel to reduce kickback noise, the buffer may be reused from what is the passive imaging readout path, and the integration cap may be disconnected via opening the passive mode switch. In certain embodiments, the voltage ramp may be disconnected, the integration cap may be connected to the buffer, rst2 and rst1 enabled according to the ALPD readout may remain disabled until the passive imaging readout occurs, and the ADC for TOF2_out may be disabled.

[0033] In accordance with at least one aspect of the present disclosure, the pixel may include any suitable embodiment of a pixel disclosed herein (e.g., as described above), e.g., pixel 201, 401. For example, the pixel may include a pulse trigger assembly configured to detect a pulse at one or more threshold voltages, and a timer system connected to the pulse trigger assembly, the timer system including one or more trigger switches. The pulse trigger assembly may be configured to actuate the one or more trigger switches in response to detecting the pulse at the one or more threshold voltages. The timer system may include a voltage buffer configured to connect to at least one voltage ramp, one or more column buffers configured to connect to one or more respective analog-to-digital converters (ADCs), and one or more ramp capacitors connected to each column buffer for receiving a voltage from the voltage ramp, the one or more trigger switches being disposed between each column buffer and the voltage buffer. The pulse trigger assembly may include a diode, an amplifier connected to the diode to receive a voltage therefrom, one or more high pass filters connected to the amplifier, a comparator for each of the one or more threshold voltages, a voltage threshold trigger line connecting each comparator to a respective one of the one or more trigger switches, and one or more TOF mode switches configured to selectively enable the one or more trigger switches to operate. The one or more trigger switches may include a first trigger switch and a second trigger switch connected to the first comparator and the second comparator, respectively, and configured to be activated at a first threshold voltage of the pulse and a second threshold voltage of the pulse, respectively.

[0034] In accordance with at least one aspect of the present disclosure, the method may include determining a time-of-flight (TOF) of the output signal by first determining that a pulse is received at a pixel at two or more threshold voltages to determine a single time value at which the pulse is received. The method may then include using a voltage ramp to compare an initial voltage to a ramp voltage at the single time value at which the pulse is received to determine a voltage difference, and then correlating the voltage difference with the TOF based on the correlation data. The method may further include selecting between a TOF multiple threshold mode of operation and a different mode of operation.

[0035] In certain embodiments, the method may include receiving data points for each of a plurality of thresholds and extrapolating a single time of arrival value from the plurality of data points. For example, the TOF module 209, 409 may perform this function (e.g., by linearly extrapolating / estimating the time of arrival from the threshold crossing time). The method may include correlating the plurality of threshold crossings with the respective pulse signal. The method may include using the single time of arrival to calculate the TOF. The method may include disambiguating to determine two signals of identical arrival time, for example, by determining a match of a single time of arrival between the two signals at least within an error range, or to determine that a simultaneous threshold crossing was accompanied by two or more non-coincident signals. The method may include any other suitable method(s) and / or portion(s) thereof. Suitable methods disclosed herein may be stored in a computer-readable medium and / or otherwise executable by a suitable computer.

[0036] In accordance with the present disclosure, a laser pulse may be shone on a diode (e.g., a photosensitive element) and generate a voltage pulse. The amplifier may be coupled to a reference voltage (e.g., V ref ) the input signal may be amplified according to a first threshold (e.g., V th1, a predetermined set voltage). When the output of the amplifier is as high as or higher than the threshold, the comparator may output a signal to trip (e.g., close a trigger switch).

[0037] The voltage ramp may be used to time the flight of the signal. For example, when the laser signal is first transmitted, the voltage ramp may be at a fixed rate, for example 200 millivolts per second. The TOF module may later mark the start voltage / time use to calculate the TOF. When a pulse is received and the trigger switch is actuated, the ramp voltage may be read out and correlated to time, thus giving the TOF.

[0038] Certain embodiments may also include a passive imaging system. In certain embodiments, a passive capacitor may obtain a voltage from a current mirror connected to a diode. An ADC may read out the passive capacitor voltage. In certain embodiments, the passive imaging system may share one or more components (e.g., a capacitor, a buffer, and / or an ADC) with the timing system, such that in passive mode, a component is used to read out the passive signal when a pulse is detected, and in TOF mode, a component is used to read out the ramp voltage.

[0039] Voltage ramps can be advantageous because certain imaging devices may already have them on-board. Ramping the voltage and clamping to digitize the voltage at a trigger point is just one embodiment of recording time. Additionally or alternatively, embodiments may include one or more digital counters that count the elapsed time and send out a digital signal directly. For example, counters or clocks may be used, but they may be more power intensive and take up more space than using a voltage ramp, for example.

[0040] The embodiments provide a system for performing improved time-of-flight measurements. The embodiments allow for multiple thresholds (e.g., at least dual thresholds) for monitoring pulse signals. th1 A second threshold value different from th2 ) may include a replicated second path for the first capacitor. Embodiments may allow for independent simultaneous measurements of samples for multiple capacitors allowing for two points of data. As shown in FIG. 6, a single threshold measurement may be taken, but will introduce errors that may or may not be acceptable or desirable.

[0041] As shown in FIG. 7, a comparison between single and dual threshold measurements shows the advantage of using dual threshold measurements. As can be seen with dual threshold measurements (bottom of FIG. 7), having two data points allows the TOF module (e.g., 209, 409) to extrapolate the data points into a line that allows for a more accurate determination of the signal type and time of flight. For example, where a single threshold measurement would erroneously consider simultaneously occurring signals of different amplitudes (e.g., the same signal pulling from two different materials at the same distance, top left of FIG. 7) as two different signals, a dual threshold system allows the point of intersection to form a line that intersects the time axis indicating signals arriving at the same time regardless of amplitude (indicating a single signal reflected from multiple surfaces, e.g., bottom left of FIG. 7). Where a single threshold measurement would erroneously consider multiple signals arriving at different times as a single signal (e.g., top right of FIG. 7), a dual threshold measurement accurately separates two separate signals into two different arrival times. Using the times generated by the multi-threshold approach, the TOF module can extrapolate a more accurate time of arrival and use that value to calculate the TOF (e.g., to determine the range of the target).

[0042] The embodiments can, for example, detect a pulse twice within a single pulse and reduce time / depth ambiguity caused by signal amplitude. Certain embodiments add, for example, a new mode for TOF detection with minimal additional transistors. The new mode allows for two samples of a single laser pulse signal waveform, simultaneous readout, and proper processing of the simultaneous readout. The embodiments can eliminate or reduce motion artifacts and reduce depth ambiguity due to other reasons that cause signal amplitude differences, such as target reflectivity differences, backscattering, etc. The embodiments can still support TOF signal calibration via the TOF imaging path. The gain / buffer component embodiments can have adjustable gain and bandwidth via bias current adjustment, the high pass filter angular frequency can be voltage adjustable, the current gain / attenuation of the current mirror can be adjustable, and in certain embodiments, during TOF mode, the input PMOS TX is biased to V to maintain DI behavior. dd or may be voltage isolated.

[0043] For example, specific pixel / readout block diagrams are shown herein. Any components not described herein or shown in the drawings can be readily understood to have a function as recognized by one of ordinary skill in the art at least in light of the present disclosure. Embodiments can implement improved fidelity and direct time-of-flight (TOF) imaging with passive imaging along with active pulse detection. Embodiments can enable leading edge pulse detection to be obtained, thereby mitigating range / reflection ambiguity challenges.

[0044] As will be appreciated by those skilled in the art, aspects of the present disclosure may be embodied as a system, method, or computer program product. Accordingly, aspects of the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects, all of which may be referred to herein as a "circuit," "module," or "system." A "circuit," "module," or "system" may include one or more portions of one or more separate physical hardware and / or software components that together may perform the disclosed functions of the "circuit," "module," or "system," or a "circuit," "module," or "system" may be a single, self-contained unit (e.g., of hardware and / or software). Additionally, aspects of the present disclosure may take the form of a computer program product embodied in one or more computer-readable medium(s) having computer-readable program code embodied thereon.

[0045] Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (non-exhaustive list) of computer readable storage media include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this specification, a computer readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0046] A computer-readable signal medium may include a propagated data signal having computer-readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including but not limited to, electrical-magnetic, optical, or any suitable combination thereof. A computer-readable signal medium may not be a computer-readable storage medium but any computer-readable medium capable of communicating, propagating, or carrying a program for use by or in connection with an instruction execution system, apparatus, or device.

[0047] The program code embodied on the computer readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, fiber optic cable, RF, etc., or any suitable combination of the foregoing.

[0048] Computer program code for carrying out operations for aspects of the present disclosure may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, Smalltalk, or C++, and traditional procedural programming languages ​​such as the "C" programming language or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or partially on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or a connection to an external computer may be made (e.g., through the Internet using an Internet Service Provider).

[0049] Aspects of the present disclosure may be described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present disclosure. Each block of any flowchart illustration and / or block diagram, and combinations of blocks in any flowchart illustration and / or block diagram, may be implemented by computer program instructions. Those computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing apparatus generate means for performing the function / act specified in the block or block(s) of any flowchart and / or block diagram.

[0050] Computer program instructions may also be stored on a computer-readable medium, which may direct a computer, other programmable data processing apparatus, or other device to function in a particular manner to produce an article of manufacture including instructions that implement the function / act specified in the flowchart and / or block diagram block or block(s).

[0051] Computer program instructions may also be loaded into a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other device to generate computer-implemented processes, such that the instructions, which execute on the computer or other programmable apparatus, result in processes to perform the functions / operations specified herein.

[0052] One of ordinary skill in the art will understand that any numerical value disclosed herein may be an exact value or may be a value within a range. Additionally, approximations (e.g., "about," "approximately," "around" and the like) used in this disclosure may refer to a stated value within a range. For example, in certain embodiments, the range may be within 20% (plus or minus), within 10%, within 5%, within 2%, or within any other suitable percentage or number as recognized by one of ordinary skill in the art (e.g., relative to a known tolerance limit or margin of error).

[0053] As used herein and in the appended claims, the articles "a," "an," and "the" are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article, unless the context clearly indicates otherwise. By way of example, "an element" means one element or more than one element.

[0054] The phrase "and / or" as used in the specification and claims should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are conjointly present in some cases and disjointly present in other cases. Multiple elements marked with "and / or" should be interpreted in the same manner, i.e., "one or more" of the elements so conjoined. Other elements other than the elements specifically identified by the "and / or" clause may optionally be present, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to "A and / or B," when used with open-ended language such as "comprising," may refer in one embodiment to only A (optionally including elements other than B), in another embodiment to only B (optionally including elements other than A), in yet another embodiment to both A and B (optionally including other elements), etc.

[0055] As used in the specification and claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" should be understood as inclusive, i.e., including at least one, but also including more than one number or list of elements, and optionally including additional unlisted items. Only terms clearly indicated to the contrary, such as "only one of" or "exactly one of," or, when used in the claims, "consisting of," refer to the inclusion of exactly one element of a number or list of elements. In general, the term "or" as used herein should only be interpreted as an exclusive alternative (i.e., "one or the other, but not both") when preceded by an exclusive term, such as "either," "only one of," or "exactly one of."

[0056] Any suitable combination(s) of any of the disclosed embodiments and / or any suitable portion(s) thereof, as would be recognized by one of ordinary skill in the art having reference to this disclosure, is contemplated herein.

[0057] The embodiments of the present disclosure described above and illustrated in the drawings represent improvements in the art to which they pertain. While the subject disclosure includes reference to specific embodiments, those skilled in the art will readily recognize that changes and / or modifications thereto may be made without departing from the spirit and scope of the subject disclosure.

Claims

1. 1. A pixel system for an imaging device, comprising: one or more pixels, at least one of which includes a pulse trigger assembly configured to detect pulses at two or more threshold voltages; a timer system forming part of and / or connected to the one or more pixels, the timer system including one or more trigger switches, the pulse trigger assembly configured to actuate the one or more trigger switches in response to detecting the pulse at the two or more threshold voltages; a time-of-flight (TOF) module operatively connected to the one or more pixels and / or the timer system to determine a time-of-flight (TOF) based on an output from the timer system; A pixel system comprising:

2. 2. The pixel system of claim 1, wherein the timer system includes at least one voltage ramp configured to enable the TOF module to determine a TOF of a signal based on voltage values ​​of the at least one voltage ramp that change over time.

3. 3. The pixel system of claim 2, wherein the timer system includes one or more analog-to-digital converters (ADCs), the one or more ADCs configured to receive a voltage value from the at least one voltage ramp when the one or more trigger switches are actuated by the pulse.

4. 4. The pixel system of claim 3, wherein the one or more pixels include a voltage buffer connected to the at least one voltage ramp, an ADC buffer connected to each of the one or more ADCs, and a ramp capacitor connected to the ADC buffer, and the one or more trigger switches are arranged between each ADC buffer and the voltage buffer connected to the at least one voltage ramp.

5. 5. The pixel system of claim 4, wherein the pulse trigger assembly includes a diode, an amplifier connected to the diode to receive a voltage therefrom, one or more high pass filters connected to the amplifier, a comparator for each of the two or more threshold voltages, and a voltage threshold trigger line connecting each comparator to a corresponding one of the one or more trigger switches.

6. The pixel system of claim 5 , wherein the pulse trigger assembly includes one or more TOF mode switches configured to selectively enable the one or more trigger switches to operate.

7. 7. The pixel system of claim 6, wherein the one or more trigger switches comprise a first trigger switch and a second trigger switch coupled to a first comparator and a second comparator, respectively, and configured to be actuated at a first threshold voltage of the pulse and a second threshold voltage of the pulse, respectively.

8. 8. The pixel system of claim 7, wherein the one or more TOF mode switches include a first TOF switch and a second TOF switch, and in a first TOF mode, the first TOF switch is actuated to be capable of actuating the first trigger switch, and in a second TOF mode, the second TOF switch is actuated to be capable of actuating the second trigger switch.

9. the pulse trigger assembly includes an asynchronous laser pulse detection (ALPD) system selectively connected to a first voltage threshold trigger line via an ALPD mode switch; 9. The pixel system of claim 8, wherein the first voltage threshold trigger line is the voltage threshold trigger line that connects the first trigger switch to the first comparator.

10. 10. The pixel system of claim 9, wherein the ALPD system is connected between the first comparator and the first TOF switch, and the first TOF switch is between the first comparator and the first trigger switch.

11. The pixel system of claim 10 , wherein the second TOF switch is connected between the amplifier and the second comparator.

12. 11. The pixel system of claim 10, wherein the pixel includes a passive imaging system connected to the diode, the passive imaging system including at least one passive imaging mode switch configured to enable a passive imaging signal to be output from the diode to at least one of the one or more ADCs in a passive imaging mode.

13. 13. The pixel system of claim 12, wherein the pixel is configured such that the passive imaging mode can be operated in the first TOF mode but not in the second TOF mode, and an ALPD mode can be operated in the passive imaging mode.

14. 9. The pixel system of claim 8, wherein the one or more pixels are operable together such that a first TOF mode and the second TOF mode provide a multi-threshold readout that enables the TOF module to reduce or eliminate one or more errors.

15. The pixel system of claim 13 , wherein the one or more high pass filters comprises a single high pass filter operatively connected to each comparator.

16. The pixel system of claim 15, wherein the voltage ramp is connected to a passive imaging line by a ramp switch in front of the voltage buffer.

17. a pulse trigger assembly configured to detect a pulse at one or more threshold voltages; a timer system connected to the pulse trigger assembly, the timer system including one or more trigger switches, the pulse trigger assembly configured to actuate the one or more trigger switches in response to detecting the pulse at the one or more thresholds; The timer system comprises: a voltage buffer configured to couple to the at least one voltage ramp; one or more analog-to-digital converters (ADC) buffers configured to connect to one or more respective ADCs, the one or more trigger switches being disposed between each of the ADC buffers and the voltage buffer; one or more ramp capacitors connected to each of the ADC buffers for receiving a voltage from the voltage ramp; The pulse trigger assembly includes: A diode and an amplifier connected to said diode to receive a voltage therefrom; one or more high pass filters coupled to the amplifier; a comparator for each of the one or more threshold voltages; a voltage threshold trigger line connecting each comparator to a corresponding one of the one or more trigger switches; one or more TOF mode switches configured to selectively enable the one or more trigger switches to be operated, the one or more trigger switches including a first trigger switch and a second trigger switch coupled to a first comparator and a second comparator, respectively, and configured to be actuated at a first threshold voltage of the pulse and a second threshold voltage of the pulse, respectively; Pixel.

18. 18. The pixel of claim 17, wherein the one or more TOF mode switches include a first TOF switch and a second TOF switch, and in a first TOF mode, the first TOF switch is actuated to actuate the first trigger switch, and in a second TOF mode, the second TOF switch is actuated to actuate the second trigger switch.

19. A method for determining a time-of-flight (TOF) of a signal output to a pixel system of an imaging device, comprising: First, determining a single time value for receiving a pulse of a signal in the pixel system by a pulse trigger assembly of a pixel of the pixel system that detects pulses at two or more threshold voltages; then using a voltage ramp having voltage values ​​that vary over time, determining a voltage difference by comparing an initial voltage of the voltage ramp when the signal is first transmitted with a ramp voltage of the voltage ramp at a single time value at which the pulse is received; and then correlating the voltage difference with the TOF based on the correlation data.

20. 20. The method of claim 19, further comprising selecting between a multi-threshold mode of operation of the TOF and a different mode of operation.

21. A pixel system for an imaging device, comprising: one or more pixels, at least one of which includes a pulse trigger assembly configured to detect pulses at two or more threshold voltages; a timer system forming part of and / or connected to the one or more pixels, the timer system including one or more trigger switches, the pulse trigger assembly configured to actuate the one or more trigger switches in response to detecting the pulse at the two or more threshold voltages; a time-of-flight (TOF) module operatively connected to the one or more pixels and / or the timer system to determine a time-of-flight (TOF) based on an output from the timer system; Equipped with the timer system includes at least one voltage ramp configured to enable the TOF module to determine a TOF of a signal based on voltage values ​​of the at least one voltage ramp that change over time; the timer system includes one or more analog-to-digital converters (ADCs), the one or more ADCs configured to receive a voltage value from the at least one voltage ramp when the one or more trigger switches are actuated by the pulse; the one or more pixels include a voltage buffer connected to the at least one voltage ramp, an ADC buffer connected to each of the one or more ADCs, and a ramp capacitor connected to the ADC buffer, the one or more trigger switches being arranged between each ADC buffer and the voltage buffer connected to the at least one voltage ramp; the pulse trigger assembly includes a diode, an amplifier connected to the diode to receive a voltage therefrom, one or more high pass filters connected to the amplifier, a comparator for each of the two or more threshold voltages, and a voltage threshold trigger line connecting each comparator to a corresponding one of the one or more trigger switches; the pulse trigger assembly includes one or more TOF mode switches configured to selectively enable the one or more trigger switches to be operated; the one or more trigger switches include a first trigger switch and a second trigger switch respectively connected to a first comparator and a second comparator and configured to be actuated at a first threshold voltage of the pulse and a second threshold voltage of the pulse, respectively.

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