CN209356671U - A kind of laser radar background dark noise response cancellation element - Google Patents
A kind of laser radar background dark noise response cancellation element Download PDFInfo
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- CN209356671U CN209356671U CN201820210693.0U CN201820210693U CN209356671U CN 209356671 U CN209356671 U CN 209356671U CN 201820210693 U CN201820210693 U CN 201820210693U CN 209356671 U CN209356671 U CN 209356671U
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Abstract
The utility model provides a kind of laser radar background dark noise response cancellation element, and laser radar emits laser pulse signal to detection target；Camera lens is received to receive the optical signal reflected by detection target and be transmitted to photodetector；Convert optical signals into electric signal；Two voltage threshold Threshold of back-end processing circuit setting heightH、ThresholdL, electric echo signal will generate trigger signal after crossing threshold value.Low threshold generates trigger signal TrigLTriggered time information TL is extracted by high precision time measurement module, high threshold generates trigger signal TrigHPostponed by Postponement module；Receiving TrigLTrig can be received in short time window TW after triggeringH, then it is assumed that it is effective echo event triggering, such as fails to receive Trig in time windowHThen it is considered the errored response that the noise letter that detector dark counting generates generates；For example noise signal then not subsequent processing, for example true echo-signal, by TLAs the difference of its arrival time and launch time as pulse time-of-flight, target range is solved according to the light velocity, and reduces false alarm rate.
Description
Technical field
The utility model relates to laser radar technique fields more particularly to a kind of laser thunder background dark noise to respond elimination side
Method and device.
Background technique
Laser radar is a kind of spatial information active probe means, and basic functional principle is similar with conventional radar: laser
Then radar collects the optical signal being reflected by receiver to detection objective emission laser, pass through measurement transmitting signal
The advantages that two-way time determines the distance of target, the high coherence that has due to laser, directionality, monochromaticjty, laser radar
System can be realized remote, high-precision distance measurement function, in automatic Pilot, 3 d modeling of building, mapping, friendship
It many occasions such as can dock to be applied.
Laser radar carries out the extraction of distance signal frequently with pulse time-of-flight method, and basic principle is to objective emission
It grows, the laser pulse light beam of high-peak power, by the light of target reflection by the reception shots of laser radar, and records in short-term
It is subtracted each other with pulse time is sent, obtains the time of the round-trip target point of laser pulse, and then by the light velocity by its arrival time information
Seek out target range information.
When the other factors such as transmitting laser peak power, reception camera lens remain unchanged, received by laser radar anti-
It penetrates light intensity and will become with target range and far reduce rapidly, signal-to-noise ratio is caused to reduce, and then influence range accuracy, improve false alarm rate
And false dismissed rate.It is general to be made up using raising transmitting laser peak power in order to compensate for the penalty, however improve laser
Peak power will increase system burden, and excessively high laser peak power is easy so that electrical power consumed is also doubled and redoubled accordingly
Human eye is damaged, the application of laser radar is limited；
In view of above-mentioned factor, laser output power can not be promoted infinitely, be needed using highly sensitive photodetector
Echo is detected, to improve the detection range of laser radar, due to background noise interference and highly sensitive photodetection
The influence of device dark counting interference itself, the interference signal that Airborne Lidar slowdown monitoring circuit receives at this time also increase significantly, usually adopt
Noise is excluded with the mode for improving echo amplitude features threshold value, but this method will bring serious time drift problem: echo letter
Electric impulse signal will be become number after photoelectric conversion, rising edge typically lasts for the time of nanosecond, under same distance
When the target of different reflectivity is detected, the echo pulse signal with different amplitudes will be obtained, use same voltage at this time
The pulse arrival time that discrimination threshold obtains can be variant, ultimately causes range error, and the difference is with the increasing of voltage threshold
Deteriorate greatly, to avoid the problem, needs to design a kind of novel laser radar pulse echo processing method, can filter out and make an uproar
Sound bring false triggering, and can guarantee good range accuracy.
Therefore, it is necessary to be improved to the prior art to overcome above-mentioned technological deficiency.
Utility model content
This paper presents a kind of laser radar background dark noise cancellation elements, solve photodetector sheet in echo-signal
Body dark counting noise jamming problem, can effectively reduce false alarm rate.
To realize foregoing purpose, the utility model provides a kind of laser radar dark noise response cancellation element, including, light
Electric explorer, high threshold trigger module, Low threshold trigger module, high precision time measurement module, Postponement module, time window meet
Module, echo ranging processing module, wherein Low threshold trigger module and high threshold trigger module receive photodetector respectively
Electric signal, the high precision time measurement module and Low threshold trigger module are electrically connected, Postponement module and high threshold trigger mode
Block is electrically connected, and the time window meets module and split-second precision module, Postponement module, echo ranging processing module electrically connect
It connects.
Further, high threshold trigger module is made of voltage threshold initialization circuit and voltage comparator circuit；
Further, Low threshold trigger module is made of voltage threshold initialization circuit and high speed voltage comparator circuit；
Further, high precision time measurement module: by clock counting circuit and delay chain HIGH RESOLUTION TIME interpolating circuit
Composition；
Further, it Postponement module: is made of shift register circuit；
Further, time window meets module: meeting two-way trigger signal, judges whether in the same event
Dark counting noise and true echo-signal are screened in triggering；
Further, echo ranging processing module provides trigger signal for laser emitting module, compares the triggered time and connects
The echo time received calculates distance.
Further, the workflow of above-mentioned apparatus are as follows:
The utility model is the utility model has the advantages that the method for institute's utility model can effectively distinguish actual signal and dark counting noise letter
Number, to effectively reduce errored response, improve the accuracy rate of range measurement.
Compared with prior art, include: the advantages of the utility model
1, method is simply easily realized: sentencing method for distinguishing completion dark counting noise and true echo by increasing high threshold all the way
The quick examination of signal is distinguished, and using effect is good, and power dissipation overhead is small, it is easy to accomplish with it is integrated.
2, real-time is good: laser radar echo detection channels are in continuous operation mode, any echo triggering under this method
It can be screened and be performed corresponding processing in real time, real-time is good, the laser radar system suitable for high sweep speed.
Detailed description of the invention
Fig. 1 is that the system of the utility model realizes the schematic diagram of frame；
Fig. 2 is the laser radar operation schematic diagram of the utility model；
Fig. 3 is that the system of the utility model filters out the schematic diagram of dark noise response theory.
Specific embodiment
The utility model is described in detail below with reference to specific embodiment shown in the drawings.
It should also be noted that unless specifically stated otherwise, the opposite cloth of the component and step that otherwise illustrate in these embodiments
It sets, numerical expression and the unlimited the scope of the utility model processed of numerical value.
Be to the description only actually of at least one exemplary embodiment below it is illustrative, never as to this is practical
Novel and its application or any restrictions used.
Technology and equipment known to person of ordinary skill in the relevant may be not discussed in detail, but in appropriate situation
Under, the technology and equipment should be considered as part of specification.
It is shown here and discuss all examples in, any occurrence should be construed as merely illustratively, without
It is as limitation.Therefore, other examples of exemplary embodiment can have different values.
It should also be noted that similar label and letter indicate similar terms in following attached drawing, therefore, once a certain Xiang Yi
It is defined in a attached drawing, then in subsequent attached drawing does not need that it is further discussed.
It please join shown in Fig. 1 to 3, a kind of 12 background dark noise of laser radar response removing method and device include:
1) laser radar 12 emits laser pulse signal to detection target 5；
2) camera lens 21 is received to receive the optical signal reflected by detection target 5 and be transmitted to photodetector 22；
3) photodetector 22 converts optical signals into electric signal；
4) two voltage threshold Threshold of back-end processing circuit setting heightH、ThresholdL, electric echo signal crosses threshold
Trigger signal will be generated after value.The trigger signal Trig that Low threshold generatesLIt is extracted and is triggered by high precision time measurement module
Temporal information TL, the trigger signal Trig of high threshold generationHPostponed by Postponement module；
5) Trig is being receivedLTrig can be received in short time window TW after triggeringH, then it is assumed that it is effective echo thing
Part triggering, such as fails to receive Trig in time windowHThen it is considered the noise letter generation that photodetector dark counting generates
Errored response；
6) for example noise signal is then without subsequent processing, for example true echo-signal, by TLAs its arrival time with
The difference of launch time solves target range as pulse time-of-flight, and then according to the light velocity.
The trigger signal of Low threshold described in step (4) is generated by high speed low latency voltage comparator, high threshold
Trigger signal common voltage comparator can be used generated；When the high precision time measurement module passes through dedicated high performance
Between digital quantizer chip or realized in FPGA by carry chain interpolation；The Postponement module by dedicated delay core piece or when
Clock shift LD is realized.
The utility model additionally provides a kind of laser radar dark noise response cancellation element, including, high threshold trigger module
31, Low threshold trigger module 32, high precision time measurement module, Postponement module, time window meet module, echo ranging processing mould
Block.
High threshold trigger module 31 is made of voltage threshold initialization circuit and voltage comparator circuit；
Low threshold trigger module 32 is made of voltage threshold initialization circuit and high speed voltage comparator circuit；
High precision time measurement module: it is made of clock counting circuit and delay chain HIGH RESOLUTION TIME interpolating circuit；
Postponement module: it is made of shift register circuit；
Time window meets module: meeting two-way trigger signal, judges whether to trigger in the same event, screen
Dark counting noise and true echo-signal；
Echo ranging processing module provides trigger signal for laser emitting module, compares the triggered time and returns with what is received
The wave time calculates distance.
The workflow of above-mentioned apparatus are as follows: when one-shot measurement starts, the optical signal that laser radar 12 is launched is by visiting
It surveys after target 5 reflects and is transferred to the photodetector 22 for receiving signal, be transformed into after electric signal and the preset electricity of two-way
Pressure threshold value is input to threshold triggers module together, and threshold triggers module is when the voltage magnitude of signal is more than or less than voltage threshold
By output switching activity signal, when triggering according to two-way whether in time window, judge the signal for dark counting noise signal also
It is true echo-signal, such as in window, then high precision time measurement module output time is sought into difference with triggering moment and obtained
Pulse time-of-flight, and then it is converted into target range, otherwise without processing, excludes accidentally to respond to reach, reduce false alarm rate
Purpose.
The system of the utility model method realizes that example is as shown in Figure 2: it is imaged using scanning imagery laser radar 12,
Laser radar 12 includes transmitting optics 13, and electronic system includes photodetector 22 and back-end processing circuit, at the rear end
Managing circuit includes Low threshold trigger module 32, high threshold trigger module 31, laser drive circuit 11, master control and signal processing module
4.It also comprises by receiving optical lens 21.Photodetector 22 uses SIPM silicon photomultiplier, photosensitive member size 6mm*
6mm.Laser uses 905nm, peak power 1W, and laser cooperates 1000000 trigger pulses of the every sending of scan frequency.Secretly
High-low threshold value is respectively set to 8mV, 32mV in noise response cancellation element.High precision time measurement module in FPGA by using
High-precision carry chain is realized that Postponement module is deposited by Clock-lag and realized.Meet time window and is set as 10ns.
Fig. 3 is the principle of this method wiping out background dark noise response, when triggering according to two-way whether in time window,
Judge the signal for dark counting noise signal or true echo-signal, it is such as in window, then high precision time measurement module is defeated
Moment and triggering moment seek difference and obtain pulse time-of-flight out, and then are converted into target range, otherwise abandon not to data
It is handled.The reception device of scanning laser radar 12 is stopped with lens cap, it is caused at this time without echo reception
Response time all background dark noise responses, being acquired by host computer and counting event number per second is 448/second, and comparison is not
Using the scanning imagery laser radar 12 of dark noise removing method, background dark counting is 19200/second, it can be seen that this method
The response of background dark noise has effectively been filtered out, the signal-to-noise ratio of system is improved.
It should be appreciated that although this specification is described in terms of embodiments, but not each embodiment only includes one
A independent technical solution, this description of the specification is merely for the sake of clarity, and those skilled in the art should will say
As a whole, the technical solution in each embodiment may also be suitably combined to form those skilled in the art can for bright book
With the other embodiments of understanding.
Tool of the series of detailed descriptions listed above only for the feasible embodiment of the utility model
Body explanation, they are all without departing from made by the utility model skill spirit not to limit the protection scope of the utility model
Equivalent implementations or change should be included within the scope of protection of this utility model.
Claims (6)
1. a kind of laser radar background dark noise responds cancellation element, it is characterised in that: including photodetector, high threshold touching
Hair module, Low threshold trigger module, high precision time measurement module, Postponement module, time window meet module, echo ranging processing
Module, wherein Low threshold trigger module and high threshold trigger module receive the electric signal of photodetector, the high-precision respectively
Time measurement module and Low threshold trigger module are electrically connected, and Postponement module and high threshold trigger module are electrically connected, when described
Between window meets module and split-second precision module, Postponement module, echo ranging processing module are electrically connected.
2. a kind of laser radar background dark noise according to claim 1 responds cancellation element, it is characterised in that: the height
Threshold triggers module is made of voltage threshold initialization circuit and voltage comparator circuit.
3. a kind of laser radar background dark noise according to claim 1 responds cancellation element, it is characterised in that: described low
Threshold triggers module is made of voltage threshold initialization circuit and high speed voltage comparator circuit.
4. a kind of laser radar background dark noise according to claim 1 responds cancellation element, it is characterised in that: the height
Precision Time measurement module is made of clock counting circuit and delay chain HIGH RESOLUTION TIME interpolating circuit.
5. a kind of laser radar background dark noise according to claim 1 responds cancellation element, it is characterised in that: described to prolong
Slow module is made of shift register circuit.
6. a kind of laser radar background dark noise according to claim 1 responds cancellation element, it is characterised in that: when described
Between window meet module two-way trigger signal met, judge whether to trigger in the same event, screen dark counting noise
With true echo-signal；The echo ranging processing module, provides trigger signal for laser emitting module, compare the triggered time with
The echo time received calculates distance.
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| CN201820210693.0U CN209356671U (en) | 2018-02-07 | 2018-02-07 | A kind of laser radar background dark noise response cancellation element |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113009455A (en) * | 2021-04-14 | 2021-06-22 | 吉林大学 | Method and system for improving pulse laser ranging precision |
| WO2022056743A1 (en) * | 2020-09-16 | 2022-03-24 | Huawei Technologies Co., Ltd. | Method for measuring distance using time-of-flight method and system for measuring distance |
| CN114637021A (en) * | 2022-05-18 | 2022-06-17 | 四川吉埃智能科技有限公司 | Sub-centimeter-level full-waveform laser radar ranging method and device |
| WO2022126429A1 (en) * | 2020-12-16 | 2022-06-23 | 深圳市大疆创新科技有限公司 | Ranging apparatus, ranging method, and movable platform |
-
2018
- 2018-02-07 CN CN201820210693.0U patent/CN209356671U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022056743A1 (en) * | 2020-09-16 | 2022-03-24 | Huawei Technologies Co., Ltd. | Method for measuring distance using time-of-flight method and system for measuring distance |
| WO2022126429A1 (en) * | 2020-12-16 | 2022-06-23 | 深圳市大疆创新科技有限公司 | Ranging apparatus, ranging method, and movable platform |
| CN113009455A (en) * | 2021-04-14 | 2021-06-22 | 吉林大学 | Method and system for improving pulse laser ranging precision |
| CN114637021A (en) * | 2022-05-18 | 2022-06-17 | 四川吉埃智能科技有限公司 | Sub-centimeter-level full-waveform laser radar ranging method and device |
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Granted publication date: 20190906 Termination date: 20200207 |