Vehicle-mounted tracking system and associated method

Abstract

A tracking system (S) comprising at least one tracking device (3) and a detection device (4) configured to detect the position and angular orientation of the tracking device (3), the detection device (4) comprising a receiving device (1) configured to receive a projected predetermined reference image (IM1), the receiving device (1) comprising an optical sensor (14) configured to capture a portion of the projection of the received predetermined reference image (IM1) onto a receiving area (11), and a computing device (19) configured to determine a deformation of at least one predetermined oriented pattern (M1-M15) of the predetermined reference image (IM1) so as to deduce a position vector (vecR). Abstract figure: Figure 1

Description

Title of the invention: Tracking system configured for mounting in a vehicle and associated method. Technical field

[0001] The present invention relates to the field of tracking an object or individual, particularly in a vehicle, and in particular, a light aircraft. The invention is especially applicable in the field of virtual, mixed, or augmented reality.

[0002] As is known, a light aircraft allows movement through the air, particularly between two airfields. For this purpose, such a vehicle includes a cabin housing one or more operators to manipulate the flight controls. Navigation based solely on the operators' external vision from the cabin is difficult and requires the use of a navigation map to locate the aircraft using points of interest visible to the naked eye. This implementation has the disadvantage of dividing the operators' attention and increases the risks during piloting. To eliminate this drawback, the operator can be equipped with a headset featuring a mixed or augmented reality system displaying an enhanced external scene.This mixed or augmented reality system allows points of interest to be displayed on the pilot's screen, enabling clearer navigation and allowing the pilot to dedicate their full attention to navigation and piloting itself. It is known to use a mixed or augmented reality system that includes a device for detecting the orientation and position of the headset within a cockpit frame, in order to modify the display of elements superimposed on the external scene based on the headset's orientation and position.

[0003] The cabin of such a light aircraft is subject to many different accelerations during a flight, making the use of inertial sensors unsuitable for angular detection of the operator's helmet.

[0004] In the prior art, several detection devices are known. In particular, a magnetic detection device is known that generates magnetic fields and determines the orientation and position of the helmet by analyzing these magnetic fields. Such a detection device is not suitable for a light aircraft because it is likely to interfere with the electronic equipment of said aircraft.

[0005] A detection device is also known, comprising several fixed observation cameras mounted in the vehicle's cabin and directed towards the operator wearing the helmet. Markers are positioned on the helmet so as to determine its orientation and position by processing the images from the observation cameras. In practice, the installation of observation cameras in the The vehicle's cabin is complex due to the density of equipment within it. Furthermore, this necessitates a communication system between the observation cameras and the helmet, which is a significant constraint.

[0006] An alternative solution would be to mount one or more observation cameras directly on the helmet and to position markers in the vehicle cabin to detect the helmet's orientation and position. In practice, to accurately detect the orientation and position, it may be necessary to model the cabin interior, for example, using machine learning, which is time-consuming, computationally expensive, and cumbersome. Furthermore, real-time cabin modeling introduces latency in determining the helmet's orientation and position, causing discomfort for the operator who experiences a lag between head movements and the video feed from the outside scene displayed in the helmet. Another drawback is that the marker positions must be determined for each type of vehicle, which increases complexity.

[0007] It is also known to provide one or more observation cameras directly on the helmet and to use tracking algorithms to detect the orientation and position of the helmet. This avoids the need to determine the position of markers, but it nevertheless presents drawbacks similar to the solution mentioned above.

[0008] The invention thus aims to eliminate at least some of these drawbacks by providing a high-performance and robust object tracking system (for helmets, glasses, etc.) that can be conveniently installed in any type of vehicle. The invention also aims to allow an operator to view augmented, mixed, or virtual reality without any inconvenience or latency.

[0009] The system is also applicable to systems using virtual reality, for example in the case of simulators. PRESENTATION OF THE INVENTION

[0010] The invention relates to a tracking system comprising: • At least one tracking device configured to be attached to an object to be tracked or a person to be tracked, • at least one detection device configured to detect the position and angular orientation of the tracking equipment.

[0011] The invention is remarkable in that the detection device comprises: • A receiving device, mounted in a reference frame or on the tracking equipment, configured to receive a predetermined reference image projected by a transmitting device mounted on the other part of the reference frame or tracking equipment, the predetermined reference image having at least one pre-oriented pattern determined, • the receiving device comprising: • at least one receiving area configured to receive at least a portion of the predetermined reference image projection and • at least one optical sensor configured to capture a current image received in the receiving area, • at least one computing device configured to determine the deformation of at least one predetermined oriented pattern in the current image so as to deduce a position vector which is specific to the receiving device and defined with respect to the transmitting device from the determined deformation.

[0012] By "oriented motif", it is indicated that two axes can be determined allowing the orientation of the motif to be determined in a plane.

[0013] Thanks to the invention, the receiving device locally detects deformation by analyzing the current image captured on the receiving area. This eliminates the need for magnetic means or cabin modeling, resulting in low-cost implementation. The detection system is universal and can be adapted to any vehicle or reference frame. Projecting a predetermined reference image containing predetermined oriented patterns allows the position vector to be conveniently defined from the sensor of one or more oriented patterns, from which all the geometric data specific to the position vector can be deduced. The determination of the position vector can advantageously be performed locally, enabling real-time operation without latency.

[0014] According to one aspect, the reference image comprises a plurality of predetermined oriented patterns, each possessing its own identity. This makes it possible to determine the observed portion of the image and therefore the angles between the emitting device and the projection device. The predetermined oriented patterns are thus identifiable.

[0015] According to one aspect, the emitting device emits the predetermined reference image over a predetermined wavelength range, and the optical sensor is sensitive only within this predetermined wavelength range. Such selective operation makes it possible to reduce interference from other light sources in the frame of reference, in particular, the cabin.

[0016] Preferably, the predetermined wavelength range is invisible to the naked eye, preferably in the infrared. This advantageously allows for use in the dark. It also prevents blinding the operator.

[0017] According to one aspect, the receiving zone is in the form of a diffusive transmissive surface configured to receive, on a first face, at least one A portion of the projection of the predetermined reference image is captured, with the optical sensor configured to capture the current image on a second face opposite the first. The intersection of the plane of the receiving area and the light from the reference image causes a distortion of the latter. This allows for the precise detection of this distortion in the reference image to determine the position vector. It also provides optimal protection for the optical sensor while enabling the capture of a robust current image free from environmental noise.

[0018] According to one aspect, the detection device comprises at least one transmitting device, mounted on the other of the reference frame or tracking equipment, configured to project the predetermined reference image onto the receiving area of ​​the receiving device. The transmitting device has a limited footprint.

[0019] According to one aspect, the emitting device comprises a divergent projection device. This advantageously allows, with a small emitting device, coverage of a large operating area in which an operator can move.

[0020] According to one aspect, the emission device comprises a transparent surface configured to allow the projection of the predetermined standard image to pass through.

[0021] According to one aspect, the divergent projection device takes the form of a screen in which each pixel is an independent light source.

[0022] According to one aspect, the diverging projection device comprises a reflector and a light source projecting light onto the reflector, the reflector comprising a plurality of reflective elements configured to form the predetermined oriented patterns of the predetermined reference image. This makes it possible to obtain a very high contrast, which facilitates image processing by the receiving device.

[0023] According to one aspect, the reflecting element being configured to form the predetermined standard image forward, the reflecting element comprises a transparent front support and a rear absorbing surface, the plurality of reflective elements being positioned between the rear absorbing surface and the transparent front support. This also makes it possible to obtain a very high contrast while filtering out light disturbances, which facilitates image processing by the receiving device.

[0024] According to one aspect, the emission device comprises at least one diffractive element and a monochromatic light source enabling the creation of an image characterized by a pattern predetermined by the diffractive element.

[0025] According to one aspect, the tracking equipment is configured to display at least one additional data point that is a function of the position vector. This allows the operator to be shown fixed reference points in virtual space, for example during a landing maneuver.

[0026] In one aspect, the tracking equipment is a helmet. This advantageously allows an operator to wear the tracking equipment naturally while also allowing for the display of additional data.

[0027] The invention also relates to a vehicle, in particular a light aircraft vehicle, the vehicle comprising a cabin configured to house at least one operator, the vehicle comprising at least one reality, mixed or augmented tracking system, as previously described, configured to display an augmented, mixed, or virtual outdoor scene, enriched according to a position and angular orientation of the tracking equipment.

[0028] The invention relates to a method of using a tracking system as described above, the tracking system comprising at least one tracking device configured to be attached to an object to be tracked or a person to be tracked and at least one detection device configured to detect the position and angular orientation of the tracking device, the detection device comprising a transmitting device mounted in the reference frame, and a receiving device mounted on the tracking device. The method comprises the steps of: • Project a predetermined standard image from the transmitting device to the receiving device so as to receive at least a portion of the projection of the predetermined standard image onto a receiving area of ​​the receiving device, the predetermined standard image comprising at least one predetermined oriented pattern, • Capture a current image received at the receiving area, • Determine a deformation of at least one predetermined oriented pattern in the current image and • Determine a position vector that is specific to the receiving device and defined relative to the transmitting device from the determined deformation.

[0029] According to one aspect, the projection and capture steps are performed continuously. This makes it possible to provide a real-time position vector, allowing for its manipulation without latency.

[0030] According to one aspect, the deformation determination step comprises substeps consisting of: • Determine a separation distance between the receiving device and the transmitting device by deforming at least one predetermined oriented pattern projected onto the current image, • Determine the angular position of the receiving device relative to the transmitting device by deforming at least one oriented pattern. determined projected into the current image and • Determine the angular orientation of the receiving device relative to the transmitting device by means of the deformation of at least one predetermined oriented pattern projected into the current image.

[0031] According to one aspect, the substeps of the deformation determination step are carried out in parallel. This reduces the time required to determine the position vector, thus avoiding any latency.

[0032] According to one aspect, the method of use includes a step of determining the position vector by correlation from the current image and a previous current image for which a previous position vector has already been determined. This reduces the number of computational steps by determining the position vector by simple correlation when there is only a slight modification of the current image. The computational cost is drastically reduced.

[0033] According to one aspect, the method of use includes a step in which the tracking equipment displays an augmented, mixed, or virtual outdoor scene, enhanced according to the position and angular orientation of the tracking equipment. This makes it possible to use the determined data to enable an augmented, mixed, or virtual reality application without requiring any display equipment other than the tracking equipment. PRESENTATION OF THE FIGURES

[0034] The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0035] Fig. 1 is a schematic representation of a vehicle comprising a tracking system according to one embodiment of the invention.

[0036] Fig. 2 is a schematic cross-sectional representation of a detection device according to one embodiment of the invention comprising a transmitting device and a receiving device.

[0037] Fig. 3 is a schematic cross-sectional representation of a reflector element of the emission device.

[0038] The [Fig.4] is a schematic representation of a predetermined standard image.

[0039] Figure 5 is a schematic representation of a current image on the projection of the predetermined standard image at the receiving device level.

[0040] Fig. 6 is a schematic representation of a method of using the tracking system.

[0041] Figure 7 is a schematic representation in a vertical plane of the projection of the predetermined reference image to determine a separation distance.

[0042] The [Fig.8] is a schematic representation in a vertical plane of the projection of the predetermined standard image to determine a vertical divergence angle.

[0043] Fig. 9 is a schematic representation in a horizontal plane of the projection of the predetermined standard image to determine a horizontal divergence angle.

[0044] The [Fig. 10] is a schematic representation in a horizontal plane of the projection of the predetermined standard image to determine a horizontal orientation angle.

[0045] The [Fig. 11] is a schematic representation in a vertical plane of the projection of the predetermined standard image to determine a vertical orientation angle.

[0046] The [Fig. 12] is a schematic representation of a distortion between the predetermined standard image and the current image.

[0047] It should be noted that the figures set out the invention in detail to implement the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0048] With reference to [Fig. 1], a light aircraft vehicle 100 is shown, comprising a cabin 101 housing an operator (OP). In this example, the light aircraft vehicle 100 is a pleasure aircraft, but it is understood that the invention applies to any type of vehicle, for example, a land vehicle, a boat, or a submersible. It is understood that the invention also applies to any application using virtual, mixed, or augmented reality, such as a video game. Similarly, a single operator (OP) has been shown, but it is understood that the invention applies to several operators (OPs) in one or more cabins 101 of the vehicle 100. Likewise, the invention also applies to an object to be tracked.

[0049] According to the invention, the vehicle 100 comprises a tracking system S for tracking the movements of the operator OP. It is understood that any target or object could be tracked by the tracking system S. The tracking system S makes it possible, in particular, to determine data enabling, for example, a virtual, mixed, or augmented reality application, based on the movements of the operator OP.

[0050] The tracking system S includes a tracking device 3 configured to be worn by the operator. This tracking device 3 enables the tracking system S to track the movements of the operator. Preferably, as seen in this example, the tracking device 3 is a helmet. It is understood that the tracking device 3 could take another form, such as a bra, a harness, or goggles.

[0051] According to one embodiment, with reference to [Fig. 1], particularly in the case of the In mixed reality, the tracking equipment 3 may include one or more cameras 102 configured to capture a video stream VI of an outdoor scene SC. Hereafter, the outdoor video stream VI is defined as the video stream, from one or more cameras 102 mounted on the tracking equipment 3, which is supplied to the tracking system S.

[0052] With reference to [Fig. 1], the tracking system S which receives the external video stream VI is shown.

[0053] According to one aspect, the tracking equipment 3 includes a display screen (not shown) on which is displayed a portion of the external video stream V1 which is a function of the position and angular orientation of the tracking equipment 3 in the cabin 101.

[0054] As illustrated in [Fig. 1], such a tracking device 3 is configured to receive a position vector vecR, determining the position and angular orientation of the headset 3 in the cabin 101. The tracking device 3 advantageously includes a communication element for receiving, either wired or wirelessly, the position vector vecR and, in one embodiment, the external video stream VI. Such a tracking device 3 is known to those skilled in the art and will not be described in further detail.

[0055] According to a third embodiment, the tracking equipment 3 can receive the position vector vecR and a stream of virtual images.

[0056] According to another aspect, information, for example from satellite data or provided upstream, can be displayed in the tracking equipment 3 depending on the position and angular orientation of the tracking equipment 3 in the cabin 101, particularly within the framework of a mixed or augmented reality system. The tracking equipment 3 then receives the position vector vecR and, in the case of mixed reality, a portion of the external video stream VL. Displaying this information, adapted to the position of the tracking equipment 3, allows an operator OP to focus their attention on points of interest in the external scene SC according to the situation by moving their head naturally. In the case of virtual reality, the tracking equipment 3 can receive the stream of virtual images and display them according to the position vector vecR.

[0057] Still with reference to [Fig.1], the tracking system S further includes a detection device 4 configured to detect the position and angular orientation of the tracking equipment 3, i.e., to determine the position vector vecR.

[0058] The detection device 4 comprises, on the one hand, a transmitting device 2 configured to project a predetermined standard image IM1 towards the operator OP's tracking equipment 3 and, on the other hand, a receiving device 1 configured to receive at least a portion of the predetermined standard image IM1 so as to deduce the position vector vecR. Thus, the receiving device 1 has no need to model cabin 101 to determine the position vector vecR. All the necessary information is received directly by the receiving device 1. This eliminates the need to consider the specific characteristics of each vehicle; the detection device 4 can therefore be mounted in different reference frames, for example, a cabin or other.

[0059] The emission device 2 will now be presented.

[0060] With reference to [Fig. 2], a transmitting device 2 is shown according to one embodiment of the invention. In this example, the transmitting device 2 comprises a diverging projection device 21 of a predetermined reference image IM1. The diverging projection device 21 has a projection axis X, oriented from back to front, and a divergence point PDD, which is theoretical in nature, located on the projection axis X at the rear of the diverging projection device 21 as illustrated in [Fig. 2]. The diverging projection device 21 is configured to project forward, i.e., toward the receiving device 1.

[0061] The diverging projection device 21 is oriented to cover an operating area ZF in which the operator OP's tracking equipment 3 is likely to move. Due to the divergence, a diverging projection device 21 makes it possible to cover a large operating area ZF while maintaining a compact transmitting device 2. The divergence also promotes distortion of the predetermined reference image IM1, as will be explained later.

[0062] Each emitting device 2 is associated with an operating zone ZF which is aligned with the projection axis X and is a function of a divergence angle. The divergence angle is preferably between 30° and 45°. Therefore, to cover a very large operating zone, it may be possible to provide several emitting devices 2.

[0063] With reference to [Fig.2], a standard distance "De" is defined along the X projection axis between the predetermined standard image IM1 formed on the emission device 2 and the divergence point PDD which is predetermined.

[0064] In this example, with reference to [Fig. 4], the predetermined reference image IM1 comprises several predetermined oriented patterns M1-M15. The predetermined reference image IM1 will be presented in more detail later.

[0065] In this example, with reference to [Fig. 2], the emitting device 2 comprises a housing 20 in which the diverging projection device 21 is mounted. The diverging projection device 21 comprises a light source 5 for illuminating a reflector 6 and generating the predetermined standard image IM1 through an opening formed in the housing 20. In this example, the diverging projection device 21 comprises, at the opening, a transparent surface 22 allowing the diverging light from the light source 5 to pass through. Advantageously, the The transparent surface 22 allows the emitting device 2 to be dustproof and thus protect the predetermined reference image IM1. The reflector 6 is configured to form the predetermined reference image IM1 forwards following illumination by the light source 5.

[0066] With reference to [Fig. 3], the reflector 6 comprises a transparent front support 61 having a rear surface on which are mounted reflective elements DI-DI5 configured to form the predetermined oriented patterns M1-M15 of the predetermined standard image IM1. The reflector 6 further comprises a rear absorbing surface 62 fixed to the transparent front support 61 such that the plurality of reflective elements DI-DI5 are positioned between the rear absorbing surface 62 and the transparent front support 61. Thus, the reflection of the reflective elements DI-DI5 is transmitted primarily.

[0067] Preferably, the light source 5 emits light at a wavelength invisible to the naked eye so as to limit interference with the light sources present in the cabin 101, while avoiding blinding the user. In this example, the light source 5 emits infrared radiation. Preferably, the light source 5 is coupled with a laser of a different wavelength. This advantageously allows the infrared radiation to be used at night and the laser for daytime use, thus enabling operation at any time. Preferably, the reflector 6 is formed from a mirror treated for infrared radiation.

[0068] By way of example, the transparent front support 61 comprises a transparent material within the wavelength range of the light source 5. Preferably, this is the infrared-transparent portion of a mirror treated for infrared at the wavelength of the light source 5. The materials used may, for example, be infrared-transparent plastics or plexiglass, or lead germanate or arsenic pentaselenium As2Se5-based glasses, or germanium sheets, or sintered glasses known as Irtran (MgF2, ZnS, etc.). By way of example, the reflective elements D1-D15 are produced by abstracting the surfaces external to the reflective elements D1-D15 onto the rear face of the infrared-treated mirror. The abstraction of the infrared-reflecting metal of the mirror can be achieved using a precision laser tracing, such as a fiber laser.Preferably, the size of the reflector 6 and the number of reflectors DI-DI 5 are dimensioned according to the optics of the light source 5 and the operating zone ZF. In this example, the reflector 6 has a surface area less than 50 mm by 50 mm, preferably on the order of 30 mm by 30 mm. As an example, the rear absorbing surface 62 can be made from chloroheptamethenes (cationic cyanine DD+, anionic cyanine AA-, neutral cyanine DA, or other). The absorbing surface 62 is configured to have low light reflection in the . wavelength range of the light emitted by the light source 5 so as to form the predetermined oriented patterns Ml-Ml 5 with strong contrast.

[0069] The reflector 6 is configured to be oriented so that the transparent front support 61 is facing the light source 5 and the transparent surface 22 so as to generate the predetermined oriented patterns M1-M15 from the reflective elements D1-D15.

[0070] It is self-evident that the diverging projection device 21 could natively be a diverging projector. For example, the diverging projection device 21 could be in the form of a screen where each pixel is an independent light source, in the form of a vertical cavity surface-emitting laser diode array (VCSEL), in the form of a LASER source combined with a holographic film containing the oriented patterns, or in the form of a LASER source combined with one or more diffractive films enabling the creation of the oriented patterns.

[0071] With reference to [Fig. 4], the reference image IM1 comprises several predetermined oriented patterns M1-M15. In this example, the reference image IM1 comprises 15 predetermined oriented patterns M1-M15 arranged in three rows and five columns. In this example, the predetermined oriented patterns M1-M15 are spaced the same distance apart in each row and column to simplify calculations. However, it is understood that this could be different. Each predetermined oriented pattern M1-M15 allows for the local definition of an oriented coordinate system, which is advantageous for determining the position vector vecR. Preferably, the predetermined oriented patterns M1-M15 are arranged in a grid.

[0072] Preferably, each predetermined oriented pattern M1-M15 is unique. In this example, each predetermined oriented pattern M1-M15 is in the form of a QR code, but it goes without saying that any pattern identifiable by its shape could be suitable. In practice, the position of each predetermined oriented pattern M1-M15 is perfectly known in the predetermined reference image IM1. In particular, the distance between the predetermined oriented patterns M1-M15, the divergence angles per column (vertical divergence angle), and the divergence angles per row (horizontal divergence angle) defined with respect to the projection axis X for each predetermined oriented pattern M1-M15 are known. The distance "De" between the predetermined reference image IM1 and the divergence point PDD is also known.

[0073] The receiving device 1 will now be presented.

[0074] The receiving device 1 is mounted on the tracking equipment 3 and is configured to receive the predetermined standard image IM1 which was projected by the transmitting device 2 into the operating zone ZF. Hereafter, the projection of the predetermined standard image IM1 at the level of the receiving device 1.

[0075] In detail, with reference to [Fig. 2], the receiving device 1 comprises a housing 10, which is fixed to or integrated directly into the tracking equipment 3, and a receiving area 11 for receiving at least a portion of the projected reference image IM1'. In this example, the receiving area 11 is planar and lies on a receiving plane PR. Preferably, the housing 10 is hermetically sealed against dust by the receiving area 11.

[0076] The receiving device 1 includes an optical sensor 14 for capturing a current image IM2 received on the receiving area 11. To this end, the optical sensor 14 is positioned inside the housing 10 so that its aperture angle covers the entire receiving area 11. The receiving area 11 forms a diffusive transmissive surface such that a projection on one face is visible on an opposite face, thus enabling capture by the optical sensor 14. The optical sensor 14 has high sensitivity to the wavelength of the light source 5, in particular, infrared. According to one aspect of the invention, the receiving area 11 is formed by a microlens surface.

[0077] Thus, the receiving area 11 allows the capture of a current image IM2 which corresponds to a portion of the projected reference image IM1' when the tracking equipment 3 is in the operating zone ZF. The projected reference image IM1' is distorted, relative to the predetermined reference image IM1, on the receiving area 11 according to the position and orientation of the tracking equipment 3. With reference to [Fig. 2], the optical sensor 14 has a capture axis X14, oriented towards the receiving surface 11. The point of intersection between the capture axis X14 and the receiving surface 11 forms an intersection point PL. The intersection point PI is positioned at the center of the current image IM2.

[0078] In this example, still referring to [Fig. 2], the receiving area 11 forms part of the housing 10, in particular, a rear portion. The receiving area 11 is opposite the transmitting device 2. The optical sensor 14 is fixed inside the housing 10 and oriented towards the receiving area 11.

[0079] In this example, the receiving device 1 further comprises a computing device 19 which is mounted in the housing 10. However, the computing device 19 could belong to the detection device 4 while being separate from the receiving device 1. The optical sensor 14 is connected to the computing device 19 so as to transmit to it in real time the current image IM2 formed on the receiving area 11.

[0080] According to the invention, the calculation device 19 is configured to, on the one hand, determine a deformation of at least one predetermined oriented pattern projected M1'-M15' in the current image IM2 and, on the other hand, determine a position vector vecR specific to the receiving device 1 with respect to the transmitting device 2. The vector of position vecR can then be provided to the S tracking system to enable a virtual, mixed or augmented reality application from the movements of the OP operator.

[0081] To implement the present invention, with reference to [Fig. 6], the process comprises steps consisting of: • Project the predetermined standard image IM1 by the transmitting device 2 towards the receiving device 1 in such a way that at least a portion of the projection of the projected standard image IM1' is received on the receiving area 11 of the receiving device 1, • Capture E2 a current image IM2 received on the receiving area 11, • Determine E3, a deformation of at least one predetermined oriented pattern Ml-Ml5 in the current image IM2, • Determine E4 a position vector vecR which is specific to the receiving device 1 and defined with respect to the transmitting device 2 from the determined deformation.

[0082] Steps E3, E4, which determine the deformation and the position vector vecR of the receiving device 1, are implemented in a preferred manner by the calculation device 19 and will now be detailed.

[0083] In this example of implementation, as illustrated in [Fig.5], the current image IM2 comprises four projected oriented patterns M9', M10', M14', M15'.

[0084] As illustrated in [Fig. 6], the deformation determination step E3 preferably comprises a distance determination substep E31, an angular position determination substep E32, and an angular orientation determination substep E33. Not all substeps are necessarily implemented. Preferably, the substeps of the determination step E3 are performed in parallel to limit processing time and reduce latency.

[0085] With reference to [Fig.6], the deformation determination step E3 preferably includes a substep consisting of detecting E31 a separation distance Da between the acquisition point Pa, located at the center of the current image IM2, and the divergence point PDD along the projection axis X.

[0086] To do this, the position of the projected oriented patterns M9', M10', M14', M15' in the current image IM2 is determined, for example. In practice, the projected oriented patterns M9', M10', M14', M15' are detected by an image processing algorithm, in particular, by pattern recognition. Since the projected oriented patterns M9', M10', M14', M15' are unique, this makes it possible to determine the portion of the projected reference image IM1' that is visible in the current image IM2.

[0087] Advantageously, with reference to [Fig.5] and [Fig.7], the spacing distances dl'-d4' between the oriented motifs can thus be determined by measurement projected M9', M10', M14', M15' in the current image IM2. Given that the spacing distances dl-d4 between the predetermined oriented patterns M9, M10, M14, M15 in the predetermined standard image IM1 and the standard distance De are known, a separation distance Da can be determined quickly and conveniently between the receiving plane PR and the divergence point PDD along the projection axis X.

[0088] Thanks to the diverging optics of the emitting device 2, the separation distance Da can be determined from the standard distance De, the separation distances dl-d4 between the predetermined oriented motifs M9, M10, M14, M15, and the separation distances dl'-d4' between the projected oriented motifs M9', M10', M14', M15'. For example, the separation distance Da is determined by the following formula, applying Thales' theorem: dl'a = , H nevertheless goes without saying that the distance The distance d4 Da could be measured differently.

[0089] With reference to [Fig. 6], the deformation determination step E3 preferably includes a substep consisting of determining E32 the angular position Pang of the current image IM2, and therefore the angular position of the intersection point PI, with respect to the projection axis X. In practice, in this example, the angular position Pang of the current image IM2, and therefore of the intersection point PI, is defined by two divergence angles measured in two orthogonal planes. In this example, with reference to [Fig. 4], the predetermined reference image has a reference point Pa located at the intersection of the diagonal lines of the quadrilateral formed by four predetermined oriented motifs M9, M10, M14, M15. It is understood that several reference points can be established.

[0090] With reference to [Fig. 8], a vertical cross-sectional view is shown along a first vertical plane PV passing through the projection axis X. A first straight line DR1 is defined passing through the projection of the acquisition point Pa and the divergence point PDD. A vertical divergence angle [3r] is determined between a projection of the first straight line DR1 in the first vertical plane PV and the projection axis X. The vertical divergence angle [3r] is determined practically since the vertical divergence angles [39, [310, [314,

[315] of the predetermined oriented patterns M9, M10, M14, M15 with respect to the projection axis X are known.

[0091] Similarly, with reference to [Fig. 9], a horizontal cross-sectional view is shown along a second horizontal plane PH passing through the projection axis X. A horizontal divergence angle ar is determined between a projection of the first line DR1 into the first horizontal plane PH and the projection axis X. The horizontal divergence angle ar is determined practically since the horizontal divergence angles a9, al0, al4, al5 of the predetermined oriented patterns M9, M10, M14, M15 with respect to the projection axis X are known.

[0092] In this example, the point of intersection PI and the projection Pa' of the reference point Pa coincide. When they do not, as shown in [Fig. 10], the method presented above allows us to determine the angles separating the projection Pa' of the reference point Pa and the projection axis X. The angles separating the projection Pa' of the reference point Pa and the point of intersection PI are then added to them in order to determine the divergence angles ar, [3r.

[0093] The polar position of the intersection point PI with respect to the projection axis X is thus known; that is, the angular position Pang of the current image IM2 with respect to the projection axis X is thus known (Pang = (ar; [3r]). Knowing the separation distance Da and the angular position Pang makes it possible to determine precisely the position of the receiving device 1 with respect to the transmitting device 2, in particular, with respect to the divergence point PDD.

[0094] The determination step E3 preferably includes a substep consisting of determining E33 the angular orientation OR1 of the current image IM2, and thus the angular orientation of the plane PR, with respect to the projection axis X. The angular orientation OR1 can be determined in different ways. In particular, a horizontal angle aorR can be determined in a horizontal plane PH ([Fig. 10]) and a vertical angle [3orR] can be determined in a vertical plane PV ([Fig. 11]).

[0095] With reference to [Fig. 2], the projection axis X of the transmitting device 1 is not parallel to the capture axis X14. The current image IM2 thus corresponds to the projected reference image IM1' distorted obliquely as illustrated in [Fig. 12]. The angular orientation OR1 can be determined, for example, by determining the distortion of a quadrilateral Qa defined between the centers of the predetermined oriented patterns M9, M10, M14, M15 into a projected quadrilateral Qa' defined between the centers of the projected oriented patterns M9', M10', M14', M15'. The calculation of the angular orientation can for example be carried out using knowledge of the Euclidean geometry of the quadrilateral formed by M9, M10, M14, M15 to deduce the equations in projective geometry which allow to analyze M9', M10', M14', M15' to deduce the angle parameters sought.It goes without saying that other methods based on the use of artificial intelligence can also be used.

[0096] The cumulative knowledge of the distance Da, the angular position Pang and the angular orientation OR1 makes it possible to determine (step E4) precisely the position of the receiving device 1 but also its orientation relative to the transmitting device 2. A position vector vecR is thus formed comprising the distance Da, the angular position Pang and the angular orientation ORL. The position vector vecR can be provided directly to the tracking equipment 3 to allow it to determine its position and its angular orientation.

[0097] In practice, determining the recession distance Da, the angular position Pang, and the angular orientation OR1 is computationally expensive and time-consuming. Therefore, with reference to [Fig. 6], to enable real-time operation without latency, the method includes a step E5 for determining the position vector vecR by correlation. In practice, the position vector vecR is determined from the current image IM2 and a previous current image IM2* for which a previous position vector vecR* has already been determined.

[0098] In other words, the position vector vecR is determined by analyzing the correlations between the current image IM2 and the previous current image IM2*. This significantly reduces computation time when the current images IM2* and IM2 are close together. Preferably, the correlation calculation is performed by an algorithm using Local Methods known to those skilled in the art. Preferably, if the current images IM2* and IM2 are far apart, the position vector vecR is determined conventionally by first determining the separation distance Da, the angular position Pang, and the angular orientation OR1 in the current image IM2. The resources of the computing device 19 are thus used sparingly.

[0099] Thanks to the invention, by way of example, if the tracking equipment 3 is a helmet 3, the operator OP located in the vehicle 100 simply needs to wear the helmet 3 to obtain a suitable display. Preferably, additional data is displayed on the helmet 3 according to the position vector vecR of the detection device 4. In one aspect, the external video V1 is also displayed according to the position vector vecR of the detection device 4. When the operator OP turns their head, the position and orientation of the helmet 3 change. This is detected by the detection device 4, which modifies the position vector vecR. The helmet 3 adapts its display to show the additional data, and in one embodiment, the portion of the external video stream VI corresponding to the direction in which the operator OP is looking.This advantageously allows the operator (OP) to observe the external scene (SC) of vehicle 100 while also receiving additional data to aid in navigation.

[0100] Advantageously, the detection device 4 is simple to implement. In particular, the receiving device 1 is lightweight and can be attached to the helmet 3 without causing discomfort to the operator. Furthermore, the transmitting device 2 can be easily mounted in the cab 101, and there is no need to position light markers or create a 3D reconstruction of the cab 101. The detection device 4 can thus be used universally in any type of vehicle. It goes without saying that the transmitting device 2 could be attached to the helmet 3 and the receiving device 1 on cabin 101.

[0101] Advantageously, the invention is usable in enclosed environments and may be subject to vibration, acceleration or attitude constraints, in particular in all types of vehicles, whether maritime, land or air.

[0102] The invention is presented in a fixed reference frame but it also applies to an orbital reference frame, in particular, an orbital station.

[0103] The invention advantageously allows tracking the position of an object or person in a dark or totally dark environment.

[0104] The invention advantageously allows for contactless tracking of the relative position between 2 mechanical parts in all degrees of freedom such as actuator position sensors or for example during the final docking / landing phase of a space capsule.

[0105] Furthermore, the S tracking system can also be used in other applications such as an autonomous vacuum cleaner searching for its charging station.

[0106] The invention has a low total mass and advantageously allows flexible use in multiple fields where weight is a constraint, for example in the field of body motion capture by combining transmitter / receiver on different parts of the body or in the space and aeronautical field.

Claims

Demands

1. Tracking system (S) comprising: • At least one tracking device (3) configured to be attached to an object to be tracked or a person to be tracked (OP), • at least one detection device (4) configured to detect the position and angular orientation of the tracking device (3), • Tracking system (S) characterized in that the detection device (4) comprises: • A receiving device (1), mounted in a datum (100) or on the tracking device (3), configured to receive a predetermined standard image (IM1) projected by a transmitting device (2) mounted on the other of the datum (100) or of the tracking device (3), the predetermined standard image (IM1) comprising at least one predetermined oriented pattern (M1-M15),• the receiving device (1) comprising: • at least one receiving zone (11) configured to receive at least a portion of the projection of the predetermined reference image (IM1) and • at least one optical sensor (14) configured to capture a current image (IM2) received on the receiving zone (11), • at least one computing device (19) configured to determine the deformation of at least one predetermined oriented pattern (M1-M15) in the current image (IM2) so as to deduce a position vector (vecR) which is specific to the receiving device (1) and defined with respect to the transmitting device (2) from the determined deformation.

2. A tracking system (S) according to claim 1, wherein the emitting device (2) emits the predetermined reference image (IM1) over a predetermined wavelength range, the optical sensor (14) is sensitive only in the predetermined wavelength range preferably, the predetermined wavelength range is not visible to the naked eye, preferably in the infrared.

3. Tracking system (S) according to any one of claims 1 to 2, wherein the receiving area (11) is in the form of a diffusive transmissive surface configured to receive, on a first face, at least a portion of the projection of the predetermined standard image (IM1), the optical sensor (14) being configured to capture the current image (IM2) on a second face opposite to the first.

4. Tracking system (S) according to any one of claims 1 to 3, wherein the detection device (4) comprises at least one emitting device (2), mounted on the other of the reference frame (100) or of the tracking equipment (3), configured to project the predetermined standard image (IM1) onto the receiving area (11) of the receiving device (1).

5. Tracking system (S) according to claim 4, wherein the emission device (2) comprises a divergent projection device (21).

6. Tracking system (S) according to claim 5, wherein the emitting device (2) comprises a transparent surface (22) configured to allow the projection of the predetermined standard image (IM1) to pass through.

7. Tracking system (S) according to any one of claims 5 to 6, wherein the diverging projection device (21) comprises a reflector (6) and a light source (5) projecting light onto the reflector (6), the reflector (6) comprising a plurality of reflective elements (D1-D15) configured to form the predetermined oriented patterns (M1-M15) of the predetermined standard image (IM1).

8. Tracking system (S) according to claim 7, wherein, the reflector (6) being configured to form the predetermined standard image (IM1) forward, the reflector (6) comprises a transparent front support (61) and a rear absorbing surface (62), the plurality of reflective elements (DI-DI5) being positioned between the rear absorbing surface (62) and the transparent front support (61).

9. Tracking system (S) according to claims 1 to 8, wherein the tracking equipment (3) is configured to display at least one additional data that is a function of the position vector (vecR).

10. Tracking system (S) according to any one of claims 1 to 9, wherein the tracking equipment (3) is a helmet (3).

11. Vehicle (100), in particular a light aircraft vehicle, the vehicle (100) comprising a cabin (101) configured to house at least one operator (OP), the vehicle (100) comprising at least one tracking system (S), according to any one of claims 1 to 10, configured to display an augmented, mixed or virtual outdoor scene (SC), enriched according to a position and angular orientation of the tracking equipment (3).

12. A method of using a tracking system (S) according to any one of claims 1 to 10, the tracking system (S) comprising at least one tracking device (3) configured to be attached to an object to be tracked or a person to be tracked and at least one detection device (4) configured to detect the position and angular orientation of the tracking device (3), the detection device (4) comprising a transmitting device (2) mounted in the reference frame, and a receiving device (1) mounted on the tracking device (3), the method characterized in that it comprises steps consisting of: • Projecting (E1) a predetermined standard image (IM1) by the transmitting device (2) towards the receiving device (1) so as to receive at least a portion of the projection of the predetermined standard image (IM1) on a receiving area (11) of the receiving device (1),• Capture (E2) a predetermined reference image (IM1) containing at least one predetermined oriented pattern (M1-M15), • Capture (E2) a current image (IM2) received on the receiving area (11), • Determine (E3) a deformation of at least one predetermined oriented pattern (M1-M15) in the current image (IM2), and • Determine (E4) a position vector (vecR) which is specific to the receiving device (1) and defined with respect to the transmitting device (2) from the determined deformation.

13. Method of use according to claim 12 in which the projection step (E1) and the capture step (E2) are carried out continuously.

14. A method of use according to any one of claims 12 to 13, wherein the deformation determination step (E3) comprises substeps consisting of: • Determining (E31) a separation distance (Da) between the receiving device (1) and the transmitting device (2) by means of the deformation of at least one predetermined oriented pattern projected (Ml'-M15') in the current image (IM2), • Determine (E32) the angular position (Pang) of the receiving device (1) relative to the transmitting device (2) by means of the deformation of at least one predetermined oriented pattern projected (Ml'-M15') in the current image (IM2) and • Determine (E33) the angular orientation (OR1) of the receiving device (1) relative to the transmitting device (2) by means of the deformation of at least one predetermined oriented pattern projected (Ml'-M15') in the current image (IM2).

15. A method of use according to claim 14, wherein the substeps of the deformation determination step (E3) are carried out in parallel.

16. Method of use according to any one of claims 12 to 15, comprising a step of determining (E5) the position vector (vecR) by correlation from the current image (IM2) and a previous current image (IM2*) for which a previous position vector (vecR*) has already been determined.

17. A method of use according to any one of claims 12 to 16, comprising a step of displaying by the tracking equipment (3) an augmented, mixed or virtual outdoor scene (SC), enriched according to a position and angular orientation of the tracking equipment (3).

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