FR3149698A1 - Pace control device displaying a light point in augmented reality - Google Patents

Abstract

Augmented reality glasses (1) for racing sports, comprising in particular a tall and narrow screen (11) arranged between the eyes (20) of the user (2). These glasses allow the user to see, superimposed on the real environment, a virtual luminous point (3) appearing as if projected on the ground (4) in front of him. The luminous point serves as a "hare": it progresses on the ground at a set pace predefined by the user, so that the latter only has to follow the point to respect said pace.

Description

Pace control device displaying a light point in augmented reality

The invention falls within the field of sports assistance solutions. More specifically, the invention relates to systems and methods enabling participants in running sports to control their pace.

1. Pace control in running sports

In the practice of running sports, in training or in competition, maximizing performance often relies on respecting a predetermined pace.

• Catégorie 1 : les méthodes utilisant une cible se déplaçant à l’allure voulue et qu’il suffit de suivre. La cible est par exemple un sportif spécialisé (appelé familièrement « lièvre »), un véhicule, ou encore une cible lumineuse projetée sur le sol depuis un véhicule. La cible peut également être figurée par un chenillard lumineux, disposé le long du parcours.
• Catégorie 2 : les appareils électroniques individuels dotés d’un récepteur GPS, tels les montres de sport, qui mesurent la vitesse du sportif et lui signalent le non-respect de l’allure par un affichage sur écran ou un message sonore.

But maintaining a precise pace is difficult. Athletes therefore commonly resort to assistance solutions, which can be classified into two categories:

• Category 1: methods using a target moving at the desired speed and which only needs to be followed. The target is for example a specialized athlete (colloquially called a "hare"), a vehicle, or a luminous target projected onto the ground from a vehicle. The target can also be represented by a luminous caterpillar, placed along the route.
• Category 2: individual electronic devices equipped with a GPS receiver, such as sports watches, which measure the athlete's speed and notify them of any failure to comply with the pace by displaying it on the screen or by sounding an audible message.

Category 1 methods are instinctive in use, but they are difficult to implement. Category 2 devices are simple to implement, but they are not very instinctive and therefore in practice not very effective when all attention is absorbed by the effort.

Patent FR3121612 describes a pace control device that is both easy to implement - because it is individual and portable - and instinctive to use - because it is based on the principle of tracking a target. It uses a laser to project a light point onto the ground that moves at the desired pace. The point thus plays the role of a small autonomous animal that runs in front of the user at the set pace. The user only has to follow it, as they would follow a human "hare". If the user runs too fast, they gradually catch up with the point. If they run too slowly, the point outdistances them. If they stop suddenly, the point continues on its way at the set pace.

The disadvantage of such a device is the power required by the projector, especially when used in direct sunlight.

The device that is the subject of the present invention is similar to that described in FR3121612. It is nevertheless distinguished by the fact that it does not project a luminous target on the ground in a real way, but virtually, through augmented reality glasses, thus solving the problem of the power of the projector.

2. Augmented reality glasses

The so-called "augmented reality" technologies are those that allow the realistic embedding of virtual objects in the image of a real environment. A well-known example is that of mobile interior design applications: we look at our living room via the camera of our mobile phone, and we can add a virtual sofa as a superimposition, for example.

In everyday language, "augmented reality glasses" are all transparent glasses equipped with an optical device that allows an image from a screen to be embedded in the visual field. This image is collimated, meaning that it appears to the user as if it is positioned far in front of them, which allows them to see it clearly without having to accommodate.

However, many models of augmented reality glasses are misnamed, because they actually only offer the “head-up display” function. This function allows an athlete, for example, to have physiological data such as speed and heart rate permanently present in their field of vision. In this case, there is no realistic integration of virtual objects into the real landscape, so no augmented reality strictly speaking.

• Les lunettes de première génération, utilisant des écrans larges et des miroirs semi-transparents. Elles ont l’avantage de permettre un large champ de vision (Field-of- Viewen anglais) et une région oculaire étendue (eyeboxen anglais), mais ont le défaut d’être encombrantes.
• Les lunettes des générations ultérieures, basées sur des technologies plus récentes (guides d’ondes, micro-projecteurs…). Elles sont moins encombrantes, mais ont le handicap d’être restreintes en termes de champ de vision et de région oculaire.

Schematically, we can divide augmented reality glasses into two groups:

• First generation glasses, using large screens and semi-transparent mirrors. They have the advantage of allowing a wide field of vision ( Field-of- View in English) and an extended ocular region ( eyebox in English), but have the disadvantage of being bulky.
• Later generation glasses, based on more recent technologies (waveguides, micro-projectors, etc.). They are less bulky, but have the disadvantage of being restricted in terms of field of vision and ocular region.

One of the objectives of the present invention is to propose augmented reality glasses that are not bulky, but nevertheless have a wide field of vision (with a particularity that we will explain) and an extended ocular region.

Schematic representation of a runner equipped with the device which is the subject of the invention, according to a particular embodiment and use of the invention.

Schematic side view of the device which is the subject of the invention, in section, according to a particular embodiment of the invention.

Schematic top view of the device which is the subject of the invention, in section, according to a particular embodiment of the invention.

Schematic view of two state-of-the-art devices.

Presentation of the invention

In the remainder of the document, paragraphs not beginning with the words “In a variant” or “In variants” relate to the particular embodiment and use shown in Figures 1, 2 and 3. On the contrary, paragraphs beginning with “In a variant” or “In variants” relate to other modes of use or embodiment of the invention.

The device (1) which is the subject of the invention is a pair of augmented reality glasses worn by a runner (2).

In variants, the device takes the form of a visor fixed to a helmet, or it is attached to a support held against the forehead by an elastic strap going around the head.

Through these glasses, the runner can see her surroundings through transparency, but also a virtual luminous point (3), appearing as if projected on the ground (4) at a distance (d) in front of her.

Just like in FR3121612, the light point serves as a “hare”: it moves at a set pace predefined by the runner, so that she only has to follow it to maintain the said pace.

The projection of the light point (3) into the runner's field of vision is accomplished by lighting up a single pixel (12) of the curved screen (11), part of the light coming from this pixel being reflected by the semi-reflecting mirror (10) towards the runner's eyes (20).

In variants, the luminous point (3) is replaced by a line or by any other virtual object, possibly involving the lighting of several pixels of the screen (11).

The horizontal distance (d) perceived by the runner between herself and the light point (3) is made independent of her head nods. To this end, the device according to the invention comprises an inertial unit (15) responsible for measuring the orientation of the device, and a microcontroller (13) responsible for choosing the correct pixel to light up according to said orientation.

The microcontroller (13) is also responsible for making the light point (3) move on the ground (4) at the speed set by the runner.

Description of the head-up display

To integrate the light point (3) into the user's field of vision, the device that is the subject of the invention is inspired by techniques used in certain existing augmented reality glasses, those that combine large screens and freeform semi-reflective mirrors .

• Deux écrans (30), d’une taille pouvant dépasser les cinq centimètres en largeur et hauteur, sont placés au niveau du front de l’utilisateur, au-dessus des yeux (20), parallèlement à la ligne des sourcils. Selon les modèles, les écrans font face au sol (schéma de gauche) ou sont inclinés vers l’arrière (schéma de droite).
• La lumière projetée par chaque écran est réfléchie vers l’œil de l’utilisateur par un miroir semi-réfléchissant concave.

There illustrates how these state-of-the-art glasses work:

• Two screens (30), which can be more than five centimeters in width and height, are placed at the user's forehead, above the eyes (20), parallel to the eyebrow line. Depending on the model, the screens face the ground (left diagram) or are tilted backwards (right diagram).
• The light projected by each screen is reflected towards the user's eye by a concave semi-reflecting mirror.

• il est impossible de déplacer les écrans pour qu’ils dépassent moins, sous peine de les mettre devant les yeux de l’utilisateur ou de heurter son front ; et
• il n’est pas souhaitable de réduire la taille des écrans, car les lois de l’optique entraînent alors une réduction du champ de vision (Field-of- Viewen anglais, la zone du miroir dans laquelle l’image projetée est visible) et de la zone de perception (eyeboxen anglais, la zone du miroir en face de laquelle doit obligatoirement se trouver la pupille).

The disadvantage of such devices is clearly apparent from the : the size of the screens (and therefore the mirrors) and their position make the whole thing protruding, and therefore unsightly, bulky and uncomfortable. However, unfortunately:

• it is impossible to move the screens so that they protrude less, otherwise they would be in front of the user's eyes or hit their forehead; and
• It is not desirable to reduce the size of the screens, because the laws of optics then lead to a reduction in the field of vision ( Field-of- View in English, the area of the mirror in which the projected image is visible) and the area of perception ( eyebox in English, the area of the mirror in front of which the pupil must necessarily be located).

• les lunettes sont moins protubérantes,
• le champ de vision verticale est étendu,
• le champ de vision horizontale est étroit.

Comme nous le verrons par la suite, ces caractéristiques originales sont précisément celles qui nous intéressent pour la présente invention.In the present invention, unlike the state of the art, the screen (11) is high (several centimeters) and narrow, so that it can be placed between the user's eyes. This configuration results in the following characteristics:

• the glasses are less prominent,
• the vertical field of vision is extended,
• the horizontal field of vision is narrow.

As we will see later, these original characteristics are precisely those which interest us for the present invention.

The screen (11) is arranged such that its light is projected towards the mirror (10) and not directly towards the user's eyes. Depending on the screen technology used, it may be necessary to add a mask to obscure the screen from the user's eyes.

In variants, the screen (11) is replaced by any type of display or light source, these alternative means constituting examples of light point projectors.

The semi-reflecting mirror (10) is a single piece and placed in front of the user's two eyes. It allows the user to see their environment through transparency, but also allows part of the light coming from the screen (11) to be reflected towards their eyes (20).

In variations, the device projects light into only one eye, or two separate mirrors are used, one for each eye.

Another desirable feature of the mirror (10) is that all the light rays coming from the same point on the screen (11), when reflected in the axis of the user's gaze, enter the pupil while being parallel to each other. This property, called collimation, allows the image projected into the user's eye to appear to him as formed at infinity, thus requiring no accommodation on his part to be perceived as clear.

The exact shapes of the screen (11) and the mirror (10) are the result of arbitration. The optical calculation of a projector and a free-form mirror, which the person skilled in the art performs using specialized software, rarely has a perfect solution. Indeed, any attempt to reduce an optical defect (aberration, partial collimation, etc.) generally reinforces another.

The microcontroller program (13) is responsible for switching on and off the pixels of the screen (11) so that the luminous point (3) appears as if projected onto the ground (4) at an angle (b) relative to the device.

For example, on the , the pixel (12) is lit. Its light is partially reflected by the mirror (10) towards the eye (20). As a result, the user believes he sees the light point at an angle (b) of approximately 40°.

Description of the augmented reality method

True augmented reality glasses are not limited to the "head-up display" function, but allow the realistic integration of virtual objects into the visual field. They therefore necessarily include a mechanism for compensating for the user's movements, so that when the user moves their head, the virtual objects move in their field of vision in the opposite direction in order to give the impression that they are stationary in the real world.

In the present invention, this motion compensation is only necessary in the vertical dimension; it is unnecessary in the horizontal dimension.

Indeed, when the user turns his head from right to left, we want the light point, virtually projected on the ground, to also turn from right to left to remain in front of the user's gaze. No motion compensation is therefore required in this case.

On the other hand, when the user nods, we want the light point to give the illusion of remaining on the ground at a constant distance (d) from the user. The lit pixel (12) must therefore “move” vertically on the screen (11) to compensate for the nodding movement.

This specific need (compensation of only vertical head movements) corresponds perfectly to the optical characteristics of the device which is the subject of the invention, namely an extended vertical field of vision and a narrow horizontal field of vision.

The inertial unit (15) transmits to the microcontroller program (13) the information necessary for calculating the orientation of the device in space, said inertial unit constituting an example of a means of knowing the angle (c) of the device relative to the vertical (which is 90° on the ).

If (c) is varied, the microcontroller program (13) acts on the angle (b) to keep the angle (a) between the direction of the light point (3) and the vertical constant. This has the effect of keeping the horizontal distance (d) between the user and the light point (3) constant when the user nods.

Description of the speed control means

• de connaître l’allure de l’utilisateur ; et
• de permettre la saisie depuis la montre :
  1. de l’allure de consigne (cette dernière pouvant être variable au cours du temps, par exemple fonction du relief), et
  2. de la hauteur (h) du dispositif par rapport au sol.

The Bluetooth interface (14) allows the device to be connected to a sports watch equipped with a GPS receiver, and thus:

• to know the user's pace; and
• to allow entry from the watch:
  1. of the set pace (the latter may vary over time, for example depending on the relief), and
  2. of the height (h) of the device relative to the ground.

• un récepteur GPS, qui constitue un autre exemple de moyen de connaître l’allure du dispositif ; et
• une interface utilisateur permettant la saisie de données, basée sur l’écran (11) et sur un bouton tactile situé sur une branche des lunettes, ladite interface utilisateur constituant un autre exemple de moyen de connaître l’allure de consigne et la hauteur (h).

In a variant independent of any external device, the device comprises:

• a GPS receiver, which is another example of a way to know the speed of the device; and
• a user interface for data entry, based on the screen (11) and on a touch button located on a branch of the glasses, said user interface constituting another example of a means of knowing the set point and the height (h).

From the speed of the device, the set speed and the height (h), the microcontroller program (13) prints to the angle (a) a calculated angular speed so that the light point (3) appears to the user as moving on the ground following the set speed.

The ground tilt introduces an inaccuracy that is advantageous to correct. For this purpose, the Bluetooth interface (14) allows the device to be connected to a sports watch, to receive the GPS altitude and to deduce the ground tilt.

In one variant, the device comprises a barometric altimeter which makes it possible to calculate the inclination of the ground by deriving the altitude, said altimeter constituting another example of a means of periodically knowing the inclination of the ground.

The microcontroller program (13) takes into account the ground tilt in calculating the angular velocity of the angle (a).

The mathematics used to calculate the angular velocity of angle (a) is the same as that presented in FR3121612.

Claims (5)

Augmented reality device (1) comprising:

1. a digital screen (11) or any other type of light point projector, characterized in that it measures several centimeters high and is arranged between the user's eyes;
2. at least one semi-reflecting mirror (10) arranged in front of at least one eye (20) of the user (2), characterized in that it allows:
   1. the user to see, through transparency, all or part of their environment; and
   2. to a portion of the light from the screen (11) being reflected towards the user's eye or eyes.

The device of the preceding claim, further comprising a microcontroller (13) responsible for switching on and off the pixels of the screen (11) so that the user has the illusion of seeing a virtual object (3) projected on the ground (4) at an adjustable angle (b) relative to the device. The device of the preceding claim, further comprising means (15) for knowing the angle (c) of the device relative to the vertical, and where, in the event of variations of (c), the microcontroller (13) acts on the angle (b) so that the angle (a) between the direction of the virtual object (3) and the vertical remains constant. The device of the preceding claim, further comprising means (14) for periodically knowing:

1. the appearance of the device;
2. a set pace; and
3. the height (h) of the device relative to the ground (4);

and where the microcontroller (13) dynamically varies the angle (a) so that the virtual object (3) appears to the user (2) as moving relative to the ground (4) at the set speed. The device of the preceding claim, further comprising a means (14) for periodically knowing the inclination of the ground (4), and where the microcontroller (13) takes this into account in the calculation of the angle (a) to reinforce the impression that the virtual object (3) is moving relative to the ground (4) according to the set speed.