CA2710212C - Detection and ranging methods and systems - Google Patents
Detection and ranging methods and systems Download PDFInfo
- Publication number
- CA2710212C CA2710212C CA2710212A CA2710212A CA2710212C CA 2710212 C CA2710212 C CA 2710212C CA 2710212 A CA2710212 A CA 2710212A CA 2710212 A CA2710212 A CA 2710212A CA 2710212 C CA2710212 C CA 2710212C
- Authority
- CA
- Canada
- Prior art keywords
- pulse
- signal
- points
- trace
- acquiring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 100
- 238000001514 detection method Methods 0.000 title claims description 37
- 230000003287 optical effect Effects 0.000 claims abstract description 72
- 238000005286 illumination Methods 0.000 claims abstract description 26
- 230000010363 phase shift Effects 0.000 claims abstract description 20
- 230000000630 rising effect Effects 0.000 claims description 25
- 238000009825 accumulation Methods 0.000 claims description 21
- 230000006870 function Effects 0.000 claims description 19
- 238000012935 Averaging Methods 0.000 claims description 14
- 238000001914 filtration Methods 0.000 claims description 8
- 230000002123 temporal effect Effects 0.000 claims description 8
- 238000004364 calculation method Methods 0.000 claims description 7
- 238000012417 linear regression Methods 0.000 claims description 6
- 230000007704 transition Effects 0.000 claims description 6
- 230000003467 diminishing effect Effects 0.000 claims 1
- 238000005070 sampling Methods 0.000 claims 1
- 230000010354 integration Effects 0.000 description 36
- 230000035508 accumulation Effects 0.000 description 19
- 238000012545 processing Methods 0.000 description 17
- 239000000523 sample Substances 0.000 description 17
- 230000008569 process Effects 0.000 description 14
- 238000005259 measurement Methods 0.000 description 12
- 238000010586 diagram Methods 0.000 description 7
- 239000002245 particle Substances 0.000 description 6
- 230000001360 synchronised effect Effects 0.000 description 6
- 238000004458 analytical method Methods 0.000 description 5
- 238000010183 spectrum analysis Methods 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 238000003708 edge detection Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 230000011218 segmentation Effects 0.000 description 3
- 230000003044 adaptive effect Effects 0.000 description 2
- 230000001934 delay Effects 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 238000002592 echocardiography Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 239000000779 smoke Substances 0.000 description 2
- 238000012358 sourcing Methods 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 230000001960 triggered effect Effects 0.000 description 2
- BNPSSFBOAGDEEL-UHFFFAOYSA-N albuterol sulfate Chemical compound OS(O)(=O)=O.CC(C)(C)NCC(O)C1=CC=C(O)C(CO)=C1.CC(C)(C)NCC(O)C1=CC=C(O)C(CO)=C1 BNPSSFBOAGDEEL-UHFFFAOYSA-N 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000004883 computer application Methods 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 238000005314 correlation function Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000007726 management method Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 230000000116 mitigating effect Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000001208 nuclear magnetic resonance pulse sequence Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000003909 pattern recognition Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000012163 sequencing technique Methods 0.000 description 1
- 230000011664 signaling Effects 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
- G01S7/486—Receivers
- G01S7/487—Extracting wanted echo signals, e.g. pulse detection
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
- G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/04—Display arrangements
- G01S7/06—Cathode-ray tube displays or other two dimensional or three-dimensional displays
- G01S7/10—Providing two-dimensional and co-ordinated display of distance and direction
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
- G01S7/486—Receivers
- G01S7/4861—Circuits for detection, sampling, integration or read-out
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
- G01S7/486—Receivers
- G01S7/4865—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Electromagnetism (AREA)
- Optical Radar Systems And Details Thereof (AREA)
Abstract
There is provided a system and a method for acquiring a detected light optical signal and generating an accumulated digital trace The method comprises providing a light source for illumination of a field of view, an optical detector, an analog-to-digital converter (ADC), emitting one pulse from the light source in the field of view, detecting a reflection signal of the pulse by the optical detector, acquiring j points for the detected reflection signal by the ADC, storing, in a buffer, the digital signal waveform of j points, introducing a phase shift of 2pi / P, repeating, P times, the steps of emitting, detecting, acquiring, storing and introducing, to store, in the buffer, an interleaved waveform of P x j points, accumulating M traces of interleaved P x j points for a total of N = M x P acquisition sets, N being a total number of pulses emitted, creating one combined trace of the reflected signal of j x P points by adding each point of the M traces Additionally, the combined trace can be compared to a detected reference reflection signal of the pulse to determine a distance traveled by the pulse
Description
CA 2,710,212 DETECTION AND RANGING METHODS AND SYSTEMS
TECHNICAL FIELD
The invention relates to methods and systems for improving the measurement of light transit time reflected by different types of objects in detection and ranging methods and systems.
BACKGROUND OF THE ART
Several methods are used to measure the distance between an apparatus and an object. Optical range-finding systems frequently rely on the time-of-flight principle and determine the distance between the apparatus and the object by measuring the time a short pulse of light emitted from the apparatus takes to reach an object and be reflected to a photo-detection circuit. Conventional optical rangefinders use a counter initiated at the starting pulse and then stopped when the receiver circuit detects the pulse echo of a value higher than a specific threshold. This threshold can be set low to provide sensitivity but the system will generate false alarms from transient noise. It can be set high to avoid false alarms but the system will not detect objects that return weak signal reflection. In bad weather conditions, such as rain or snow, several pulse echoes can be generated. Some techniques help to detect a certain number of echoes and may be used the reject some reflections but they have their limitations.
Some optical rangefinders use other methods to be more robust against false alarms. One method is based on the use of an analog-to-digital converter (ADC) for the digitalization of the waveform of the echoed back signal. Once digitalized, the waveform can be processed by digital signal processing circuits to improve the performance of the system.
Several techniques are already known for improving the performance of an optical rangefinder using an ADC. Averaging is an efficient way to improve the signal to noise ratio (SNR). However, averaging has an impact on response time and may render the system too slow for some applications.
The resolution of distance measurement can be enhanced by using a clock pulsed delay circuit technique. Using an integer (N) division of the clock pulse signal CA 2,710,212 with a delay circuit and by rearranging each echo light pulse sample data, this technique improves the resolution by a factor N. However, this technique has an impact on the number of averages if the averaging technique is also used to improve the SNR.
Digital correlation is another digital processing technique for increasing the resolution of the range measurement. By correlating the echo pulse signal with a pre-stored waveform, the distance to the object can be estimated by using the peak value of the result of the correlation function.
Several digital processing techniques have been elaborated to improve the performance of rangefinders but none consider that the need, in terms of resolution and signal to noise improvement, is not constant as a function of the range for most of range-finding applications.
SUMMARY
It is therefore an aim of the present invention to address at least one of the above mentioned difficulties The present system improves the detection of the presence and the measure of the distance of objects, while optimizing the performance (resolution, repetition rate, etc) by adapting a range-dependant processing as a function of the need of different applications.
The present system can be adapted for use with a lighting system for lighting purposes as well as for the detection and ranging purposes.
The present system also improves the detection of rain, snow, fog, smoke and can provide information about current weather conditions.
According to one broad aspect of the present invention, there is provided a method for acquiring a detected light optical signal and generating an accumulated digital trace which comprises providing a light source for illumination of a field of view; an optical detector; an analog-to-digital converter (ADC); emitting one pulse from the light source in the field of view; detecting a reflection signal of the pulse by the optical detector; acquiring j points for the detected reflection signal by the ADC;
storing, in a buffer, the digital signal waveform of j points; introducing a phase shift
TECHNICAL FIELD
The invention relates to methods and systems for improving the measurement of light transit time reflected by different types of objects in detection and ranging methods and systems.
BACKGROUND OF THE ART
Several methods are used to measure the distance between an apparatus and an object. Optical range-finding systems frequently rely on the time-of-flight principle and determine the distance between the apparatus and the object by measuring the time a short pulse of light emitted from the apparatus takes to reach an object and be reflected to a photo-detection circuit. Conventional optical rangefinders use a counter initiated at the starting pulse and then stopped when the receiver circuit detects the pulse echo of a value higher than a specific threshold. This threshold can be set low to provide sensitivity but the system will generate false alarms from transient noise. It can be set high to avoid false alarms but the system will not detect objects that return weak signal reflection. In bad weather conditions, such as rain or snow, several pulse echoes can be generated. Some techniques help to detect a certain number of echoes and may be used the reject some reflections but they have their limitations.
Some optical rangefinders use other methods to be more robust against false alarms. One method is based on the use of an analog-to-digital converter (ADC) for the digitalization of the waveform of the echoed back signal. Once digitalized, the waveform can be processed by digital signal processing circuits to improve the performance of the system.
Several techniques are already known for improving the performance of an optical rangefinder using an ADC. Averaging is an efficient way to improve the signal to noise ratio (SNR). However, averaging has an impact on response time and may render the system too slow for some applications.
The resolution of distance measurement can be enhanced by using a clock pulsed delay circuit technique. Using an integer (N) division of the clock pulse signal CA 2,710,212 with a delay circuit and by rearranging each echo light pulse sample data, this technique improves the resolution by a factor N. However, this technique has an impact on the number of averages if the averaging technique is also used to improve the SNR.
Digital correlation is another digital processing technique for increasing the resolution of the range measurement. By correlating the echo pulse signal with a pre-stored waveform, the distance to the object can be estimated by using the peak value of the result of the correlation function.
Several digital processing techniques have been elaborated to improve the performance of rangefinders but none consider that the need, in terms of resolution and signal to noise improvement, is not constant as a function of the range for most of range-finding applications.
SUMMARY
It is therefore an aim of the present invention to address at least one of the above mentioned difficulties The present system improves the detection of the presence and the measure of the distance of objects, while optimizing the performance (resolution, repetition rate, etc) by adapting a range-dependant processing as a function of the need of different applications.
The present system can be adapted for use with a lighting system for lighting purposes as well as for the detection and ranging purposes.
The present system also improves the detection of rain, snow, fog, smoke and can provide information about current weather conditions.
According to one broad aspect of the present invention, there is provided a method for acquiring a detected light optical signal and generating an accumulated digital trace which comprises providing a light source for illumination of a field of view; an optical detector; an analog-to-digital converter (ADC); emitting one pulse from the light source in the field of view; detecting a reflection signal of the pulse by the optical detector; acquiring j points for the detected reflection signal by the ADC;
storing, in a buffer, the digital signal waveform of j points; introducing a phase shift
- 2 -CA 2,710,212 of 2n / P; repeating, P times, the steps of emitting, detecting, acquiring, storing and introducing, to store, in the buffer, an interleaved waveform of P x j points;
accumulating M traces of interleaved P x j points for a total of N=MxP
acquisition sets, N being a total number of pulses emitted; creating one combined trace of the reflected signal of j x P points by adding each point of the M traces.
Additionally, the combined trace can be compared to a detected reference reflection signal of the pulse to determine a distance traveled by the pulse.
Alternatively, a timer can be triggered to calculate a time elapsed between the emission of the pulse and the detection of the reflection signal to determine a distance traveled by the pulse based on the time elapsed.
According to another broad aspect of the present invention, there is provided a method for detecting a distance to an object. The method comprises providing a lighting system having at least one pulse width modulated visible-light source for illumination of a field of view; emitting an illumination signal for illuminating the field of view for a duration of time y using the visible-light source at a time t; integrating a reflection energy for a first time period from a time t-x to a time t+x; determining a first integration value for the first time period;
integrating the reflection energy for a second time period from a time t+y-x to a time t+y+x;
determining a second integration value for the second time period; calculating a difference value between the first integration value and the second integration value;
determining a propagation delay value proportional to the difference value;
determining the distance to the object from the propagation delay value.
According to another broad aspect of the present invention, there is provided a powered lighting system for acquiring a detected light optical signal and generating an accumulated digital trace. The powered lighting system comprising at least one light source for illumination of a field of view and emitting a pulse in the field of view; an illumination driver for driving the light source; an optical detector for detecting a reflection signal of a reflection of the pulse; an analog-to-digital converter (ADC) with a sample rate of F Hz and B bits of resolution for acquiring j points for the detected reflection signal by acquiring one of the j points at each 1 / F
second thereby converting the optical reflection signal into a digital signal waveform
accumulating M traces of interleaved P x j points for a total of N=MxP
acquisition sets, N being a total number of pulses emitted; creating one combined trace of the reflected signal of j x P points by adding each point of the M traces.
Additionally, the combined trace can be compared to a detected reference reflection signal of the pulse to determine a distance traveled by the pulse.
Alternatively, a timer can be triggered to calculate a time elapsed between the emission of the pulse and the detection of the reflection signal to determine a distance traveled by the pulse based on the time elapsed.
According to another broad aspect of the present invention, there is provided a method for detecting a distance to an object. The method comprises providing a lighting system having at least one pulse width modulated visible-light source for illumination of a field of view; emitting an illumination signal for illuminating the field of view for a duration of time y using the visible-light source at a time t; integrating a reflection energy for a first time period from a time t-x to a time t+x; determining a first integration value for the first time period;
integrating the reflection energy for a second time period from a time t+y-x to a time t+y+x;
determining a second integration value for the second time period; calculating a difference value between the first integration value and the second integration value;
determining a propagation delay value proportional to the difference value;
determining the distance to the object from the propagation delay value.
According to another broad aspect of the present invention, there is provided a powered lighting system for acquiring a detected light optical signal and generating an accumulated digital trace. The powered lighting system comprising at least one light source for illumination of a field of view and emitting a pulse in the field of view; an illumination driver for driving the light source; an optical detector for detecting a reflection signal of a reflection of the pulse; an analog-to-digital converter (ADC) with a sample rate of F Hz and B bits of resolution for acquiring j points for the detected reflection signal by acquiring one of the j points at each 1 / F
second thereby converting the optical reflection signal into a digital signal waveform
- 3 -CA 2,710,212 of j points; a buffer for storing the digital signal waveform; a processor for controlling the illumination driver and the optical detector; sending information for storage in the buffer, wherein a length of the buffer is at least j x P and a number of bits of each element in the buffer is B + 2m; introducing a phase shift of 2n / P
between the emission of the light pulse and a beginning of the acquisition of the j points by the ADC; causing to repeat, P times, the emitting, detecting, acquiring, storing and introducing, to obtain an interleaved waveform of P x j points, the interleaved waveform being equivalent to a single acquisition with a temporal resolution of 1 / (F x P) second; accumulating M traces of interleaved P x j points for a total of N=MxP acquisition sets, N being a total number of pulses emitted;
creating one combined trace of the reflected signal using the N sets, by adding each point of the M traces, point per point, to generate one accumulated digital trace of j x P points, each point in the combined trace being an accumulation of M = N
/ P sets and an effective time resolution of the combined trace being 1 / (F x P) second;
wherein the sample rate of the ADC is virtually increased thereby allowing a low cost ADC having a low sample rate F to be used.
BRIEF DESCRIPTION OF THE DRAWINGS
Having thus generally described the nature of the invention, reference will now be made to the accompanying drawings, showing by way of illustration a preferred embodiment thereof and in which:
Figure 1 is a block diagram of an embodiment of the lighting system;
Figure 2 shows an example of a reflected signal with accumulation and phase shift techniques wherein Figure 2a is a trace obtained with no accumulation and no phase shift, Figure 2b has accumulation and phase shift improvements and Figure 2c has a greater number of accumulations and phase shifts;
Figure 3 is a table of example setup parameters for the segmentation;
Figure 4 shows an example of a reflected signal with adjusted parameters as a function of the distance;
Figure 5 is a flow chart of an embodiment of the segmentation process;
between the emission of the light pulse and a beginning of the acquisition of the j points by the ADC; causing to repeat, P times, the emitting, detecting, acquiring, storing and introducing, to obtain an interleaved waveform of P x j points, the interleaved waveform being equivalent to a single acquisition with a temporal resolution of 1 / (F x P) second; accumulating M traces of interleaved P x j points for a total of N=MxP acquisition sets, N being a total number of pulses emitted;
creating one combined trace of the reflected signal using the N sets, by adding each point of the M traces, point per point, to generate one accumulated digital trace of j x P points, each point in the combined trace being an accumulation of M = N
/ P sets and an effective time resolution of the combined trace being 1 / (F x P) second;
wherein the sample rate of the ADC is virtually increased thereby allowing a low cost ADC having a low sample rate F to be used.
BRIEF DESCRIPTION OF THE DRAWINGS
Having thus generally described the nature of the invention, reference will now be made to the accompanying drawings, showing by way of illustration a preferred embodiment thereof and in which:
Figure 1 is a block diagram of an embodiment of the lighting system;
Figure 2 shows an example of a reflected signal with accumulation and phase shift techniques wherein Figure 2a is a trace obtained with no accumulation and no phase shift, Figure 2b has accumulation and phase shift improvements and Figure 2c has a greater number of accumulations and phase shifts;
Figure 3 is a table of example setup parameters for the segmentation;
Figure 4 shows an example of a reflected signal with adjusted parameters as a function of the distance;
Figure 5 is a flow chart of an embodiment of the segmentation process;
- 4 -CA 2,710,212 Figure 6 shows an example of the accumulation and phase shift technique for a 10 m range finder using the one sample by optical pulse technique;
Figure 7 is a table of example setup configuration for the accumulation and phase shift technique using the one sample by optical pulse technique;
Figure 8 is a block diagram of a lidar module using an embedded processor;
Figure 9 shows a noisy signal fitted and filtered;
Figure 10 presents a Gaussian pulse with a zero-crossing point of the first derivative;
Figure 11 shows a typical PWM pattern with slope adjustment;
Figure 12 shows a rising edge signal from a source and reflected signals;
Figure 13 shows a 10% to 90% rising edge of an echo back noisy signal with linear regression;
Figure 14 is a flow chart of an embodiment of the PWM edge technique for detection and ranging; and Figure 15 shows a rising edge with overshoot stabilizing after one cycle of the resonance frequency;
Figure 16 shows a timing diagram of the method using an integration signal from the reflected signal and synchronized with rising edge and falling edge of the PWM lighting source;
Figure 17 is a flow chart of the main steps of a method for acquiring a detected light optical signal and generating an accumulated digital trace; and Figure 18 is a flow chart of the main steps of a method for detecting a distance to an object.
It will be noted that throughout the appended drawings, like features are identified by like reference numerals.
DETAILED DESCRIPTION
Fig. 1 is a block diagram illustrating an embodiment of a lighting system equipped with the present system. The lighting system 100 has a visible-light source 112. The visible-light source 12 has, as a first purpose, the emission of visible light for illumination or visual communication of information, like signaling, for human
Figure 7 is a table of example setup configuration for the accumulation and phase shift technique using the one sample by optical pulse technique;
Figure 8 is a block diagram of a lidar module using an embedded processor;
Figure 9 shows a noisy signal fitted and filtered;
Figure 10 presents a Gaussian pulse with a zero-crossing point of the first derivative;
Figure 11 shows a typical PWM pattern with slope adjustment;
Figure 12 shows a rising edge signal from a source and reflected signals;
Figure 13 shows a 10% to 90% rising edge of an echo back noisy signal with linear regression;
Figure 14 is a flow chart of an embodiment of the PWM edge technique for detection and ranging; and Figure 15 shows a rising edge with overshoot stabilizing after one cycle of the resonance frequency;
Figure 16 shows a timing diagram of the method using an integration signal from the reflected signal and synchronized with rising edge and falling edge of the PWM lighting source;
Figure 17 is a flow chart of the main steps of a method for acquiring a detected light optical signal and generating an accumulated digital trace; and Figure 18 is a flow chart of the main steps of a method for detecting a distance to an object.
It will be noted that throughout the appended drawings, like features are identified by like reference numerals.
DETAILED DESCRIPTION
Fig. 1 is a block diagram illustrating an embodiment of a lighting system equipped with the present system. The lighting system 100 has a visible-light source 112. The visible-light source 12 has, as a first purpose, the emission of visible light for illumination or visual communication of information, like signaling, for human
- 5 -CA 2,710,212 vision. The primary purpose of emitting light is controlled according to specific criteria like optical power, field of view and light color, to meet requirements defined through a number of regulations. In the preferred embodiment, the visible-light source 112 has one or more solid-state lighting devices, LEDs or OLEDs for instance.
The visible-light source 112 is connected to a source controller 114, so as to be driven into producing visible light. In addition to emitting light, the system 100 performs detection of objects and particles (vehicles, passengers, pedestrians, airborne particles, gases and liquids) when these objects are part of the environment/scene illuminated by the light source 112. Accordingly, the source controller 114 drives the visible-light source 112 in a predetermined mode, such that the emitted light takes the form of a light signal, for instance by way of amplitude-modulated or pulsed light emission.
These light signals are such that they can be used to provide the lighting illumination level required by the application, through data/signal processor 118 and source controller 114, while producing a detectable signal. Accordingly, it is possible to obtain a light level equivalent to a continuous light source by modulating the light signal fast enough (e.g., frequency more than 100 Hz) to be generally imperceptible to the human eye and having an average light power equivalent to a continuous light source.
In an embodiment, the source controller 114 is designed to provide an illumination drive signal, such as a constant DC signal or a pulse-width modulated (PWM) signal, that is normally used in lighting systems to produce the required illumination and control its intensity. The illumination drive signal is produced by the illumination driver sub-module 114A of the controller 114.
A modulated/pulsed driving signal supplies the fast modulation/pulse sequence required for remote object detection. This modulated/pulsed drive signal is produced by a modulation driver sub-module 1148 of the controller 114. The amplitude of short-pulse (typ. <50 ns) can be several time the nominal value while the duty cycle is low (typ. <0.1%).
The modulator driver 114B can also be used to send data for optical communication. Both driving signals can be produced independently or in
The visible-light source 112 is connected to a source controller 114, so as to be driven into producing visible light. In addition to emitting light, the system 100 performs detection of objects and particles (vehicles, passengers, pedestrians, airborne particles, gases and liquids) when these objects are part of the environment/scene illuminated by the light source 112. Accordingly, the source controller 114 drives the visible-light source 112 in a predetermined mode, such that the emitted light takes the form of a light signal, for instance by way of amplitude-modulated or pulsed light emission.
These light signals are such that they can be used to provide the lighting illumination level required by the application, through data/signal processor 118 and source controller 114, while producing a detectable signal. Accordingly, it is possible to obtain a light level equivalent to a continuous light source by modulating the light signal fast enough (e.g., frequency more than 100 Hz) to be generally imperceptible to the human eye and having an average light power equivalent to a continuous light source.
In an embodiment, the source controller 114 is designed to provide an illumination drive signal, such as a constant DC signal or a pulse-width modulated (PWM) signal, that is normally used in lighting systems to produce the required illumination and control its intensity. The illumination drive signal is produced by the illumination driver sub-module 114A of the controller 114.
A modulated/pulsed driving signal supplies the fast modulation/pulse sequence required for remote object detection. This modulated/pulsed drive signal is produced by a modulation driver sub-module 1148 of the controller 114. The amplitude of short-pulse (typ. <50 ns) can be several time the nominal value while the duty cycle is low (typ. <0.1%).
The modulator driver 114B can also be used to send data for optical communication. Both driving signals can be produced independently or in
- 6 -CA 2,710,212 combination. Sequencing of the drive signals is controlled by the data/signal processor 118. The light source 112 can be monitored by the optical detector 116 and the resulting parameters sent to the data/signal processor 118 for optimization of data processing.
An alternative for sourcing the light signal for detection involves an auxiliary light source (ALS) 122, which can be a visible or non-visible source (e.g., UV or IR light, LEDs or laser) using the modulation driver 14B. The auxiliary light source 122 provides additional capabilities for detecting objects and particles. UV
light source (particularly around 250 nm) can be used to limit the impact of the sunlight when used with a UV detector. IR light can be used to increase the performance and the range of the detection area. IR lights and other types of light can be used to detect several types of particles by selecting specific wavelengths. The auxiliary light source 122 can also be useful during the installation of the system by using it as a pointer and distance meter reference. It can also be used to determine the condition of the lens.
The visible-light source 112 is preferably made up of LEDs. More specifically, LEDs are well suited to be used in the lighting system 100 since LED
intensity can be efficiently modulated/pulsed at suitable speed. Using this feature, current lighting systems already installed and featuring LEDs for standard lighting applications can be used as the light source 112 for detection applications, such as presence detection for energy savings, distance and speed measurements, fog, rain, snow or smoke detection and spectroscopic measurements for gas emission or smog detection.
The system 100 has at least one lens 130 through which light is emitted in an appropriate way for specific applications. At least one input lens section 130a of at least one lens 130 is used for receiving the light signal, for instance reflected or diffused (i.e., backscattered) by the objects/particles 134. This input lens section 130a can be at a single location or distributed (multiple zone elements) over the lens 130 and have at least one field of view. Several types of lens 130 can be used, such as Fresnel lenses for example. A sub-section of the lens 130 can be used for infrared wavelength. A sub-section of the lens 130 can be used for optical data reception.
An alternative for sourcing the light signal for detection involves an auxiliary light source (ALS) 122, which can be a visible or non-visible source (e.g., UV or IR light, LEDs or laser) using the modulation driver 14B. The auxiliary light source 122 provides additional capabilities for detecting objects and particles. UV
light source (particularly around 250 nm) can be used to limit the impact of the sunlight when used with a UV detector. IR light can be used to increase the performance and the range of the detection area. IR lights and other types of light can be used to detect several types of particles by selecting specific wavelengths. The auxiliary light source 122 can also be useful during the installation of the system by using it as a pointer and distance meter reference. It can also be used to determine the condition of the lens.
The visible-light source 112 is preferably made up of LEDs. More specifically, LEDs are well suited to be used in the lighting system 100 since LED
intensity can be efficiently modulated/pulsed at suitable speed. Using this feature, current lighting systems already installed and featuring LEDs for standard lighting applications can be used as the light source 112 for detection applications, such as presence detection for energy savings, distance and speed measurements, fog, rain, snow or smoke detection and spectroscopic measurements for gas emission or smog detection.
The system 100 has at least one lens 130 through which light is emitted in an appropriate way for specific applications. At least one input lens section 130a of at least one lens 130 is used for receiving the light signal, for instance reflected or diffused (i.e., backscattered) by the objects/particles 134. This input lens section 130a can be at a single location or distributed (multiple zone elements) over the lens 130 and have at least one field of view. Several types of lens 130 can be used, such as Fresnel lenses for example. A sub-section of the lens 130 can be used for infrared wavelength. A sub-section of the lens 130 can be used for optical data reception.
- 7 -CA 2,710,212 A detector 116 is associated with the visible-light source 112 and/or auxiliary light source 122 and the lens 130. The detector module 116 is an optical detector (or detectors) provided so as to collect light emitted by the light source 112/ALS 122 and back-scattered (reflected) by the objects/particles 134.
Detector module 116 can also monitor the visible-light source 112 or auxiliary light source 122. The light signal can also come from an object 134 being the direct source of this light (such as a remote control) in order to send information to the data/signal processor through the optical detector module 116. The optical detector module is, for example, composed of photodiodes, avalanche photodiodes (APD), photomultipliers (PMT), complementary metal-oxide semiconductor (CMOS) or charge-coupled device (CCD) array sensors.
Filters are typically provided with the detector module 116 to control background ambient light emitted from sources other than the lighting system 100.
Filters can also be used for spectroscopic measurements and to enhance performance of the light source 112.
A front-end and analog-to-digital converter (ADC) 124 is connected to detector 116 and receives detected light data therefrom and controls the detector 116.
For instance, adjusting the Vbias of an APD detector can be one of the detector controls to optimize the gain of the receiver section for an Automatic Gain Control (AGC). Analog filters can be used for discriminating specific frequencies or to measure the DC level.
A detection and ranging digital processing unit 126 is connected to the front-end 124, and controls parameters such as gain of amplifier, synchronization and sample rate of the ADC. The detection and ranging digital processing unit 126 receives data from ADC and pre-processes the data.
The data/signal processor 118 is connected to the detection and ranging processing module 126 and receives pre-processed data. The data/signal processor 118 is also connected to the source controller 114, so as to receive driving data therefrom. The data/signal processor 118 has a processing unit (e.g., CPU) so as to interpret the pre-processed data from the detection module 126, in comparison with the driving data of the source controller 114, which provides information about the
Detector module 116 can also monitor the visible-light source 112 or auxiliary light source 122. The light signal can also come from an object 134 being the direct source of this light (such as a remote control) in order to send information to the data/signal processor through the optical detector module 116. The optical detector module is, for example, composed of photodiodes, avalanche photodiodes (APD), photomultipliers (PMT), complementary metal-oxide semiconductor (CMOS) or charge-coupled device (CCD) array sensors.
Filters are typically provided with the detector module 116 to control background ambient light emitted from sources other than the lighting system 100.
Filters can also be used for spectroscopic measurements and to enhance performance of the light source 112.
A front-end and analog-to-digital converter (ADC) 124 is connected to detector 116 and receives detected light data therefrom and controls the detector 116.
For instance, adjusting the Vbias of an APD detector can be one of the detector controls to optimize the gain of the receiver section for an Automatic Gain Control (AGC). Analog filters can be used for discriminating specific frequencies or to measure the DC level.
A detection and ranging digital processing unit 126 is connected to the front-end 124, and controls parameters such as gain of amplifier, synchronization and sample rate of the ADC. The detection and ranging digital processing unit 126 receives data from ADC and pre-processes the data.
The data/signal processor 118 is connected to the detection and ranging processing module 126 and receives pre-processed data. The data/signal processor 118 is also connected to the source controller 114, so as to receive driving data therefrom. The data/signal processor 118 has a processing unit (e.g., CPU) so as to interpret the pre-processed data from the detection module 126, in comparison with the driving data of the source controller 114, which provides information about the
- 8 -CA 2,710,212 predetermined mode of emission of the light signals emitted by the visible-light source 112.
Accordingly, information about the object (e.g., presence, distance, speed of displacement, composition, dimension, etc. ) is calculated by the data/signal processor 118 as a function of the relationship (e.g., phase difference, relative intensity, spectral content, time of flight, etc.) between the driving data and the detected light data, is optionally pre-processed by the front-end and ADC 24 and the detection and ranging processing unit 126. A database 120 may be provided in association with the data/signal processor 118 so as to provide historical data or tabulated data to accelerate the calculation of the object parameters.
In view of the calculation it performs, the data/signal processor 118 controls the source controller 114 and thus the light output of the visible-light source 112. For instance, the visible-light source 112 may be required to increase or reduce its intensity, or change the parameters of its output. For example, changes in its output power can adapt the lighting level required in daytime conditions versus nighttime conditions or in bad visibility conditions such as fog, snow or rain.
The system 100 can be provided with sensors 132 connected to the data/signal processor 118. Sensors 132 can be an inclinometer, accelerometer, temperature sensor, day/night sensors, etc. Sensors 132 can be useful during the installation of the system and during operation of the system. For example, data from an inclinometer and accelerometer can be used to compensate for the impact on the field of view of an effect of the wind or any kind of vibration. Temperature sensors are useful to provide information about weather (internal, external or remote temperature with FIR lens). Information from sensors 132 and data/signal processor 118 and light from light source 112 and auxiliary light source 122 can be used during installation, in particular for adjusting the field of view of the optical receiver. The auxiliary light source 112 can be used as a pointer and distance meter.
The system 100 has a power supply and interface 128. The interface section is connected to a Data/signal processor and communicates to an external traffic management system (via wireless, power line, Ethernet, CAN bus, USB, etc.).
Segmentation of the digital processing as a function of the range
Accordingly, information about the object (e.g., presence, distance, speed of displacement, composition, dimension, etc. ) is calculated by the data/signal processor 118 as a function of the relationship (e.g., phase difference, relative intensity, spectral content, time of flight, etc.) between the driving data and the detected light data, is optionally pre-processed by the front-end and ADC 24 and the detection and ranging processing unit 126. A database 120 may be provided in association with the data/signal processor 118 so as to provide historical data or tabulated data to accelerate the calculation of the object parameters.
In view of the calculation it performs, the data/signal processor 118 controls the source controller 114 and thus the light output of the visible-light source 112. For instance, the visible-light source 112 may be required to increase or reduce its intensity, or change the parameters of its output. For example, changes in its output power can adapt the lighting level required in daytime conditions versus nighttime conditions or in bad visibility conditions such as fog, snow or rain.
The system 100 can be provided with sensors 132 connected to the data/signal processor 118. Sensors 132 can be an inclinometer, accelerometer, temperature sensor, day/night sensors, etc. Sensors 132 can be useful during the installation of the system and during operation of the system. For example, data from an inclinometer and accelerometer can be used to compensate for the impact on the field of view of an effect of the wind or any kind of vibration. Temperature sensors are useful to provide information about weather (internal, external or remote temperature with FIR lens). Information from sensors 132 and data/signal processor 118 and light from light source 112 and auxiliary light source 122 can be used during installation, in particular for adjusting the field of view of the optical receiver. The auxiliary light source 112 can be used as a pointer and distance meter.
The system 100 has a power supply and interface 128. The interface section is connected to a Data/signal processor and communicates to an external traffic management system (via wireless, power line, Ethernet, CAN bus, USB, etc.).
Segmentation of the digital processing as a function of the range
- 9 -CA 2,710,212 Several range finding applications need different performances as a function of the range. For automotive applications, such as Adaptive Cruise Control (ACC), it could be useful to detect a vehicle more than 100 meters ahead but the needs in terms of accuracy and repetition rate are not the same as for short range applications such as pre-crash mitigation. Basically, for a short range application, the reflected signal is strong but, usually, the needs for a good resolution and fast refresh rate of the data are high. For a long range application, the opposite is true, the reflected signal is weak and noisy but the need for resolution and refresh rate is less demanding.
Phase shifting control techniques can improve accuracy using a digital acquisition system with low sample rate. For instance, a relatively low cost ADC
(ex.: 50MSPS) can have an improved temporal resolution if successive acquisitions are delayed by an equivalent fraction of the acquisition time period but this technique has an impact on SNR and refresh rate when averaging is used.
To optimize the performance, one can adjust specific parameters as a function of the distance. Using the detection and ranging digital processing unit 126 and the Data/signal Processor 118, allows to control the number of shift delay by period, the number of accumulation and the refresh rate for each data point sampled or for several segments. For shorter distances, with an echo back signal which is relatively strong, the number of shift delays and the refresh rate can be higher to improve the resolution and the response time. The number of accumulation (or other time-integration techniques) would be lower but sufficient at short distances (trade-off between signal-to-noise ratio, resolution and number of results per second).
The accumulation technique improves the signal-to-noise ratio of the detected light signal using multiple measurements.. In order to produce one distance measurement, the technique uses M light pulses and for each light pulse, a signal detected by the optical detector is sampled by the ADC with an ADC time resolution of 1/F second thereby generating M lidar traces of j points (Si to Si) each.
Points of the M lidar traces are added point per point to generate one accumulated digital lidar trace of j points.
Phase shifting control techniques can improve accuracy using a digital acquisition system with low sample rate. For instance, a relatively low cost ADC
(ex.: 50MSPS) can have an improved temporal resolution if successive acquisitions are delayed by an equivalent fraction of the acquisition time period but this technique has an impact on SNR and refresh rate when averaging is used.
To optimize the performance, one can adjust specific parameters as a function of the distance. Using the detection and ranging digital processing unit 126 and the Data/signal Processor 118, allows to control the number of shift delay by period, the number of accumulation and the refresh rate for each data point sampled or for several segments. For shorter distances, with an echo back signal which is relatively strong, the number of shift delays and the refresh rate can be higher to improve the resolution and the response time. The number of accumulation (or other time-integration techniques) would be lower but sufficient at short distances (trade-off between signal-to-noise ratio, resolution and number of results per second).
The accumulation technique improves the signal-to-noise ratio of the detected light signal using multiple measurements.. In order to produce one distance measurement, the technique uses M light pulses and for each light pulse, a signal detected by the optical detector is sampled by the ADC with an ADC time resolution of 1/F second thereby generating M lidar traces of j points (Si to Si) each.
Points of the M lidar traces are added point per point to generate one accumulated digital lidar trace of j points.
-10-CA 2,710,212 The phase shift technique is used to improve the time resolution of the trace acquired by the ADC and limited by its sample rate F Hz. The phase shift technique allows for the use of a low cost ADC having a low sample rate F by virtually increasing the effective sample rate. The effective sample rate is increased by a factor By combining the accumulation and the phase shift techniques, an accumulation of M sets is performed for each one of the P phase shifts, for a total of N = MxP acquisition sets. Using the N sets, the detection and ranging digital processing unit 126 and the Data/signal Processor 118 creates one combined trace of the reflected light pulse. Each point in the combined trace is an accumulation of
-11-CA 2,710,212 Figure 3 shows one example of setup configurations for this method using different parameters as a function of the distance.. For different distances (for instance, for a range from 1 m to 100 m), one can optimize the temporal resolution, the number of accumulation and the refresh rate and make tradeoffs in terms of sensibility, accuracy and speed as a function of the distance to a target.
Figure 4 shows a reflected signal with a first echo from an object closer to the system and a second echo from another object further from the source. The amplitude of the first echo is higher and the system optimizes the temporal resolution.
The amplitude of the second echo back pulse from the farther object is lower and the system optimizes the SNR by using more accumulation instead of optimizing the resolution.
The value of each parameter can be adaptive as a function of the echo back signal. After analyzing the level of the noise, the system can optimize the process by adjusting parameters as a function of the priority (resolution, refresh rate, SNR). For example, if the noise is lower than expected, the system can reduce the number of accumulation and increase the number of shift delays to improve the resolution.
Figure 5 shows a flow chart of a typical process for this method. In this flowchart and in all other flowcharts of the present application, some steps may be optional. Some optional steps are identified by using a dashed box for the step.
Configuration 500 sets several parameters before the beginning of the process.
Acquisition 502 starts the process by the synchronization of the emission of the optical pulses and the acquisition of samples by the ADC. Digital filtering and processing of the data 504 make the conditioning for the extraction and storage in memory of a lidar trace 506. Detection and estimation of the distance 508 is made, typically using a reference signal and measuring the lapse of time between the emission and the reception of the signal. The transmission of the results 510 (the detection and the estimation of the distance) are transmitted to a external system.
Noise analysis 512 is performed and an adjustment of the parameters as a function of the level of the noise 514 can be made to optimize the process.
Based on shift delay and accumulation techniques, it is possible to optimize the cost of optical range finder systems particularly for short range distance
Figure 4 shows a reflected signal with a first echo from an object closer to the system and a second echo from another object further from the source. The amplitude of the first echo is higher and the system optimizes the temporal resolution.
The amplitude of the second echo back pulse from the farther object is lower and the system optimizes the SNR by using more accumulation instead of optimizing the resolution.
The value of each parameter can be adaptive as a function of the echo back signal. After analyzing the level of the noise, the system can optimize the process by adjusting parameters as a function of the priority (resolution, refresh rate, SNR). For example, if the noise is lower than expected, the system can reduce the number of accumulation and increase the number of shift delays to improve the resolution.
Figure 5 shows a flow chart of a typical process for this method. In this flowchart and in all other flowcharts of the present application, some steps may be optional. Some optional steps are identified by using a dashed box for the step.
Configuration 500 sets several parameters before the beginning of the process.
Acquisition 502 starts the process by the synchronization of the emission of the optical pulses and the acquisition of samples by the ADC. Digital filtering and processing of the data 504 make the conditioning for the extraction and storage in memory of a lidar trace 506. Detection and estimation of the distance 508 is made, typically using a reference signal and measuring the lapse of time between the emission and the reception of the signal. The transmission of the results 510 (the detection and the estimation of the distance) are transmitted to a external system.
Noise analysis 512 is performed and an adjustment of the parameters as a function of the level of the noise 514 can be made to optimize the process.
Based on shift delay and accumulation techniques, it is possible to optimize the cost of optical range finder systems particularly for short range distance
- 12-CA 2,710,212 measurement. By using only one sample per optical pulse, the ADC has to acquire samples at the frequency of the optical pulse emission. For a system driving optical pulses at L Hz, the ADC converts L samples per second with P shift delay of D
ns of delay. Figure 6 shows an example of that technique for a ten meter range finder. The source emits a 20 ns optical pulse at T=0 ns at several KHz (ex.: 100 KHz). In the air, the optical pulse takes approximately 65ns to reach a target at ten meters and to reflect back to the sensor of the system. Each time a pulse is emitted, the ADC
acquires only one sample. The ADC works at same frequency as the optical pulse driver (ex.:
KHz). For each one of the first twenty optical pulses, the system synchronizes a shift delay of 5ns between the optical pulse driver and the ADC. After 20 pulses, the system samples the reflected back signal 95ns after the pulse was emitted, just enough to detect the end of the reflected back signal from a target at 10 meters. For this example, if the system works at 100 KHz, after 200us, a complete 10 meters Lidar trace is recorded. To improve the signal-to-noise ratio, one can accumulate up to 5000 times to have one complete lidar trace per second. Fig 7 is a table showing setup configuration for this method. For a maximum range of 10 meters and 30 meters, the table shows tradeoffs between accuracy (temporal resolution), sensibility (improvement of the signal to noise ratio by accumulation) and speed (refresh rate).
Nowadays, embedded processors, microcontrollers and digital signal processor, have a lot of processing power with fixed-point or floating-point units with hundreds of Mega FLOating point Operations per Second (MFLOPS) of performance.
They are highly integrated with analog-to-digital converters, timers, PWM
modules and, several types of interface (USB, Ethernet, CAN bus, etc). Using the last technique described, mainly because the requirement in terms of speed of the ADC is low, the major part of the range finder system can be integrated in an embedded processor. Fig 8 shows a block diagram of a lidar module 800 using an embedded processor optimizing the cost of the range finder system. The embedded processor 801 controls the timing for the driver 802 sourcing the light source 803. A
light signal is emitted in a direction determined by the optical lens 804. A reflection signal from objects/particules 834 is received on the optical lens 804 and collected by the optical detector and amplifier 805. The embedded processor 801 uses an embedded ADC to
ns of delay. Figure 6 shows an example of that technique for a ten meter range finder. The source emits a 20 ns optical pulse at T=0 ns at several KHz (ex.: 100 KHz). In the air, the optical pulse takes approximately 65ns to reach a target at ten meters and to reflect back to the sensor of the system. Each time a pulse is emitted, the ADC
acquires only one sample. The ADC works at same frequency as the optical pulse driver (ex.:
KHz). For each one of the first twenty optical pulses, the system synchronizes a shift delay of 5ns between the optical pulse driver and the ADC. After 20 pulses, the system samples the reflected back signal 95ns after the pulse was emitted, just enough to detect the end of the reflected back signal from a target at 10 meters. For this example, if the system works at 100 KHz, after 200us, a complete 10 meters Lidar trace is recorded. To improve the signal-to-noise ratio, one can accumulate up to 5000 times to have one complete lidar trace per second. Fig 7 is a table showing setup configuration for this method. For a maximum range of 10 meters and 30 meters, the table shows tradeoffs between accuracy (temporal resolution), sensibility (improvement of the signal to noise ratio by accumulation) and speed (refresh rate).
Nowadays, embedded processors, microcontrollers and digital signal processor, have a lot of processing power with fixed-point or floating-point units with hundreds of Mega FLOating point Operations per Second (MFLOPS) of performance.
They are highly integrated with analog-to-digital converters, timers, PWM
modules and, several types of interface (USB, Ethernet, CAN bus, etc). Using the last technique described, mainly because the requirement in terms of speed of the ADC is low, the major part of the range finder system can be integrated in an embedded processor. Fig 8 shows a block diagram of a lidar module 800 using an embedded processor optimizing the cost of the range finder system. The embedded processor 801 controls the timing for the driver 802 sourcing the light source 803. A
light signal is emitted in a direction determined by the optical lens 804. A reflection signal from objects/particules 834 is received on the optical lens 804 and collected by the optical detector and amplifier 805. The embedded processor 801 uses an embedded ADC to
- 13 -CA 2,710,212 make the acquisition of the lidar trace and processes the data and sends the information to an external system 840.The system 800 can use several sources being driven sequentially using one sensor or several sensors. The frequency of acquisition is at the frequency of optical source multiplied by the number of optical sources.
Moving average, filters, frequency analysis and peak detection Instead of collecting N data and then performing an average (one average at each 1/N x [frequency of the source]), moving average techniques permit to constantly have the last N samples to perform an average. Using a FIFO by adding a new data and subtracting the first data accumulated is an example of an implementation of that technique.
Using too much integration time for averaging can generate a problem when detecting moving objects. Averaging techniques can consider a signal from moving objects as noise and will fail to discriminate it. Frequency domain analysis can be useful for this kind of situation. Wavelet transform is very efficient for signal analysis in time/frequency domain and is sensitive to the transient signals.
By separating the echo back signal in several segments and analyzing the spectral frequency, the system can detect the frequency of the pulse of the source in a specific segment. Averaging parameters can be adjusted as a function of events detected by the spectral analysis process. For instance, the number of averages should be reduced when moving objects are detected sequentially in different segments.
Low pass filters can be used as pre-processes on each trace before averaging. Filters may be particularly efficient when more than one sample is available on an echo pulse. Information from noise analysis and from the information of the signal waveform emitted by the source can also help to discriminate a signal and to adjust the parameters. Specific processing functions can be used for each point of the trace or by segment.
Another way to optimize the detection of an object and the measurement of the distance is using a reference signal and making a fit with the lidar trace. The reference signal can be a pattern signal stored in memory or a reference reflection signal of an optical pulse detected by a reference optical detector. This reference optical detector acquires a reference zero value and this reference signal is compared
Moving average, filters, frequency analysis and peak detection Instead of collecting N data and then performing an average (one average at each 1/N x [frequency of the source]), moving average techniques permit to constantly have the last N samples to perform an average. Using a FIFO by adding a new data and subtracting the first data accumulated is an example of an implementation of that technique.
Using too much integration time for averaging can generate a problem when detecting moving objects. Averaging techniques can consider a signal from moving objects as noise and will fail to discriminate it. Frequency domain analysis can be useful for this kind of situation. Wavelet transform is very efficient for signal analysis in time/frequency domain and is sensitive to the transient signals.
By separating the echo back signal in several segments and analyzing the spectral frequency, the system can detect the frequency of the pulse of the source in a specific segment. Averaging parameters can be adjusted as a function of events detected by the spectral analysis process. For instance, the number of averages should be reduced when moving objects are detected sequentially in different segments.
Low pass filters can be used as pre-processes on each trace before averaging. Filters may be particularly efficient when more than one sample is available on an echo pulse. Information from noise analysis and from the information of the signal waveform emitted by the source can also help to discriminate a signal and to adjust the parameters. Specific processing functions can be used for each point of the trace or by segment.
Another way to optimize the detection of an object and the measurement of the distance is using a reference signal and making a fit with the lidar trace. The reference signal can be a pattern signal stored in memory or a reference reflection signal of an optical pulse detected by a reference optical detector. This reference optical detector acquires a reference zero value and this reference signal is compared
- 14 -CA 2,710,212 to the lidar trace. Detection and distance is based on comparison between both signals. Fit can be made by convolution.
= Fig 9 shows a noisy signal fitted and filtered to diminish the effects of the noise. Figure 9 presents the effect of signal filtering and curve fitting. The raw data curve is the noisy signal as received from the sensor. The filter curve is the raw data curve after filtering by correlation with an ideal (no noise) pulse. This removes the high-frequency noise. Finally the fit curve presents the optimal fitting of an ideal pulse on the filtered signal. Fitting can improve distance stability especially when the signal is weak and still too noisy even after filtering.
When a signal waveform has a Gaussian profile, it is possible to use a method based on a zero-crossing point of the first derivative to detect the peak of the waveform. This technique requires a previous filtering to remove the noise.
When the detection of an event (echo back pulse from an object) occurs, the system will detect N consecutive points over a predetermined threshold. The value of N depends notably on the sample rate and the width of the pulse from the source. By computing the first derivative of those selected points and interpolating to find the zero-crossing point, an estimation of the peak of the signal can be found.
Figure 10 shows an example of a Gaussian pulse with selected data over a predefined threshold and the result from the derivative calculation of those selected data. One can see the zero crossing from the derivative plot representing the peak of the pulse.
Illumination driver as a source for rangefinder with edge detection Switch-mode LED drivers are very useful notably for their efficiency compared to linear drivers. PWMs permit a very high dimming ratio without drifting the wavelength usually generated by linear drivers. Their performance is particularly well suited for high power LEDs. However, switch-mode LED drivers are noisier and the EMI can be an issue for some applications. One way to address this issue is to use a gate rising/falling slope adjust circuit to decrease the speed of transitions.
Transitions at lower speed mean less EMI. Figure 11 presents a typical PWM
signal with slope adjustment.
= Fig 9 shows a noisy signal fitted and filtered to diminish the effects of the noise. Figure 9 presents the effect of signal filtering and curve fitting. The raw data curve is the noisy signal as received from the sensor. The filter curve is the raw data curve after filtering by correlation with an ideal (no noise) pulse. This removes the high-frequency noise. Finally the fit curve presents the optimal fitting of an ideal pulse on the filtered signal. Fitting can improve distance stability especially when the signal is weak and still too noisy even after filtering.
When a signal waveform has a Gaussian profile, it is possible to use a method based on a zero-crossing point of the first derivative to detect the peak of the waveform. This technique requires a previous filtering to remove the noise.
When the detection of an event (echo back pulse from an object) occurs, the system will detect N consecutive points over a predetermined threshold. The value of N depends notably on the sample rate and the width of the pulse from the source. By computing the first derivative of those selected points and interpolating to find the zero-crossing point, an estimation of the peak of the signal can be found.
Figure 10 shows an example of a Gaussian pulse with selected data over a predefined threshold and the result from the derivative calculation of those selected data. One can see the zero crossing from the derivative plot representing the peak of the pulse.
Illumination driver as a source for rangefinder with edge detection Switch-mode LED drivers are very useful notably for their efficiency compared to linear drivers. PWMs permit a very high dimming ratio without drifting the wavelength usually generated by linear drivers. Their performance is particularly well suited for high power LEDs. However, switch-mode LED drivers are noisier and the EMI can be an issue for some applications. One way to address this issue is to use a gate rising/falling slope adjust circuit to decrease the speed of transitions.
Transitions at lower speed mean less EMI. Figure 11 presents a typical PWM
signal with slope adjustment.
-15-CA 2,710,212 For range-finding applications, the rapid transition of the signal is generally required. Usually, to get good performance, electronic circuits need to detect fast transition signals within a few nanosecond of resolution. Using a LED light source with a PWM driver with adjustment to diminish the speed of the slope as the source for detection and ranging is, in principle, not very helpful.
One solution is to use the same LED light source for illumination and for detection and ranging with a PWM circuit controlling the intensity of illumination.
The PWM LED light source has a relatively constant slope during its rising/falling edge to reduce EMI (rising/falling edge of 100ns for example). The optical signal from the source is sampled to be able to determine the starting time of the pulse (TO).
Electrical synchronization signal can also be used to indicate the starting point. The reflected signal is sampled with enough temporal resolution to have several points during the slope of the signal when an object in the field of view returns a perceptible echo.
Figure 12 shows an example of a rising edge from a source, an echo back signal from an object 4.5 meters away from the source (=-10 ns later) and another from an object at 7 meters from the source (z45 ns later). Calculating the slope by linear regression or other means, an evaluation of the origin of the signal is made and the elapsed time between the signal from the source and an echo back signal can be determined. Based on that result, one can estimate the presence and the distance of the object reflecting the signal.
Figure 13 represents a 10% to 90% rising edge of an echo back noisy signal from an object at 4.5 meters from the source. With linear regression, one can calculate the intercept point and get a good estimate of the delay between the two signals. Samples close to the end of the slope have a better SNR. One can determine different weights in the calculation as a function of the level of the noise.
Both rising and falling edges can be used. During the calibration process, a threshold can be set to discriminate the presence or the absence of an object. Averaging and filtering techniques can be used to diminish the level of noise and shifting techniques can also be used to have more points in the slope. As shown in Figure 9, even with a noisy signal, this method can give good results.
One solution is to use the same LED light source for illumination and for detection and ranging with a PWM circuit controlling the intensity of illumination.
The PWM LED light source has a relatively constant slope during its rising/falling edge to reduce EMI (rising/falling edge of 100ns for example). The optical signal from the source is sampled to be able to determine the starting time of the pulse (TO).
Electrical synchronization signal can also be used to indicate the starting point. The reflected signal is sampled with enough temporal resolution to have several points during the slope of the signal when an object in the field of view returns a perceptible echo.
Figure 12 shows an example of a rising edge from a source, an echo back signal from an object 4.5 meters away from the source (=-10 ns later) and another from an object at 7 meters from the source (z45 ns later). Calculating the slope by linear regression or other means, an evaluation of the origin of the signal is made and the elapsed time between the signal from the source and an echo back signal can be determined. Based on that result, one can estimate the presence and the distance of the object reflecting the signal.
Figure 13 represents a 10% to 90% rising edge of an echo back noisy signal from an object at 4.5 meters from the source. With linear regression, one can calculate the intercept point and get a good estimate of the delay between the two signals. Samples close to the end of the slope have a better SNR. One can determine different weights in the calculation as a function of the level of the noise.
Both rising and falling edges can be used. During the calibration process, a threshold can be set to discriminate the presence or the absence of an object. Averaging and filtering techniques can be used to diminish the level of noise and shifting techniques can also be used to have more points in the slope. As shown in Figure 9, even with a noisy signal, this method can give good results.
- 16-CA 2,710,212 Figure 14 shows a flow chart of the typical process for this method. The echo back signal is filtered 1400, typically using a band-pass filter based on the frequency of the transition. Rising and falling edges are detected 1402 and samples are taken in the slope 1404 to memorize a digital waveform of the slope. The calculation of the linear regression 1406 is made and permits to calculate the intercept point 1408. Based on that information, the calculation of the difference in time between the signal emission and the signal received 1410 allows to estimate the distance to the object 1412.
This method can be improved by using demodulation and spectral analysis techniques. The base frequency of the PWM can be demodulated and the result of this demodulation will give an indication of a presence of an object. By selecting a frequency based on an harmonic coming from the slopes of the PWM signal, one can estimate the position of the object by spectral analysis of different segments. Knowing the approximated position, the acquisition of samples will be adjusted to target the rising and the falling edge.
By using the edge detection technique, one can use a standard LED driver for the purpose of lighting and also for the purpose of detection and ranging.
The frequency of the PWM might be in the range from a few KHz up to 1MHz. High frequency modulation can improve the SNR notably by averaging techniques. When the optical output of the source is coupled by optical path (reflection from lens or mirror or use of fiber optic), this method permits using a PWM source for a LED
lighting system completely electrically isolated from the receiver.
Other types of rising/falling edge detection can be used with this method with the appropriate curve fitting technique. If EMI is not an issue, the electronic driver can generate a fast rising edge and/or falling edge with some overshoot at a resonance frequency. This signal adds more power at a specific frequency and increase the signal that can be detected by the receiver. Figure 15 shows a rising edge with overshoot stabilizing after one cycle of the resonance frequency.
Recognition of predetermined patterns Different shapes of objects reflect a modified waveform of the original signal. The echo back signal from a wall is different when compared to the echo back
This method can be improved by using demodulation and spectral analysis techniques. The base frequency of the PWM can be demodulated and the result of this demodulation will give an indication of a presence of an object. By selecting a frequency based on an harmonic coming from the slopes of the PWM signal, one can estimate the position of the object by spectral analysis of different segments. Knowing the approximated position, the acquisition of samples will be adjusted to target the rising and the falling edge.
By using the edge detection technique, one can use a standard LED driver for the purpose of lighting and also for the purpose of detection and ranging.
The frequency of the PWM might be in the range from a few KHz up to 1MHz. High frequency modulation can improve the SNR notably by averaging techniques. When the optical output of the source is coupled by optical path (reflection from lens or mirror or use of fiber optic), this method permits using a PWM source for a LED
lighting system completely electrically isolated from the receiver.
Other types of rising/falling edge detection can be used with this method with the appropriate curve fitting technique. If EMI is not an issue, the electronic driver can generate a fast rising edge and/or falling edge with some overshoot at a resonance frequency. This signal adds more power at a specific frequency and increase the signal that can be detected by the receiver. Figure 15 shows a rising edge with overshoot stabilizing after one cycle of the resonance frequency.
Recognition of predetermined patterns Different shapes of objects reflect a modified waveform of the original signal. The echo back signal from a wall is different when compared to the echo back
-17-CA 2,710,212 signal from an object with an irregular shape. Reflection from two objects with a short longitudinal distance between them also generates a distinct waveform. By memorizing in database a several types of waveforms, this data can be used to improve the digital processing performance. Digital correlation can be done to detect a predetermined pattern.
Tracking Averaging techniques do not perform very well with moving objects. By tracking a moving object, one can anticipate the position of the object and adapt to the situation. Averaging with shifting proportional to the estimated position is a way to improve the SNR even in the case of moving objects. Tracking edges is another way to adjust the acquisition of the waveform with more points in the region of interest.
Spectral analysis can also be used to lock and track an object.
Weather information and condition monitoring The system can be used as a road weather information system (RW1S) and thus provide information about temperature, visibility (fog, snow, rain, dust), condition of the road (icy) and pollution (smog). Pattern recognition based on low frequency signals and spikes can be implemented to do so. The recognition of bad weather condition patterns helps to discriminate noise from objects. The system can be used to adjust the intensity of light depending on weather conditions.
Monitoring the condition of the lens is also possible (dirt, accumulation of snow, etc).
This monitoring can be done by the measurement of the reflection on the lens from the source or from an auxiliary source.
Detection based on integration time Figure 16 shows a timing diagram of the method using an integration signal from the reflected signal and synchronized with the rising edge and the falling edge of the PWM lighting source.
This method uses a sensor or an array of sensors (1D or 2D array - CCD, CMOS) with an integrator, or electronic shutter, and a PWM light source or a pulsed auxiliary light source. Figure 16 shows a PWM signal (PWM curve 1601) with an adjustable duty cycle to control the intensity of light for illumination purposes. Before
Tracking Averaging techniques do not perform very well with moving objects. By tracking a moving object, one can anticipate the position of the object and adapt to the situation. Averaging with shifting proportional to the estimated position is a way to improve the SNR even in the case of moving objects. Tracking edges is another way to adjust the acquisition of the waveform with more points in the region of interest.
Spectral analysis can also be used to lock and track an object.
Weather information and condition monitoring The system can be used as a road weather information system (RW1S) and thus provide information about temperature, visibility (fog, snow, rain, dust), condition of the road (icy) and pollution (smog). Pattern recognition based on low frequency signals and spikes can be implemented to do so. The recognition of bad weather condition patterns helps to discriminate noise from objects. The system can be used to adjust the intensity of light depending on weather conditions.
Monitoring the condition of the lens is also possible (dirt, accumulation of snow, etc).
This monitoring can be done by the measurement of the reflection on the lens from the source or from an auxiliary source.
Detection based on integration time Figure 16 shows a timing diagram of the method using an integration signal from the reflected signal and synchronized with the rising edge and the falling edge of the PWM lighting source.
This method uses a sensor or an array of sensors (1D or 2D array - CCD, CMOS) with an integrator, or electronic shutter, and a PWM light source or a pulsed auxiliary light source. Figure 16 shows a PWM signal (PWM curve 1601) with an adjustable duty cycle to control the intensity of light for illumination purposes. Before
-18-CA 2,710,212 the rising edge of the PWM pulse, at time t-x, the sensor starts the integration (sensor integration curve 1603) of the reflected signal. At time t+x, the sensor stops the integration. The same process is performed at the falling edge of the PWM. The light pulse from the source is delayed (delay curve 1602) proportionally to the travelled distance. The delta curve 1604 shows that the integration P1 for the rising edge is smaller than the integration P2 for the falling edge because of the delay of travel of the light signal. In fact, if an object is very close to the source, the integration value from the rising edge will be approximately equal to the integration value from the falling edge. But, if an object is further, the integration value of rising edge will be less than the integration value of the falling edge. The difference between the values is proportional to the distance. The relationship is:
Distance = c X (INT/4) * (P2-P1)/(P2+P1), where c represents the velocity of light, TNT represents the integration time, represents the integration value synchronized with the rising edge of the optical pulse and P2 represents the integration value synchronized on the falling edge of the optical pulse.
When an illumination background from other lighting sources is not negligible, measurement of the background B during an integration time TNT
when the optical source of the system is off can be made and subtracted from each integration value P1 and P2. The relationship with non negligible background is:
Distance = c X (INT/4) * ((P2-B)-(P1 -B))/(P2+P1-2B), where B is the integration value of the optical background level when the optical source of the system is off.
In the case where the integration time is larger than the width of the pulse of the optical source, the same technique can be used by switching the synchronisation of the signal of the optical source and the signal to the sensor integration time. The result becomes:
Distance = c X (INT/4) * (P1-P2)/(P2+P1), where c represents the velocity of light, TNT represents the integration time, represents the integration value when optical pulse is synchronized with the rising
Distance = c X (INT/4) * (P2-P1)/(P2+P1), where c represents the velocity of light, TNT represents the integration time, represents the integration value synchronized with the rising edge of the optical pulse and P2 represents the integration value synchronized on the falling edge of the optical pulse.
When an illumination background from other lighting sources is not negligible, measurement of the background B during an integration time TNT
when the optical source of the system is off can be made and subtracted from each integration value P1 and P2. The relationship with non negligible background is:
Distance = c X (INT/4) * ((P2-B)-(P1 -B))/(P2+P1-2B), where B is the integration value of the optical background level when the optical source of the system is off.
In the case where the integration time is larger than the width of the pulse of the optical source, the same technique can be used by switching the synchronisation of the signal of the optical source and the signal to the sensor integration time. The result becomes:
Distance = c X (INT/4) * (P1-P2)/(P2+P1), where c represents the velocity of light, TNT represents the integration time, represents the integration value when optical pulse is synchronized with the rising
- 19-CA 2,710,212 edge of integration and P2 represents the integration value when the optical pulse is synchronized with the falling edge of integration.
When an illumination background from other lighting sources is not negligible, the relationship is:
Distance = c X (INT/4) * ((Pl-B)-(P2-B))/(P2+P1-2B).
Values from the signal integration are memorized. In the case of an array of sensors, each "pixel" is memorized. Several integrations can be performed and an averaging process can be done to improve signal to noise ratio. In the case of an array, we also can improve signal to noise ratio by using a groups of pixel and combining them to form a larger pixel (binning).
In summary, with reference to Figure 17, the main steps of the method for acquiring a detected light optical signal and generating an accumulated digital trace are shown. The method comprises providing a light source with an optical detector for illumination of a field of view 1700; providing an analog-to-digital converter (ADC) 1702; emitting one pulse from the light source in the field of view 1704;
detecting a reflection signal of the pulse by the optical detector 1706; acquiring j points for the detected reflection signal by the ADC 1708; storing, in a buffer, the digital signal waveform of j points 1710; introducing a phase shift of 2n/ P 1712; repeating, P
times 1714, the steps of emitting 1704, detecting 1706, acquiring 1708, storing 1710 and introducing 1712 to store 1710, in the buffer, an interleaved waveform of P x j points; accumulating 1716 M traces of interleaved P x j points for a total of N=MxP
acquisition sets, N being a total number of pulses emitted; creating one combined trace of the reflected signal of j x P points by adding each point of the M
traces 1718.
Additionally, the combined trace can be compared 1720 to a detected reference reflection signal of the pulse to determine 1722 a distance traveled by the pulse.
Alternatively, a timer can be triggered to calculate a time elapsed 1724 between the emission of the pulse and the detection of the reflection signal to determine a distance traveled 1722 by the pulse based on the time elapsed.
In summary, with reference to Figure 18, the main steps of the method for detecting a distance to an object are shown. The method comprises providing a
When an illumination background from other lighting sources is not negligible, the relationship is:
Distance = c X (INT/4) * ((Pl-B)-(P2-B))/(P2+P1-2B).
Values from the signal integration are memorized. In the case of an array of sensors, each "pixel" is memorized. Several integrations can be performed and an averaging process can be done to improve signal to noise ratio. In the case of an array, we also can improve signal to noise ratio by using a groups of pixel and combining them to form a larger pixel (binning).
In summary, with reference to Figure 17, the main steps of the method for acquiring a detected light optical signal and generating an accumulated digital trace are shown. The method comprises providing a light source with an optical detector for illumination of a field of view 1700; providing an analog-to-digital converter (ADC) 1702; emitting one pulse from the light source in the field of view 1704;
detecting a reflection signal of the pulse by the optical detector 1706; acquiring j points for the detected reflection signal by the ADC 1708; storing, in a buffer, the digital signal waveform of j points 1710; introducing a phase shift of 2n/ P 1712; repeating, P
times 1714, the steps of emitting 1704, detecting 1706, acquiring 1708, storing 1710 and introducing 1712 to store 1710, in the buffer, an interleaved waveform of P x j points; accumulating 1716 M traces of interleaved P x j points for a total of N=MxP
acquisition sets, N being a total number of pulses emitted; creating one combined trace of the reflected signal of j x P points by adding each point of the M
traces 1718.
Additionally, the combined trace can be compared 1720 to a detected reference reflection signal of the pulse to determine 1722 a distance traveled by the pulse.
Alternatively, a timer can be triggered to calculate a time elapsed 1724 between the emission of the pulse and the detection of the reflection signal to determine a distance traveled 1722 by the pulse based on the time elapsed.
In summary, with reference to Figure 18, the main steps of the method for detecting a distance to an object are shown. The method comprises providing a
- 20 -CA 2,710,212 lighting system 1800 having at least one pulse width modulated visible-light source for illumination of a field of view; emitting an illumination signal 1802 for illuminating the field of view for a duration of time y using the visible-light source at a time t; integrating a reflection energy for a first time period from a time t-x to a time t+x 1808; determining a first integration value for the first time period 1810;
integrating the reflection energy for a second time period from a time t+y-x to a time t+y+x 1812; determining a second integration value for the second time period 1814;
calculating a difference value between the first integration value and the second integration value 1816; determining a propagation delay value proportional to the difference value 1818; determining the distance to the object from the propagation delay value 1820.
While illustrated in the block diagrams as groups of discrete components communicating with each other via distinct data signal connections, it will be understood by those skilled in the art that the illustrated embodiments may be provided by a combination of hardware and software components, with some components being implemented by a given function or operation of a hardware or software system, and many of the data paths illustrated being implemented by data communication within a computer application or operating system. The structure illustrated is thus provided for efficiency of teaching the described embodiment.
integrating the reflection energy for a second time period from a time t+y-x to a time t+y+x 1812; determining a second integration value for the second time period 1814;
calculating a difference value between the first integration value and the second integration value 1816; determining a propagation delay value proportional to the difference value 1818; determining the distance to the object from the propagation delay value 1820.
While illustrated in the block diagrams as groups of discrete components communicating with each other via distinct data signal connections, it will be understood by those skilled in the art that the illustrated embodiments may be provided by a combination of hardware and software components, with some components being implemented by a given function or operation of a hardware or software system, and many of the data paths illustrated being implemented by data communication within a computer application or operating system. The structure illustrated is thus provided for efficiency of teaching the described embodiment.
-21-
Claims (25)
1. A method for acquiring a detected light optical signal and generating an accumulated digital trace, the method comprising:
providing a light source for illumination of a field of view;
an optical detector;
an analog-to-digital converter (ADC) with a sample rate of F Hz and B bits of resolution;
emitting one pulse from said light source in said field of view;
detecting a reflection signal of said pulse by the optical detector;
acquiring j points for said reflection signal by said ADC by acquiring one of said j points at each 1 / F second thereby converting said reflection signal into a digital signal waveform of j points;
storing, in a buffer, said digital signal waveform of j points;
introducing a phase shift of 2n divided by a factor P between said emitting light pulse and a beginning of said acquiring j points by the ADC;
repeating, P times, said steps of emitting, detecting, acquiring, storing and introducing, to store, in said buffer, an interleaved waveform of P x j points, said interleaved waveform being equivalent to a single acquisition with a temporal resolution of 1 / (F x P) second;
accumulating M traces of interleaved P x j points for a total of N = M x P
acquisition sets, N being a total number of pulses emitted;
using the N sets, creating one combined trace of the reflected signal by adding each point of the M traces, point per point, to generate one accumulated digital trace of j x P points, each point in the combined trace being an accumulation of M = N / P sets and an effective time resolution of the combined trace being 1 / (F x P) second;
wherein a length of said buffer is at least j x P and a number of bits of each element in said buffer is B+log2M;
wherein said sample rate of said ADC is virtually increased thereby allowing a low cost ADC having a low sample rate F to be used.
providing a light source for illumination of a field of view;
an optical detector;
an analog-to-digital converter (ADC) with a sample rate of F Hz and B bits of resolution;
emitting one pulse from said light source in said field of view;
detecting a reflection signal of said pulse by the optical detector;
acquiring j points for said reflection signal by said ADC by acquiring one of said j points at each 1 / F second thereby converting said reflection signal into a digital signal waveform of j points;
storing, in a buffer, said digital signal waveform of j points;
introducing a phase shift of 2n divided by a factor P between said emitting light pulse and a beginning of said acquiring j points by the ADC;
repeating, P times, said steps of emitting, detecting, acquiring, storing and introducing, to store, in said buffer, an interleaved waveform of P x j points, said interleaved waveform being equivalent to a single acquisition with a temporal resolution of 1 / (F x P) second;
accumulating M traces of interleaved P x j points for a total of N = M x P
acquisition sets, N being a total number of pulses emitted;
using the N sets, creating one combined trace of the reflected signal by adding each point of the M traces, point per point, to generate one accumulated digital trace of j x P points, each point in the combined trace being an accumulation of M = N / P sets and an effective time resolution of the combined trace being 1 / (F x P) second;
wherein a length of said buffer is at least j x P and a number of bits of each element in said buffer is B+log2M;
wherein said sample rate of said ADC is virtually increased thereby allowing a low cost ADC having a low sample rate F to be used.
2. The method as claimed in claim 1, wherein j equals 1, thereby acquiring only one point per pulse.
3. The method as claimed in claim 1, wherein at least one of P and M is adjusted as a function of j.
4. The method as claimed in claim 1, further comprising convoluting a reference signal with said combined trace.
5. The method as claimed in claim 1, further comprising:
detecting a reference reflection signal of said pulse by a reference optical detector at said emission of said pulse thereby acquiring a reference zero value and a reference trace for said pulse;
comparing said reference trace for said pulse to said combined trace;
determining a distance traveled by said pulse based on said comparison.
detecting a reference reflection signal of said pulse by a reference optical detector at said emission of said pulse thereby acquiring a reference zero value and a reference trace for said pulse;
comparing said reference trace for said pulse to said combined trace;
determining a distance traveled by said pulse based on said comparison.
6. The method as claimed in claim 1, further comprising:
providing a timer;
triggering said timer to calculate a time elapsed between said emission of said pulse and said detection of said reflection signal;
determining a distance traveled by said pulse based on said time elapsed.
providing a timer;
triggering said timer to calculate a time elapsed between said emission of said pulse and said detection of said reflection signal;
determining a distance traveled by said pulse based on said time elapsed.
7. The method as claimed in claim 1, wherein said introducing a phase shift comprises delaying a clock of the ADC by a fraction of a period.
8. The method as claimed in claim 1, wherein said introducing a phase shift comprises delaying a driver of the light source.
9. The method as claimed in claim 1, wherein said light source comprises several optical sources being driven sequentially using at least one sensor, a frequency of acquisition is a frequency of the optical source multiplied by a number of said optical sources.
10. The method as claimed in claim 1, further comprising:
determining a time at which said emitting occurred;
choosing a filter based on a frequency of a transition;
filtering the reflection signal using said filter to obtain a filtered reflection signal;
detecting at least one of rising and falling edges for said filtered reflection signal and locating at least one of a rising and a falling slope;
acquiring samples in said at least one of a rising and a falling slope to memorize a digital waveform of the slope;
calculating a linear regression on said digital waveform of the slope;
calculating an intercept point in said linear regression;
calculating a difference in time between said emitting and said intercept point to estimate a distance to an object causing said reflection signal.
determining a time at which said emitting occurred;
choosing a filter based on a frequency of a transition;
filtering the reflection signal using said filter to obtain a filtered reflection signal;
detecting at least one of rising and falling edges for said filtered reflection signal and locating at least one of a rising and a falling slope;
acquiring samples in said at least one of a rising and a falling slope to memorize a digital waveform of the slope;
calculating a linear regression on said digital waveform of the slope;
calculating an intercept point in said linear regression;
calculating a difference in time between said emitting and said intercept point to estimate a distance to an object causing said reflection signal.
11. The method as claimed in claim 10, wherein said determining a time comprises sampling said signal from said source.
12. The method as claimed in claim 11, wherein said determining a time comprises using an electrical synchronization signal.
13. The method as claimed in claim 11, further comprising determining different weights in the calculation as a function of the level of the noise.
14. The method as claimed in claim 11, further comprising:
providing a threshold; and determining the presence of an object at a predetermined target distance using said threshold.
providing a threshold; and determining the presence of an object at a predetermined target distance using said threshold.
15. The method as claimed in claim 11, further comprising diminishing a level of noise using at least one of an averaging and a filtering technique.
16. The method as claimed in claim 11, further comprising using a shifting technique to acquire more points.
17. A powered lighting system for acquiring a detected light optical signal and generating an accumulated digital trace, the powered lighting system comprising:
at least one light source for illumination of a field of view and emitting a pulse in said field of view;
an illumination driver for driving said light source;
an optical detector for detecting a reflection signal of a reflection of said pulse;
an analog-to-digital converter (ADC) with a sample rate of F Hz and B bits of resolution for acquiring j points for said reflection signal by acquiring one of said j points at each 1 / F second thereby converting said reflection signal into a digital signal waveform of j points;
a buffer for storing said digital signal waveform;
a processor for controlling said illumination driver and said optical detector;
sending information for storage in said buffer, wherein a length of said buffer is at least j x a factor P and a number of bits of each element in said buffer is B+log2M;
introducing a phase shift of 2.pi./ P between said emission of said light pulse and a beginning of said acquisition of said j points by the ADC;
causing to repeat, P times, said emitting, detecting, acquiring, storing and introducing, to obtain an interleaved waveform of P x j points, said interleaved waveform being equivalent to a single acquisition with a temporal resolution of 1 / (F x P) second;
accumulating M traces of interleaved P x j points for a total of N=MxP
acquisition sets, N being a total number of pulses emitted;
creating one combined trace of the reflected signal using the N sets, by adding each point of the M traces, point per point, to generate one accumulated digital trace of j x P points, each point in the combined trace being an accumulation of M = N / P sets and an effective time resolution of the combined trace being 1 / (F x P) second;
wherein said sample rate of said ADC is virtually increased thereby allowing a low cost ADC having a low sample rate F to be used.
at least one light source for illumination of a field of view and emitting a pulse in said field of view;
an illumination driver for driving said light source;
an optical detector for detecting a reflection signal of a reflection of said pulse;
an analog-to-digital converter (ADC) with a sample rate of F Hz and B bits of resolution for acquiring j points for said reflection signal by acquiring one of said j points at each 1 / F second thereby converting said reflection signal into a digital signal waveform of j points;
a buffer for storing said digital signal waveform;
a processor for controlling said illumination driver and said optical detector;
sending information for storage in said buffer, wherein a length of said buffer is at least j x a factor P and a number of bits of each element in said buffer is B+log2M;
introducing a phase shift of 2.pi./ P between said emission of said light pulse and a beginning of said acquisition of said j points by the ADC;
causing to repeat, P times, said emitting, detecting, acquiring, storing and introducing, to obtain an interleaved waveform of P x j points, said interleaved waveform being equivalent to a single acquisition with a temporal resolution of 1 / (F x P) second;
accumulating M traces of interleaved P x j points for a total of N=MxP
acquisition sets, N being a total number of pulses emitted;
creating one combined trace of the reflected signal using the N sets, by adding each point of the M traces, point per point, to generate one accumulated digital trace of j x P points, each point in the combined trace being an accumulation of M = N / P sets and an effective time resolution of the combined trace being 1 / (F x P) second;
wherein said sample rate of said ADC is virtually increased thereby allowing a low cost ADC having a low sample rate F to be used.
18. The system as claimed in claim 17, wherein j equals 1, thereby acquiring only one point per pulse.
19. The system as claimed in claim 17, wherein at least one of P and M is adjusted as a function of j.
20. The system as claimed in claim 17, further comprising:
a memory for providing a reference signal;
said processor convoluting said reference signal with said combined trace.
a memory for providing a reference signal;
said processor convoluting said reference signal with said combined trace.
21. The system as claimed in claim 17, further comprising:
a reference detector for detecting a reference reflection signal of said pulse at said emission of said pulse thereby acquiring a reference zero value and a reference trace for said pulse;
said processor comparing said reference trace for said pulse to said combined trace and determining a distance traveled by said pulse based on said comparison.
a reference detector for detecting a reference reflection signal of said pulse at said emission of said pulse thereby acquiring a reference zero value and a reference trace for said pulse;
said processor comparing said reference trace for said pulse to said combined trace and determining a distance traveled by said pulse based on said comparison.
22. The system as claimed in claim 17, further comprising:
a timer;
said processor triggering said timer to calculate a time elapsed between said emission of said pulse and said detection of said reflection signal and determining a distance traveled by said pulse based on said time elapsed.
a timer;
said processor triggering said timer to calculate a time elapsed between said emission of said pulse and said detection of said reflection signal and determining a distance traveled by said pulse based on said time elapsed.
23. The system as claimed in claim 17, wherein said introducing a phase shift comprises delaying a clock of the ADC by a fraction of a period.
24. The system as claimed in claim 17, wherein said introducing a phase shift comprises delaying a driver of the light source.
25. The system as claimed in claim 17, wherein said powered lighting system comprises several optical sources being driven sequentially using at least one sensor, a frequency of acquisition is a frequency of the optical source multiplied by a number of said optical sources.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA2857826A CA2857826C (en) | 2007-12-21 | 2008-12-19 | Detection and ranging methods and systems |
Applications Claiming Priority (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US1573807P | 2007-12-21 | 2007-12-21 | |
US1586707P | 2007-12-21 | 2007-12-21 | |
US61/015,738 | 2007-12-21 | ||
US61/015,867 | 2007-12-21 | ||
US4242408P | 2008-04-04 | 2008-04-04 | |
US61/042,424 | 2008-04-04 | ||
PCT/CA2008/002268 WO2009079789A1 (en) | 2007-12-21 | 2008-12-19 | Detection and ranging methods and systems |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA2857826A Division CA2857826C (en) | 2007-12-21 | 2008-12-19 | Detection and ranging methods and systems |
Publications (2)
Publication Number | Publication Date |
---|---|
CA2710212A1 CA2710212A1 (en) | 2009-07-02 |
CA2710212C true CA2710212C (en) | 2014-12-09 |
Family
ID=40800622
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA2857826A Active CA2857826C (en) | 2007-12-21 | 2008-12-19 | Detection and ranging methods and systems |
CA2710212A Active CA2710212C (en) | 2007-12-21 | 2008-12-19 | Detection and ranging methods and systems |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA2857826A Active CA2857826C (en) | 2007-12-21 | 2008-12-19 | Detection and ranging methods and systems |
Country Status (5)
Country | Link |
---|---|
US (4) | US8310655B2 (en) |
EP (2) | EP2235561B8 (en) |
JP (3) | JP5671345B2 (en) |
CA (2) | CA2857826C (en) |
WO (1) | WO2009079789A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9235988B2 (en) | 2012-03-02 | 2016-01-12 | Leddartech Inc. | System and method for multipurpose traffic detection and characterization |
US9378640B2 (en) | 2011-06-17 | 2016-06-28 | Leddartech Inc. | System and method for traffic side detection and characterization |
US11567179B2 (en) | 2020-07-21 | 2023-01-31 | Leddartech Inc. | Beam-steering device particularly for LIDAR systems |
Families Citing this family (92)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8242476B2 (en) | 2005-12-19 | 2012-08-14 | Leddartech Inc. | LED object detection system and method combining complete reflection traces from individual narrow field-of-view channels |
US8600656B2 (en) | 2007-06-18 | 2013-12-03 | Leddartech Inc. | Lighting system with driver assistance capabilities |
CA2691141C (en) | 2007-06-18 | 2013-11-26 | Leddartech Inc. | Lighting system with traffic management capabilities |
CA2857826C (en) | 2007-12-21 | 2015-03-17 | Leddartech Inc. | Detection and ranging methods and systems |
EP2232462B1 (en) | 2007-12-21 | 2015-12-16 | Leddartech Inc. | Parking management system and method using lighting system |
WO2009136184A2 (en) * | 2008-04-18 | 2009-11-12 | Bae Systems Plc | Improvements in lidars |
CA2778977C (en) | 2009-12-14 | 2018-04-10 | Montel Inc. | Entity detection system and method for monitoring an area |
EP2517189B1 (en) * | 2009-12-22 | 2014-03-19 | Leddartech Inc. | Active 3d monitoring system for traffic detection |
WO2012011037A1 (en) | 2010-07-23 | 2012-01-26 | Leddartech Inc. | 3d optical detection system and method for a mobile storage system |
US8908159B2 (en) | 2011-05-11 | 2014-12-09 | Leddartech Inc. | Multiple-field-of-view scannerless optical rangefinder in high ambient background light |
GB2492848A (en) * | 2011-07-15 | 2013-01-16 | Softkinetic Sensors Nv | Optical distance measurement |
US9069061B1 (en) | 2011-07-19 | 2015-06-30 | Ball Aerospace & Technologies Corp. | LIDAR with analog memory |
US20150071566A1 (en) * | 2011-07-22 | 2015-03-12 | Raytheon Company | Pseudo-inverse using weiner-levinson deconvolution for gmapd ladar noise reduction and focusing |
DE202011105139U1 (en) * | 2011-08-29 | 2011-11-30 | Robert Bosch Gmbh | rangefinder |
US8988081B2 (en) | 2011-11-01 | 2015-03-24 | Teradyne, Inc. | Determining propagation delay |
US8994926B2 (en) * | 2012-02-14 | 2015-03-31 | Intersil Americas LLC | Optical proximity sensors using echo cancellation techniques to detect one or more objects |
CN103245938B (en) * | 2012-02-14 | 2017-11-14 | 英特赛尔美国有限公司 | The optical proximity sensor of one or more objects is detected using ECT echo cancellation technique |
JP6021670B2 (en) * | 2012-02-16 | 2016-11-09 | オリンパス株式会社 | Endoscope system and A / D converter |
DE102012106149A1 (en) * | 2012-07-09 | 2014-01-09 | Endress + Hauser Gmbh + Co. Kg | Method and device for the laser-based determination of the filling level of a filling material in a container |
EP2703837B1 (en) * | 2012-09-03 | 2014-07-16 | Sick Ag | Safety laser scanner |
CA2884160C (en) * | 2012-09-13 | 2020-03-31 | Mbda Uk Limited | Room occupancy sensing apparatus and method |
DE102013100367A1 (en) * | 2013-01-15 | 2014-07-17 | Sick Ag | Distance measuring optoelectronic sensor and method for determining the distance of objects |
US9304203B1 (en) * | 2013-03-13 | 2016-04-05 | Google Inc. | Methods, devices, and systems for improving dynamic range of signal receiver |
US9671489B1 (en) * | 2013-03-15 | 2017-06-06 | Epitaxial Technologies, Llc | Electromagnetic sensor and optical detection system for detecting angle of arrival of optical signals and a range of a source of the optical signals |
WO2015020645A1 (en) * | 2013-08-07 | 2015-02-12 | Halliburton Energy Services, Inc. | Monitoring a well flow device by fiber optic sensing |
US10203399B2 (en) | 2013-11-12 | 2019-02-12 | Big Sky Financial Corporation | Methods and apparatus for array based LiDAR systems with reduced interference |
US9250714B2 (en) * | 2013-11-27 | 2016-02-02 | Intersil Americas LLC | Optical proximity detectors |
US20150168163A1 (en) * | 2013-12-12 | 2015-06-18 | Douglas Chase | Method for enhanced gps navigation |
US20150170517A1 (en) * | 2013-12-12 | 2015-06-18 | Chen Yan | Vehicle parking management system with guidance for indicating floor vacant vehicular parking dock |
US11471697B2 (en) * | 2015-02-10 | 2022-10-18 | Andrew Hewitson | Laser therapy device and method of use |
US9606228B1 (en) | 2014-02-20 | 2017-03-28 | Banner Engineering Corporation | High-precision digital time-of-flight measurement with coarse delay elements |
US9360554B2 (en) | 2014-04-11 | 2016-06-07 | Facet Technology Corp. | Methods and apparatus for object detection and identification in a multiple detector lidar array |
US9921300B2 (en) * | 2014-05-19 | 2018-03-20 | Rockwell Automation Technologies, Inc. | Waveform reconstruction in a time-of-flight sensor |
US9696424B2 (en) | 2014-05-19 | 2017-07-04 | Rockwell Automation Technologies, Inc. | Optical area monitoring with spot matrix illumination |
US11243294B2 (en) | 2014-05-19 | 2022-02-08 | Rockwell Automation Technologies, Inc. | Waveform reconstruction in a time-of-flight sensor |
US9256944B2 (en) | 2014-05-19 | 2016-02-09 | Rockwell Automation Technologies, Inc. | Integration of optical area monitoring with industrial machine control |
US11143749B2 (en) | 2014-05-23 | 2021-10-12 | Signify Holding B.V. | Object detection system and method |
US10488492B2 (en) | 2014-09-09 | 2019-11-26 | Leddarttech Inc. | Discretization of detection zone |
US9625108B2 (en) | 2014-10-08 | 2017-04-18 | Rockwell Automation Technologies, Inc. | Auxiliary light source associated with an industrial application |
US9977512B2 (en) | 2014-10-24 | 2018-05-22 | Intersil Americas LLC | Open loop correction for optical proximity detectors |
US10795005B2 (en) | 2014-12-09 | 2020-10-06 | Intersil Americas LLC | Precision estimation for optical proximity detectors |
US10036801B2 (en) * | 2015-03-05 | 2018-07-31 | Big Sky Financial Corporation | Methods and apparatus for increased precision and improved range in a multiple detector LiDAR array |
JP6519238B2 (en) * | 2015-03-11 | 2019-05-29 | サンケン電気株式会社 | Current detection circuit |
WO2016174659A1 (en) | 2015-04-27 | 2016-11-03 | Snapaid Ltd. | Estimating and using relative head pose and camera field-of-view |
US9642215B2 (en) * | 2015-07-28 | 2017-05-02 | Intersil Americas LLC | Optical sensors that compensate for ambient light and interference light |
US10408926B2 (en) | 2015-09-18 | 2019-09-10 | Qualcomm Incorporated | Implementation of the focal plane 2D APD array for hyperion lidar system |
US9992477B2 (en) | 2015-09-24 | 2018-06-05 | Ouster, Inc. | Optical system for collecting distance information within a field |
US10063849B2 (en) | 2015-09-24 | 2018-08-28 | Ouster, Inc. | Optical system for collecting distance information within a field |
US9866816B2 (en) | 2016-03-03 | 2018-01-09 | 4D Intellectual Properties, Llc | Methods and apparatus for an active pulsed 4D camera for image acquisition and analysis |
WO2017149526A2 (en) | 2016-03-04 | 2017-09-08 | May Patents Ltd. | A method and apparatus for cooperative usage of multiple distance meters |
JP6641006B2 (en) * | 2016-06-02 | 2020-02-05 | シャープ株式会社 | Optical sensors and electronic devices |
WO2018039432A1 (en) | 2016-08-24 | 2018-03-01 | Ouster, Inc. | Optical system for collecting distance information within a field |
US20180172807A1 (en) * | 2016-12-20 | 2018-06-21 | Analog Devices Global | Method of Providing Enhanced Range Accuracy |
US10520592B2 (en) | 2016-12-31 | 2019-12-31 | Waymo Llc | Light detection and ranging (LIDAR) device with an off-axis receiver |
DE102017101945A1 (en) * | 2017-02-01 | 2018-08-02 | Osram Opto Semiconductors Gmbh | Measuring arrangement with an optical transmitter and an optical receiver |
US11181622B2 (en) | 2017-03-29 | 2021-11-23 | Luminar, Llc | Method for controlling peak and average power through laser receiver |
EP3615901A4 (en) | 2017-05-15 | 2020-12-16 | Ouster, Inc. | Optical imaging transmitter with brightness enhancement |
DE102017005395B4 (en) * | 2017-06-06 | 2019-10-10 | Blickfeld GmbH | LIDAR distance measurement with scanner and FLASH light source |
JP7159224B2 (en) | 2017-06-07 | 2022-10-24 | 上海禾賽科技有限公司 | multi line radar |
DE102017112955A1 (en) * | 2017-06-13 | 2018-12-13 | Automotive Lighting Reutlingen Gmbh | Bifunctional light module for a motor vehicle headlamp with Lidar function |
DE102017211141A1 (en) | 2017-06-30 | 2019-01-03 | Osram Gmbh | EFFECT LIGHT, LUMINAIRE GROUP, ARRANGEMENT AND PROCEDURE |
US10564219B2 (en) | 2017-07-27 | 2020-02-18 | Teradyne, Inc. | Time-aligning communication channels |
US10677899B2 (en) * | 2017-08-07 | 2020-06-09 | Waymo Llc | Aggregating non-imaging SPAD architecture for full digital monolithic, frame averaging receivers |
US10852438B2 (en) | 2017-08-21 | 2020-12-01 | Caterpillar Inc. | LIDAR waveform classification |
US10914824B2 (en) * | 2017-11-21 | 2021-02-09 | Analog Devices International Unlimited Company | Systems and methods for measuring a time of flight in a lidar system |
DE102017221784A1 (en) * | 2017-12-04 | 2019-06-06 | Osram Gmbh | Method of operating a lidar sensor, lidar sensor and means of locomotion |
US11340336B2 (en) | 2017-12-07 | 2022-05-24 | Ouster, Inc. | Rotating light ranging system with optical communication uplink and downlink channels |
EP3538920A1 (en) | 2018-01-03 | 2019-09-18 | Hybrid Lidar Systems AG | Arrangement and method for runtime measurement of a signal between two events |
JP6950558B2 (en) * | 2018-02-15 | 2021-10-13 | 株式会社デンソー | Distance measuring device |
EP3540991B1 (en) | 2018-03-13 | 2021-07-28 | ABB Schweiz AG | Intelligent electronic device comprising a cellular radio module |
DE102018113711A1 (en) | 2018-06-08 | 2019-12-12 | Osram Opto Semiconductors Gmbh | APPARATUS AND HEADLIGHTS |
US10732032B2 (en) | 2018-08-09 | 2020-08-04 | Ouster, Inc. | Scanning sensor array with overlapping pass bands |
US10739189B2 (en) | 2018-08-09 | 2020-08-11 | Ouster, Inc. | Multispectral ranging/imaging sensor arrays and systems |
JP2020034455A (en) * | 2018-08-30 | 2020-03-05 | パイオニア株式会社 | Map data structure |
JP2020034456A (en) * | 2018-08-30 | 2020-03-05 | パイオニア株式会社 | Signal processing device |
US11175006B2 (en) | 2018-09-04 | 2021-11-16 | Udayan Kanade | Adaptive lighting system for even illumination |
US11513198B2 (en) * | 2019-01-04 | 2022-11-29 | Waymo Llc | LIDAR pulse elongation |
EP3696572A1 (en) * | 2019-02-13 | 2020-08-19 | Infineon Technologies AG | Method, apparatus and computer program for detecting a presence of airborne particles |
GB201902508D0 (en) | 2019-02-25 | 2019-04-10 | Intersurgical Ag | Improvements relating to humidifiers for respiratory gases |
US11947041B2 (en) | 2019-03-05 | 2024-04-02 | Analog Devices, Inc. | Coded optical transmission for optical detection |
EP3936896A4 (en) * | 2019-03-29 | 2022-02-23 | Huawei Technologies Co., Ltd. | Distance measurement method and device based on detection signal |
US11698641B2 (en) * | 2019-04-26 | 2023-07-11 | GM Global Technology Operations LLC | Dynamic lidar alignment |
JP7240947B2 (en) | 2019-05-09 | 2023-03-16 | 株式会社アドバンテスト | Optical test equipment |
US11635496B2 (en) | 2019-09-10 | 2023-04-25 | Analog Devices International Unlimited Company | Data reduction for optical detection |
DE102019215835A1 (en) * | 2019-10-15 | 2021-04-15 | Robert Bosch Gmbh | Expansion of a dynamic range of SPAD-based detectors |
TWI734252B (en) * | 2019-11-08 | 2021-07-21 | 立積電子股份有限公司 | Radar and method of updating background components of echo signal for radar |
US20210253048A1 (en) * | 2020-02-14 | 2021-08-19 | Magna Electronics Inc. | Vehicular sensing system with variable power mode for thermal management |
CA3125716C (en) | 2020-07-21 | 2024-04-09 | Leddartech Inc. | Systems and methods for wide-angle lidar using non-uniform magnification optics |
EP4185892A1 (en) | 2020-07-21 | 2023-05-31 | Leddartech Inc. | Beam-steering devices and methods for lidar applications |
EP4241110A1 (en) * | 2020-10-30 | 2023-09-13 | Nalu Scientific, LLC | System and method for high dynamic range waveform digitization |
EP4285146A1 (en) * | 2021-09-17 | 2023-12-06 | Banner Engineering Corporation | Time of flight detection systems with efficient phase measurement |
JP7233628B1 (en) * | 2022-09-30 | 2023-03-06 | 三菱電機株式会社 | light controller |
Family Cites Families (281)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR690519A (en) | 1929-02-26 | 1930-09-23 | Winch | |
US3045231A (en) * | 1958-04-17 | 1962-07-17 | Thompson Ramo Wooldridge Inc | Signal analyzing method and system |
DE2002012A1 (en) | 1969-01-21 | 1970-08-13 | Del Signore Dr Giovanni | Device and method for reporting obstacles and for displaying the distance of the obstacles |
DE2229887C3 (en) * | 1972-06-19 | 1980-07-17 | Siemens Ag, 1000 Berlin Und 8000 Muenchen | Distance measuring device with a laser working as a transmitter and its application for speed measurement |
JPS5844902Y2 (en) | 1979-10-30 | 1983-10-12 | 新東工業株式会社 | Mold gas vent forming device |
DE3215845C1 (en) * | 1982-04-28 | 1983-11-17 | Eltro GmbH, Gesellschaft für Strahlungstechnik, 6900 Heidelberg | Distance sensor for a projectile igniter |
JPS6023138U (en) | 1983-07-20 | 1985-02-16 | 三井造船株式会社 | Container handling equipment |
JPH0619432B2 (en) | 1985-01-09 | 1994-03-16 | 株式会社トプコン | Liquid level measuring device |
US4553033A (en) * | 1983-08-24 | 1985-11-12 | Xerox Corporation | Infrared reflectance densitometer |
US4717862A (en) | 1984-11-19 | 1988-01-05 | The United States Government As Represented By The Secretary Of The Navy | Pulsed illumination projector |
US4766421A (en) | 1986-02-19 | 1988-08-23 | Auto-Sense, Ltd. | Object detection apparatus employing electro-optics |
US4808997A (en) | 1987-05-21 | 1989-02-28 | Barkley George J | Photoelectric vehicle position indicating device for use in parking and otherwise positioning vehicles |
US4891624A (en) | 1987-06-12 | 1990-01-02 | Stanley Electric Co., Ltd. | Rearward vehicle obstruction detector using modulated light from the brake light elements |
JPS6444819A (en) | 1987-08-13 | 1989-02-17 | Nitto Machinery | Level gage utilizing laser light |
JP2509129Y2 (en) | 1987-08-28 | 1996-08-28 | 株式会社講談社 | Gage graph for knitting |
GB8727824D0 (en) | 1987-11-27 | 1987-12-31 | Combustion Dev Ltd | Monitoring means |
GB8826624D0 (en) | 1988-11-14 | 1988-12-21 | Martell D K | Traffic congestion monitoring system |
US4928232A (en) | 1988-12-16 | 1990-05-22 | Laser Precision Corporation | Signal averaging for optical time domain relectometers |
US5095203A (en) * | 1989-10-16 | 1992-03-10 | Fujitsu Limited | Article detection device and method with shift registers and sampling |
GB8925384D0 (en) * | 1989-11-09 | 1989-12-28 | Ongar Enterprises Ltd | Vehicle spacing system |
US5134393A (en) | 1990-04-02 | 1992-07-28 | Henson H Keith | Traffic control system |
GB9018174D0 (en) | 1990-08-17 | 1990-10-03 | Pearpoint Ltd | Apparatus for reading vehicle number-plates |
EP0476562A3 (en) | 1990-09-19 | 1993-02-10 | Hitachi, Ltd. | Method and apparatus for controlling moving body and facilities |
JPH0833444B2 (en) * | 1990-10-05 | 1996-03-29 | 三菱電機株式会社 | Distance measuring device |
JPH0827345B2 (en) * | 1990-10-05 | 1996-03-21 | 三菱電機株式会社 | Distance measuring device |
JPH04172285A (en) * | 1990-11-02 | 1992-06-19 | Mitsubishi Electric Corp | Distance measuring apparatus |
US5179286A (en) * | 1990-10-05 | 1993-01-12 | Mitsubishi Denki K.K. | Distance measuring apparatus receiving echo light pulses |
FR2671653B1 (en) | 1991-01-11 | 1995-05-24 | Renault | MOTOR VEHICLE TRAFFIC MEASUREMENT SYSTEM. |
US5357331A (en) | 1991-07-02 | 1994-10-18 | Flockencier Stuart W | System for processing reflected energy signals |
US5102218A (en) | 1991-08-15 | 1992-04-07 | The United States Of America As Represented By The Secretary Of The Air Force | Target-aerosol discrimination by means of digital signal processing |
US5194747A (en) | 1991-10-21 | 1993-03-16 | Midland Manufacturing Corp. | Liquid level gauge comparing moldulations of incident and reflected loser beams |
US5257090A (en) | 1991-11-27 | 1993-10-26 | United Technologies Corporation | Laser diode liquid-level/distance measurement |
GB2264411B (en) | 1992-02-13 | 1995-09-06 | Roke Manor Research | Active infrared detector system |
US5291031A (en) | 1992-04-06 | 1994-03-01 | Telecommunications Research Laboratories | Optical phase difference range determination in liquid level sensor |
FR2690519B1 (en) | 1992-04-23 | 1994-06-10 | Est Centre Etu Tech Equipement | DEVICE FOR ANALYZING THE PATH OF MOBILES. |
US5298905A (en) * | 1992-06-12 | 1994-03-29 | Motorola, Inc. | Visible light detection and ranging apparatus and method |
US5546188A (en) | 1992-11-23 | 1996-08-13 | Schwartz Electro-Optics, Inc. | Intelligent vehicle highway system sensor and method |
US5587908A (en) * | 1992-12-22 | 1996-12-24 | Mitsubishi Denki Kabushiki Kaisha | Distance measurement device and vehicle velocity control device for maintaining inter-vehicular distance |
DE4304298A1 (en) | 1993-02-15 | 1994-08-18 | Atlas Elektronik Gmbh | Method for classifying vehicles passing a given waypoint |
US5510800A (en) | 1993-04-12 | 1996-04-23 | The Regents Of The University Of California | Time-of-flight radio location system |
US5389921A (en) | 1993-05-17 | 1995-02-14 | Whitton; John M. | Parking lot apparatus and method |
US5471215A (en) * | 1993-06-28 | 1995-11-28 | Nissan Motor Co., Ltd. | Radar apparatus |
US5565870A (en) * | 1993-06-28 | 1996-10-15 | Nissan Motor Co., Ltd. | Radar apparatus with determination of presence of target reflections |
US5396510A (en) * | 1993-09-30 | 1995-03-07 | Honeywell Inc. | Laser sensor capable of measuring distance, velocity, and acceleration |
US5381155A (en) | 1993-12-08 | 1995-01-10 | Gerber; Eliot S. | Vehicle speeding detection and identification |
US5552767A (en) | 1994-02-14 | 1996-09-03 | Toman; John R. | Assembly for, and method of, detecting and signalling when an object enters a work zone |
US5714754A (en) | 1994-03-04 | 1998-02-03 | Nicholas; John Jacob | Remote zone operation of lighting systems for above-ground enclosed or semi-enclosed parking structures |
JPH07280940A (en) * | 1994-04-12 | 1995-10-27 | Mitsubishi Electric Corp | Radar for vehicle |
US7630806B2 (en) * | 1994-05-23 | 2009-12-08 | Automotive Technologies International, Inc. | System and method for detecting and protecting pedestrians |
JPH07333339A (en) | 1994-06-03 | 1995-12-22 | Mitsubishi Electric Corp | Obstacle detector for automobile |
US5519209A (en) * | 1994-06-15 | 1996-05-21 | Alliedsignal Inc. | High range resolution active imaging system using a high speed shutter and a light pulse having a sharp edge |
JP3185547B2 (en) * | 1994-06-28 | 2001-07-11 | 三菱電機株式会社 | Distance measuring device |
EP0716297B1 (en) | 1994-11-26 | 1998-04-22 | Hewlett-Packard GmbH | Optical time domain reflectometer and method for time domain reflectometry |
US5633629A (en) | 1995-02-08 | 1997-05-27 | Hochstein; Peter A. | Traffic information system using light emitting diodes |
DE19604338B4 (en) | 1995-02-18 | 2004-07-15 | Leich, Andreas, Dipl.-Ing. | Vehicle counting and classification device |
US6259862B1 (en) | 1995-04-11 | 2001-07-10 | Eastman Kodak Company | Red-eye reduction using multiple function light source |
KR0150110B1 (en) | 1995-04-21 | 1998-12-15 | 이호림 | Permanent pool cavity seal for nuclear reactor |
JP2002515116A (en) | 1995-04-28 | 2002-05-21 | シユワルツ・エレクトロ−オプテイクス・インコーポレーテツド | Intelligent vehicles, roads, systems, sensors and methods |
DE19517001A1 (en) | 1995-05-09 | 1996-11-14 | Sick Optik Elektronik Erwin | Method and device for determining the light propagation time over a measuring section arranged between a measuring device and a reflecting object |
JPH0912723A (en) | 1995-06-23 | 1997-01-14 | Toshiba Silicone Co Ltd | Polyether-modified polyorganosiloxane |
US5764163A (en) | 1995-09-21 | 1998-06-09 | Electronics & Space Corp. | Non-imaging electro-optic vehicle sensor apparatus utilizing variance in reflectance |
US5633801A (en) * | 1995-10-11 | 1997-05-27 | Fluke Corporation | Pulse-based impedance measurement instrument |
US5648844A (en) | 1995-11-20 | 1997-07-15 | Midland Manufacturing Corp. | Laser liquid level gauge with diffuser |
JP3206414B2 (en) | 1996-01-10 | 2001-09-10 | トヨタ自動車株式会社 | Vehicle type identification device |
JP3379324B2 (en) | 1996-02-08 | 2003-02-24 | トヨタ自動車株式会社 | Moving object detection method and apparatus |
JP3365196B2 (en) * | 1996-02-15 | 2003-01-08 | 日産自動車株式会社 | Radar equipment |
SE9600897D0 (en) * | 1996-03-07 | 1996-03-07 | Geotronics Ab | RANGE-FINDER |
DE59702873D1 (en) | 1996-03-25 | 2001-02-15 | Mannesmann Ag | Method and system for traffic situation detection by stationary data acquisition device |
ES2195127T3 (en) | 1996-04-01 | 2003-12-01 | Gatsometer Bv | METHOD AND APPLIANCE TO DETERMINE THE SPEED AND SITUATION OF A VEHICLE. |
US5838116A (en) | 1996-04-15 | 1998-11-17 | Jrs Technology, Inc. | Fluorescent light ballast with information transmission circuitry |
US5760887A (en) | 1996-04-30 | 1998-06-02 | Hughes Electronics | Multi-pulse, multi-return, modal range processing for clutter rejection |
JPH1048338A (en) * | 1996-05-20 | 1998-02-20 | Olympus Optical Co Ltd | Distance measuring apparatus |
US5777564A (en) | 1996-06-06 | 1998-07-07 | Jones; Edward L. | Traffic signal system and method |
DE19624043A1 (en) * | 1996-06-17 | 1997-12-18 | Bayerische Motoren Werke Ag | Measuring method for the distance between a motor vehicle and an object |
IT1286684B1 (en) | 1996-07-26 | 1998-07-15 | Paolo Sodi | DEVICE AND METHOD FOR DETECTION OF ROAD INFRINGEMENTS WITH DYNAMIC POINTING SYSTEMS |
US20030154017A1 (en) | 1996-09-25 | 2003-08-14 | Ellis Christ G. | Apparatus and method for vehicle counting, tracking and tagging |
US20040083035A1 (en) | 1996-09-25 | 2004-04-29 | Ellis Christ G. | Apparatus and method for automatic vision enhancement in a traffic complex |
US5812249A (en) | 1996-09-26 | 1998-09-22 | Envirotest Systems Corporation | Speed and acceleration monitoring device using visible laser beams |
DE19643475C1 (en) | 1996-10-22 | 1998-06-25 | Laser Applikationan Gmbh | Speed measurement method based on the laser Doppler principle |
JP2917942B2 (en) * | 1996-12-09 | 1999-07-12 | 日本電気株式会社 | Pulse light time interval measurement method and pulse light time interval measurement method |
JPH10171497A (en) * | 1996-12-12 | 1998-06-26 | Oki Electric Ind Co Ltd | Background noise removing device |
WO2006041486A1 (en) | 2004-10-01 | 2006-04-20 | Franklin Philip G | Method and apparatus for the zonal transmission of data using building lighting fixtures |
DE19701803A1 (en) | 1997-01-20 | 1998-10-01 | Sick Ag | Light sensor with light transit time evaluation |
US5995900A (en) | 1997-01-24 | 1999-11-30 | Grumman Corporation | Infrared traffic sensor with feature curve generation |
US6417783B1 (en) | 1997-02-05 | 2002-07-09 | Siemens Aktiengesellschaft | Motor vehicle detector |
ATE269569T1 (en) | 1997-02-19 | 2004-07-15 | Atx Europe Gmbh | DEVICE FOR DETECTING MOVING OBJECTS |
DE19708014A1 (en) | 1997-02-27 | 1998-09-10 | Ernst Dr Hoerber | Device and method for detecting an object in a predetermined spatial area, in particular vehicles for traffic monitoring |
US5942753A (en) | 1997-03-12 | 1999-08-24 | Remote Sensing Technologies | Infrared remote sensing device and system for checking vehicle brake condition |
JPH1123709A (en) * | 1997-07-07 | 1999-01-29 | Nikon Corp | Distance-measuring device |
GB9715166D0 (en) | 1997-07-19 | 1997-09-24 | Footfall Limited | Video imaging system |
JP3281628B2 (en) | 1997-07-22 | 2002-05-13 | オート−センス リミテッド | Multi-frequency photoelectric detection system |
JPH1164518A (en) * | 1997-08-12 | 1999-03-05 | Mitsubishi Electric Corp | Optical radar device for vehicle |
US6548967B1 (en) | 1997-08-26 | 2003-04-15 | Color Kinetics, Inc. | Universal lighting network methods and systems |
US5828320A (en) | 1997-09-26 | 1998-10-27 | Trigg Industries, Inc. | Vehicle overheight detector device and method |
JPH11101637A (en) * | 1997-09-29 | 1999-04-13 | Aisin Seiki Co Ltd | Distance measuring device |
EP1034522B1 (en) | 1997-11-24 | 2004-01-28 | Michel Cuvelier | Device for detection by photoelectric cells |
DE19804958A1 (en) | 1998-02-07 | 1999-08-12 | Itt Mfg Enterprises Inc | Evaluation concept for distance measuring methods |
DE19804957A1 (en) | 1998-02-07 | 1999-08-12 | Itt Mfg Enterprises Inc | Distance measurement method with adaptive amplification |
US6104314A (en) | 1998-02-10 | 2000-08-15 | Jiang; Jung-Jye | Automatic parking apparatus |
US6404506B1 (en) | 1998-03-09 | 2002-06-11 | The Regents Of The University Of California | Non-intrusive laser-based system for detecting objects moving across a planar surface |
DE19816004A1 (en) | 1998-04-09 | 1999-10-14 | Daimler Chrysler Ag | Arrangement for road condition detection |
US6794831B2 (en) | 1998-04-15 | 2004-09-21 | Talking Lights Llc | Non-flickering illumination based communication |
US6040897A (en) | 1998-04-29 | 2000-03-21 | Laser Technology, Inc. | Remote sensor head for laser level measurement devices |
AT406093B (en) * | 1998-05-19 | 2000-02-25 | Perger Andreas Dr | METHOD FOR OPTICAL DISTANCE MEASUREMENT |
US6044336A (en) | 1998-07-13 | 2000-03-28 | Multispec Corporation | Method and apparatus for situationally adaptive processing in echo-location systems operating in non-Gaussian environments |
US6452666B1 (en) * | 1998-10-29 | 2002-09-17 | Photobit Corporation | Optical range finder |
JP3972491B2 (en) | 1998-11-16 | 2007-09-05 | マツダ株式会社 | Vehicle control device |
US6142702A (en) | 1998-11-25 | 2000-11-07 | Simmons; Jason | Parking space security and status indicator system |
DE19856478C1 (en) | 1998-12-02 | 2000-06-21 | Ddg Ges Fuer Verkehrsdaten Mbh | Parking space detection |
US6115113A (en) | 1998-12-02 | 2000-09-05 | Lockheed Martin Corporation | Method for increasing single-pulse range resolution |
US6166645A (en) | 1999-01-13 | 2000-12-26 | Blaney; Kevin | Road surface friction detector and method for vehicles |
US6107942A (en) | 1999-02-03 | 2000-08-22 | Premier Management Partners, Inc. | Parking guidance and management system |
US6771185B1 (en) | 1999-02-03 | 2004-08-03 | Chul Jin Yoo | Parking guidance and management system |
EP1163129A4 (en) | 1999-02-05 | 2003-08-06 | Brett Hall | Computerized parking facility management system |
US6407803B1 (en) | 1999-03-25 | 2002-06-18 | Endress + Hauser Gbmh + Co. | Laser measuring device |
EP1043602B1 (en) | 1999-04-06 | 2003-02-05 | Leica Geosystems AG | Method for detecting the distance of at least one target |
DE19919061A1 (en) | 1999-04-27 | 2000-11-02 | Robot Foto Electr Kg | Traffic monitoring device with polarization filters |
DE19919925C2 (en) | 1999-04-30 | 2001-06-13 | Siemens Ag | Arrangement and method for the simultaneous measurement of the speed and the surface shape of moving objects |
US6522395B1 (en) * | 1999-04-30 | 2003-02-18 | Canesta, Inc. | Noise reduction techniques suitable for three-dimensional information acquirable with CMOS-compatible image sensor ICS |
US6285297B1 (en) | 1999-05-03 | 2001-09-04 | Jay H. Ball | Determining the availability of parking spaces |
US6392747B1 (en) * | 1999-06-11 | 2002-05-21 | Raytheon Company | Method and device for identifying an object and determining its location |
JP2001013244A (en) * | 1999-06-30 | 2001-01-19 | Minolta Co Ltd | Range-finding device |
GB2354898B (en) | 1999-07-07 | 2003-07-23 | Pearpoint Ltd | Vehicle licence plate imaging |
US6502011B2 (en) | 1999-07-30 | 2002-12-31 | Gerhard Haag | Method and apparatus for presenting and managing information in an automated parking structure |
US6946974B1 (en) | 1999-09-28 | 2005-09-20 | Racunas Jr Robert Vincent | Web-based systems and methods for internet communication of substantially real-time parking data |
CN1190789C (en) | 1999-10-29 | 2005-02-23 | 松下电器产业株式会社 | Optical disk player and playback method |
US6411204B1 (en) | 1999-11-15 | 2002-06-25 | Donnelly Corporation | Deceleration based anti-collision safety light control for vehicle |
GB9927623D0 (en) | 1999-11-24 | 2000-01-19 | Koninkl Philips Electronics Nv | Illumination source |
US6927700B1 (en) | 2000-01-04 | 2005-08-09 | Joseph P. Quinn | Method and apparatus for detection and remote notification of vehicle parking space availability data |
US7123166B1 (en) | 2000-11-17 | 2006-10-17 | Haynes Michael N | Method for managing a parking lot |
AU2001222082A1 (en) | 2000-01-26 | 2001-08-07 | Instro Precision Limited | Optical distance measurement |
US6147624A (en) | 2000-01-31 | 2000-11-14 | Intel Corporation | Method and apparatus for parking management system for locating available parking space |
JP2001264439A (en) * | 2000-03-17 | 2001-09-26 | Olympus Optical Co Ltd | Device and method for measuring distance |
US20020033884A1 (en) | 2000-05-03 | 2002-03-21 | Schurr George W. | Machine vision-based sorter verification |
US6581461B1 (en) | 2000-05-25 | 2003-06-24 | Trn Business Trust | Electro-optic sensor for levelmeter providing output signal with frequency modulated by surface level |
US6765495B1 (en) | 2000-06-07 | 2004-07-20 | Hrl Laboratories, Llc | Inter vehicle communication system |
US6502053B1 (en) | 2000-06-12 | 2002-12-31 | Larry Hardin | Combination passive and active speed detection system |
US6642854B2 (en) | 2000-06-14 | 2003-11-04 | Mcmaster Steven James | Electronic car park management system |
US6429429B1 (en) * | 2000-06-22 | 2002-08-06 | Ford Global Technologies, Inc. | Night vision system utilizing a diode laser illumination module and a method related thereto |
DE10034976B4 (en) | 2000-07-13 | 2011-07-07 | iris-GmbH infrared & intelligent sensors, 12459 | Detecting device for detecting persons |
AU2001286513A1 (en) | 2000-08-16 | 2002-02-25 | Raytheon Company | Switched beam antenna architecture |
JP2002059608A (en) | 2000-08-21 | 2002-02-26 | Olympus Optical Co Ltd | Printer |
US6643466B1 (en) * | 2000-09-29 | 2003-11-04 | Lucent Technologies Inc. | Method and apparatus for controlling signal power level in free space communication |
US6665621B2 (en) | 2000-11-28 | 2003-12-16 | Scientific Technologies Incorporated | System and method for waveform processing |
JP4595197B2 (en) * | 2000-12-12 | 2010-12-08 | 株式会社デンソー | Distance measuring device |
JP2002181934A (en) * | 2000-12-15 | 2002-06-26 | Nikon Corp | Apparatus and method for clocking as well as distance measuring apparatus |
US6753766B2 (en) | 2001-01-15 | 2004-06-22 | 1138037 Ontario Ltd. (“Alirt”) | Detecting device and method of using same |
ATE478405T1 (en) | 2001-02-07 | 2010-09-15 | Vehiclesense Inc | PARK MANAGEMENT SYSTEM |
US6559776B2 (en) | 2001-02-15 | 2003-05-06 | Yoram Katz | Parking status control system and method |
DE10115152A1 (en) * | 2001-03-27 | 2002-10-10 | Hella Kg Hueck & Co | Distance measurement method using time-of-flight measurement of laser pulses for vehicles |
JP2002311138A (en) * | 2001-04-06 | 2002-10-23 | Mitsubishi Electric Corp | Distance measuring device for vehicle |
JP2002342896A (en) | 2001-05-21 | 2002-11-29 | Seiko Epson Corp | Parking lot guiding system and parking lot guiding program |
JP2002365362A (en) * | 2001-06-07 | 2002-12-18 | Mitsubishi Electric Corp | Pulse radar device |
JP4457525B2 (en) * | 2001-06-11 | 2010-04-28 | 株式会社デンソー | Distance measuring device |
JP2002372578A (en) | 2001-06-15 | 2002-12-26 | Kaijo Corp | Range finder |
WO2003000520A1 (en) | 2001-06-21 | 2003-01-03 | Tis, Inc. | Parking guidance and vehicle control system |
US6426708B1 (en) | 2001-06-30 | 2002-07-30 | Koninklijke Philips Electronics N.V. | Smart parking advisor |
AUPR631801A0 (en) | 2001-07-12 | 2001-08-02 | Luscombe, Andrew | Roadside sensor system |
DE50208355D1 (en) * | 2001-08-06 | 2006-11-16 | Siemens Ag | METHOD AND DEVICE FOR RECEIVING A THREE-DIMENSIONAL DISTANCE IMAGE |
ITBO20010571A1 (en) | 2001-09-20 | 2003-03-20 | Univ Bologna | VEHICLE TRAFFIC MONITORING SYSTEM AND CONTROL UNIT AND RELATED OPERATING METHOD |
US6556916B2 (en) | 2001-09-27 | 2003-04-29 | Wavetronix Llc | System and method for identification of traffic lane positions |
WO2003029046A1 (en) | 2001-10-03 | 2003-04-10 | Maryann Winter | Apparatus and method for sensing the occupancy status of parking spaces in a parking lot |
US6715437B1 (en) | 2002-01-29 | 2004-04-06 | Electromechanical Research Laboratories, Inc. | Liquid-cargo loss detection gauge |
US7489865B2 (en) * | 2002-02-01 | 2009-02-10 | Cubic Corporation | Integrated optical communication and range finding system and applications thereof |
KR100459475B1 (en) | 2002-04-04 | 2004-12-03 | 엘지산전 주식회사 | System and method for judge the kind of vehicle |
EP1499852A4 (en) * | 2002-04-15 | 2008-11-19 | Toolz Ltd | Distance measurement device with short distance optics |
DE10220073A1 (en) * | 2002-05-04 | 2003-11-13 | Bosch Gmbh Robert | Short-range radar system with variable pulse duration |
US6885312B1 (en) | 2002-05-28 | 2005-04-26 | Bellsouth Intellectual Property Corporation | Method and system for mapping vehicle parking |
US7733464B2 (en) * | 2002-08-05 | 2010-06-08 | Elbit Systems Ltd. | Vehicle mounted night vision imaging system and method |
EP1388739A1 (en) * | 2002-08-09 | 2004-02-11 | HILTI Aktiengesellschaft | Laser range finder with phase difference measurement |
US6783425B2 (en) | 2002-08-26 | 2004-08-31 | Shoot The Moon Products Ii, Llc | Single wire automatically navigated vehicle systems and methods for toy applications |
JP3822154B2 (en) | 2002-09-12 | 2006-09-13 | 本田技研工業株式会社 | Vehicle detection device |
US6842231B2 (en) | 2002-09-30 | 2005-01-11 | Raytheon Company | Method for improved range accuracy in laser range finders |
US6825778B2 (en) | 2002-10-21 | 2004-11-30 | International Road Dynamics Inc. | Variable speed limit system |
DE10251133B3 (en) | 2002-10-31 | 2004-07-29 | Gerd Reime | Device for controlling lighting, in particular for vehicle interiors, and method for controlling it |
DE10252756A1 (en) | 2002-11-13 | 2004-05-27 | Robert Bosch Gmbh | A / D converter with improved resolution |
JP2006521536A (en) * | 2002-11-26 | 2006-09-21 | ジェームス エフ. マンロ | High-precision distance measuring apparatus and method |
US6759977B1 (en) | 2002-12-20 | 2004-07-06 | Saab Marine Electronics Ab | Method and apparatus for radar-based level gauging |
US7426450B2 (en) | 2003-01-10 | 2008-09-16 | Wavetronix, Llc | Systems and methods for monitoring speed |
JP4235729B2 (en) * | 2003-02-03 | 2009-03-11 | 国立大学法人静岡大学 | Distance image sensor |
JP4037774B2 (en) * | 2003-02-19 | 2008-01-23 | 富士通テン株式会社 | Radar equipment |
US7148813B2 (en) | 2003-03-20 | 2006-12-12 | Gentex Corporation | Light emitting traffic sign having vehicle sensing capabilities |
US7081832B2 (en) | 2003-04-25 | 2006-07-25 | General Electric Capital Corporation | Method and apparatus for obtaining data regarding a parking location |
EP1623400A1 (en) | 2003-05-07 | 2006-02-08 | Koninklijke Philips Electronics N.V. | Traffic information system for conveying information to drivers |
FR2854692B1 (en) | 2003-05-07 | 2006-02-17 | Peugeot Citroen Automobiles Sa | OPTICAL EXPLORATION DEVICE AND VEHICLE COMPRISING SUCH A DEVICE |
WO2004100551A1 (en) | 2003-05-08 | 2004-11-18 | Siemens Aktiengesellschaft | Method and device for detecting an object or a person |
US6917307B2 (en) | 2003-05-08 | 2005-07-12 | Shih-Hsiung Li | Management method and system for a parking lot |
ATE491309T1 (en) | 2003-05-22 | 2010-12-15 | Pips Technology Inc | AUTOMATED SITE SECURITY, MONITORING AND ACCESS CONTROL SYSTEM |
US7026954B2 (en) | 2003-06-10 | 2006-04-11 | Bellsouth Intellectual Property Corporation | Automated parking director systems and related methods |
KR100464584B1 (en) | 2003-07-10 | 2005-01-03 | 에이앤디엔지니어링 주식회사 | Laser Rangefinder and method thereof |
DE102004035856A1 (en) | 2003-08-14 | 2005-03-10 | Roland Bittner | Electrical auxiliary device for use in a traffic system, e.g. a traffic data collection system or traffic warning system, whereby the device is mounted at least partially in a mounting tube or pipe of existing infrastructure |
US7821422B2 (en) | 2003-08-18 | 2010-10-26 | Light Vision Systems, Inc. | Traffic light signal system using radar-based target detection and tracking |
JP2007504551A (en) | 2003-09-03 | 2007-03-01 | ストラテック システムズ リミテッド | Apparatus and method for locating, recognizing and tracking a vehicle in a parking lot |
JP2005085187A (en) | 2003-09-11 | 2005-03-31 | Oki Electric Ind Co Ltd | Parking lot management system utilizing radio lan system |
US7688222B2 (en) | 2003-09-18 | 2010-03-30 | Spot Devices, Inc. | Methods, systems and devices related to road mounted indicators for providing visual indications to approaching traffic |
ITTO20030770A1 (en) | 2003-10-02 | 2005-04-03 | Fiat Ricerche | LONG-DETECTION DETECTOR LONG ONE |
EP1522870B1 (en) | 2003-10-06 | 2013-07-17 | Triple-IN Holding AG | Distance measurement |
US20050117364A1 (en) | 2003-10-27 | 2005-06-02 | Mark Rennick | Method and apparatus for projecting a turn signal indication |
US7230545B2 (en) | 2003-11-07 | 2007-06-12 | Nattel Group, Inc. | Automobile communication and registry system |
JP4449443B2 (en) | 2003-12-10 | 2010-04-14 | 日産自動車株式会社 | LED lamp device with radar function |
FR2864932B1 (en) | 2004-01-09 | 2007-03-16 | Valeo Vision | SYSTEM AND METHOD FOR DETECTING CIRCULATION CONDITIONS FOR A MOTOR VEHICLE |
US20050187701A1 (en) | 2004-02-23 | 2005-08-25 | Baney Douglas M. | Traffic communication system |
JP2005290813A (en) | 2004-03-31 | 2005-10-20 | Honda Motor Co Ltd | Parking guidance robot |
US7106214B2 (en) | 2004-04-06 | 2006-09-12 | Mongkol Jesadanont | Apparatus and method of finding an unoccupied parking space in a parking lot |
JP4274028B2 (en) * | 2004-04-07 | 2009-06-03 | 株式会社デンソー | Radar equipment for vehicles |
JP4238766B2 (en) | 2004-04-15 | 2009-03-18 | 株式会社デンソー | Roundabout vehicle information system |
JP2005331468A (en) * | 2004-05-21 | 2005-12-02 | Sharp Corp | Lighting system equipped with ranging function |
JP3935897B2 (en) * | 2004-06-15 | 2007-06-27 | 北陽電機株式会社 | Lightwave ranging device |
EP1628278A1 (en) | 2004-08-16 | 2006-02-22 | Alcatel | Method and system for detecting available parking places |
US7405676B2 (en) | 2004-09-10 | 2008-07-29 | Gatsometer B.V. | Method and system for detecting with laser the passage by a vehicle of a point for monitoring on a road |
JP4487715B2 (en) * | 2004-10-01 | 2010-06-23 | 株式会社デンソー | Radar equipment for vehicles |
CN101080733A (en) | 2004-10-15 | 2007-11-28 | 田纳西州特莱科产品公司 | Object detection system with a VCSEL diode array |
DE102004051999A1 (en) | 2004-10-26 | 2006-04-27 | Endress + Hauser Gmbh + Co. Kg | Level measurement process based on runtime principle, e.g. used in food processing or chemical processing industry, involves using echo signals obtained from liquid filling container to determine level of liquid inside container |
EP2420954B8 (en) | 2004-12-01 | 2017-04-12 | Datalogic USA, Inc. | Data reader with automatic exposure adjustment and methods of operating a data reader |
GB2421383A (en) * | 2004-12-07 | 2006-06-21 | Instro Prec Ltd | Surface profile measurement |
JP2006172210A (en) | 2004-12-16 | 2006-06-29 | Matsushita Electric Works Ltd | Distance image sensor for vehicle, and obstacle monitoring device using the same |
US7233683B2 (en) | 2005-01-04 | 2007-06-19 | Deere & Company | Method and system for guiding a vehicle with vision-based adjustment |
US7610123B2 (en) | 2005-01-04 | 2009-10-27 | Deere & Company | Vision-aided system and method for guiding a vehicle |
WO2006077588A2 (en) * | 2005-01-20 | 2006-07-27 | Elbit Systems Electro-Optics Elop Ltd. | Laser obstacle detection and display |
JP4830311B2 (en) | 2005-02-21 | 2011-12-07 | 株式会社デンソー | Automotive radar equipment |
US7242281B2 (en) | 2005-02-23 | 2007-07-10 | Quintos Mel Francis P | Speed control system |
ITTO20050138A1 (en) | 2005-03-04 | 2006-09-05 | Fiat Ricerche | EVALUATION SYSTEM OF THE FLUIDITY OF ROAD OR MOTORWAY TRAFFIC AND OF PREDICTION OF TAIL TRAINING AND SLOWDOWN |
WO2006100672A2 (en) | 2005-03-21 | 2006-09-28 | Visonic Ltd. | Passive infra-red detectors |
GB0506722D0 (en) | 2005-04-02 | 2005-05-11 | Agd Systems Ltd | Detector systems |
US7312722B2 (en) | 2005-05-09 | 2007-12-25 | The Boeing Company | System and method for assessing parking space occupancy and for reserving same |
DE102005027185A1 (en) * | 2005-06-07 | 2006-12-14 | Schefenacker Vision Systems Germany Gmbh | Device for adjusting the light intensity of a light source, in particular at least one light source of a rear light of a motor vehicle, and method for adjusting the light intensity |
US7359039B2 (en) * | 2005-07-13 | 2008-04-15 | Mariusz Kloza | Device for precise distance measurement |
JP5153062B2 (en) | 2005-07-13 | 2013-02-27 | 新光電気工業株式会社 | Solid oxide fuel cell |
WO2007026779A1 (en) | 2005-08-30 | 2007-03-08 | National University Corporation Shizuoka University | Semiconductor distance measuring element and solid state imaging device |
US20110099126A1 (en) | 2005-08-30 | 2011-04-28 | Sensact Applications, Inc. | Automated Parking Policy Enforcement System |
US7714265B2 (en) | 2005-09-30 | 2010-05-11 | Apple Inc. | Integrated proximity sensor and light sensor |
US20070086860A1 (en) | 2005-10-17 | 2007-04-19 | Shaw Lee A | Concrete template and method of use |
US7417718B2 (en) * | 2005-10-28 | 2008-08-26 | Sharp Kabushiki Kaisha | Optical distance measuring apparatus |
JP2007121116A (en) * | 2005-10-28 | 2007-05-17 | Sharp Corp | Optical distance measuring device |
JP2007132848A (en) | 2005-11-11 | 2007-05-31 | Sharp Corp | Optical range finder |
US7573400B2 (en) | 2005-10-31 | 2009-08-11 | Wavetronix, Llc | Systems and methods for configuring intersection detection zones |
GB2445767A (en) | 2005-11-24 | 2008-07-23 | Linda Long | Illuminated car park space indicator. |
CA2633377C (en) | 2005-12-19 | 2016-05-10 | Institut National D'optique | Object-detecting lighting system and method |
US8242476B2 (en) | 2005-12-19 | 2012-08-14 | Leddartech Inc. | LED object detection system and method combining complete reflection traces from individual narrow field-of-view channels |
JP2007216722A (en) * | 2006-02-14 | 2007-08-30 | Takata Corp | Object detection system, operating device control system, and vehicle |
WO2007096814A1 (en) | 2006-02-20 | 2007-08-30 | Koninklijke Philips Electronics N.V. | Portable illumination device |
ES2315078B1 (en) | 2006-03-06 | 2009-11-05 | Quality Informations System, S.A. | ESTIMATION SYSTEM FOR VEHICLE LOCATION IN PARKING. |
US7944548B2 (en) * | 2006-03-07 | 2011-05-17 | Leica Geosystems Ag | Increasing measurement rate in time of flight measurement apparatuses |
JP2007248227A (en) | 2006-03-15 | 2007-09-27 | Toyota Central Res & Dev Lab Inc | Object detection device |
ITTO20060214A1 (en) | 2006-03-22 | 2007-09-23 | Kria S R L | VEHICLE DETECTION SYSTEM |
US7991542B2 (en) | 2006-03-24 | 2011-08-02 | Wavetronix Llc | Monitoring signalized traffic flow |
DE102006016050A1 (en) | 2006-04-04 | 2007-10-11 | Siemens Ag | System to administer a parking zone, with a number of payment parking bays, has a detector at each parking space with a radio link to the payment machine to report the presence of a parked vehicle |
DE102006025020B4 (en) | 2006-05-26 | 2017-02-09 | PMD Technologie GmbH | displacement measuring system |
WO2008024910A2 (en) | 2006-08-25 | 2008-02-28 | Invensys Systems, Inc. | Lidar-based level measurement |
US9202373B2 (en) | 2006-09-25 | 2015-12-01 | Bosch Security Systems Bv | Micro-diffractive surveillance illuminator |
US9460619B2 (en) | 2007-01-17 | 2016-10-04 | The Boeing Company | Methods and systems for controlling traffic flow |
GB2445757B (en) | 2007-01-22 | 2009-07-22 | Gary Richardson | Paint drying apparatus |
US7639347B2 (en) | 2007-02-14 | 2009-12-29 | Leica Geosystems Ag | High-speed laser ranging system including a fiber laser |
US8600656B2 (en) | 2007-06-18 | 2013-12-03 | Leddartech Inc. | Lighting system with driver assistance capabilities |
CA2691141C (en) | 2007-06-18 | 2013-11-26 | Leddartech Inc. | Lighting system with traffic management capabilities |
US8319949B2 (en) | 2007-06-18 | 2012-11-27 | Leddartech Inc. | Method for detecting objects with visible light |
IL184815A0 (en) | 2007-07-24 | 2008-11-03 | Elbit Systems Ltd | System and method for level of visibility determination and vehicle counting |
US7746450B2 (en) * | 2007-08-28 | 2010-06-29 | Science Applications International Corporation | Full-field light detection and ranging imaging system |
EP2048515B1 (en) | 2007-10-11 | 2012-08-01 | JENOPTIK Robot GmbH | Method for determining and documenting traffic violations at a traffic light |
GB2455061A (en) | 2007-10-30 | 2009-06-03 | Sharp Kk | Liquid Crystal Device with three sets of electrodes for controlling tilt and azimuth angles |
US7640122B2 (en) | 2007-11-07 | 2009-12-29 | Institut National D'optique | Digital signal processing in optical systems used for ranging applications |
EP2232462B1 (en) | 2007-12-21 | 2015-12-16 | Leddartech Inc. | Parking management system and method using lighting system |
CA2857826C (en) | 2007-12-21 | 2015-03-17 | Leddartech Inc. | Detection and ranging methods and systems |
ES2330499B1 (en) | 2007-12-31 | 2010-09-21 | Imagsa Technologies, S.A. | PROCEDURE AND SYSTEM FOR DETECTION OF MOVING OBJECTS. |
US7957900B2 (en) | 2008-02-08 | 2011-06-07 | Gaurav Chowdhary | Tracking vehicle locations in a parking lot for definitive display on a GUI |
NL1035051C2 (en) | 2008-02-20 | 2009-08-24 | Markus Henricus Beuvink | Method, system and optical communication composition for obtaining traffic information. |
US7554652B1 (en) | 2008-02-29 | 2009-06-30 | Institut National D'optique | Light-integrating rangefinding device and method |
US8237791B2 (en) | 2008-03-19 | 2012-08-07 | Microsoft Corporation | Visualizing camera feeds on a map |
DE202008003979U1 (en) | 2008-03-20 | 2008-06-26 | Fraas, Alfred, Dipl.-Ing. | Measuring system for traffic flow analysis |
US7697126B2 (en) | 2008-04-02 | 2010-04-13 | Spatial Integrated Systems, Inc. | Three dimensional spatial imaging system and method |
WO2009121181A1 (en) | 2008-04-04 | 2009-10-08 | Leddartech Inc. | Optical level measurement device and method |
DE202008007078U1 (en) | 2008-05-26 | 2008-09-04 | Signalbau Huber Gmbh | Video detection with PMD sensors |
US20090299633A1 (en) | 2008-05-29 | 2009-12-03 | Delphi Technologies, Inc. | Vehicle Pre-Impact Sensing System Having Terrain Normalization |
JP5505761B2 (en) | 2008-06-18 | 2014-05-28 | 株式会社リコー | Imaging device |
US7635854B1 (en) | 2008-07-09 | 2009-12-22 | Institut National D'optique | Method and apparatus for optical level sensing of agitated fluid surfaces |
US8010316B2 (en) * | 2008-12-11 | 2011-08-30 | Intermec Ip Corp. | System and method for laser range-finding |
FR2947228B1 (en) | 2009-06-25 | 2012-11-30 | Bosch Gmbh Robert | POWER BRAKE BRAKE SYSTEM |
US8400511B2 (en) | 2009-12-04 | 2013-03-19 | Lockheed Martin Corporation | Optical detection and ranging sensor system for sense and avoid, and related methods |
EP2517189B1 (en) | 2009-12-22 | 2014-03-19 | Leddartech Inc. | Active 3d monitoring system for traffic detection |
JP2014194950A (en) | 2014-05-30 | 2014-10-09 | Makita Corp | Battery device for power tool |
US10428823B2 (en) | 2014-11-06 | 2019-10-01 | General Electric Company | Centrifugal compressor apparatus |
-
2008
- 2008-12-19 CA CA2857826A patent/CA2857826C/en active Active
- 2008-12-19 US US12/809,235 patent/US8310655B2/en active Active
- 2008-12-19 WO PCT/CA2008/002268 patent/WO2009079789A1/en active Application Filing
- 2008-12-19 EP EP08863916.6A patent/EP2235561B8/en active Active
- 2008-12-19 JP JP2010538303A patent/JP5671345B2/en active Active
- 2008-12-19 EP EP17162120.4A patent/EP3206046B1/en active Active
- 2008-12-19 CA CA2710212A patent/CA2710212C/en active Active
-
2012
- 2012-10-01 US US13/632,191 patent/US8619241B2/en not_active Ceased
-
2014
- 2014-09-25 JP JP2014194950A patent/JP6023138B2/en active Active
-
2016
- 2016-06-20 JP JP2016121676A patent/JP6437487B2/en active Active
-
2018
- 2018-06-19 US US16/011,820 patent/USRE49342E1/en active Active
-
2022
- 2022-11-10 US US17/984,975 patent/USRE49950E1/en active Active
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9378640B2 (en) | 2011-06-17 | 2016-06-28 | Leddartech Inc. | System and method for traffic side detection and characterization |
US9235988B2 (en) | 2012-03-02 | 2016-01-12 | Leddartech Inc. | System and method for multipurpose traffic detection and characterization |
US11567179B2 (en) | 2020-07-21 | 2023-01-31 | Leddartech Inc. | Beam-steering device particularly for LIDAR systems |
Also Published As
Publication number | Publication date |
---|---|
WO2009079789A1 (en) | 2009-07-02 |
USRE49950E1 (en) | 2024-04-30 |
CA2857826C (en) | 2015-03-17 |
JP2011506979A (en) | 2011-03-03 |
JP6437487B2 (en) | 2018-12-12 |
EP3206046A1 (en) | 2017-08-16 |
USRE49342E1 (en) | 2022-12-20 |
US20130044310A1 (en) | 2013-02-21 |
EP2235561A1 (en) | 2010-10-06 |
JP5671345B2 (en) | 2015-02-18 |
EP2235561A4 (en) | 2013-10-23 |
JP6023138B2 (en) | 2016-11-09 |
EP2235561B1 (en) | 2017-04-05 |
EP2235561B8 (en) | 2017-05-31 |
EP3206046B1 (en) | 2021-08-25 |
US20100277713A1 (en) | 2010-11-04 |
JP2016183974A (en) | 2016-10-20 |
US8310655B2 (en) | 2012-11-13 |
CA2710212A1 (en) | 2009-07-02 |
US8619241B2 (en) | 2013-12-31 |
JP2015017994A (en) | 2015-01-29 |
CA2857826A1 (en) | 2009-07-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
USRE49950E1 (en) | Distance detection method and system | |
USRE46930E1 (en) | Distance detection method and system | |
CN106597471B (en) | Vehicle and method with transparent barriers object automatic detection function | |
TWI432768B (en) | Procedure and device to determining a distance by means of an opto-electronic image sensor | |
KR100770805B1 (en) | Method and device for recording a three-dimensional distance-measuring image | |
US7952690B2 (en) | Method and system for acquiring a 3-D image of a scene | |
US7645974B2 (en) | Method and apparatus for distance measurement | |
JP2011506979A5 (en) | ||
US20100194595A1 (en) | Lighting system with traffic management capabilities | |
JP2014517921A (en) | Multi-field scannerless optical rangefinder under bright ambient background light | |
CA3015002C (en) | Determination of an item of distance information for a vehicle | |
EP3540460A1 (en) | Light receiving apparatus, object detection apparatus, distance measurement apparatus, mobile object apparatus, noise measuring method, object detecting method, and distance measuring method | |
JP2008014722A (en) | Radar device | |
CA3075721A1 (en) | Full waveform multi-pulse optical rangefinder instrument | |
WO2014038527A1 (en) | Vehicle radar device, and method of controlling detection range of same | |
JP6265882B2 (en) | Object detection apparatus and object detection method | |
JP2903746B2 (en) | Inter-vehicle distance detection device | |
JP2015152428A (en) | Laser radar device and object detection method | |
JP7316175B2 (en) | rangefinder | |
WO2004029656A1 (en) | A range finder and method of determining range |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
EEER | Examination request |
Effective date: 20131210 |