WO2016004537A1

WO2016004537A1 - Scanning system and methods therefor

Info

Publication number: WO2016004537A1
Application number: PCT/CA2015/050646
Authority: WO
Inventors: Dhanushan Balachandreswaran
Original assignee: Sulon Technologies Inc.
Priority date: 2014-07-11
Filing date: 2015-07-10
Publication date: 2016-01-14

Abstract

Various embodiments of scanning systems configured to scan a physical environment for a multi dynamic environment and location based active augmented reality (AR) system are described. The scanning systems may be comprised within in the head mounted device (HMD) of a user in a physical environment, and the scanning may be performed from the point of view of a user wearing the HMD. The scanning systems prevent over-twisting of wiring needed for control of the scanning systems. The scanning system may incorporate a Fresnel lens to enable a compact configuration of system components. In use, the scanning system emits an incident signal outwards towards the physical environment. When the incident signal encounters obstacles within the physical environment, it is reflected back towards the scanning system as a corresponding reflected signal. The scanning system detects the reflected signal and measures the distance between the scanning system and the encountered obstacle.

Description

SCANNING SYSTEM AND METHODS THEREFOR TECHNICAL FIELD [0001] The following relates to a range finder and more specifically to a scanning system for virtual reality and augmented reality applications. BACKGROUND [0002] Augmented reality (AR) and virtual reality (VR) visualisation applications are increasingly popular. The range of applications for AR and VR visualisation has increased with the advent of wearable technologies and 3-dimensional (3D) rendering techniques. AR and VR exist on a continuum of mixed reality visualisation. SUMMARY [0003] In one embodiment a scanning system is provided for scanning a physical environment for augmented reality application. The scanning system may comprise: a base; a disc rotatably mounted to the base, the disc having a co-axial aperture disposed therethrough; a drive module mounted to the base and mechanically coupled to the disc for rotatably driving the disc; a mirror mounted to the disc and having a reflective surface facing the aperture at an angle of reflection; a Fresnel lens disposed in coaxial alignment with the disc between the base and the mirror; a transmitter mounted to the base between the Fresnel lens and the base to emit an incident beam for focusing by the Fresnel lens and reflection by the mirror into the physical environment, the incident beam, upon encountering an obstacle in the physical environment being reflected by the obstacle as a corresponding reflected beam toward the mirror; a receiver mounted to the base in coaxial alignment with the disc between the base and the transmitter; a concavely shaped collector unit mounted to the base, the collector unit comprising curved sidewalls which converge at an apex circumscribing the receiver to receive the reflected beam from the mirror and direct the reflected beam towards the receiver. [0004] The sidewalls may comprise a pair of identically sized and curved mirrors opposed to each other on either side of the receiver. [0005] The scanning system may further comprise a housing enclosing at least the mirror. The housing permits passage of the incident beam from the mirror into the physical environment and passage of the reflected beam from the physical environment onto the mirror. [0006] In embodiments, the drive module comprises a motor mounted to the base, a drive shaft rotated by the motor, and a mechanical link mechanically coupled to the drive shaft and the disc to rotate the disc when the motor is driven. The transmitter may be, for example, a laser diode or a light emitting diode to emit the incident beam, and the receiver may be correspondingly configured to detect the resulting reflected beam. The transmitter may be configured to emit the incident beam as a phase modulated beam and the receiver is configured to detect the corresponding phase of the reflected beam for calculation by a processor of the elapsed travel distance based on the difference between the phases of the incident beam and the reflected beam. The scanning system may be configured to emit the incident beam at a plurality of angles along a rotational path, track at which angles the incident beam is emitted, collect the reflected beam along a plurality of angles and determine the distances to the obstacles corresponding to those angles. [0007] In embodiments, the processor generates a map of the physical environment using the distances. The scanning system may be mounted to a head mounted device worn by a user occupying the physical environment. [0008] In further embodiments, the scanning system may enable continuous rotational scanning of the physical environment while mitigating tangling of wiring. The scanning system of may comprise wires coupled solely to elements of the scanning system which are stationary relative to the base. [0009] The scanning system may further comprise a stabiliser unit to stabilise the scanning system. The stabiliser unit may comprise gimbals. [0010] The scanning system may be configured for 2D or 3D scanning. [001 1] These and other aspects are contemplated and described herein. It will be appreciated that the foregoing summary sets out representative aspects of range finders and methods therefor to assist skilled readers in understanding the following detailed description. DESCRIPTION OF THE DRAWINGS [0012] A greater understanding of the embodiments will be had with reference to the Figures, in which: [0013] Fig. 1 is a view of a head mounted device for use with a scanning system or method; [0014] Fig. 2 is a side view of an embodiment of a system for scanning a physical environment; [0015] Fig. 3 is a detailed view of the signal mirroring in the scanning system shown in Fig. 2; [0016] Fig. 4 is a top view of the scanning system shown in Fig. 2; and [0017] Fig. 5 is a flowchart illustrating a method of scanning a physical environment. DETAILED DESCRIPTION [0018] For simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the Figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein may be practised without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the embodiments described herein. Also, the description is not to be considered as limiting the scope of the embodiments described herein. [0019] Various terms used throughout the present description may be read and understood as follows, unless the context indicates otherwise: "or" as used throughout is inclusive, as though written "and/or"; singular articles and pronouns as used throughout include their plural forms, and vice versa; similarly, gendered pronouns include their counterpart pronouns so that pronouns should not be understood as limiting anything described herein to use, implementation, performance, etc. by a single gender; "exemplary" should be understood as "illustrative" or "exemplifying" and not necessarily as "preferred" over other embodiments. Further definitions for terms may be set out herein; these may apply to prior and subsequent instances of those terms, as will be understood from a reading of the present description. [0020] Any module, unit, component, server, computer, terminal, engine or device exemplified herein that executes instructions may include or otherwise have access to computer readable media such as storage media, computer storage media, or data storage devices (removable and/or non-removable) such as, for example, magnetic discs, optical discs, or tape. Computer storage media may include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data. Examples of computer storage media include RAM, ROM, EEPROM, flash memory or other memory technology, CD- ROM, digital versatile discs (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disc storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by an application, module, or both. Any such computer storage media may be part of the device or accessible or connectable thereto. Further, unless the context clearly indicates otherwise, any processor or controller set out herein may be implemented as a singular processor or as a plurality of processors. The plurality of processors may be arrayed or distributed, and any processing function referred to herein may be carried out by one or by a plurality of processors, even though a single processor may be exemplified. Any method, application or module herein described may be implemented using computer readable/executable instructions that may be stored or otherwise held by such computer readable media and executed by the one or more processors. [0021] The present disclosure is directed to systems and methods for augmented reality (AR). However, the term "AR" as used herein may encompass several meanings. In the present disclosure, AR includes: the interaction by a user with real physical objects and structures along with virtual objects and structures overlaid thereon; and the interaction by a user with a fully virtual set of objects and structures that are generated to include renderings of physical objects and structures and that may comply with scaled versions of physical environments to which virtual objects and structures are applied, which may alternatively be referred to as an "enhanced virtual reality". Further, the virtual objects and structures could be dispensed with altogether, and the AR system may display to the user a version of the physical environment which solely comprises an image stream of the physical environment. Finally, a skilled reader will also appreciate that by discarding aspects of the physical environment, the systems and methods presented herein are also applicable to virtual reality (VR) applications, which may be understood as "pure" VR. For the reader's convenience, the following may refer to "AR" but is understood to include all of the foregoing and other variations recognized by the skilled reader. [0022] Certain AR applications require mapping the physical environment in order to later model and render objects within the physical environment and/or render a virtual environment layered upon the physical environment. Achieving an accurate and robust mapping is, therefore, crucial to the accuracy and realism of the AR application. [0023] One aspect involved in a mapping process is scanning the environment using a scanning system. A scanning system for mapping a physical environment for an AR application is provided herein. The scanning system comprises a transmitter, a receiver and a processor. The transmitter may comprise a laser diode, a light emitting diode or other signal emitter to emit an incident signal, such as, for example an infrared or laser beam, and the receiver may comprise a photodiode or other optical receiver operable to capture a reflected signal corresponding to the reflection of the incident signal from obstacles in the physical environment. The transmitter and receiver cooperate to generate sensor readings which are obtained by the processor. The processor processes the sensor readings to determine distances between the scanning system (at a particular moment in time) and surrounding obstacles in the physical environment. The processor can then generate a map of the physical environment using the distances. [0024] The singular "processor" is used herein, but processing tasks may be distributed amongst one or more processors and/or controllers. The processors and controllers may be communicatively connected to one another, and mounted throughout the scanning system or remotely therefrom. For example, one or more processing tasks may be performed by a processor in network, wireless or wired communication with components of the scanning system described and contemplated herein. Further, a processor may comprise a dedicated time-of- flight (TOF) chip, as described herein in greater detail. [0025] The scanning system may be mounted to a head mounted device (HMD) worn by a user occupying a physical environment, such as, for example, a room. In aspects, the scanning system may thereby enable inside-out mapping of the physical environment, i.e., mapping from the point of view of the user wearing the HMD, rather than from a fixed location in the physical environment and scanning toward the user. [0026] Some alternative scanning systems utilize rotating sensors to generate sensor readings. The sensors are generally electrically coupled to the processor by wiring. It has been found that such an implementation is often problematic because the wires may become tangled during rotation of the sensors. [0027] The scanning system provided herein also permits rotational scanning of the physical environment but avoids or mitigates tangling of wiring. In embodiments, the scanning system provided herein avoids the coupling of wiring to any rotating elements of the system. [0028] In embodiments, the scanning system is configured to scan and map a physical environment in 2- and/or 3-dimensions. The processor may provide the model of the physical environment to a graphics engine operable to generate a rendered image stream comprising computer generated imagery (CGI) for the modelled physical environment to augment user interaction with, and perception of, the physical environment. The CGI may be provided to the user via an HMD as a rendered image stream or layer. The rendered image stream may be dynamic, i.e., it may vary from one instance to the next in accordance with changes in the physical environment and the user's interaction therewith. The rendered image stream may comprise characters, obstacles and other graphics suitable for, for example, "gamifying" the physical environment by displaying the physical environment as an AR. [0029] In particular embodiments, the scanning system may be mounted to an HMD for being removably worn by a user. Referring now to Fig. 1 , an exemplary HMD 12 configured as a helmet is shown; however, other configurations are contemplated. The HMD 12 may comprise: a processor 130 in communication with one or more of the following components: (i) a scanning, local positioning and orientation module 128 comprising a scanning system for scanning the physical environment, a local positioning system ("LPS") for determining the HMD's 12 position within the physical environment, and an orientation detection system for detecting the orientation of the HMD 12 (such as an inertia measuring unit "IMU" 127); (ii) an imaging system, such as, for example, a camera system comprising one or more cameras 123, to capture image streams of the physical environment; (iii) a display system 121 for displaying to a user of the HMD 12 the AR and the image stream of the physical environment; (iv) a power management system (not shown) for distributing power to the components; and (v) an audio system 124 with audio input and output to provide audio interaction. The processor 130 may further comprise a wireless communication system 126 having, for example, antennae, to communicate with other components in an AR system, such as, for example, other HMDs, a gaming console, a router, or at least one peripheral to enhance user engagement with the AR. [0030] The processor 130 may carry out multiple functions, including rendering, imaging, mapping, positioning, and display. The processor may obtain the outputs from the LPS, the IMU and the scanning system to model the physical environment in a map (i.e. , to map the physical environment) and generate a rendered image stream comprising computer generated imagery ("CGI") with respect to the mapped physical environment. The processor may then transmit the rendered image stream to the display system of the HMD for display to user thereof. [0031] In conjunction with the processor 130, the scanning system is configured to scan and map the surrounding physical environment, whether in 2D or 3D. The generated map may be stored locally in the HMD or remotely in a console or server. The processor may continuously update the map as the user's location and orientation within the physical environment change. The map serves as the basis for AR rendering of the physical environment, allowing, for example, the user to safely and accurately navigate and interact with the physical environment. [0032] The scanning system comprises a transmitter and receiver. The scanning system may comprise a scanning laser range finder (SLRF) which scans the physical environment by emitting an incident signal from the transmitter towards the physical environment and receiving at the receiver a corresponding reflected signal back from the physical environment. When the incident signal encounters an obstacle in the physical environment, the incident signal is reflected as a reflected signal from the obstacle towards the scanning system. The receiver detects the reflected signal and the processor of the scanning system determines the distance from the scanning system to the obstacle. The processor may calculate the travelled distances using any suitable calculation techniques, such as, for example, phase shift modulation or time- of-flight (TOF), according to the configuration of the electronic components comprised by the scanning system. In a TOF calculation, a TOF integrated circuit (IC) or other processor records the elapsed time between emission and receipt of the signal 336, 336' and correlates the elapsed time to a travelled distance. According to at least one TOF approach, the transmitter emits a modulated incident signal having a phase, and the receiver detects the reflected signal and its phase. The processor or TOF IC calculates the phase shift between the incident and reflected signals to compute a TOF. [0033] The scanning system may be configured to emit the incident signal from the HMD at a plurality of angles along its rotational path, and to track at which angle the incident signal has been emitted. Correspondingly, by collecting reflected signals along a plurality of angles and determining the distances to various obstacles corresponding to those angles, it is possible to generate a map of the surrounding environment. [0034] When the scanning system is mounted to an HMD worn by a user, the orientation of the scanning system relative to the physical environment captured thereby may vary in accordance with the user's movements throughout the physical environment. The processor may thus acquire orientation information for the HMD from the orientation detection system of the HMD to adjust the tracked angle of emission for the incident signal by the change in the orientation of the HMD. [0035] Further, a user moving throughout the physical environment is likely to move his head and/or body, thereby causing the HMD and, correspondingly, the scanning system to constantly move in 3 dimensions and about 3 axes. These movements may decrease scanning accuracy. Therefore, the scanning system is preferably stabilised with a stabiliser unit, such as, for example a stabiliser unit comprising gimbals for mounting and stabilising the scanning system. [0036] Referring now to Figs. 2-4, shown therein is an embodiment of a scanning system 300 for scanning a physical environment. The scanning system 300 comprises: a base 350; a disc 340 rotatably mounted to the base 350 with a coaxial aperture 342 disposed therethrough; a drive module 310 mounted to the base 350 and mechanically coupled to the disc 340 for rotatably driving the disc 340; a mirror 334 mounted to the disc 340 and having a reflective surface facing the aperture 342 at an angle of reflection; a Fresnel lens 380 mounted to the base 350 in coaxial alignment with the disc 340 between base 350 and the mirror 334; a transmitter 326 mounted to the base 350 between the Fresnel lens 380 and the base 350 for emitting an incident signal 336 for focusing by the Fresnel lens 380 and reflection by the mirror 334 into the physical environment; a receiver 328 mounted to the base 350 in coaxial alignment with the disc 340 between the base 350 and the transmitter 326; and a concavely shaped collector unit 392 mounted to the base 350, the collector unit 392 comprising curved sidewalls which converge at an apex circumscribing the receiver 328 to receive a reflected beam 336' corresponding to the incident beam 336 reflected from an obstacle in the physical environment from the mirror and direct the reflected beam 336' beam towards the receiver 328. [0037] The scanning system 300 may further comprise support electronics 322, such as, for example, resistors, capacitors, regulators, an ambient light meter, a thermometer (to adjust time of flight calculations), transimpedance amplifiers for increasing the gain of the reflected signal 336' received by the receiver 328 and accordingly increasing the accuracy of any measurement relating to a measurement of the signal 336, 336' (such as a calculated distance), an encoder, such as, for example, a rotary encoder or shaft encoder, to determine the angle of emission of the incident signal 336 and the angle of reception of the reflected signal 336', and a TOF IC for measuring the time of travel of the signal 336, 336'; and wires 308. [0038] The controller 324 may be connected to the receiver 328, the transmitter 326, the support electronics 322 and the processor 130 by wires 308. The controller 324 controls the speed and angle of the drive module 310. The processor 130 may be configured to process characteristics of a reflected signal 336' measured by the receiver 328 in order to calculate the distance travelled by the incident signal 336 and reflected signal 336', given characteristics of the incident signal 336, as determined by controller 324 and transmitter 326, and characteristics of the reflected signal 336', as measured by the receiver 328. The processor 130 may comprise hardware to calculate the distance travelled by the signal, such as a micro-control unit (MCU) to perform some or all the processing tasks required. [0039] The drive module 310 is mounted to the base 350 and is communicatively coupled to a motor controller 301 by wires 308 and mechanically coupled to the disc 340 for driving the rotation of the mirror 334. [0040] The scanning system 300 incorporates the Fresnel lens 380 to focus the incident signal 336 onto the mirror 334. The inherently short focal length of Fresnel lenses may enable the mirror 334 to be positioned more closely to the transmitter 326 than in various scanning system that do not incorporate a Fresnel lens. In use, the incident light 336 is transmitted through the Fresnel lens 380, then through the aperture 342, to the mirror 334, by which it is deflected outwardly from the scanning system 300 into the physical environment. [0041] Still further, the concave reflector unit 392 may enhance angular acceptance of the reflected signal 336' by the receiver 328. The collector unit 392 focuses dispersed reflected signals towards the receiver 328 at its apex. The collector unit 392 may comprise a set of curved mirrors opposed to each other on either side of the receiver 328, each mirror being the identically sized and curved. Parallel rays of reflected light beam 336' encountering the collector unit 392 each arrive at different incident angles corresponding to the tangent of the collector unit 392 at the respective encounter point. The curvature of the walls of the collector unit 392 is configured to direct the rays of the reflected light beam 336' towards the receiver 328, as shown in greater detail in Fig. 4. The curvature is dependent on the size of the collector unit 392 and the shape, size and location of the receiver 328. In use, the collector unit 392 functions to focus disperse rays from a reflected light beam 336' arriving from the mirror 334 onto the receiver 328. [0042] The base 350 may be comprised of a region of an HMD, or the base may be a discrete component for mounting to an HMD. Further, the transmitter 326 may be configured to emit, and the receiver 328 may be configured to detect one or more suitable signal types, such as, for example, an infrared (IR) beam or a laser beam. [0043] The aperture 342 disposed co-axially through the disc 340 serves as a passageway for signals travelling between the mirror 334 and the transmitter 326 and receiver 328. The mirror 334 is mounted to the disc 340 at an angle of reflection along the signal path of the transmitter 328 and receiver 326 to reflect the incident signal 336 outwardly from the transmitter 328 to the physical environment and inwardly from the physical environment to the receiver 326. For example, the mirror may be angled by 45 degrees relative to the disc 342 to reflect the incident signal 336 by 90 degree angle relative to its trajectory between the transmitter 326 and the mirror 334. In further embodiments, the transmitter and/or receiver may themselves comprise mirrors and/or lenses that nevertheless provide for a signal to be reflected from the mirror 334. [0044] The scanning system 300 may comprise a housing 332 for covering and protecting at least the driven components of the scanning system 300. In this case, at least a region of the housing that lies in the signal path is translucent, transparent or defines an aperture configured to permit passage of signals outwardly through the wall of the housing 332 for passage into the physical environment. In at least one embodiment, the housing 332 comprises a top 331 and translucent or transparent sidewalls 333 for permitting passage of light signals therethrough. In another embodiment, the housing 332 comprises a plurality of thin, rigid members mounted to the base 350 and extending upwardly therefrom, the rigid members supporting a top disposed over the mirror module 330 to form a rigid housing surrounding the mirror module 330. The members permit the housing to provide openings at least in the signal paths. [0045] The drive module 310 comprises: a motor 306 mounted to the base 350 and comprising a drive shaft 304; a mechanical link 302 mechanically coupled to the drive shaft 304 and the disc 342 to rotate the disc 342 when the motor 306 is driven; and a motor controller 301 electrically connected via wires 308 to the motor 306 for controllably driving the motor 306. The motor controller may be physically remote from the scanning system 300 or mounted to the base 350 as shown. If the scanning system 300 comprises a housing 332, as shown, the housing 332 may define an aperture or other suitable access passage to receive therethrough the mechanical link 302. In the illustrated embodiment, the housing 332 defines an aperture therethrough where the mechanical link 302 traverses the housing 332. [0046] The illustrated wires 308 may communicatively link drive module 310 and transceiver module 320 to one another and to processor 130. Further, wires 308 may electrically connect the drive module 310 and the transceiver module 320 to a power management system (not shown) for powering their components. The power management system may comprise or be electrically coupled to a power source, such as, for example a battery or mains power, and may further comprise a transformer to suitably transform the incoming current to an output current for the scanning system 300. [0047] Various embodiments of the mechanical link 302 are contemplated. In some embodiments, the mechanical link 302 comprises a belt, band or chain coupled to the drive shaft 304 for transmitting mechanical force from the motor 306 to the disc 340. In further embodiments, the mechanical link 302 comprises a gear train for transmitting mechanical force from the motor 306 to the disc 340. In still further embodiments, the mechanical link 302 comprises a planetary gear surrounding the disc 340 for transmitting mechanical force from the motor 306 to the disc 340. Other suitable embodiments are also contemplated. [0048] In various embodiments, the motor 306 is communicatively linked to a motor controller 301 for controlling operation of the motor. In various embodiments, the motor controller 301 is configured to control the rotational angle of the drive shaft 304 at any given time. The motor controller 301 may be configured to provide sensor readings of the angle of the motor output shaft 304 to the processor 130. The motor controller 301 may further be configured to process sensor readings of the angle of the drive shaft 304 to determine a corresponding angle of the disc 342 and mirror 330. The motor controller 301 may further be configured to provide a signal indicating the angle of the mirror 330 to the processor 130. [0049] In embodiments, the motor controller is configured to rotate the drive shaft 304 according to a predetermined angular displacement at predetermined intervals of time, thus enabling 360 degree rotation comprising a plurality of intervals at known angles from the HMD. [0050] In embodiments, increasing or decreasing the diameter of the disc 342 corresponds to a respective increase or decrease in the mechanical resolution provided by the mechanical link 302, such that a given angular displacement of the drive shaft 304 displaces the disc 342 and the mirror 334 by a respectively lower or greater amount. [0051] The disc 340 is rotatably mounted to the base 350 by a rotatable coupling 344. The coupling 344 comprises an interface for retaining the disc 340 to the base 350 while permitting substantially free rotation of the disc 340 relative to the base 350. The interface may comprise, for example, roller bearings or a lubricated region engageable with an adjacent region of the base 350 or disc 340. The coupling 344 may retain the disc 340 distal or adjacent the base 350. The coupling 344 may further mount the Fresnel lens 380 to the base 350. The coupling may comprise legs or walls to retain the disc 340 distal the base 350 while permitting substantially free passage of the signal 336, 336' through the coupling. The coupling 344 may rotate with the disc 340 relative to the base 350, or vice versa. [0052] Referring now to Fig. 5, shown therein is a flowchart illustrating blocks 400 relating to a method of operating the scanning system 300, i.e. for a single scan at a single angle. At block 402 the transmitter 326 is turned on by the controller 324. In some embodiments, operation of the scanning system may be triggered by the processor 130 instructing the controller 324 to begin scanning the physical environment. At block 404 an incident signal 336 is emitted from the transmitter towards the mirror 334. The incident signal 336 then reflects off the mirror 334 and is directed outwardly from the scanning system 300. At block 406 the incident signal encounters an obstacle (not shown) in the physical environment and reflects back towards the mirror 334 as reflected signal 336'. At block 408 the reflected signal 336' is detected and evaluated by the receiver 328. At block 410 the transmitter 326 is turned off. At block 412 the processor 130 processes sensor readings provided by receiver 328 relating to the detected reflected signal 336', and the TOF IC of the supporting electronics calculates the distance travelled by the signal to and from the encountered obstacle within the physical environment. The calculated distance may be provided to processor 130 for use in mapping the physical environment surrounding the scanning system 300 for use in AR applications, such as, for example, to map a plurality of calculated distances as a corresponding plurality of points in a point cloud representation of the physical environment. At block 414 the controller 301 actuates the motor 306, causing the disc 342 and mirror 334 to rotate by a predetermined angle. Alternatively, block 414 could be called upon to rotate the disc 342 after a plurality of time-of- flight readings have been calculated, to ensure accuracy of such readings. As illustrated, the blocks may then be repeated to provide additional calculations of distance. The blocks 400 may be repeated so long as the processor 130 controls the controller 324 to continue scanning the physical environment. The processing of a reflected signal to determine distance travelled by the signal, and required hardware, was described in more detail above in relation to the operation of the SLRF. [0053] In some embodiments, instead of the processor 130 carrying out calculations to determine the distance travelled by the signal, the TOF IC of the support electronics 322 may calculate the distances based on the elapsed time between emissions and detection of the signal 336. [0054] As the mirror 334 rotates about the environment at predetermined angular increments in conjunction with repetitions of the steps described in relation to the blocks 400 (i.e. additional scans of the environment), the processor 130 may be provided with calculated distances to obstacles located along 360 degrees about the system 300. The system 300 may thus provide calculated distances to processor 130 for further processing and for use in mapping the physical environment surrounding the system 300. The calculated distances provided by the system 300 may be used by the processor 130 for use in further AR applications. Specifically, in some embodiments, the processor 130 may be configured to receive a signal from the controller 301 indicating an angle of the mirror 334 and a signal from the TOF IC indicating a calculated distance to an obstacle at that angle, and the processor may be able to process each signal in order to determine the distance from the HMD to an obstacle at a given angle from the HMD's field of view. The processor 130 may further be configured to process signals from additional scans from the scanning system 300, i.e. repetition of the blocks 400, in order to provide a map of the physical environment comprising distances to obstacles at 360 degrees around the HMD. [0055] In an alternate embodiment, instead of the transmitter being turned off and on at each repetition of the steps described in relation to blocks 400, the transmitter constantly transmits incident signals 336 and the processor 130 continuously processes received sensor readings provided by receiver 328. Alternately, the transmitter 326 may constantly transmit incident signals 336 and the processor 130 may only process sensor readings periodically or intermittently. [0056] In further embodiments, instead of the controller merely being activated intermittently, the motor may operate continuously. In such embodiments, the functions of the transmitter 326, controller 324, receiver 328 and processor 130 may be performed at a predetermined frequency, when polled by the processor 130, or continually. In some embodiments, the transmitter 326 is always active to emit incident signals, but the receiver 328 and controller 324 are only intermittently activated by the processor to perform their functions, such as capturing a reflected signal. [0057] In some embodiments, the speed of the motor may be varied by controller 301 in order to vary the frequency with which repeated scans according to blocks 400 will map 360 degrees around the system 300. [0058] Referring again to Figs. 2-4, the scanning system 300 maybe configured to further enable effect tilting of the mirror 334 relative to the disc 340 to which it may be tiltably mounted. A tilt actuator 360 is mechanically coupled to the mirror 334 to tilt the mirror 334 toward and away from the disc 340. Tilting the mirror 334 may allow the mirror 334 to redirect and capture the signal 336, 336' upwardly and downwardly toward the physical environment to provide potential 3D scanning and mapping. Wiring 308 may electrically and communicably couple the tilt actuator 360 via a slip ring 352 disposed within the aperture 342 to the transceiver module 320, the controller 301 , the processor 130, or any other electronic components located mounted to the base 350, in order to control and power the tilt actuator 360 to tilt the mirror 334. The angular rotation of the tilt actuator 360 is selectable and determinable. For example, the tilt actuator 360 may be a stepper motor, or it may comprise an optical encoder to provide the angular rotation of the actuator. [0059] The scanning system 300, when configured to provide tilting of the mirror 334, may enable 3-dimensional mapping of the physical environment surrounding the system 300. The processor 130 may subsequently correlate the tilt angle of the mirror 334 to a given distance measurement. Accordingly, the processor 130 may be configured to receive signals indicative of the tilt angle of the mirror 334, the rotational angle of the mirror 334 with respect to the field of view of an HMD (as previously described), as well as transmitter 326 and receiver 328 readings, and the processor 130 may be configured to further process the received signals in order to generate a three dimensional map of the physical environment surrounding the scanning system 300. [0060] Alternatively, in order to scan in 2D, the receiver 1028 may be ambivalent to the location on the surface of the sensor at which any reflected beam of flight encounters the sensor. In such a configuration, any collimation may result in collimating the reflected signal 1036' to convergence or to less than convergence. In contrast, in a 3D scanning configuration, even without the mirror 334 being tiltable, the receiver 328 may comprise an arrayed sensor having a surface divided into n x n pixels. For any given pixel detecting a ray in the reflected signal 336', a processor (not shown) communicatively coupled to the receiver 328 will determine which pixel detects the ray, as well as the travel distance to the obstacle reflected by that ray. The processor may thereby recognise 3 dimensions in the reflected signal 336'. In a 3D scanning configuration, any collimation may not collimate the rays in the reflected signal 336' to complete convergence since complete convergence would result in the rays converging to a single or relatively few pixels on the sensor. Collimation converges the reflected signal 336' so that most or all rays within the reflected signal 1036' encounter the receiver 328 within the lateral range of the n x n pixels. [0061] Although the foregoing has been described with reference to certain specific embodiments, various modifications thereto will be apparent to those skilled in the art without departing from the spirit and scope of the invention as outlined in the appended claims. The entire disclosures of all references recited above are incorporated herein by reference.

Claims

1. A scanning system for scanning a physical environment for augmented reality

applications, the scanning system comprising: a. a base;

b. a disc rotatably mounted to the base, the disc having a co-axial aperture disposed therethrough;

c. a drive module mounted to the base and mechanically coupled to the disc for rotatably driving the disc;

d. a mirror mounted to the disc and having a reflective surface facing the aperture at an angle of reflection;

e. a Fresnel lens disposed in coaxial alignment with the disc between the base and the mirror;

f. a transmitter mounted to the base between the Fresnel lens and the base to emit an incident beam for focusing by the Fresnel lens and reflection by the mirror into the physical environment, the incident beam being reflected as a reflected beam toward the mirror upon encountering an obstacle in the physical; g. a receiver mounted to the base in coaxial alignment with the disc between the base and the transmitter; and

h. a concavely shaped collector unit mounted to the base, the collector unit

comprising curved sidewalls which converge at an apex circumscribing the receiver to receive the reflected beam from the mirror and direct the reflected beam towards the receiver.

2. The scanning system of claim 1 , wherein the sidewalls comprise a pair of identically sized and curved mirrors opposed to each other on either side of the receiver.

3. The scanning system of claim 1 , wherein the mirror is disposed at an angle of 45

degrees relative to the disc.

4. The scanning system of claim 1 , further comprising a housing enclosing at least the mirror, the housing permitting passage of the incident beam from the mirror into the physical environment and passage of the reflected beam from the physical environment onto the mirror.

5. The scanning system of claim 1 , wherein the drive module comprises a motor mounted to the base, a drive shaft rotated by the motor, and a mechanical link mechanically coupled to the drive shaft and the disc to rotate the disc when the motor is driven.

6. The scanning system of claim 1 , wherein the transmitter comprises one of: a laser diode and a light emitting diode to emit the incident beam and wherein the receiver is configured to detect the resulting reflected beam.

7. The scanning system of claim 1 , wherein the transmitter is configured to emit the

incident beam as a phase modulated beam and the receiver is configured to detect the corresponding phase of the reflected beam for calculation by a processor of the elapsed travel distance based on the difference between the phases of the incident beam and the reflected beam.

8. The scanning system of claim 7, wherein the processor generates a map of the physical environment using the distances.

9. The scanning system of claim 1 , wherein the system is mounted to a head mounted device worn by a user occupying the physical environment

10. The scanning system of claim 1 , wherein the system permits continuous rotational scanning of the physical environment while mitigating tangling of wiring.

11. The scanning system of claim 1 , wherein the system comprises wires coupled solely to stationary elements relative to the base.

12. The scanning system of claim 1 , wherein the system is configured to emit the incident beam at a plurality of angles along a rotational path, track at which angles the incident beam is emitted, collect the reflected beam along a plurality of angles and determine the distances to the obstacles corresponding to those angles.

13. The scanning system of claim 1 , further comprising a stabiliser unit to stabilise the

scanning system.

14. The scanning system of claim 1 , wherein the stabiliser unit comprises gimbals.

15. The scanning system of claim 1 , wherein the scanning system is configured for 3D scanning.

16. The scanning system of claim 1 , wherein the scanning system is configured for 2D scanning.

17. The scanning system of claim 1 , further comprising a stabiliser unit to stabilise the scanning system.