WO2020113360A1 - 一种采样电路、采用方法及测距装置、移动平台 - Google Patents

一种采样电路、采用方法及测距装置、移动平台 Download PDF

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Publication number
WO2020113360A1
WO2020113360A1 PCT/CN2018/118876 CN2018118876W WO2020113360A1 WO 2020113360 A1 WO2020113360 A1 WO 2020113360A1 CN 2018118876 W CN2018118876 W CN 2018118876W WO 2020113360 A1 WO2020113360 A1 WO 2020113360A1
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Prior art keywords
signal
digital conversion
conversion module
time
sampling
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English (en)
French (fr)
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黄森洪
梅雄泽
刘祥
洪小平
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SZ DJI Technology Co Ltd
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SZ DJI Technology Co Ltd
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Priority to PCT/CN2018/118876 priority Critical patent/WO2020113360A1/zh
Priority to CN201880068016.2A priority patent/CN111527419A/zh
Publication of WO2020113360A1 publication Critical patent/WO2020113360A1/zh
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T3/00—Measuring neutron radiation

Definitions

  • the invention relates to the technical field of laser radar, in particular to a sampling circuit, an adopting method, a distance measuring device, and a mobile platform.
  • Lidar is a radar system that emits laser beams to detect the target's position, speed and other characteristic quantities.
  • the light sensor of the lidar can convert the acquired light pulse signal into an electrical signal, and obtain the time information corresponding to the electrical signal based on the comparator, thereby obtaining the distance information between the lidar and the target.
  • a first aspect of the present invention provides a sampling circuit, including: a time-to-digital conversion module and an analog-to-digital conversion module set in parallel, and the sampling circuit further includes a control module;
  • the time-to-digital conversion module is used to receive the electrical signal converted from the optical pulse signal and compare the electrical signal with a preset threshold to collect time information corresponding to the electrical signal;
  • the analog-to-digital conversion module is used to receive the electrical signal converted from the optical pulse signal and collect the amplitude of the electrical signal corresponding to the acquisition time within the sampling clock frequency;
  • the control module is configured to select and calculate signals collected by the time-to-digital conversion module and/or the analog-to-digital conversion module to obtain parameter values of the optical pulse signal.
  • the time-to-digital conversion module includes a plurality of channels, where each of the channels includes a comparator and a time-to-digital converter, wherein the first input terminal of the comparator is used to receive the conversion from the optical pulse signal For the obtained electrical signal, the second input terminal of the comparator is used to receive the preset threshold of the comparator, the output terminal of the comparator is used to output the result of the comparison operation, the time-to-digital converter and the The output terminal of the comparator is electrically connected to extract the time information corresponding to the electrical signal according to the result of the comparison operation output by the comparator;
  • the preset thresholds of the comparators in the different channels are different.
  • the analog-to-digital conversion module includes at least one analog-to-digital converter for collecting the amplitude of the electrical signal corresponding to the collection time.
  • control module is used to calculate the selected signal by fitting to restore the pattern of the optical pulse signal
  • control module is used to calculate the selected signal by using explicit statistics to obtain the parameter value of the optical pulse signal.
  • control module collects at least part of the signal of the time-to-digital conversion module and at least part of the signal collected by the analog-to-digital conversion module to perform the fitting.
  • control module is further configured to convert the sampling of the time-to-digital conversion module into the sampling of the analog-to-digital conversion module;
  • control module is also used to convert the samples of the analog-to-digital conversion module into the samples of the time-to-digital conversion module.
  • control module is used to first calculate the sampled signal of the analog-to-digital conversion module by fitting to obtain a graph of the optical pulse signal, and then on the graph of the optical pulse signal Calibrate preset thresholds and corresponding time information.
  • control module selects the signal:
  • the width of the optical pulse signal is less than the set value of the pulse width, the signal collected by the time-to-digital conversion module is selected; and/or
  • the signal collected by the analog-to-digital conversion module is selected; and/or
  • the width of the optical pulse signal is greater than the set value of the pulse width and the pulse height of the optical pulse signal is greater than the set value of the pulse height, if the information on the arrival time and pulse width of the optical pulse signal is required to have higher accuracy At this time, at least the signal collected by the time-to-digital conversion module is selected; if higher precision is required for the pulse energy and amplitude information of the optical pulse signal, at least the signal collected by the analog-to-digital conversion module is selected.
  • the parameter value includes at least one of pulse arrival time, pulse width, pulse energy, and amplitude.
  • the invention also provides a sampling method based on a sampling circuit, including:
  • the signals collected by the time-to-digital conversion module and/or the analog-to-digital conversion module are selected and calculated to obtain the parameter value of the optical pulse signal.
  • the time-to-digital conversion module includes multiple channels, and the multiple channels receive the electrical signal in parallel and perform a comparison operation on the electrical signal to collect time information corresponding to the electrical signal.
  • different preset thresholds are respectively set for the multiple channels to receive the electrical signals in parallel and perform comparison operations on the electrical signals.
  • the step of selecting and calculating the signal to obtain the parameter value of the optical pulse signal includes:
  • the explicit signal is used to calculate the selected signal to obtain the parameter value of the optical pulse signal.
  • At least a part of the signals of the time-to-digital conversion module and a part of the signals collected by the analog-to-digital conversion module are selected for the fitting.
  • the method further includes:
  • control module is also used to convert the samples of the analog-to-digital conversion module into the samples of the time-to-digital conversion module.
  • the sampled signal of the analog-to-digital conversion module is first calculated by fitting to obtain a graph of the optical pulse signal, and then a preset threshold is calibrated on the graph structure of the optical pulse signal and Corresponding time information.
  • the width of the optical pulse signal is less than the set value of the pulse width, the signal collected by the time-to-digital conversion module is selected; and/or
  • the signal collected by the analog-to-digital conversion module is selected; and/or
  • the width of the optical pulse signal is greater than the set value of the pulse width and the pulse height of the optical pulse signal is greater than the set value of the pulse height, if the information on the arrival time and pulse width of the optical pulse signal is required to have higher accuracy At this time, at least the signal collected by the time-to-digital conversion module is selected; if higher precision is required for the pulse energy and amplitude information of the optical pulse signal, at least the signal collected by the analog-to-digital conversion module is selected.
  • the parameter value includes at least one of pulse arrival time, pulse width, pulse energy, and pulse amplitude.
  • the invention also provides a distance measuring device, including:
  • Light emitting circuit used to emit light pulse signal
  • An optical receiving circuit configured to receive at least part of the optical signal reflected by the optical pulse signal emitted by the optical transmitting circuit through the object, and convert the received laser signal into an electrical signal;
  • the above sampling circuit is used for sampling the electrical signal from the laser receiving circuit to obtain a sampling result
  • the arithmetic circuit is used for calculating the distance between the object and the distance measuring device according to the sampling result.
  • the invention also provides a mobile platform, including:
  • a platform body, and the light emitting circuit of the distance measuring device is installed on the platform body.
  • the mobile platform includes at least one of an unmanned aerial vehicle, a car, and a robot.
  • the present invention provides the above sampling circuit, method, distance measuring device, and mobile platform.
  • the sampling circuit is provided with a time-to-digital conversion module and an analog-to-digital conversion module in parallel. Sampling is performed by the above two methods, and there are more sampling points. The degree of shape reduction is better, which provides a better basis for the extraction of pulse information.
  • the sampling circuit and the method of the present invention combine the advantages of the two types of sampling to achieve the effect of complementary advantages. On the one hand, it can take into account various information such as energy and time. For example, it can obtain higher energy accuracy while ensuring time accuracy.
  • the pulse shape requirements can be widened.
  • low-amplitude wide pulses that cannot be processed by the time-to-digital conversion module can be processed by the analog-to-digital conversion module, and narrow pulses that cannot be processed by the analog-to-digital conversion module can be adopted by the time-to-digital conversion module deal with.
  • Pulses with appropriate amplitude and pulse width can obtain better results than any solution of the analog-to-digital conversion module and the time-to-digital conversion module.
  • both the analog-to-digital conversion module and the time-to-digital conversion module can contribute more sampling points, and the combined use of the two can improve the accuracy of pulse information extraction.
  • FIG. 1 is a schematic structural diagram of a sampling signal obtained by a time-to-digital conversion method according to an embodiment of the present invention
  • FIG. 2 is a schematic structural diagram of a sampling signal obtained by an analog-to-digital conversion method in an embodiment of the present invention
  • FIG. 3 is a schematic structural diagram of a sampling circuit in an embodiment of the invention.
  • FIG. 4 is a schematic frame diagram of a distance measuring device according to an embodiment of the present invention.
  • FIG. 5 is a schematic diagram of an embodiment of a distance measuring device provided by an embodiment of the present invention using a coaxial optical path.
  • the methods of digitizing optical pulses mainly include time-to-digital conversion methods (for example, using a time-to-digital converter Time-to-Digital Converter (TDC) and analog-to-digital conversion methods (for example, using an analog-to-digital converter, Analog-to-Digital Converter, ADC).
  • time-to-digital conversion methods for example, using a time-to-digital converter Time-to-Digital Converter (TDC)
  • analog-to-digital conversion methods for example, using an analog-to-digital converter, Analog-to-Digital Converter, ADC.
  • TDC and ADC have their own advantages and disadvantages, and it is usually difficult to take into account the accuracy of extracting a variety of information.
  • TDC can only achieve parallel acquisition of N channels, then at most N+1 amplitude values can be collected, and its sampling accuracy and discrimination in voltage amplitude are low, especially for the amplitude sampling of pulse signals is missing .
  • the current TDC scheme cannot measure continuously multiple times. If the threshold is too low, after the TDC is triggered by noise, once the real pulse signal is encountered, it can no longer respond to the real pulse signal .
  • the sampling rate is very high (or the sampling interval is very small).
  • the available ADC sampling rate is generally in the GHz range, that is, a point is taken every 1 ns. In the pulse signal of about 10ns, only about 10 points can be collected, which is not enough for the acquisition of pulse information.
  • the ADC sampling time is random with respect to the pulse signal, that is, the position of the sampling point relative to the arrival time for pulses arriving at different times is not fixed, and in actual applications, accurate pulse time information can be obtained to obtain accurate The measurement distance of the sample is worse than the random sampling method of pulse time.
  • the number of points collected by the ADC is limited.
  • the pulse signal received by the detector varies with the distance, reflectivity, diffuse reflection path, etc. of the measured object, and the amplitude and pulse width of the optical pulse will change to varying degrees. Therefore, the digital circuit and The processing method needs to adapt to pulse signals with different pulse widths and different amplitudes that change within a wide range, which puts forward higher requirements on the current TDC scheme or ADC scheme.
  • the present invention provides a sampling circuit, in which the time-to-digital conversion module and the analog-to-digital conversion module are provided in parallel in the adoption circuit, and the sampling method is provided in the adoption circuit in parallel, thereby realizing two
  • the advantages of the method are complementary to obtain the parameter value of the optical pulse signal.
  • the parameter value includes but is not limited to the following information: pulse arrival time, pulse width, pulse energy and amplitude, etc.
  • two sampling methods of ADC and TDC are integrated, including a single channel ADC module and N channel TDC modules.
  • the sampling rate of the ADC module is f
  • the number of quantization bits is M bits
  • the TDC of each channel includes a comparator, and each channel sets different thresholds according to requirements to obtain the rising and falling time of the pulse at different amplitudes .
  • each channel is set with a different amplitude threshold, and the rising time and falling time of the pulse at the corresponding value are intercepted.
  • TDC is a given threshold acquisition time. Only when the pulse arrives and reaches the threshold will the TDC sampling be triggered, which can achieve high-precision time measurement at the picosecond level.
  • the time-to-digital conversion module includes multiple channels, for example, including 1 to N channels, where N is a natural number greater than 2.
  • the preset thresholds of the comparators in the different channels are different, for example, a threshold 1 to a threshold N are set.
  • Each of the channels includes a comparator and a time-to-digital converter TDC.
  • the first input end of the comparator is used to receive an electrical signal converted from an optical pulse signal.
  • the comparator The second input terminal is used to receive the preset threshold of the comparator, the output terminal of the comparator is used to output the result of the comparison operation, and the time-to-digital converter TDC is electrically connected to the output terminal of the comparator, Used to extract time information corresponding to the electrical signal according to the result of the comparison operation output by the comparator
  • the preset thresholds set in different channels are threshold 1, threshold 2 up to threshold N, and the electrical signal input to the first input terminal of the comparator includes an electrical pulse signal.
  • the preset threshold value is threshold value 1 and when the intensity of the electrical pulse signal exceeds threshold value 1, the electrical pulse signal triggers the comparator to output a high-level signal to obtain time information corresponding to triggering threshold value 1.
  • the principle of a time extraction method is: an electrical signal input to a comparator is compared with a threshold value N to obtain a first square wave signal shown by a dotted line, the first The time TN of the transition edge of the square wave signal can be regarded as the time when the electrical signal traverses the comparator.
  • the electrical signal input to the comparison circuit is compared with the preset threshold value 1 to obtain a second square wave signal as shown by the dotted line.
  • the time T1 of the transition edge of the second square wave signal can be regarded as the electrical signal passing through the comparator Time.
  • the method of acquiring the time signal is the same for other channels.
  • the TDC scheme has a very high time resolution ability (tens of ps level), especially in the relatively fast pulse signal edge acquisition has sufficient advantages, and contributes more to the accurate collection of pulse signal time. Therefore, when there are many samples with moderate pulse height and width, the TDC scheme can be used to obtain higher-precision information such as arrival time and pulse width information.
  • the advantage of the ADC method is that it has higher voltage acquisition accuracy, and may have more contributions in the amplitude and energy of the pulse.
  • the sampling method of the ADC module is shown in Figure 2.
  • the sampling rate of the ADC is 1-10 GHz, for example, a point is taken every 1 ns.
  • sampling at time t will obtain the first amplitude signal
  • sampling at time 2t will obtain the second amplitude information
  • sampling at Kt time will obtain the first K amplitude signal to obtain the amplitude of the electrical signal corresponding to the acquisition time.
  • the above two methods are used together, that is, it can have sufficient advantages for fast pulse signal edge acquisition and can also ensure a higher voltage acquisition accuracy.
  • the pulse amplitude energy In terms of accessibility.
  • the ADC module and the N-channel TDC module run in parallel to generate digital sample data of A1, B1, B2, ...BN, and transmit them to the control module for processing in parallel.
  • the module is used to select and calculate the signal collected by the time-to-digital conversion module and/or the analog-to-digital conversion module to obtain the parameter value of the optical pulse signal.
  • control module uses a Micro Controller Unit (MCU) to process data.
  • MCU Micro Controller Unit
  • the method for the control module to select the signals collected by the time-to-digital conversion module and/or the analog-to-digital conversion module may include any one of the following solutions or a combination of any at least two solutions:
  • the pulse width setting value is used to characterize the extent to which the width of the optical pulse signal can be used to extract pulse information using the TDC scheme, and its specific value can be selected according to actual needs, and is not limited to a certain value range. Using the TDC method can avoid the insufficient sampling of the ADC due to the small pulse width.
  • the ADC scheme is used to extract pulse information, wherein the set value of the pulse height is used to characterize the extent to which the height of the optical pulse signal can be Using the ADC scheme to extract pulse information, the specific value can be selected according to actual needs, and is not limited to a certain value range. Using the ADC method can avoid the situation where the TDC is insufficiently sampled because the pulse height is too small.
  • At least one of the ADC method and the TDC method may be selected, or Use two schemes for sampling at the same time. That is, when there are many samples with moderate pulse height and width, the TDC scheme can be used to obtain higher precision information for TDC schemes such as arrival time and pulse width information, and the higher precision information can be used for ADC schemes such as pulse energy/amplitude. ADC solution.
  • the optical pulse signal can also be selected according to the required parameters and precision of the optical pulse signal. For example, if higher precision is required for the arrival time and pulse width information of the optical pulse signal, at least the signal collected by the time-to-digital conversion module is selected; When the pulse energy and amplitude information of the optical pulse signal require higher accuracy, at least the signal collected by the analog-to-digital conversion module is selected. Of course, it is also possible to select two signals obtained by the module at the same time.
  • the control module After obtaining the signal collected by the time-to-digital conversion module and/or the analog-to-digital conversion module, the control module is used to calculate the selected signal.
  • the calculation method includes any one of the following schemes or two Combination of options:
  • the fitting method is to mark the acquired pulse signal at a corresponding position in the pattern of the optical pulse signal, and then restore the pulse pattern of the optical pulse signal After obtaining the pulse pattern of the pulse signal, the required information such as at least one of pulse arrival time, pulse width, pulse energy and amplitude can be further read on the pulse pattern.
  • the control module calculates the selected signal by using explicit statistics. In this calculation method, each selected sampling point is calculated correspondingly to obtain the corresponding value at each sampling point.
  • the parameter values of the optical pulse signal are used to obtain numerous point values.
  • control module calculates the selected signal. It should be noted that the above two methods for the control module to calculate the selected signal are also applicable to any combination of the following two processing methods or other processing methods. Without special instructions, fitting processing and explicit The methods of statistics are all explained above.
  • sampling points of the two types of sampling modules are fitted together to obtain the pulse pattern of the pulse signal.
  • certain sampling points can also be extracted separately for fitting, for example, sampling points with rising edges are selected for fitting.
  • the pulse arrival time, pulse width, pulse energy, etc. are extracted.
  • the two types of sampling together can provide more sampling points than either method, so the accuracy of the fitting can be improved, thereby improving the accuracy of the extraction of pulse information.
  • Conversion refers to the conversion of one of the adopted results into the adoption of another method, which is then processed, including:
  • the TDC scheme method is used for information extraction; otherwise, if the TDC sampling is converted to ADC sampling, the ADC scheme method is used.
  • Information extraction should include two types of sampling: TDC sampling + ADC conversion sampling, or ADC sampling + TDC conversion sampling.
  • the method of first fitting/interpolation and then sampling can be used.
  • the sampling of the ADC is firstly fitted in a fitting manner to obtain a graph of the optical pulse signal, and after fitting, a threshold is given in a manner of simulating TDC to acquire time.
  • the present invention provides a sampling circuit in which a time-to-digital conversion module and an analog-to-digital conversion module are provided in parallel, sampling is performed by the above two methods, there are more sampling points, and the degree of restoration of the pulse shape is better, which is a pulse Information extraction provides a better basis.
  • the sampling circuit and the method in the present invention combine the advantages of the two types of sampling to achieve the effect of complementary advantages. On the one hand, it can take into account various information such as energy and time. For example, it can obtain higher energy accuracy while ensuring time accuracy.
  • the pulse shape requirements can be widened.
  • low-amplitude wide pulses that cannot be processed by the time-to-digital conversion module can be processed by the analog-to-digital conversion module, and narrow pulses that cannot be processed by the analog-to-digital conversion module can be adopted by the time-to-digital conversion module. deal with. Pulses with appropriate amplitude and pulse width can obtain better results than any solution of the analog-to-digital conversion module and the time-to-digital conversion module.
  • both the analog-to-digital conversion module and the time-to-digital conversion module can contribute more sampling points, and the combined use of the two can improve the accuracy of pulse information extraction.
  • a sampling method based on a sampling circuit including:
  • the signals collected by the time-to-digital conversion module and/or the analog-to-digital conversion module are selected and calculated to obtain the parameter value of the optical pulse signal.
  • the time-to-digital conversion module and the analog-to-digital conversion module are set in parallel in the adopting circuit, and the sampling method is set in parallel in the adopting circuit, so as to realize the complementary advantages of the two adopting methods to obtain the optical pulse signal
  • the parameter value includes but is not limited to the following information: pulse arrival time, pulse width, pulse energy and amplitude, etc.
  • the sampling rate of the ADC sampling method is f
  • the number of quantization bits is M bits
  • the TDC of each channel includes a comparator, and each channel sets different thresholds according to requirements to obtain the rising edge time and falling time of pulses with different amplitudes Along time.
  • each channel is set with a different amplitude threshold, and the rising time and falling time of the pulse at the corresponding value are intercepted.
  • TDC is a given threshold acquisition time. Only when the pulse arrives and reaches the threshold will the TDC sampling be triggered, which can achieve high-precision time measurement at the picosecond level.
  • the time-to-digital conversion module includes multiple channels, for example, including 1 to N channels, where N is a natural number greater than 2.
  • the preset thresholds of the comparators in the different channels are different, for example, a threshold 1 to a threshold N are set.
  • Each of the channels includes a comparator and a time-to-digital converter TDC.
  • the preset thresholds set in different channels are threshold 1, threshold 2 up to threshold N, and the electrical signal input to the first input terminal of the comparator includes an electrical pulse signal.
  • the preset threshold value is threshold value 1 and when the intensity of the electrical pulse signal exceeds threshold value 1, the electrical pulse signal triggers the comparator to output a high-level signal to obtain time information corresponding to triggering threshold value 1.
  • the principle of a time extraction method is: an electrical signal input to a comparator is compared with a threshold value N to obtain a first square wave signal shown by a dotted line, the first The time TN of the transition edge of the square wave signal can be regarded as the time when the electrical signal traverses the comparator.
  • the electrical signal input to the comparison circuit is compared with the preset threshold value 1 to obtain a second square wave signal as shown by the dotted line.
  • the time T1 of the transition edge of the second square wave signal can be regarded as the electrical signal passing through the comparator Time.
  • the method of acquiring the time signal is the same for other channels.
  • the TDC scheme has a very high time resolution ability (tens of ps level), especially in the relatively fast pulse signal edge acquisition has sufficient advantages, and contributes more to the accurate collection of pulse signal time. Therefore, when there are many samples with moderate pulse height and width, the TDC scheme can be used to obtain higher-precision information such as arrival time and pulse width information.
  • the advantage of the ADC method is that it has higher voltage acquisition accuracy, and may have more contributions in the amplitude and energy of the pulse.
  • the sampling method of the ADC module is shown in Figure 2.
  • the sampling rate of the ADC is 1-10 GHz, for example, a point is taken every 1 ns.
  • sampling at time t will obtain the first amplitude signal
  • sampling at time 2t will obtain the second amplitude information
  • sampling at Kt time will obtain the first K amplitude signal to obtain the amplitude of the electrical signal corresponding to the acquisition time.
  • the above two methods are used together, that is, it can have sufficient advantages for fast pulse signal edge acquisition and can also ensure a higher voltage acquisition accuracy.
  • the pulse amplitude energy In terms of accessibility.
  • the ADC module and the N-channel TDC module run in parallel to generate digital sample data of A1, B1, B2, ...BN, and transmit them to the control module for processing in parallel.
  • the module is used to select and calculate the signal collected by the time-to-digital conversion module and/or the analog-to-digital conversion module to obtain the parameter value of the optical pulse signal.
  • control module uses a Micro Controller Unit (MCU) to process data.
  • MCU Micro Controller Unit
  • the method for the control module to select the signals collected by the time-to-digital conversion module and/or the analog-to-digital conversion module may include any one of the following solutions or a combination of any at least two solutions:
  • the pulse width setting value is used to characterize the extent to which the width of the optical pulse signal can be used to extract pulse information using the TDC scheme, and its specific value can be selected according to actual needs, and is not limited to a certain value range. Using the TDC method can avoid the insufficient sampling of the ADC due to the small pulse width.
  • the ADC scheme is used to extract pulse information, wherein the set value of the pulse height is used to characterize the extent to which the height of the optical pulse signal can be Using the ADC scheme to extract pulse information, the specific value can be selected according to actual needs, and is not limited to a certain value range. Using the ADC method can avoid the situation where the TDC is insufficiently sampled because the pulse height is too small.
  • the width of the optical pulse signal is greater than the set value of the pulse width and the pulse height of the optical pulse signal is greater than the set value of the pulse height
  • at least one of the ADC method and the TDC method may be selected, or Sampling is performed using both schemes. That is, when there are many samples with moderate pulse height and width, the TDC scheme can be used to obtain higher precision information for TDC schemes such as arrival time and pulse width information, and the higher precision information can be used for ADC schemes such as pulse energy/amplitude. ADC solution.
  • the optical pulse signal can also be selected according to the required parameters and precision of the optical pulse signal. For example, if higher precision is required for the arrival time and pulse width information of the optical pulse signal, at least the signal collected by the time-to-digital conversion module is selected; When the pulse energy and amplitude information of the optical pulse signal require higher accuracy, at least the signal collected by the analog-to-digital conversion module is selected. Of course, it is also possible to select two signals obtained by the module at the same time.
  • the control module After obtaining the signal collected by the time-to-digital conversion module and/or the analog-to-digital conversion module, the control module is used to calculate the selected signal.
  • the calculation method includes any one of the following schemes or two Combination of options:
  • the fitting method is to mark the acquired pulse signal at a corresponding position in the pattern of the optical pulse signal, and then restore the pulse pattern of the optical pulse signal After obtaining the pulse pattern of the pulse signal, the required information such as at least one of pulse arrival time, pulse width, pulse energy and amplitude can be further read on the pulse pattern.
  • the control module calculates the selected signal by using explicit statistics. In this calculation method, each selected sampling point is calculated correspondingly to obtain the corresponding value at each sampling point.
  • the parameter values of the optical pulse signal are used to obtain numerous point values.
  • control module calculates the selected signal. It should be noted that the above two methods for the control module to calculate the selected signal are also applicable to any combination of the following two processing methods or other processing methods. Without special instructions, fitting processing and explicit The methods of statistics are all explained above.
  • sampling points of the two types of sampling modules are fitted together to obtain the pulse pattern of the pulse signal.
  • certain sampling points can also be extracted separately for fitting, for example, sampling points with rising edges are selected for fitting.
  • the pulse arrival time, pulse width, pulse energy, etc. are extracted.
  • the two types of sampling together can provide more sampling points than either method, so the accuracy of the fitting can be improved, thereby improving the accuracy of the extraction of pulse information.
  • Conversion refers to the conversion of one of the adopted results into the adoption of another method, which is then processed, including:
  • the TDC scheme method is used for information extraction; otherwise, if the TDC sampling is converted to ADC sampling, the ADC scheme method is used.
  • Information extraction should include two types of sampling: TDC sampling + ADC conversion sampling, or ADC sampling + TDC conversion sampling.
  • the method of first fitting/interpolation and then sampling can be used.
  • the sampling of the ADC is firstly fitted in a fitting manner to obtain a graph of the optical pulse signal, and after fitting, a threshold is given in a manner of simulating TDC to acquire time.
  • the sampling circuits provided by various embodiments of the present invention may be applied to a distance measuring device, and the distance measuring device may be an electronic device such as a laser radar or a laser distance measuring device.
  • the distance measuring device is used to sense external environment information, for example, distance information, azimuth information, reflection intensity information, speed information, etc. of the environmental target.
  • the distance measuring device can detect the distance between the detecting object and the distance measuring device by measuring the time of light propagation between the distance measuring device and the detection object, that is, Time-of-Flight (TOF).
  • TOF Time-of-Flight
  • the distance measuring device may also detect the distance between the detected object and the distance measuring device through other techniques, such as a distance measuring method based on phase shift measurement, or a distance measuring method based on frequency shift measurement. There are no restrictions.
  • the distance measuring device 100 may include a transmitting circuit 110, a receiving circuit 120, a sampling circuit 130 and an arithmetic circuit 140.
  • the transmission circuit 110 may transmit a sequence of light pulses (for example, a sequence of laser pulses).
  • the receiving circuit 120 can receive the optical pulse sequence reflected by the detected object, and photoelectrically convert the optical pulse sequence to obtain an electrical signal, which can be output to the sampling circuit 130 after processing the electrical signal.
  • the sampling circuit 130 may sample the electrical signal to obtain the sampling result.
  • the arithmetic circuit 140 may determine the distance between the distance measuring device 100 and the detected object based on the sampling result of the sampling circuit 130.
  • the distance measuring apparatus 100 may further include a control circuit 150, which may control other circuits, for example, may control the working time of each circuit and/or set parameters for each circuit.
  • a control circuit 150 may control other circuits, for example, may control the working time of each circuit and/or set parameters for each circuit.
  • the distance measuring device shown in FIG. 4 includes a transmitting circuit, a receiving circuit, a sampling circuit, and an arithmetic circuit for emitting a beam of light for detection
  • the embodiments of the present application are not limited thereto, and the transmitting circuit
  • the number of any one of the receiving circuit, the sampling circuit, and the arithmetic circuit may also be at least two, for emitting at least two light beams in the same direction or respectively in different directions; wherein, the at least two light paths may be simultaneously
  • the shot may be shot at different times.
  • the light-emitting chips in the at least two emission circuits are packaged in the same module.
  • each emitting circuit includes a laser emitting chip, and the die in the laser emitting chips in the at least two emitting circuits are packaged together and accommodated in the same packaging space.
  • the distance measuring device 100 may further include a scanning module for changing at least one laser pulse sequence emitted by the transmitting circuit to change the propagation direction.
  • the module including the transmitting circuit 110, the receiving circuit 120, the sampling circuit 130, and the arithmetic circuit 140, or the module including the transmitting circuit 110, the receiving circuit 120, the sampling circuit 130, the arithmetic circuit 140, and the control circuit 150 may be referred to as measurement Distance module, the distance measuring module may be independent of other modules, for example, a scanning module.
  • a coaxial optical path may be used in the distance measuring device, that is, the light beam emitted by the distance measuring device and the reflected light beam share at least part of the optical path in the distance measuring device.
  • the distance measuring device may also adopt an off-axis optical path, that is, the light beam emitted by the distance measuring device and the reflected light beam are respectively transmitted along different optical paths in the distance measuring device.
  • FIG. 5 shows a schematic diagram of an embodiment of the distance measuring device of the present invention using a coaxial optical path.
  • the distance measuring device 200 includes a distance measuring module 210.
  • the distance measuring module 210 includes a transmitter 203 (which may include the above-mentioned transmitting circuit), a collimating element 204, and a detector 205 (which may include the above-mentioned receiving circuit, sampling circuit, and arithmetic circuit) and Optical path changing element 206.
  • the ranging module 210 is used to emit a light beam, and receive back light, and convert the back light into an electrical signal.
  • the transmitter 203 may be used to transmit a light pulse sequence.
  • the transmitter 203 may emit a sequence of laser pulses.
  • the laser beam emitted by the transmitter 203 is a narrow-bandwidth beam with a wavelength outside the visible light range.
  • the collimating element 204 is disposed on the exit optical path of the emitter, and is used to collimate the light beam emitted from the emitter 203, and collimate the light beam emitted from the emitter 203 into parallel light to the scanning module.
  • the collimating element is also used to converge at least a part of the return light reflected by the detection object.
  • the collimating element 204 may be a collimating lens or other element capable of collimating the light beam.
  • the optical path changing element 206 is used to combine the transmitting optical path and the receiving optical path in the distance measuring device before the collimating element 204, so that the transmitting optical path and the receiving optical path can share the same collimating element, so that the optical path More compact.
  • the transmitter 203 and the detector 205 may respectively use respective collimating elements, and the optical path changing element 206 is disposed on the optical path behind the collimating element.
  • the light path changing element can use a small-area mirror to change The transmitting optical path and the receiving optical path are combined.
  • the light path changing element may also use a reflector with a through hole, where the through hole is used to transmit the outgoing light of the emitter 203, and the reflector is used to reflect the return light to the detector 205. This can reduce the blocking of the return light by the support of the small mirror in the case of using the small mirror.
  • the optical path changing element is offset from the optical axis of the collimating element 204. In some other implementations, the optical path changing element may also be located on the optical axis of the collimating element 204.
  • the distance measuring device 200 further includes a scanning module 202.
  • the scanning module 202 is placed on the exit optical path of the distance measuring module 210.
  • the scanning module 202 is used to change the transmission direction of the collimated light beam 219 emitted through the collimating element 204 and project it to the external environment, and project the return light to the collimating element 204 .
  • the returned light is converged on the detector 205 via the collimating element 204.
  • the scanning module 202 may include at least one optical element for changing the propagation path of the light beam, wherein the optical element may change the propagation path of the light beam by reflecting, refracting, diffracting, etc. the light beam.
  • the scanning module 202 includes a lens, a mirror, a prism, a galvanometer, a grating, a liquid crystal, an optical phased array (Optical Phased Array), or any combination of the above optical elements.
  • at least part of the optical element is moving, for example, the at least part of the optical element is driven to move by a driving module, and the moving optical element can reflect, refract, or diffract the light beam to different directions at different times.
  • multiple optical elements of the scanning module 202 may rotate or vibrate about a common axis 209, and each rotating or vibrating optical element is used to continuously change the direction of propagation of the incident light beam.
  • the multiple optical elements of the scanning module 202 may rotate at different rotation speeds, or vibrate at different speeds.
  • at least part of the optical elements of the scanning module 202 can rotate at substantially the same rotational speed.
  • the multiple optical elements of the scanning module may also rotate around different axes.
  • the multiple optical elements of the scanning module may also rotate in the same direction, or rotate in different directions; or vibrate in the same direction, or vibrate in different directions, which is not limited herein.
  • the scanning module 202 includes a first optical element 214 and a driver 216 connected to the first optical element 214.
  • the driver 216 is used to drive the first optical element 214 to rotate about a rotation axis 209 to change the first optical element 214 The direction of the collimated light beam 219.
  • the first optical element 214 projects the collimated light beam 219 to different directions.
  • the angle between the direction of the collimated light beam 219 changed by the first optical element and the rotation axis 109 changes as the first optical element 214 rotates.
  • the first optical element 214 includes a pair of opposed non-parallel surfaces through which the collimated light beam 219 passes.
  • the first optical element 214 includes a prism whose thickness varies along at least one radial direction.
  • the first optical element 214 includes a wedge-angle prism, aligning the straight beam 219 for refraction.
  • the scanning module 202 further includes a second optical element 215 that rotates about a rotation axis 209.
  • the rotation speed of the second optical element 215 is different from the rotation speed of the first optical element 214.
  • the second optical element 215 is used to change the direction of the light beam projected by the first optical element 214.
  • the second optical element 115 is connected to another driver 217, and the driver 217 drives the second optical element 215 to rotate.
  • the first optical element 214 and the second optical element 215 may be driven by the same or different drivers, so that the first optical element 214 and the second optical element 215 have different rotation speeds and/or rotations, thereby projecting the collimated light beam 219 to the outside space Different directions can scan a larger spatial range.
  • the controller 218 controls the drivers 216 and 217 to drive the first optical element 214 and the second optical element 215, respectively.
  • the rotation speeds of the first optical element 214 and the second optical element 215 can be determined according to the area and pattern expected to be scanned in practical applications.
  • Drives 216 and 217 may include motors or other drives.
  • the second optical element 215 includes a pair of opposed non-parallel surfaces through which the light beam passes. In one embodiment, the second optical element 215 includes a prism whose thickness varies along at least one radial direction. In one embodiment, the second optical element 215 includes a wedge angle prism.
  • the scanning module 202 further includes a third optical element (not shown) and a driver for driving the third optical element to move.
  • the third optical element includes a pair of opposed non-parallel surfaces through which the light beam passes.
  • the third optical element includes a prism whose thickness varies along at least one radial direction.
  • the third optical element includes a wedge angle prism. At least two of the first, second and third optical elements rotate at different rotational speeds and/or turns.
  • each optical element in the scanning module 202 can project light into different directions, such as the direction and direction 213 of the projected light 211, thus scanning the space around the distance measuring device 200.
  • the light 211 projected by the scanning module 202 hits the detection object 201, a part of the light is reflected by the detection object 201 to the distance measuring device 200 in a direction opposite to the projected light 211.
  • the returned light 212 reflected by the detection object 201 passes through the scanning module 202 and enters the collimating element 204.
  • the detector 205 is placed on the same side of the collimating element 204 as the emitter 203.
  • the detector 205 is used to convert at least part of the returned light passing through the collimating element 204 into an electrical signal.
  • each optical element is coated with an antireflection coating.
  • the thickness of the antireflection film is equal to or close to the wavelength of the light beam emitted by the emitter 203, which can increase the intensity of the transmitted light beam.
  • a filter layer is coated on the surface of an element on the beam propagation path in the distance measuring device, or a filter is provided on the beam propagation path to transmit at least the wavelength band of the beam emitted by the transmitter, Reflect other bands to reduce the noise caused by ambient light to the receiver.
  • the transmitter 203 may include a laser diode through which laser pulses in the order of nanoseconds are emitted.
  • the laser pulse receiving time may be determined, for example, by detecting the rising edge time and/or the falling edge time of the electrical signal pulse. In this way, the distance measuring device 200 can calculate the TOF using the pulse reception time information and the pulse emission time information, thereby determining the distance between the detection object 201 and the distance measuring device 200.
  • the distance and orientation detected by the distance measuring device 200 can be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like.
  • the distance measuring device of the embodiment of the present invention can be applied to a mobile platform, and the distance measuring device can be installed on the platform body of the mobile platform.
  • a mobile platform with a distance measuring device can measure the external environment, for example, measuring the distance between the mobile platform and obstacles for obstacle avoidance and other purposes, and performing two-dimensional or three-dimensional mapping on the external environment.
  • the mobile platform includes at least one of an unmanned aerial vehicle, a car, a remote control car, a robot, and a camera.
  • the distance measuring device is applied to an unmanned aerial vehicle, the platform body is the fuselage of the unmanned aerial vehicle.
  • the platform body When the distance measuring device is applied to an automobile, the platform body is the body of the automobile.
  • the car may be a self-driving car or a semi-automatic car, and no restriction is made here.
  • the platform body When the distance measuring device is applied to a remote control car, the platform body is the body of the remote control car.
  • the platform body When the distance measuring device is applied to a robot, the platform body is a robot.
  • the distance measuring device is applied to a camera, the platform body is the camera itself.

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Abstract

一种采样电路（130）、采样方法及测距装置（200）、移动平台。采样电路（130）包括：并行设置的时间数字转换模块、模数转换模块，采样电路（130）还包括控制模块；其中，时间数字转换模块用于接收由光脉冲信号转化得到的电信号并将电信号与预设阈值进行比较运算，采集与电信号对应的时间信息；模数转换模块用于接收由光脉冲信号转化得到的电信号，并在采样时钟频率内采集与采集时间对应的电信号的幅值；控制模块，用于选取时间数字转换模块和/或模数转换模块采集的信号并进行计算，以得到光脉冲信号的参数值。

Description

一种采样电路、采用方法及测距装置、移动平台 技术领域
本发明涉及激光雷达技术领域，尤其涉及一种采样电路、采用方法及测距装置、移动平台。
背景技术
激光雷达是以发射激光束探测目标的位置、速度等特征量的雷达系统。激光雷达的光敏传感器可以将获取到的光脉冲信号转变为电信号，基于比较器获取该电信号对应的时间信息，从而得到激光雷达与目标物之间的距离信息。
然而，在激光雷达等激光测距相关的产品中，通常需要对能量、到达时间、形状参数等多种脉冲信息进行提取，以更为全面、准确地反应被探测场景的物体信息。对脉冲信号的采样和处理通常是关乎系统性能的瓶颈技术。
因此，需要对目前获取脉冲信息的装置和方法做进一步的改进。
发明内容
本发明第一方面提供了一种采样电路，包括：并行设置的时间数字转换模块、模数转换模块，所述采样电路还包括控制模块；
其中，所述时间数字转换模块用于接收由光脉冲信号转化得到的电信号并将所述电信号与预设阈值进行比较运算，采集与所述电信号对应的时间信息；
所述模数转换模块用于接收由所述光脉冲信号转化得到的所述电信号，并在采样时钟频率内采集与采集时间对应的电信号的幅值；
所述控制模块，用于选取所述时间数字转换模块和/或所述模数转换模块采集的信号并进行计算，以得到所述光脉冲信号的参数值。
可选地，所述时间数字转换模块包括多个通道，其中每个所述通道均包括比较器和时间数字转换器，其中，所述比较器的第一输入端用于接收由光脉冲信号转化得到的电信号，所述比较器的第二输入端用于接收所述比较器的预设阈值，所述比较器的输出端用于输出比较运算的结果，所述时间数字转换器与所述比较器的输出端电连接，用于根据所述比较器输出的比较运算的结果，提 取与所述电信号对应的时间信息；
其中，所述不同通道中的比较器的预设阈值不同。
可选地，所述模数转换模块包括至少一个模数转换器，用于采集与所述采集时间对应的电信号的幅值。
可选地，所述控制模块用于采用拟合的方式对选取的所述信号进行计算，以还原所述光脉冲信号的图形；
或者所述控制模块用于采用显式的统计量的方式对选取的所述信号进行计算，以得到所述光脉冲信号的参数值。
可选地，所述控制模块采集所述时间数字转换模块的至少部分信号和所述模数转换模块采集的至少部分信号进行所述拟合。
可选地，所述控制模块还用于将所述时间数字转换模块的采样转换为所述模数转换模块方式的采样；
或所述控制模块还用于将所述模数转换模块的采样转换为所述时间数字转换模块方式的采样。
可选地，所述控制模块用于采用拟合的方式先对所述模数转换模块的采样的信号进行计算，以得到所述光脉冲信号的图形，然后在所述光脉冲信号的图形上标定预设阈值以及对应的时间信息。
可选地，所述控制模块选取所述信号时：
当所述光脉冲信号的宽度小于脉冲宽度设定值时，则选取所述时间数字转换模块采集的信号；和/或
当所述光脉冲信号的脉冲高度小于脉冲高度设定值时，则选取所述模数转换模块采集的信号；和/或
当所述光脉冲信号的宽度大于脉冲宽度设定值时以及所述光脉冲信号的脉冲高度大于脉冲高度设定值时，若对所述光脉冲信号的到达时间和脉宽信息要求精度更高时，则至少选取所述时间数字转换模块采集的信号；若对所述光脉冲信号的脉冲能量和幅值信息要求精度更高时，则至少选取所述模数转换模块采集的信号。
可选地，所述参数值包括脉冲到达时间、脉宽、脉冲能量和幅值中的至少 一种。
本发明还提供了一种基于采样电路的采样方法，包括：
通过时间数字转换模块接收由光脉冲信号转化得到的电信号并将所述电信号与预设阈值进行比较运算，采集与所述电信号对应的时间信息；
通过模数转换模块接收由光脉冲信号转化得到的电信号，并在采样时钟频率内采集与采集时间对应的电信号的幅值信号；
选取所述时间数字转换模块和/或所述模数转换模块采集的信号并进行计算，以得到所述光脉冲信号的参数值。
可选地，所述时间数字转换模块包括多个通道，所述多个通道并行地接收所述电信号并将所述电信号进行比较运算，采集与所述电信号对应的时间信息。
可选地，所述多个通道分别设置不同的预设阈值，以并行地接收所述电信号并将所述电信号进行比较运算。
可选地，选取信号并进行计算，以得到所述光脉冲信号的参数值的步骤包括：
采用拟合的方式对选取的所述信号进行计算，以还原所述光脉冲信号的图形；
或者采用显式的统计量的方式对选取的所述信号进行计算，以得到所述光脉冲信号的参数值。
可选地，至少选取所述时间数字转换模块的部分信号和所述模数转换模块采集的部分信号进行所述拟合。
可选地，选取所述时间数字转换模块和所述模数转换模块采集的信号之后，在进行计算之前，还包括：
将所述时间数字转换模块的采样转换为所述模数转换模块方式的采样；
或所述控制模块还用于将所述模数转换模块的采样转换为所述时间数字转换模块方式的采样。
可选地，采用拟合的方式先对所述模数转换模块的采样的信号进行计算，以得到所述光脉冲信号的图形，然后在所述光脉冲信号的图形结构上标定预设阈值以及对应的时间信息。
可选地，选取所述信号时，
当所述光脉冲信号的宽度小于脉冲宽度设定值时，则选取所述时间数字转换模块采集的信号；和/或
当所述光脉冲信号的脉冲高度小于脉冲高度设定值时，则选取所述模数转换模块采集的信号；和/或
当所述光脉冲信号的宽度大于脉冲宽度设定值时以及所述光脉冲信号的脉冲高度大于脉冲高度设定值时，若对所述光脉冲信号的到达时间和脉宽信息要求精度更高时，则至少选取所述时间数字转换模块采集的信号；若对所述光脉冲信号的脉冲能量和幅值信息要求精度更高时，则至少选取所述模数转换模块采集的信号。
可选地，所述参数值包括脉冲到达时间、脉冲宽度、脉冲能量和脉冲幅值中的至少一种。
本发明还提供了一种测距装置，包括：
光发射电路，用于出射光脉冲信号；
光接收电路，用于接收所述光发射电路出射的光脉冲信号经物体反射回的至少部分光信号，以及将接收到的所述激光信号转成电信号；
上述的采样电路，用于对来自所述激光接收电路的电信号进行采样，获得采样结果；
运算电路，用于根据所述采样结果计算所述物体与所述测距装置之间的距离。
本发明还提供了一种移动平台，包括：
上述的测距装置；和
平台本体，所述测距装置的光发射电路安装在所述平台本体上。
可选地，所述移动平台包括无人飞行器、汽车和机器人中的至少一种。
本发明通过提供上述采样电路、采用方法、测距装置以及移动平台，所述采样电路中并行设置时间数字转换模块和模数转换模块，通过上述两种方式进行采样，采样点更多，对脉冲形状的还原度更好，为脉冲信息的提取提供了更好的基础。此外，本发明中采样电路、采用方法综合两类采样的优点，达到优 势互补的效果。一方面可以兼顾能量、时间等多种信息，如在保证时间精度的同时也可以获得较高能量精度等，同时发挥模数转换模块对能量采集的优势以及时间数字转换模块对时间采集的优势；另一方面可以拓宽对脉冲形状的要求，如时间数字转换模块无法处理的低幅值宽脉冲可以采用模数转换模块处理，模数转换模块无法处理的窄脉冲可以采用时间数字转换模块的方式来处理。对幅值、脉宽均适当的脉冲可以获得较模数转换模块和时间数字转换模块任一方案都好的效果。对于这类脉冲，模数转换模块和时间数字转换模块都能贡献较多的采样点，将两者综合使用可以改善脉冲信息提取的精准度。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为本发明一实施例中时间数字转换方法获取的采样信号的结构示意图；
图2为本发明一实施例中模数转换方法获取的采样信号的结构示意图；
图3为本发明一实施例中采样电路的结构示意图；
图4是本发明实施例提供的一种测距装置的示意性框架图；
图5是本发明实施例提供的测距装置采用同轴光路的一种实施例的示意图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
在激光雷达等激光测距相关的产品中，通常需要对能量、到达时间、形状参数等多种脉冲信息进行提取，目前光脉冲数字化的方法主要有时间数字转换 方法(例如，使用时间数字转换器Time-to-Digital Converter，TDC)和模数转换方法(例如使用模数转换器，Analog-to-Digital Converter，ADC)两种。
其中，TDC和ADC各有优劣，通常难以兼顾对多种信息的提取精度。TDC只能实现N个通道的并行采集，那么最多只能采集N+1个幅度值，其在电压幅值方面的采样精度、区分度较低，特别是对于脉冲信号的幅值采样是缺失的。另外，在基线附近，由于受到基线噪声的影响，目前TDC方案无法多次连续测量，若阈值过低，TDC被噪声触发后，一旦遇到真实脉冲信号后，也无法再对真实脉冲信号进行响应。
而对于ADC，采样率非常高(或者说采样间隔很小的)。可用的ADC采样率一般为GHz级别，也就是每隔1ns采一个点。在10ns左右的脉冲信号中，也就只能采集到10个点左右，对于脉冲信息获取并不足够。另外，ADC采样时间相对于脉冲信号是随机的，即对不同时刻到达的脉冲其采样点相对于到达时刻的位置是不固定的，而在实际的应用中，获取准确地脉冲时间信息才能获得准确的测量距离，相对于脉冲时间随机的采样方式采样精度差一些。
特别的，在较为快速的脉冲信号沿上，ADC所采集点的数量是有限的，脉冲信号沿越快则采集点越少，对脉冲信号的还原也就越差，而TDC方案中，不论信号沿有多快，都能采集到能够触发到的点。
在激光测距应用中，探测器所接收的脉冲信号随被测物体距离、反射率、漫反射路径等的不同而不同，光脉冲的幅度和脉宽都会不同程度地发生改变，因此数字化电路及处理方法需要适应在很大范围内变化的不同脉宽不同幅度的脉冲信号，对当前TDC方案或者ADC方案都提出了更高的要求。
为了解决上述问题，本发明提供了一种采样电路，在所述采用电路中并行的设置时间数字转换模块和模数转换模块，将所述采样方式并行的设置在采用电路中，从而实现两种采用方法的优势互补，以得到所述光脉冲信号的参数值。其中，所述参数值包括但不局限于以下信息：脉冲到达时间、脉宽、脉冲能量和幅值等。
如图3所示，本发明的一实施例中，综合了ADC和TDC两种采样方式，包括单个通道的ADC模块和N个通道的TDC模块。其中，ADC模块采样率 为f，量化位数为M比特；而每个通道的TDC包括一个比较器，各个通道根据需求设定不同的阈值，获取不同幅度下脉冲的上升沿时间和下降沿时间。
其中，在所述时间数字转换模块中，通常采用多通道的设计，各个通道设置不同的幅度阈值，截取出脉冲在相应取值下的上升沿时间和下降沿时间。TDC是给定阈值采集时间，只有当脉冲到来并达到阈值时才会触发TDC的采样，可以实现皮秒级别的高精度时间测量。
如图1所示，所述时间数字转换模块包括多个通道，例如包括1至N个通道，其中N为大于2的自然数。并且所述不同通道中的比较器的预设阈值不同，例如设置阈值1至阈值N。
其中每个所述通道均包括比较器和时间数字转换器TDC，在所述每个通道中所述比较器的第一输入端用于接收由光脉冲信号转化得到的电信号，所述比较器的第二输入端用于接收所述比较器的预设阈值，所述比较器的输出端用于输出比较运算的结果，所述时间数字转换器TDC与所述比较器的输出端电连接，用于根据所述比较器输出的比较运算的结果，提取与所述电信号对应的时间信息
在本发明的一示例中，如图1所示，不同通道中设置的预设阈值分别为阈值1、阈值2一直至阈值N，输入到比较器第一输入端的电信号包括电脉冲信号，当预设阈值为阈值1并且当所述电脉冲信号的强度超过阈值1，则电脉冲信号触发比较器输出高电平信号，以获取触发该阈值1对应的时间信息。
其中，如图1所示，本发明实施例提供的一种时间提取方法的原理为：输入比较器的电信号与阈值N进行比较运算，获得如虚线所示的第一方波信号，第一方波信号的跳变沿的时间TN可以认为是电信号穿越比较器时的时间。同理，输入比较电路的电信号与预设阈值1进行比较运算，获得如虚线所示的第二方波信号，第二方波信号的跳变沿的时间T1可以认为是电信号穿越比较器时的时间。其他通道的获取时间信号的方法相同。
其中，TDC方案有很高的时间分辨能力(数十ps级别)，特别是在较为快速的脉冲信号沿采集中有足够的优势，对脉冲信号时间的准确采集贡献更多。因此当脉冲高度及宽度适中两种采样均较多时，对到达时间、脉宽信息等TDC 方案可以获得更高精度的信息采用TDC方案。
其中，ADC方法的优势在于有较高的电压采集精度，在脉冲的幅值、能量方面或有更多贡献。ADC模块的采样方法如图2所示，采样时钟频率为f，那么每间隔t＝1/f，则有一个幅度的采样值。若有足够高的采样率，ADC的数字信号可以还原光脉冲信号的幅度随时间的变化过程。如果幅度信息量化为M比特，那么能量的精度可以达到1/2M，可以精准地测量光脉冲的幅度信息。在本发明的一示例中，ADC采样率为1-10GHz级别，例如每隔1ns采一个点。
示例性地，在t时间点上进行采样，则得到第一幅值信号，在2t时间点上进行采样，则得到第二幅值信息，依次类推，在Kt时间点上进行采样，则得到第K幅值信号，从而得到与采集时间对应的电信号的幅值。
在本发明的实施例中，将上述两种采用方式集中在一起，即可以对快速的脉冲信号沿采集中有足够的优势还可以保证有较高的电压采集精度，在脉冲的幅值、能量方面有更好的获取能力。
如图3所示，在本发明的一个示例中，ADC模块和N通道TDC模块并行运行，分别生成A1、B1、B2、…BN的数字采样数据，并行传输给控制模块进行处理，所述控制模块用于选取所述时间数字转换模块和/或所述模数转换模块采集的信号并进行计算，以得到所述光脉冲信号的参数值。
可选地，在本发明的一示例中，所述控制模块使用微程序控制单元(Micro Controller Unit，MCU)，进行数据的处理。
可选地，所述控制模块选取所述时间数字转换模块和/或所述模数转换模块采集的信号的方法可以包括以下任意一种方案或任意至少两种方案的组合：
第一，分类进行选择，充分利用每种模块进行处理时的优点。比如：
1、当所述光脉冲信号的宽度小于脉冲宽度设定值时，使用TDC方案进行脉冲信息的提取，提取所述时间数字转换模块采集的信号。其中，所述脉冲宽度设定值用于表征光脉冲信号的宽度在什么程度下可以使用TDC方案进行脉冲信息的提取，其具体数值可以根据实际需要进行选择，并不局限于某一数值范围。采用TDC方法可以避免由于脉冲宽度较小导致ADC采样不足的情况。
2、当所述光脉冲信号的脉冲高度小于脉冲高度设定值时，使用ADC方案 进行脉冲信息的提取，其中，所述脉冲高度设定值用于表征光脉冲信号的高度在什么程度下可以使用ADC方案进行脉冲信息的提取，其具体数值可以根据实际需要进行选择，并不局限于某一数值范围。采用ADC方法可以避免由于脉冲高度太小导致TDC采样不足的情况。
3、当所述光脉冲信号的宽度大于脉冲宽度设定值时以及所述光脉冲信号的脉冲高度大于脉冲高度设定值时，可以选用ADC方法和TDC方法中的至少一种，或者还可以同时使用两种方案进行采样。即脉冲高度及宽度适中两种采样均较多时，对到达时间、脉宽信息等TDC方案可以获得更高精度的信息采用TDC方案，对脉冲能量/幅度等ADC方案可以获得更高精度的信息采用ADC方案。
当然还可以根据需要的光脉冲信号参数以及精度进行选择，例如若对所述光脉冲信号的到达时间和脉宽信息要求精度更高时，则至少选取所述时间数字转换模块采集的信号；若对所述光脉冲信号的脉冲能量和幅值信息要求精度更高时，则至少选取所述模数转换模块采集的信号。当然还可以同时选取两种采用模块获得的信号。
其中，在获取所述时间数字转换模块和/或所述模数转换模块采集的信号之后，所述控制模块用于对选取的所述信号进行计算，计算的方法包括以下任意一种方案或两种方案的组合：
I，采用拟合的方式对选取的所述信号进行计算，其中拟合的方式是将获取的脉冲信号在光脉冲信号的图形中相应的位置进行标注，进而还原所述光脉冲信号的脉冲图形，在得到脉冲信号的脉冲图形之后，可以在脉冲图形上进一步读取所需要的信息，例如脉冲到达时间、脉宽、脉冲能量和幅值中的至少一种。
II，所述控制模块通过采用显式的统计量的方式对选取的所述信号进行计算，在该计算方法中对选取的每个采样点进行相应的计算，以得到在每个采样点对应的所述光脉冲信号的参数值，以得到众多的点值。
需要说明的是控制模块对选取的所述信号进行计算的上述两种方法同样适用于以下两种处理方式或其他处理方式任意的组合中，在没有特殊说明的情 况下，拟合处理和显式的统计量的方式均参照上述解释。
第二，直接深度融合的方式进行处理。在所述方法中，将两类采样模块的采样点一起进行拟合，以得到脉冲信号的脉冲图形。当然也可以分别抽取一定的采样点来进行拟合，如都选取上升沿的采样点来进行拟合等。根据拟合结果来进行脉冲到达时间、脉宽、脉冲能量等的提取。两类采样一起可以提供比其中任一方式更多的采样点，因此可以改善拟合的准确度，进而改善脉冲信息的提取精准度。
第三，转换后深度融合，转换是指将其中一种采用结果转换为另外一种方式的采用，然后再进行处理，具体包括：
1、从ADC的采样结果转换为TDC方式的采样，或/和将TDC的采样结果转换为ADC方式的采样。然后将转换的结果与另一种采样的点放在一起，统一采用某种方式进行脉冲信息的提取。例如拟合处理和显式的统计量的方式中的至少一种。
在本发明的示例中，若ADC采样被转换为TDC方式的采样，则采用TDC方案的方法来进行信息提取；反之，若是将TDC采样转换为ADC方式的采样，则采用ADC方案的方法来进行信息提取。提取时所采用的统计量应包含两类采样：TDC采样+ADC转换来的采样，或者ADC采样+TDC转换来的采样。
2、对于ADC与TDC采样之间的转换，可以采用先拟合/插值，再采样的方式。在本发明的示例中，例如采用拟合的方式先对先对ADC采样进行拟合，以得到所述光脉冲信号的图形，拟合后模拟TDC的方式给定阈值来采集时间。
本发明提供了一种采样电路，所述采样电路中并行设置时间数字转换模块和模数转换模块，通过上述两种方式进行采样，采样点更多，对脉冲形状的还原度更好，为脉冲信息的提取提供了更好的基础。此外，本发明中采样电路、采用方法综合两类采样的优点，达到优势互补的效果。一方面可以兼顾能量、时间等多种信息，如在保证时间精度的同时也可以获得较高能量精度等，同时发挥模数转换模块对能量采集的优势以及时间数字转换模块对时间采集的优势；另一方面可以拓宽对脉冲形状的要求，如时间数字转换模块无法处理的低幅值宽脉冲可以采用模数转换模块处理，模数转换模块无法处理的窄脉冲可以 采用时间数字转换模块的方式来处理。对幅值、脉宽均适当的脉冲可以获得较模数转换模块和时间数字转换模块任一方案都好的效果。对于这类脉冲，模数转换模块和时间数字转换模块都能贡献较多的采样点，将两者综合使用可以改善脉冲信息提取的精准度。
在本发明的另外一个实施例中提供了一种基于采样电路的采样方法，包括：
通过时间数字转换模块接收由光脉冲信号转化得到的电信号并将所述电信号与预设阈值进行比较运算，采集与所述电信号对应的时间信息；
通过模数转换模块接收由光脉冲信号转化得到的电信号，并在采样时钟频率内采集与采集时间对应的电信号的幅值信号；
选取所述时间数字转换模块和/或所述模数转换模块采集的信号并进行计算，以得到所述光脉冲信号的参数值。
在所述采用电路中并行的设置时间数字转换模块和模数转换模块，将所述采样方式并行的设置在采用电路中，从而实现两种采用方法的优势互补，以得到所述光脉冲信号的参数值。其中，所述参数值包括但不局限于以下信息：脉冲到达时间、脉宽、脉冲能量和幅值等。
如图3所示，本发明的一实施例中，综合了ADC和TDC两种采样方式。其中，ADC采样方法的采样率为f，量化位数为M比特；而每个通道的TDC包括一个比较器，各个通道根据需求设定不同的阈值，获取不同幅度下脉冲的上升沿时间和下降沿时间。
其中，在所述时间数字转换模块中，通常采用多通道的设计，各个通道设置不同的幅度阈值，截取出脉冲在相应取值下的上升沿时间和下降沿时间。TDC是给定阈值采集时间，只有当脉冲到来并达到阈值时才会触发TDC的采样，可以实现皮秒级别的高精度时间测量。
如图1所示，所述时间数字转换模块包括多个通道，例如包括1至N个通道，其中N为大于2的自然数。并且所述不同通道中的比较器的预设阈值不同，例如设置阈值1至阈值N。
其中每个所述通道均包括比较器和时间数字转换器TDC。在本发明的一 示例中，如图1所示，不同通道中设置的预设阈值分别为阈值1、阈值2一直至阈值N，输入到比较器第一输入端的电信号包括电脉冲信号，当预设阈值为阈值1并且当所述电脉冲信号的强度超过阈值1，则电脉冲信号触发比较器输出高电平信号，以获取触发该阈值1对应的时间信息。
其中，如图1所示，本发明实施例提供的一种时间提取方法的原理为：输入比较器的电信号与阈值N进行比较运算，获得如虚线所示的第一方波信号，第一方波信号的跳变沿的时间TN可以认为是电信号穿越比较器时的时间。同理，输入比较电路的电信号与预设阈值1进行比较运算，获得如虚线所示的第二方波信号，第二方波信号的跳变沿的时间T1可以认为是电信号穿越比较器时的时间。其他通道的获取时间信号的方法相同。
其中，TDC方案有很高的时间分辨能力(数十ps级别)，特别是在较为快速的脉冲信号沿采集中有足够的优势，对脉冲信号时间的准确采集贡献更多。因此当脉冲高度及宽度适中两种采样均较多时，对到达时间、脉宽信息等TDC方案可以获得更高精度的信息采用TDC方案。
其中，ADC方法的优势在于有较高的电压采集精度，在脉冲的幅值、能量方面或有更多贡献。ADC模块的采样方法如图2所示，采样时钟频率为f，那么每间隔t＝1/f，则有一个幅度的采样值。若有足够高的采样率，ADC的数字信号可以还原光脉冲信号的幅度随时间的变化过程。如果幅度信息量化为M比特，那么能量的精度可以达到1/2M，可以精准地测量光脉冲的幅度信息。在本发明的一示例中，ADC采样率为1-10GHz级别，例如每隔1ns采一个点。
示例性地，在t时间点上进行采样，则得到第一幅值信号，在2t时间点上进行采样，则得到第二幅值信息，依次类推，在Kt时间点上进行采样，则得到第K幅值信号，从而得到与采集时间对应的电信号的幅值。
在本发明的实施例中，将上述两种采用方式集中在一起，即可以对快速的脉冲信号沿采集中有足够的优势还可以保证有较高的电压采集精度，在脉冲的幅值、能量方面有更好的获取能力。
如图3所示，在本发明的一个示例中，ADC模块和N通道TDC模块并行运行，分别生成A1、B1、B2、…BN的数字采样数据，并行传输给控制模块 进行处理，所述控制模块用于选取所述时间数字转换模块和/或所述模数转换模块采集的信号并进行计算，以得到所述光脉冲信号的参数值。
可选地，在本发明的一示例中，所述控制模块使用微程序控制单元(Micro Controller Unit，MCU)，进行数据的处理。
可选地，所述控制模块选取所述时间数字转换模块和/或所述模数转换模块采集的信号的方法可以包括以下任意一种方案或任意至少两种方案的组合：
第一，分类进行选择，充分利用每种模块进行处理时的优点。比如：
1、当所述光脉冲信号的宽度小于脉冲宽度设定值时，使用TDC方案进行脉冲信息的提取，提取所述时间数字转换模块采集的信号。其中，所述脉冲宽度设定值用于表征光脉冲信号的宽度在什么程度下可以使用TDC方案进行脉冲信息的提取，其具体数值可以根据实际需要进行选择，并不局限于某一数值范围。采用TDC方法可以避免由于脉冲宽度较小导致ADC采样不足的情况。
2、当所述光脉冲信号的脉冲高度小于脉冲高度设定值时，使用ADC方案进行脉冲信息的提取，其中，所述脉冲高度设定值用于表征光脉冲信号的高度在什么程度下可以使用ADC方案进行脉冲信息的提取，其具体数值可以根据实际需要进行选择，并不局限于某一数值范围。采用ADC方法可以避免由于脉冲高度太小导致TDC采样不足的情况。
3、当所述光脉冲信号的宽度大于脉冲宽度设定值时以及所述光脉冲信号的脉冲高度大于脉冲高度设定值时，可以选用ADC方法和TDC方法中的至少一种，或者还可以同时使用两种方案进行采样。即脉冲高度及宽度适中两种采样均较多时，对到达时间、脉宽信息等TDC方案可以获得更高精度的信息采用TDC方案，对脉冲能量/幅度等ADC方案可以获得更高精度的信息采用ADC方案。
当然还可以根据需要的光脉冲信号参数以及精度进行选择，例如若对所述光脉冲信号的到达时间和脉宽信息要求精度更高时，则至少选取所述时间数字转换模块采集的信号；若对所述光脉冲信号的脉冲能量和幅值信息要求精度更高时，则至少选取所述模数转换模块采集的信号。当然还可以同时选取两种采用模块获得的信号。
其中，在获取所述时间数字转换模块和/或所述模数转换模块采集的信号之后，所述控制模块用于对选取的所述信号进行计算，计算的方法包括以下任意一种方案或两种方案的组合：
I，采用拟合的方式对选取的所述信号进行计算，其中拟合的方式是将获取的脉冲信号在光脉冲信号的图形中相应的位置进行标注，进而还原所述光脉冲信号的脉冲图形，在得到脉冲信号的脉冲图形之后，可以在脉冲图形上进一步读取所需要的信息，例如脉冲到达时间、脉宽、脉冲能量和幅值中的至少一种。
II，所述控制模块通过采用显式的统计量的方式对选取的所述信号进行计算，在该计算方法中对选取的每个采样点进行相应的计算，以得到在每个采样点对应的所述光脉冲信号的参数值，以得到众多的点值。
需要说明的是控制模块对选取的所述信号进行计算的上述两种方法同样适用于以下两种处理方式或其他处理方式任意的组合中，在没有特殊说明的情况下，拟合处理和显式的统计量的方式均参照上述解释。
第二，直接深度融合的方式进行处理。在所述方法中，将两类采样模块的采样点一起进行拟合，以得到脉冲信号的脉冲图形。当然也可以分别抽取一定的采样点来进行拟合，如都选取上升沿的采样点来进行拟合等。根据拟合结果来进行脉冲到达时间、脉宽、脉冲能量等的提取。两类采样一起可以提供比其中任一方式更多的采样点，因此可以改善拟合的准确度，进而改善脉冲信息的提取精准度。
第三，转换后深度融合，转换是指将其中一种采用结果转换为另外一种方式的采用，然后再进行处理，具体包括：
1、从ADC的采样结果转换为TDC方式的采样，或/和将TDC的采样结果转换为ADC方式的采样。然后将转换的结果与另一种采样的点放在一起，统一采用某种方式进行脉冲信息的提取。例如拟合处理和显式的统计量的方式中的至少一种。
在本发明的示例中，若ADC采样被转换为TDC方式的采样，则采用TDC方案的方法来进行信息提取；反之，若是将TDC采样转换为ADC方式的采样， 则采用ADC方案的方法来进行信息提取。提取时所采用的统计量应包含两类采样：TDC采样+ADC转换来的采样，或者ADC采样+TDC转换来的采样。
2、对于ADC与TDC采样之间的转换，可以采用先拟合/插值，再采样的方式。在本发明的示例中，例如采用拟合的方式先对先对ADC采样进行拟合，以得到所述光脉冲信号的图形，拟合后模拟TDC的方式给定阈值来采集时间。
本发明各个实施例提供的采样电路可以应用于测距装置，该测距装置可以是激光雷达、激光测距设备等电子设备。在一种实施方式中，测距装置用于感测外部环境信息，例如，环境目标的距离信息、方位信息、反射强度信息、速度信息等。一种实现方式中，测距装置可以通过测量测距装置和探测物之间光传播的时间，即光飞行时间(Time-of-Flight，TOF)，来探测探测物到测距装置的距离。或者，测距装置也可以通过其他技术来探测探测物到测距装置的距离，例如基于相位移动(phase shift)测量的测距方法，或者基于频率移动(frequency shift)测量的测距方法，在此不做限制。
为了便于理解，以下将结合图4所示的测距装置100对测距的工作流程进行举例描述。
如图4所示，测距装置100可以包括发射电路110、接收电路120、采样电路130和运算电路140。
发射电路110可以发射光脉冲序列(例如激光脉冲序列)。接收电路120可以接收经过被探测物反射的光脉冲序列，并对该光脉冲序列进行光电转换，以得到电信号，再对电信号进行处理之后可以输出给采样电路130。采样电路130可以对电信号进行采样，以获取采样结果。运算电路140可以基于采样电路130的采样结果，以确定测距装置100与被探测物之间的距离。
可选地，该测距装置100还可以包括控制电路150，该控制电路150可以实现对其他电路的控制，例如，可以控制各个电路的工作时间和/或对各个电路进行参数设置等。
应理解，虽然图4示出的测距装置中包括一个发射电路、一个接收电路、一个采样电路和一个运算电路，用于出射一路光束进行探测，但是本申请实施 例并不限于此，发射电路、接收电路、采样电路、运算电路中的任一种电路的数量也可以是至少两个，用于沿相同方向或分别沿不同方向出射至少两路光束；其中，该至少两束光路可以是同时出射，也可以是分别在不同时刻出射。一个示例中，该至少两个发射电路中的发光芯片封装在同一个模块中。例如，每个发射电路包括一个激光发射芯片，该至少两个发射电路中的激光发射芯片中的die封装到一起，容置在同一个封装空间中。
一些实现方式中，除了图4所示的电路，测距装置100还可以包括扫描模块，用于将发射电路出射的至少一路激光脉冲序列改变传播方向出射。
其中，可以将包括发射电路110、接收电路120、采样电路130和运算电路140的模块，或者，包括发射电路110、接收电路120、采样电路130、运算电路140和控制电路150的模块称为测距模块，该测距模块可以独立于其他模块，例如，扫描模块。
测距装置中可以采用同轴光路，也即测距装置出射的光束和经反射回来的光束在测距装置内共用至少部分光路。例如，发射电路出射的至少一路激光脉冲序列经扫描模块改变传播方向出射后，经探测物反射回来的激光脉冲序列经过扫描模块后入射至接收电路。或者，测距装置也可以采用异轴光路，也即测距装置出射的光束和经反射回来的光束在测距装置内分别沿不同的光路传输。图5示出了本发明的测距装置采用同轴光路的一种实施例的示意图。
测距装置200包括测距模块210，测距模块210包括发射器203(可以包括上述的发射电路)、准直元件204、探测器205(可以包括上述的接收电路、采样电路和运算电路)和光路改变元件206。测距模块210用于发射光束，且接收回光，将回光转换为电信号。其中，发射器203可以用于发射光脉冲序列。在一个实施例中，发射器203可以发射激光脉冲序列。可选的，发射器203发射出的激光束为波长在可见光范围之外的窄带宽光束。准直元件204设置于发射器的出射光路上，用于准直从发射器203发出的光束，将发射器203发出的光束准直为平行光出射至扫描模块。准直元件还用于会聚经探测物反射的回光的至少一部分。该准直元件204可以是准直透镜或者是其他能够准直光束的元件。
在图5所示实施例中，通过光路改变元件206来将测距装置内的发射光路和接收光路在准直元件204之前合并，使得发射光路和接收光路可以共用同一个准直元件，使得光路更加紧凑。在其他的一些实现方式中，也可以是发射器203和探测器205分别使用各自的准直元件，将光路改变元件206设置在准直元件之后的光路上。
在图5所示实施例中，由于发射器203出射的光束的光束孔径较小，测距装置所接收到的回光的光束孔径较大，所以光路改变元件可以采用小面积的反射镜来将发射光路和接收光路合并。在其他的一些实现方式中，光路改变元件也可以采用带通孔的反射镜，其中该通孔用于透射发射器203的出射光，反射镜用于将回光反射至探测器205。这样可以减小采用小反射镜的情况中小反射镜的支架会对回光的遮挡。
在图5所示实施例中，光路改变元件偏离了准直元件204的光轴。在其他的一些实现方式中，光路改变元件也可以位于准直元件204的光轴上。
测距装置200还包括扫描模块202。扫描模块202放置于测距模块210的出射光路上，扫描模块202用于改变经准直元件204出射的准直光束219的传输方向并投射至外界环境，并将回光投射至准直元件204。回光经准直元件204汇聚到探测器205上。
在一个实施例中，扫描模块202可以包括至少一个光学元件，用于改变光束的传播路径，其中，该光学元件可以通过对光束进行反射、折射、衍射等等方式来改变光束传播路径。例如，扫描模块202包括透镜、反射镜、棱镜、振镜、光栅、液晶、光学相控阵(Optical Phased Array)或上述光学元件的任意组合。一个示例中，至少部分光学元件是运动的，例如通过驱动模块来驱动该至少部分光学元件进行运动，该运动的光学元件可以在不同时刻将光束反射、折射或衍射至不同的方向。在一些实施例中，扫描模块202的多个光学元件可以绕共同的轴209旋转或振动，每个旋转或振动的光学元件用于不断改变入射光束的传播方向。在一个实施例中，扫描模块202的多个光学元件可以以不同的转速旋转，或以不同的速度振动。在另一个实施例中，扫描模块202的至少部分光学元件可以以基本相同的转速旋转。在一些实施例中，扫描模块的多个 光学元件也可以是绕不同的轴旋转。在一些实施例中，扫描模块的多个光学元件也可以是以相同的方向旋转，或以不同的方向旋转；或者沿相同的方向振动，或者沿不同的方向振动，在此不作限制。
在一个实施例中，扫描模块202包括第一光学元件214和与第一光学元件214连接的驱动器216，驱动器216用于驱动第一光学元件214绕转动轴209转动，使第一光学元件214改变准直光束219的方向。第一光学元件214将准直光束219投射至不同的方向。在一个实施例中，准直光束219经第一光学元件改变后的方向与转动轴109的夹角随着第一光学元件214的转动而变化。在一个实施例中，第一光学元件214包括相对的非平行的一对表面，准直光束219穿过该对表面。在一个实施例中，第一光学元件214包括厚度沿至少一个径向变化的棱镜。在一个实施例中，第一光学元件214包括楔角棱镜，对准直光束219进行折射。
在一个实施例中，扫描模块202还包括第二光学元件215，第二光学元件215绕转动轴209转动，第二光学元件215的转动速度与第一光学元件214的转动速度不同。第二光学元件215用于改变第一光学元件214投射的光束的方向。在一个实施例中，第二光学元件115与另一驱动器217连接，驱动器217驱动第二光学元件215转动。第一光学元件214和第二光学元件215可以由相同或不同的驱动器驱动，使第一光学元件214和第二光学元件215的转速和/或转向不同，从而将准直光束219投射至外界空间不同的方向，可以扫描较大的空间范围。在一个实施例中，控制器218控制驱动器216和217，分别驱动第一光学元件214和第二光学元件215。第一光学元件214和第二光学元件215的转速可以根据实际应用中预期扫描的区域和样式确定。驱动器216和217可以包括电机或其他驱动器。
在一个实施例中，第二光学元件215包括相对的非平行的一对表面，光束穿过该对表面。在一个实施例中，第二光学元件215包括厚度沿至少一个径向变化的棱镜。在一个实施例中，第二光学元件215包括楔角棱镜。
一个实施例中，扫描模块202还包括第三光学元件(图未示)和用于驱动第三光学元件运动的驱动器。可选地，该第三光学元件包括相对的非平行的一 对表面，光束穿过该对表面。在一个实施例中，第三光学元件包括厚度沿至少一个径向变化的棱镜。在一个实施例中，第三光学元件包括楔角棱镜。第一、第二和第三光学元件中的至少两个光学元件以不同的转速和/或转向转动。
扫描模块202中的各光学元件旋转可以将光投射至不同的方向，例如投射的光211的方向和方向213，如此对测距装置200周围的空间进行扫描。当扫描模块202投射出的光211打到探测物201时，一部分光被探测物201沿与投射的光211相反的方向反射至测距装置200。探测物201反射的回光212经过扫描模块202后入射至准直元件204。
探测器205与发射器203放置于准直元件204的同一侧，探测器205用于将穿过准直元件204的至少部分回光转换为电信号。
一个实施例中，各光学元件上镀有增透膜。可选的，增透膜的厚度与发射器203发射出的光束的波长相等或接近，能够增加透射光束的强度。
一个实施例中，测距装置中位于光束传播路径上的一个元件表面上镀有滤光层，或者在光束传播路径上设置有滤光器，用于至少透射发射器所出射的光束所在波段，反射其他波段，以减少环境光给接收器带来的噪音。
在一些实施例中，发射器203可以包括激光二极管，通过激光二极管发射纳秒级别的激光脉冲。进一步地，可以确定激光脉冲接收时间，例如，通过探测电信号脉冲的上升沿时间和/或下降沿时间确定激光脉冲接收时间。如此，测距装置200可以利用脉冲接收时间信息和脉冲发出时间信息计算TOF，从而确定探测物201到测距装置200的距离。
测距装置200探测到的距离和方位可以用于遥感、避障、测绘、建模、导航等。在一种实施方式中，本发明实施方式的测距装置可应用于移动平台，测距装置可安装在移动平台的平台本体。具有测距装置的移动平台可对外部环境进行测量，例如，测量移动平台与障碍物的距离用于避障等用途，和对外部环境进行二维或三维的测绘。在某些实施方式中，移动平台包括无人飞行器、汽车、遥控车、机器人、相机中的至少一种。当测距装置应用于无人飞行器时，平台本体为无人飞行器的机身。当测距装置应用于汽车时，平台本体为汽车的车身。该汽车可以是自动驾驶汽车或者半自动驾驶汽车，在此不做限制。当测 距装置应用于遥控车时，平台本体为遥控车的车身。当测距装置应用于机器人时，平台本体为机器人。当测距装置应用于相机时，平台本体为相机本身。
本发明实施例中所使用的技术术语仅用于说明特定实施例而并不旨在限定本发明。在本文中，单数形式“一”、“该”及“所述”用于同时包括复数形式，除非上下文中明确另行说明。进一步地，在说明书中所使用的用于“包括”和/或“包含”是指存在所述特征、整体、步骤、操作、元件和/或构件，但是并不排除存在或增加一个或多个其它特征、整体、步骤、操作、元件和/或构件。
在所附权利要求中对应结构、材料、动作以及所有装置或者步骤以及功能元件的等同形式(如果存在的话)旨在包括结合其他明确要求的元件用于执行该功能的任何结构、材料或动作。本发明的描述出于实施例和描述的目的被给出，但并不旨在是穷举的或者将被发明限制在所公开的形式。在不偏离本发明的范围和精神的情况下，多种修改和变形对于本领域的一般技术人员而言是显而易见的。本发明中所描述的实施例能够更好地揭示本发明的原理与实际应用，并使本领域的一般技术人员可了解本发明。
本发明中所描述的流程图仅仅为一个实施例，在不偏离本发明的精神的情况下对此图示或者本发明中的步骤可以有多种修改变化。比如，可以不同次序的执行这些步骤，或者可以增加、删除或者修改某些步骤。本领域的一般技术人员可以理解实现上述实施例的全部或部分流程，并依本发明权利要求所作的等同变化，仍属于发明所涵盖的范围。

Claims (21)

  1. 一种采样电路，其特征在于，包括：并行设置的时间数字转换模块、模数转换模块，所述采样电路还包括控制模块；
    其中，所述时间数字转换模块用于接收由光脉冲信号转化得到的电信号并将所述电信号与预设阈值进行比较运算，采集与所述电信号对应的时间信息；
    所述模数转换模块用于接收由所述光脉冲信号转化得到的所述电信号，并在采样时钟频率内采集与采集时间对应的电信号的幅值；
    所述控制模块，用于选取所述时间数字转换模块和/或所述模数转换模块采集的信号并进行计算，以得到所述光脉冲信号的参数值。
  2. 根据权利要求1所述的采样电路，其特征在于，所述时间数字转换模块包括多个通道，其中每个所述通道均包括比较器和时间数字转换器，其中，所述比较器的第一输入端用于接收由光脉冲信号转化得到的电信号，所述比较器的第二输入端用于接收所述比较器的预设阈值，所述比较器的输出端用于输出比较运算的结果，所述时间数字转换器与所述比较器的输出端电连接，用于根据所述比较器输出的比较运算的结果，提取与所述电信号对应的时间信息；
    其中，所述不同通道中的比较器的预设阈值不同。
  3. 根据权利要求1所述的采样电路，其特征在于，所述模数转换模块包括至少一个模数转换器，用于采集与所述采集时间对应的电信号的幅值。
  4. 根据权利要求1所述的采样电路，其特征在于，所述控制模块用于采用拟合的方式对选取的所述信号进行计算，以还原所述光脉冲信号的图形；
    或者所述控制模块用于采用显式的统计量的方式对选取的所述信号进行计算，以得到所述光脉冲信号的参数值。
  5. 根据权利要求4所述的采样电路，其特征在于，所述控制模块采集所述时间数字转换模块的至少部分信号和所述模数转换模块采集的至少部分信号进行所述拟合。
  6. 根据权利要求1所述的采样电路，其特征在于，所述控制模块还用于将所述时间数字转换模块的采样转换为所述模数转换模块方式的采样；
    或所述控制模块还用于将所述模数转换模块的采样转换为所述时间数字转换模块方式的采样。
  7. 根据权利要求6所述的采样电路，其特征在于，所述控制模块用于采用拟合的方式先对所述模数转换模块的采样的信号进行计算，以得到所述光脉冲信号的图形，然后在所述光脉冲信号的图形上标定预设阈值以及对应的时间信息。
  8. 根据权利要求1所述的采样电路，其特征在于，所述控制模块选取所述信号时：
    当所述光脉冲信号的宽度小于脉冲宽度设定值时，则选取所述时间数字转换模块采集的信号；和/或
    当所述光脉冲信号的脉冲高度小于脉冲高度设定值时，则选取所述模数转换模块采集的信号；和/或
    当所述光脉冲信号的宽度大于脉冲宽度设定值时以及所述光脉冲信号的脉冲高度大于脉冲高度设定值时，若对所述光脉冲信号的到达时间和脉宽信息要求精度更高时，则至少选取所述时间数字转换模块采集的信号；若对所述光脉冲信号的脉冲能量和幅值信息要求精度更高时，则至少选取所述模数转换模块采集的信号。
  9. 根据权利要求1所述的采样电路，其特征在于，所述参数值包括脉冲到达时间、脉宽、脉冲能量和幅值中的至少一种。
  10. 一种基于采样电路的采样方法，其特征在于，包括：
    通过时间数字转换模块接收由光脉冲信号转化得到的电信号并将所述电信号与预设阈值进行比较运算，采集与所述电信号对应的时间信息；
    通过模数转换模块接收由光脉冲信号转化得到的电信号，并在采样时钟频率内采集与采集时间对应的电信号的幅值信号；
    选取所述时间数字转换模块和/或所述模数转换模块采集的信号并进行计算，以得到所述光脉冲信号的参数值。
  11. 根据权利要求10所述的采样方法，其特征在于，所述时间数字转换模块包括多个通道，所述多个通道并行地接收所述电信号并将所述电信号进行 比较运算，采集与所述电信号对应的时间信息。
  12. 根据权利要求11所述的采样方法，其特征在于，所述多个通道分别设置不同的预设阈值，以并行地接收所述电信号并将所述电信号进行比较运算。
  13. 根据权利要求10所述的采样方法，其特征在于，选取信号并进行计算，以得到所述光脉冲信号的参数值的步骤包括：
    采用拟合的方式对选取的所述信号进行计算，以还原所述光脉冲信号的图形；
    或者采用显式的统计量的方式对选取的所述信号进行计算，以得到所述光脉冲信号的参数值。
  14. 根据权利要求13所述的采样方法，其特征在于，至少选取所述时间数字转换模块的部分信号和所述模数转换模块采集的部分信号进行所述拟合。
  15. 根据权利要求10所述的采样方法，其特征在于，选取所述时间数字转换模块和所述模数转换模块采集的信号之后，在进行计算之前，还包括：
    将所述时间数字转换模块的采样转换为所述模数转换模块方式的采样；
    或所述控制模块还用于将所述模数转换模块的采样转换为所述时间数字转换模块方式的采样。
  16. 根据权利要求15所述的采样方法，其特征在于，采用拟合的方式先对所述模数转换模块的采样的信号进行计算，以得到所述光脉冲信号的图形，然后在所述光脉冲信号的图形结构上标定预设阈值以及对应的时间信息。
  17. 根据权利要求10所述的采样方法，其特征在于，选取所述信号时，
    当所述光脉冲信号的宽度小于脉冲宽度设定值时，则选取所述时间数字转换模块采集的信号；和/或
    当所述光脉冲信号的脉冲高度小于脉冲高度设定值时，则选取所述模数转换模块采集的信号；和/或
    当所述光脉冲信号的宽度大于脉冲宽度设定值时以及所述光脉冲信号的脉冲高度大于脉冲高度设定值时，若对所述光脉冲信号的到达时间和脉宽信息要求精度更高时，则至少选取所述时间数字转换模块采集的信号；若对所述光脉冲信号的脉冲能量和幅值信息要求精度更高时，则至少选取所述模数转换模 块采集的信号。
  18. 根据权利要求10所述的采样方法，其特征在于，所述参数值包括脉冲到达时间、脉冲宽度、脉冲能量和脉冲幅值中的至少一种。
  19. 一种测距装置，其特征在于，包括：
    光发射电路，用于出射光脉冲信号；
    光接收电路，用于接收所述光发射电路出射的光脉冲信号经物体反射回的至少部分光信号，以及将接收到的所述激光信号转成电信号；
    如权利要求1至9任一项所述的采样电路，用于对来自所述激光接收电路的电信号进行采样，获得采样结果；
    运算电路，用于根据所述采样结果计算所述物体与所述测距装置之间的距离。
  20. 一种移动平台，其特征在于，包括：
    权利要求19所述的测距装置；和
    平台本体，所述测距装置的光发射电路安装在所述平台本体上。
  21. 根据权利要求20所述的移动平台，其特征在于，所述移动平台包括无人飞行器、汽车和机器人中的至少一种。
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