GB2563416A

GB2563416A - Apparatus and method for object detection

Info

Publication number: GB2563416A
Application number: GB1709488.9A
Authority: GB
Inventors: John Greenwood Jeremy; Boyd Robin; White David; Clarke Chris
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2017-06-15
Filing date: 2017-06-15
Publication date: 2018-12-19
Anticipated expiration: 2037-06-15
Also published as: GB2563416B; GB201709488D0

Abstract

A control means sends a transmit signal to an emitter to emit radiation, a first portion of which is guided to a receiver using a guide means between the emitter and receiver, and a second portion of which reaches the receiver via reflection. The control means receives a signal, from the receiver, indicative of both portions of radiation and thus detects the presence of an object. The signal may comprise components corresponding to each portion. Several receivers may be provided, each of which would receive part of the guided radiation. The location of the object may be determined based on a time difference between, or average of, received components or based on the duration of the composite receive signal. The radiation may be optical, such as in a LIDAR system. The entire apparatus may be formed in an elongate, flexible body and may be removeably attachable to a vehicle.

Description

The following terms are registered trade marks and should be read as such wherever they occur in this document:

DVD

Intellectual Property Office is an operating name of the Patent Office www.gov.uk/ipo

APPARATUS AND METHOD FOR OBJECT DETECTION

TECHNICAL FIELD

The present disclosure relates to apparatus and method for object detection, and particularly, but not exclusively, to apparatus and methods for detecting objects proximal to a vehicle.

Aspects of the invention relate to a system, to an apparatus, to a controller, to a vehicle, to a method and to a computer program.

BACKGROUND

It is desired to detect the presence of objects, and in some cases to determine the location of such objects, in many applications. One application of object detection is for vehicles. Ultrasonic transducers are often used to detect objects proximal to a vehicle, particularly objects behind or in front of the vehicles. An ultrasonic signal is transmitted and based on reflected signal the presence of an object near to the vehicle is determined. However such ultrasonic transducer based systems lack accuracy i.e. the location of the object is only determined relatively coarsely. Particularly for autonomous or semi-autonomous vehicles, greater accuracy is desired. Other more accurate sensors are known, such as LIDAR, although these systems are complicated and may be expensive. It is also known to more accurately determine a location of an object by time-of-flight (ToF) measurements. However for relatively close objects, such as in the range of a few meters, high resolution timing and synchronisation is required such as of the order of a few nano-seconds, such as around 30nS. These timing requirements impose constraints on the system concerning, for example, wiring lengths, EMC or noise constraints etc.

It is an aim of the present invention to at least mitigate one or more of the disadvantages of the prior art.

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide a system, an apparatus, a controller, a vehicle, a method and a computer program as claimed in the appended claims.

According to an aspect of the invention, there is provided an object detection system, comprising emitter means for emitting radiation, receiver means for receiving radiation, guide means arranged between the emitter means and the receiver means for guiding some of the radiation emitted by the emitter means to the receiver means, and control means for determining a location of an object based on an output of the receiver means. Advantageously, by the guide means the emitter means and receiver means are synchronised by communicated radiation. The receiver means may output an electrical signal corresponding to the received radiation.

According to an aspect of the invention, there is provided an object detection system, comprising emitter means for emitting radiation in response to a transmit signal, receiver means for outputting a receive signal in response to received radiation, guide means arranged between the emitter means and the receiver means for guiding a first portion of the radiation emitted by the emitter means to the receiver means, and control means for outputting the transmit signal and receiving the receive signal, wherein the receiver means is arranged to output the receive signal in response to the first portion of radiation and a second portion of radiation emitted by the emitter means and reflected from an object, to the receiver means and the control means is arranged to determine a presence of the object in dependence on the receive signal. Advantageously, by the guide means the emitter means and receiver means are synchronised by means of communicated radiation. Advantageously by using the first portion of radiation, a need for high-speed electronics may be reduced.

The system as described above, wherein: the emitter means may be an emitter device for emitting optical radiation; the receiver means may be at least one receiver device; the guide means may be a waveguide; and the control means may be a control unit. In some embodiments the control unit comprises one or more processing devices.

The second portion of radiation may be outwardly directed from the emitter means. Advantageously a detection of the object may be improved by the outward direction.

The guide means may be arranged to receive the first portion of the radiation emitted by the emitter means. Advantageously the first portion may be efficiently communicated. The guide means may guide the first portion of the radiation to the receiver means. Advantageously the radiation may be efficiently communicated to the receiver means.

Optionally the receive signal comprises a first component corresponding to the first portion of the radiation. Optionally the receive signal comprises a second component corresponding to the second portion of radiation. Advantageously a relationship between the first and second portions may provide information about the object.

The control means is optionally arranged to determine a location of the object about an arcuate path based the first and second components of the receive signal. Advantageously the location of the object with respect to the arcuate path may assist in determining the location of the object.

The system may comprise a plurality of receiver means. Advantageously the plurality of receiver means may provide further information about the location of the object. Optionally each of the receiver means may be arranged to receive at least part of the first portion of the radiation emitted by the emitter means via the guide means. Each receiver means may output a respective receive signal in response thereto. Advantageously each receiver means may be useful in determining the location of the object.

The control means may be arranged to receive each of the respective receive signals and to determine the presence of the object in dependence thereon. Advantageously the control means may provide centralised determination of the location of the object.

The control means is optionally arranged to determine a location of the object based on a time difference between the first component of the receive signal and the second component of the receive signal output by each of the plurality of receiver means.

Optionally the control means is arranged to determine a location of the object based on a duration of the receive signal output by each of the plurality of receiver means.

The control means may be arranged to determine a location of the object based on a combination of the first and second components of the receive signal. Optionally the combination is an average magnitude of the receive signal. Advantageously the average magnitude may provide a convenient means to determining the location of the object.

According to an aspect of the invention, there is provided an apparatus for object detection comprising emitter means for emitting optical radiation in response to a transmit signal, receiver means for outputting a receive signal in response to received radiation and guide means arranged between the emitter means and the receiver means for guiding a first portion of the radiation emitted by the emitter means to the receiver means, wherein the receiver means is arranged to receive the first portion of the radiation and a second portion of radiation reflected from an object and falling thereon from external to the apparatus.

The apparatus as described above, wherein: the emitter means may be an emitter device for emitting optical radiation; and the receiver means may be at least one receiver device;

The apparatus may be formed in an elongate body. Advantageously an elongate body may be conveniently mountable about a vehicle. Optionally the elongate body is flexible. Advantageously the flexibility may assist in mounting about a vehicle having an irregular or non-planar surface.

Optionally the apparatus is attachable to a vehicle. Advantageously the apparatus may be attached after manufacturing of the vehicle. Optionally the apparatus is removeably attachable to the vehicle. Advantageously the apparatus may be easily moved between vehicles.

According to an aspect of the invention, there is provided a controller, comprising output means for outputting a transmit signal to an emitter means, input means for receiving a receive signal from a receiver means indicative of received radiation, wherein the receive signal comprises a first component indicative of a first portion of radiation emitted by the emitter means and communicated to the receiver means via a guide, and a second component indicative of a second portion of radiation emitted by the emitter means and reflected from an object and control means arranged to determine a presence of the object based on the receive signal.

The controller as described above, wherein: the output means may be an electrical output; and the input means may be an electrical input.

The control means is optionally arranged to determine the location of the object based on a timing between the first component of the receive signal and the second component of the receive signal.

The control means may be arranged to determine a location of the object about an arcuate path based the first and second components of the receive signal.

Optionally the input means is arranged to receive a plurality of receive signals, wherein each receive signal is output from a respective receiver means and comprises a respective first component and a second component, and the control means is arranged to determine the location of the object based thereon.

The control means may be arranged to determine the location of the object based on a duration of the receive signal output by each of the plurality of receiver means.

The control means may be arranged to determine the location of the object based on a combination of the first and second components of the receive signal. Optionally the combination is an average value of the receive signal output by each of the plurality of receiver means.

The control means may be arranged to determine the location of the object based on a combination of a search signal which temporally varies in phase with each of the plurality receive signals.

According to an aspect of the invention, there is provided a method of detecting an object, comprising emitting optical radiation from an emitter means, guiding a first portion of the radiation emitted by the emitter means to a receiver means, receiving at the receiver means the first portion and a second portion of the radiation emitted by the emitter means, the second portion being reflected from the object, determining a presence of the object based on the first and second portions of radiation.

The method as described above, wherein: the emitter means may be an emitter device for emitting optical radiation; the receiver means may be at least one receiver device; and the guide means may be a waveguide.

The location of the object may be determined along an arcuate path based on a timing between the first and second portions of the receive signal.

The method may comprise receiving signals indicative of a plurality of second portions of radiation each output from a respective receiver means and determining the location of the object based on the plurality of signals.

The location of the object may be determined based on a duration of the first and second portions.

The method may comprise determining the location of the object based on a combination of the first and second portions of each receive signal; optionally the combination is an average value of the receive signal.

The location of the object may be determined as a respective distance between the object and each of the plurality of receiver means.

The method may comprise outputting an indication of the location of the object.

According to an aspect of the invention, there is provided a vehicle comprising a system according to an aspect of the invention, an apparatus according to an aspect of the invention, a controller according to an aspect of the invention or which is arranged to perform a method according to an aspect of the invention.

According to an aspect of the invention, there is provided a computer program which, when executed by a computer, is arranged to perform a method according to an aspect of the invention. Optionally the program comprises instructions. Optionally the program is stored on a computer readable medium. The program may be tangibly stored on the computerreadable medium. The computer-readable medium may be non-transitory.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a system according to embodiments of the invention;

Figure 2 shows a method according to an embodiment of the invention;

Figure 3 shows a timing diagram according to an embodiment of the invention;

Figure 4 shows an apparatus according to an embodiment of the invention;

Figure 5 shows an apparatus according to an embodiment of the invention; and

Figure 6 shows a vehicle according to an embodiment of the invention.

DETAILED DESCRIPTION

Figure 1(a) & (b) illustrate a system 100 according to an embodiment of the invention in relation to an object 101. The system comprises an apparatus 190 according to an embodiment of the invention communicably coupled to a control means 105 according to an embodiment of the invention. The system 100 is a system for detecting the object 101. The apparatus 190 is, in some embodiments, a sensor means 190 according to an embodiment of the invention. The sensor means 190 may be mounted upon, or may be removeably mountable upon, a vehicle. The vehicle may be a wheeled vehicle although this is not restrictive and other vehicles may be envisaged which use the apparatus 190 such as boats or aircraft, for example. The vehicle may be a self-propelled vehicle i.e. comprising one or both of an engine and at least one electric motor, or may be a towed vehicle, such as trailer or caravan.

The control means 105 is arranged to output a transmit signal 115 and to receive a receive signal 125 as will be explained. The transmit signal 115 is output via an electrical output of the control means 105, whilst the receive signal is input or received via at least one electrical input of the control means 105. The control means 105 may be a controller 105 or control unit 105 in one embodiment of the invention. The control unit 105 may comprise a processing means which may be formed by one or more electronic processors which may operably execute computer-readable instructions stored in a memory of the control unit 105. In other embodiments, the control unit 105 may be implemented in hardware such as an Application Specific Integrated Circuit (ASIC). Implementation in hardware may improve a timing measurement between signals. The controller 105 may comprise output means for outputting a transmit signal to the emitter means 110 and input means for receiving a receive signal from the receiver means 120 indicative of received radiation. The output means may comprise an electrical output. The input means may comprise an electrical input.

The sensor means 190 may be a sensor device 190 in some embodiments. The sensor means 190 comprises emitter means 110 for emitting radiation in response to the transmit signal 115, which may be received at an electrical connection of the apparatus 105. The apparatus 105 comprises at least one receiver means 120 for receiving radiation 150, 160, 165 and outputting one or more receive signals 125 in response thereto. The radiation output by the emitter means 110 and received by the receiver means 120 is, in some embodiments, optical radiation i.e. light. The light may be non-visible or emitted at a wavelength or wavelength band which is not visible to the human eye. The light may be infra-red (IR) such as in the band 750nm to 1mm, although other wavelengths of light may be used such as ultraviolet (UV) 100nm to 380nm or visible light.

In Figure 1(a) & (b) the control unit 105 is illustrated as being a discrete unit separate from the sensor means 190. However it will be appreciated that at least some functionality of the control unit may be distributed amongst the apparatus, such as located with the emitter means 110 and the receiver means 120. For example, the emitter means 110 may comprise an emitter control unit located proximal to the emitter means 110 and the receiver means 120 may comprise a receiver control unit located proximal to the receiver means 120. In some embodiments, as illustrated in Figure 1, the control means 105 may be located proximal to the at least one receiver means 120 in order to reduce a length of electrical connection between the control means 105 and receiver means 120. Advantageously having relatively close-coupling between the control means 105 and receiver means, or between the receiver means and the receiver control unit, may improve a timing determination of optically received signals. However, in other embodiments, where the receiver means 120 includes or is co-located with object determination means, such proximal location of the control means 105 and receiver means 120 may be unnecessary. The emitter control unit, receiver control unit and a system control unit may communicate over a wired or wireless interface. In embodiment the emitter control unit, receiver control unit and a system control unit communicate over a communication bus such as a Local Interconnect Network (LIN) bus. The emitter control unit may control the emitter means 110 to emit radiation, such as a pulse of radiation, responsive to, or in dependence on, the transmit signal from the system control unit. The receiver control unit may perform calculations as described below particularly in conjunction with Figure 3 to determine information about the object 101 which is then communicated to the control unit 101. Advantageously the local processing may remove timing and/or noise constraints. However for ease of explanation the arrangement of Figure 1 will be discussed, but it will be appreciated that this is not limiting.

The sensor device 190 comprises guide means 140 for guiding radiation there-along. The guide means 140 is arranged between the emitter means 110 and the receiver means 120 for guiding a portion 150 of the radiation emitted by the emitter means 110 to the receiver means 120, as will be explained.

The emitter means 110 is, in some embodiments, an emitter device 110 for emitting optical radiation such as a light emitting diode (LED) or laser device. The emitter device 110 is arranged to emit radiation outwardly from the sensor device 190 in a direction at least toward the object 101. When the sensor device 190 is in use mounted upon the vehicle such that the radiation is emitted outwardly i.e. generally away from the vehicle, as will be further explained.

The receiver means 120 comprises, in some embodiments, at least one receiver device 120 for receiving radiation 150, 160, 165 and outputting the at least one receive signal 125 in response thereto. The, or each, receiver device 120 is, in one embodiment, a photo-electric device for outputting an electrical signal in response to received photons. In some embodiments the receiver device 120 includes signal conditioning means 122, such that the receive signal 125 does not directly correspond to that output by the receiver device 120 but is indicative thereof. The receiver device 120 may be a photo-diode, although other devices may be used. The signal conditioning means 122 may comprise, in some embodiments, object determination means for determining one or more attributes of the object 101 based on the radiation received by the receiver device 120, as noted above.

In some embodiments the receiver means 120 comprises a plurality of receiver devices 123, 124 as shown in Figure 1(b). The receiver means 120 may, in some embodiments, comprise two receiver devices 123, 124, namely a first receiver device 123 and a second receiver device 124.

The radiation emitted by the emitter device 110 is arranged to be divided into two portions, which may be unequal in intensity i.e. a strength of the two portions may not be equal. A first portion 150 of the radiation emitted by the emitter device 110 is directed to the receiver means 120. A second portion 160 of the radiation emitted by the emitter device 110 is outwardly directed i.e. generally away from the vehicle. The outwardly directed second portion 160 is for reflection from the object 101 when proximal there-to. Radiation reflected 165 from the object 101 is at least partly received by the receiver device 120.

The emitter device 110 and receiver device 120 are spaced apart along the sensor device 190. In the embodiment illustrated in Figures 1(a) & (b), the emitter device 110 and the receiver device 120 are spaced apart by a distance d_er. The guide means 140 is arranged to guide the first portion 150 over the distance d_er between the emitter device 110 and the receiver device 120. The guide means 140 is in some embodiments a waveguide 140 for directing radiation from the emitter device 110 to the receiver device 120. A first end of the waveguide 140 is arranged proximal to the emitter device 110 for receiving the first portion of radiation and a second end of the waveguide 140 is arranged proximal to the receiver device 120 for emitting the directed first portion. One or both ends of the waveguide 140 may comprise a lens or other arrangement for receiving and emitting the radiation, respectively.

The waveguide 140 is formed from a material generally transparent or substantially nonattenuating to the radiation. The material may be a generally clear plastic material. The waveguide material may be surrounded by an external layer or cladding for retaining the first portion of radiation within the waveguide 140 by internal reflection, as illustrated by arrows 150 in Figure 1. The waveguide 140 may be flexible. In some embodiments the waveguide is formed from a fibre optic arranged between the emitter device 110 and the receiver device 120. Thus the sensor device 190 may be formed as a flexible device which may be applied to a curved surface or conveniently rolled or folded when not affixed to the vehicle.

The receiver device 120 is arranged to output a first portion of the receive signal 125 in response to the first portion 150 of radiation directed directly to the receiver device 120 by the waveguide 140. A timing of the first portion of the receive signal 125 responsive to the first portion 150 of radiation corresponds, generally, to a time of light emission from the emitter device 110 to reach the receiver device 190. Given the speed of light c being approximately 3.00 χ 10⁸ m/s in free space, where cf_er is a distance of, for example up to 0.5 m or less than 0.25 m, or around 0.1 m in some embodiments in the material of the waveguide 140 the time of arrival at the receiver device 120 is almost instantaneous. Thus, without requiring an electrical synchronisation signal being provided to the receiver device 120, the receiver device 120 is responsive to provide the first portion of the receive signal 125 corresponding to the time of transmission of radiation from the emitter device 110. The emitter device 110 and receiver device 120 are therefore optically synchronised. The optical synchronisation is provided by the first portion 150 of the radiation communicated directly from the emitter device 110 to the receiver device 120.

The second portion 160 of radiation emitted by the emitter device 110 is emitted away from the sensor device 190 to be reflected from the object 101 (when the sensor device 190 is proximal to the object 101). The reflected second portion 165 is received by the receiver device 120 to form a corresponding second portion of the receive signal 125. Based on the first and second portions of the receive signal 125, the presence of the object 101 may be determined. The location of the object 101 may be determined as a location of the object 101 along an arcuate path whose radius is determined with respect to the location of the receiver device 120. In some embodiments, one or more attributes of the object 101 may also be determined, such as a distance between the sensor device 190 and the object 101. In particular, in some embodiments the location of the object 101 is determined based on a timing between the first portion of the receive signal and the second portion of the receive signal 125. In some embodiments the location of the object 101 is determined based on a duration of the receive signal. In other embodiments, the location of the object 101 is determined based on combination of the first and second portions, such as an average value of the receive signal 125.

Figure 1(a) illustrates an embodiment of the invention comprising one receiver device 120. The receiver device 120 is arranged to receive radiation communicated via the waveguide 140 from the emitter device 110 and reflected from the object 101. Thus the receiver device 120 may output an electrical signal responsive to, or in dependence on, both of directly communicated radiation and reflected radiation. The electrical signal comprises first and second components corresponding to the first and second portions of received radiation.

In embodiments of the invention comprising two receiver devices 123, 124, as illustrated in Figure 1(b) the first receiver device 123 is optically coupled to receive radiation emitted by the emitter device 110 only via the waveguide 140 and the second receiver device 124 is outwardly directed to receive radiation emitted by the emitter device 110 and reflected from the object 101. As can be appreciated, each receiver device 123, 124 outputs an electrical signal responsive to, or in dependence on, different portions of emitted radiation. Thus the first receiver device 123 outputs a first receive signal responsive to, or in dependence on, the first portion of radiation emitted by the emitter device 110 and the second receiver device 124 outputs radiation responsive to, or in dependence on, the second portion of radiation emitted by the emitter device 110. The first receiver device 123 is arranged to output a first receive signal to the control means 105 corresponding to the first portion of radiation emitted by the emitter device 110 and the second receiver device 124 is arranged to output to the control means 105 a second receive signal corresponding to the first portion of radiation emitted by the emitter device 110.

Figure 2 illustrates a method 200 according to an embodiment of the invention. The method 200 is a method of detecting an object. In some embodiments the method 200 is performed by the system 100 illustrated in Figure 1. The method of Figure 2 will be further explained with reference to Figure 3(a) - (c).

The method comprises a step 210 of transmitting radiation. The radiation may be transmitted from the emitter device 110 illustrated in Figure 1. As explained above, the first portion 150 of the radiation emitted by the emitter device 101 is directed directly from the emitter device 110 to the receiver device 120 via the waveguide 140 i.e. without reflection from the object 101. The second portion 160 of radiation emitted by the emitter device 110 is outwardly directed with respect to the sensor device 190 for reflection from the object 101. The radiation emitted by the emitter device 110 may be one or more pulses of radiation. Each pulse may have a temporal duration of U

In step 220 the first portion of radiation is received at the receiver device 120. Even in the presence of the object 110, due to the shorter distance between the emitter device 110 and the receiver device 120 via the waveguide 140 than the distance of outward path of emitted radiation 160 and return path of reflected radiation 165, the first portion is received at the receiver device 120, at least initially, first.

In step 230 the second portion of radiation, corresponding to reflected radiation 165, is received at the receiver device 120. As noted above, it is expected that the second portion 165 is received at least partly after the first portion 150 i.e. the second portion is delayed with respect to first portion.

In step 240 the presence of the object 101 is determined in dependence on the radiation received at the receiver device 120. In particular, based on the first and second portions of the receive signal 125, the presence of the object 101 may be determined.

An embodiment of the determination of the object 101 is illustrated in Figure 3(a). An upper portion of the timing diagram shown in Figure 3(a) corresponds to the transmit signal 115. The transmit signal 115 is indicative of the transmission of a pulse of radiation from the emitter device 110 having the duration of t_d. As noted above, the first portion 150 of radiation is communicated directly and almost instantaneously from the transmitter device 110 to, in some embodiments, the receiver device 120, or to the first receiver device 123 in other embodiments, to form the first portion of the receive signal 125. The second portion of the receive signal 125 corresponds to radiation reflected 165 from the object 101 which lags or is delayed from the first portion 150. Thus the illustrated second portion of the receive signal 125 in Figure 3(a) may be that output by the second receiver device 124 in some embodiments. It is appreciated that part of the first portion 115 and the second portion 125 may overlap i.e. be received simultaneously, although for clarity a longer time delay is illustrated in Figure 3(a) with it being appreciated that this is not restrictive. A temporal delay of the second portion 125 from the first portion 115 is denoted as Δί. The value of Δί is indicative of a length of the path between the emitter device 110, the object 101 and the receiver device 120 i.e. the total of the outward path 160 and the return path 165 of radiation via the object 101. Based on the expected speed of light in air the total distance may be determined based on Δί. The distance dto the object may be calculated as:

d - c.t wherein d is distance (sum of outward and return paths), c is the speed of light (which may be the speed in air) and t is the time, in this case ΔΙ Since d_er is known, and forms the base of a triangle with sides corresponding to the outward and return paths 160, 165, a distance of the apparatus 190 to the object 101 may be determined, as will be appreciated. In embodiments including at least two receiver devices 123, 124, the second portion of the receive signal 125 corresponding to radiation reflected form the object 101 may be distinguished from that communicated by the waveguide since each is output by an independent receiver device 123, 124. However in embodiments including only one receiver device, such as illustrated in Figure 1(a), the portion of the receive signal 125 corresponding to the reflected radiation may be determined based on the duration of the transmit signal td, such as determined in dependence on a falling edge of the receive signal 125.

Figure 3(b) illustrates a timing diagram according to an embodiment of the invention in which the receive signal comprises a first portion 125a and a second portion 125b. The first portion 125a corresponds to the first portion emitted by the emitter device 110 which may be received via the waveguide 140 at the receiver device 120 of Figure 1(a) or the first receiver device 123 of Figure 1(b). The second portion 125b corresponds to the second portion of radiation emitted by the emitter device 110 which may be received at the receiver device 120 of Figure 1(a) or the second receiver device 124 of Figure 1(b). In embodiments of the invention the first and second portions are combined into one receive signal. The combination may be a logical OR, or a summation with a maximum amplitude corresponding to that of the transmit signal 115. In other words, the receive signal 125 does not have an amplitude of greater than the transmit signal 115.

As illustrated in the lower portion of Figure 1(b), the combined signal has a duration corresponding to a duration of both the first and second portions of radiation. The duration of the combined signal is thus indicative of a distance of the object 101 from the sensor device 190. The combined signal, when repeated in a pseudo-continuous manner, may be provided to a circuit, such as a resistance-capacitance (RC) circuit, as illustrated in the right-hand side. By pseudo continuous manner it is understood that sufficient repetitions occur to approximate a steady-state. A direct current (DC) level output from the RC circuit is indicative of the distance d as illustrated. It will be appreciated that other methods of determining the duration of the combined signal may be used.

Figure 3(c) illustrates an embodiment wherein, in step 210, a plurality of pulses of radiation are emitted from the emitter device 110. Figure 3(c) illustrates a phase correlation method. The plurality of pulses form a pulse train 135 comprising pulses having a predetermined temporal duration and spacing which are emitted from the emitter device 110. The temporal spacing may be a mark-space ratio of 50%, although other mark-space ratios may be envisaged. A corresponding series of pulses of radiation 145 reflected from the object 101 are received at the receiver device 120 of Figure 1(a) or the second receiver device 124 in Figure 1(b).

The correlation method utilises the pulse train 135 and a series of synch pulses forming a search signal 155 as illustrated in the lower portion of Figure 3(c). The series of synch pulses may have a variable delay i.e. a delay between pulses which changes over time. The received signal 145, which may be noisy, is multiplied by the search signal 155. This is a signal with the same duty cycle at the emitted pulse train 135 but with a phase which temporally changes in the range 0 to 360 degrees with respect to the emitted signal 135. The resultant product (of the multiplied received and search signals 145, 155) will peak when the phases of the two signal 145, 155 coincide. Advantageously, noise in the received signal 145 may be reduced or cancelled as it is equally positive and negative but the desired signal may be extracted from below a noise floor. The lower portion of Figure 3(c) illustrates an amplitude of the multiplied signals 145, 155 against phase, indicating maximum amplitude for a phase of the search signal 155 indicative of the distance of the object from the sensor device 190.

Figure 4 illustrates an apparatus 490 according to an embodiment of the invention. The apparatus is a further sensor means 490 for mounting upon a vehicle similar to that illustrated in Figure 1. The sensor means 490 illustrated in Figure 4 is a sensor array according to an embodiment of the invention. The sensor array 490 illustrated in Figure 4 comprises an emitter means 110 for emitting radiation, such as light, as in Figure 1. In the embodiment illustrated in Figure 4 the emitter means 110 is located generally central about the array 490, although other locations may be envisaged. The sensor array 490 further comprises a plurality of receiver means 410, 420, 430, 440, 450, 460. The plurality of receiver means may each be a respective receiver device 410, 420, 430, 440, 450, 460. The plurality of receiver devices 410, 420, 430, 440, 450, 460 are arranged either side of the emitter device 110. A distance d_er between the emitter device 110 and an adjacent receiver device 420 is illustrated in Figure 4. Each receiver device may be spaced apart along the array by the same distance d_er, thereby achieving a uniform distribution of receiver devices 410, 420, 430, 440, 450, 460 about the sensor array. A guide means such as the waveguide

140 (not shown) described with reference to Figure 1 is arranged within the sensor array 490 in order to allow a first portion of the radiation emitted by the emitter device 110 to be communicated for synchronisation to each of the receiver devices 410, 420, 430, 440, 450, 460. Each receiver device 410, 420, 430, 440, 450, 460 is arranged to receive a second portion of radiation reflected from the object 101.

The plurality of receiver devices 410, 420, 430, 440, 450, 460 are provided for each determining a respective distance the object, as in Figure 1, based on radiation emitted from the emitter device 110, such as illustrated in Figures 3(a) - 3(c). Based on the plurality of distances determined to the object 101, the location of the object 101 with respect to the sensor array 490, and a vehicle to which the sensor array 490 is attached in use, may be determined. A representation of the location of the location of the object 101 may be provided to a user of the vehicle such as an occupant of the vehicle or a person in charge of the vehicle i.e. the representation may be displayed on a display device possessed by the user. In other embodiments, the location of the object may be provided to an autonomous driving module of the vehicle to, for example, avoid the object. In other applications, such as where the object 101 is a trailer, for example, the autonomous driving module may position the vehicle with respect to the trailer in order to allow hitching of the trailer to the vehicle. Advantageously as the location of the object is determined based on optical radiation, an accuracy of the location determination may be improved.

Figure 5 illustrates an apparatus 590 according to an embodiment of the invention. The apparatus is a sensor device 590 according to an embodiment of the invention. The sensor device 590 comprises a plurality of receiver devices 510, 520 and an emitter device 110 similar to the embodiment shown in Figure 4. In the illustrated embodiment two receiver devices 510, 520 are shown interposed by the emitter device 110 although it will be appreciated that this is not limiting. The sensor device 590 comprises an elongate body having the emitter device 110 and receiver devices 510, 520 arranged therein. The body of the sensor device 590 may be rigid or may be flexible to allow rolling or folding. The waveguide 140 is arranged within the body to convey optical radiation from the emitter device 110 to the receiver devices 510, 520 as explained. A rear surface 595 of the sensor device 595 may be flat for removable affixing to an outer surface of a vehicle. The rear surface 595 may be self-adhesive for affixing to the vehicle or may comprise one or more magnetic elements for affixing to the vehicle. Other methods of removable attachment may be envisaged.

Figure 6 illustrates a vehicle 600 according to an embodiment of the invention. The vehicle 600 may comprising the system 100 illustrated in Figure 1, or the sensor device 490, 590 illustrated in Figures 4 and 5. The sensor device 190, 490, 590 may be mounted upon an external surface of the vehicle 600, such as upon a forward-facing surface of the vehicle 600, such as at location 610 upon a front bumper or fender of the vehicle 600. It will be appreciated that other mounting locations exist.

It will be appreciated that embodiments of the present invention can be realised in the form of hardware, software or a combination of hardware and software. Any such software may be stored in the form of volatile or non-volatile storage such as, for example, a storage device like a ROM, whether erasable or rewritable or not, or in the form of memory such as, for example, RAM, memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a CD, DVD, magnetic disk or magnetic tape. It will be appreciated that the storage devices and storage media are embodiments of machine-readable storage that are suitable for storing a program or programs that, when executed, implement embodiments of the present invention. Accordingly, embodiments provide a program comprising code for implementing a system or method as claimed in any preceding claim and a machine readable storage storing such a program. Still further, embodiments of the present invention may be conveyed electronically via any medium such as a communication signal carried over a wired or wireless connection and embodiments suitably encompass the same.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. The claims should not be construed to cover merely the foregoing embodiments, but also any embodiments which fall within the scope of the claims.

Claims

1. An object detection system, comprising:

emitter means for emitting radiation in response to a transmit signal;

receiver means for outputting a receive signal in response to received radiation;

guide means arranged between the emitter means and the receiver means for guiding a first portion of the radiation emitted by the emitter means to the receiver means; and control means for outputting the transmit signal and receiving the receive signal;

wherein the receiver means is arranged to output the receive signal in response to the first portion of radiation and a second portion of radiation emitted by the emitter means and reflected to the receiver means; and the control means is arranged to determine a presence of an object in dependence on the receive signal.

2. The system of claim 1, wherein the second portion of radiation is outwardly directed from the emitter means.

3. The system of claim 1 or 2, wherein the guide means is arranged to receive the first portion of the radiation emitted by the emitter means and to guide the first portion to the receiver means.

4. The system of any preceding claim, wherein the receive signal comprises a first component corresponding to the first portion of the radiation and a second component corresponding to the second portion of radiation.

5. The system of claim 4, wherein the control means is arranged to determine a location of the object about an arcuate path based on the first and second components of the receive signal.

6. The system of any preceding claim, comprising a plurality of receiver means each arranged to receive at least part of the first portion of the radiation emitted by the emitter means via the guide means and to output a respective receive signal in response thereto.

7. The system of claim 6, wherein the control means is arranged to receive each of the respective receive signals and to determine the presence of the object in dependence thereon.

8. The system of claim 6 when dependent on claim 4, wherein the control means is arranged to determine a location of the object based on a time difference between the first component of the receive signal and the second component of the receive signal output by each of the plurality of receiver means.

9. The system of claim 6 when dependent on claim 4, wherein the control means is arranged to determine a location of the object based on a duration of the receive signal output by each of the plurality of receiver means.

10. The system of claim 6 when dependent on claim 4, wherein the control means is arranged to determine a location of the object based on a combination of the first and second components of the receive signal; optionally the combination is an average magnitude of the receive signal.

11. An apparatus for object detection, comprising:

emitter means for emitting optical radiation in response to a transmit signal; receiver means for outputting a receive signal in response to received radiation; and guide means arranged between the emitter means and the receiver means for guiding a first portion of the radiation emitted by the emitter means to the receiver means;

wherein the receiver means is arranged to receive the first portion of the radiation and a second portion of radiation reflected from an object and falling thereon from external to the apparatus.

12. The apparatus of claim 11, wherein the apparatus is formed in an elongate body; optionally the elongate body is flexible.

13. The apparatus of claim 11 or claim 12, wherein the apparatus is attachable to a vehicle; optionally the apparatus is removeably attachable to the vehicle.

14. The apparatus of claim 11, 12 or 13, wherein the apparatus comprises a park distance controller and/or an object detection system.

15. A controller, comprising:

output means for outputting a transmit signal to an emitter means;

input means for receiving a receive signal from a receiver means indicative of received radiation, wherein the receive signal comprises a first component indicative of a first portion of radiation emitted by the emitter means and communicated to the receiver means via a guide, and a second component indicative of a second portion of radiation emitted by the emitter means and reflected from an object; and control means arranged to determine a presence of the object based on the receive signal.

16. The controller of claim 15, wherein the control means is arranged to determine the location of the object based on a timing between the first component of the receive signal and the second component of the receive signal.

17. The controller of claim 16, wherein the control means is arranged to determine a location of the object about an arcuate path based the first and second components of the receive signal.

18. The controller of claim 15, wherein the input means is arranged to receive a plurality of receive signals, wherein each receive signal is output from a respective receiver means and comprises a respective first component and a second component, and the control means is arranged to determine the location of the object based thereon.

19. The controller of claim 16, wherein the control means is arranged to determine the location of the object based on a duration of the receive signal output by each of the plurality of receiver means.

20. The controller of claim 16, wherein the control means is arranged to determine the location of the object based on a combination of the first and second components of the receive signal; optionally the combination is an average value of the receive signal output by each of the plurality of receiver means.

21. The controller of claim 16, wherein the control means is arranged to determine the location of the object based on a combination of a search signal which temporally varies in phase with each of the plurality receive signals.

22. A method of detecting an object, comprising:

emitting optical radiation from an emitter means;

guiding a first portion of the radiation emitted by the emitter means to a receiver means;

receiving at the receiver means the first portion and a second portion of the radiation emitted by the emitter means, the second portion being reflected from the object;

determining a presence of the object based on the first and second portions of radiation.

23. The method of claim 22, comprising determining the location of the object along an arcuate path based on a timing between the first and second portions of the receive signal.

24. The method of claim 22 or 23, comprising:

receiving signals indicative of a plurality of second portions or radiation each output from a respective receiver means; and determining the location of the object based on the plurality of signals.

25. The method of claim 24, wherein the location of the object is determined based on a duration of the first and second portions.

26. The method of claim 24, comprising determining the location of the object based on a combination of the first and second portions of each receive signal; optionally the combination is an average value of the receive signal.

27. The method of claim 24, 25 or 26, wherein the location of the object is determined as a respective distance between the object and each of the plurality of receiver means.

28. The method of any of claims 24 to 27, comprising outputting an indication of the location of the object.

29. A vehicle comprising the system of any of claims 1 to 10, the apparatus of any of claims 11 to 14, the controller of any of claims 15 to 21 or arranged to perform the method of any of claims 22 to 28.

30. A computer program which, when executed by a computer, is arranged to perform a method according to any of claims 21 to 28; optionally the program is stored on a computer readable medium.