Apparatus and method for mapping a visual scene onto a projection surface - Patents.com

Abstract

An apparatus and method for mapping a visual scene onto a projection surface is provided. The system includes a visual field sensor configured to measure a user's visual field associated with a specific visual task in the user's visual field. The visual field sensor is further configured to determine the user's gaze direction during the specific visual task. The system includes a head orientation and / or position sensor configured to measure the orientation and / or position of the user's head relative to the visual field during the specific visual task. The system is configured to enable calculation of the orientation of the user's eyes relative to the user's head based on the user's gaze direction and the orientation and / or position of the user's head to determine a distribution of optical parameters in a projection plane between the user's visual field and the retina.

Description

[Technical field]

[0001] Embodiments relate to concepts for customizing optical aids and their use, and in particular to systems and methods for determining the distribution of optical parameters in a projection plane. [Background technology]

[0002] Presbyopia is a condition that manifests as a deterioration in the eye's lens' ability to accommodate with the natural aging of the eye. Typical onset is above the age of 35. The condition progresses gradually until the ability to accommodate ceases completely. Multiple solutions have been developed throughout human history. Significant progress has been achieved in recent decades. The most common treatment is reading glasses used for close tasks. Reading glasses artificially increase the eye's range of accommodation. Users who also require vision correction for distance vision (e.g., due to myopia) must wear at least two pairs of glasses and switch between them based on the task required. This can be inconvenient.

[0003] Thus, a user can use glasses with multiple optical powers. This can be achieved by geometrically separating zones of different optical powers, as in the case of bifocal and trifocal glasses. The user of such glasses has the option to select the required refractive index by looking at the object of interest through the required zone. The position of each zone is selected based on a natural correlation between the task and the eye angle. Near vision tasks are typically performed by aligning the object with the lower gaze zone (reading, smartphone, etc.). Therefore, the higher power is typically placed in the lower zone (near zone). This leaves the upper zone reserved for far vision tasks (distance zone). In trifocal glasses, an intermediate zone exists between the near and distance zones to support vision in the mid-range. In addition to this, there are progressive addition lenses. Progressive addition lenses do not have a visible line separating each optical power zone, but instead have a smooth transition from one zone to another.

[0004] Such spatially separated corrective solutions are neither natural nor intuitive for the human eye. Therefore, the user must adapt to them. In particular, consideration is given to adapting the zones to the requirements of a particular user, in order to minimize the possibility of disrupting the user's viewing habits that develop throughout life. Therefore, the corrective solutions must preferably be adapted to the individual visual behavior. Such customization may include optimal mapping of refractive power and / or other optical parameters to the surface of an optical aid, such as glasses. Furthermore, the terms customization, individualization, and personalization are used interchangeably. In this specification, an optical aid may also be referred to as a visual aid or a visual aid. An optical aid may be an additional / enhancement optical element to the natural visual system of the eye, such as glasses, contact lenses, augmented or virtual reality headsets, retinal or other visual implants, corneal inlays, etc. An optical aid may be a replacement for a natural element of the visual system, such as an intraocular lens as a replacement for the crystalline lens. An optical aid may be a modification of an element of the visual system, such as a refractive surgery performed on the cornea or crystalline lens. The optical aid may be a combination of multiple optical aid forms.

[0005] While it is not essential for customization, it is important, if not essential, to understand the lens position in the finished optical aid relative to the user's eyes. In addition, it is important, if not essential, to understand the user's visual behavior, including how the user typically positions objects (associated with a particular visual task) within their field of view, and how the user positions their body, head, and eyes relative to objects associated with a particular visual task.

[0006] An exemplary visual task is reading. Handheld media (e.g., books or electronic devices) are typically positioned so that the head is approximately half-tilted relative to the object, while the remaining required tilt angle is accommodated by the eyes themselves. The difference between the head tilt angle and the eye tilt angle varies from person to person, as does the positioning of the media within the field of view.

[0007] Therefore, understanding the preferred angle between the user's gaze / eyes / head is very important in order to better customize the distribution of visual zones in the optical aid.

[0008] Optical aids may have to be optimized with respect to a user's specific preferences. Summary of the Invention [Problem to be solved by the invention]

[0009] Such needs may be met by the subject matter of the claims. [Means for solving the problem]

[0010] According to a first aspect, a system for determining a distribution of optical parameters in a projection plane is provided. The system comprises a field of view sensor. The field of view sensor is configured to measure a user's field of view related to a specific visual task, for example to identify objects in the user's field of view related to the specific visual task. The field of view sensor is further configured to determine a gaze direction of the user during the specific visual task. The system comprises a head orientation and / or position sensor. The head orientation and / or position sensor is configured to measure an orientation and / or position of the user's head relative to the field of view during the specific visual task. The system is configured to enable calculation of an orientation of the user's eyes relative to the user's head based on the user's gaze direction and the orientation and / or position of the user's head to determine a distribution of optical parameters in a projection plane between the user's field of view and the retina.

[0011] The optical parameter can be the distance to an object relevant to the visual task. This can be mathematically linked to the refractive power of the optical aid. The optical parameter can be the luminance of an object of the visual task. This can be linked to the pupil size of the eye during a particular visual task. The optical parameter can be the spectral content of light emanating from an object relevant to the visual task. The optical parameter can include the angular distribution of the light field detected from the field of view. The optical parameter can include the polarization state and degree of polarization of the light detected from the field of view.

[0012] Thus, instead of directly monitoring the user's eye movements and looking in a direction for a specific visual task, the user's eye movements relative to the head movements can be calculated from the head and gaze angles. Directly monitoring eye movements must be performed in a familiar setting of the user's daily routine, and may require sufficient statistics accumulated over long-term continuous measurements to obtain reliable estimates. However, long-term monitoring of the user's eye movements can be inconvenient due to the cumbersomeness of existing eye tracking solutions, alignment requirements, and battery consumption of the device. This can be avoided by the system according to the first aspect.

[0013] The field of view sensor can be configured to measure at least one parameter of the field of view. The parameter of the field of view can be measured in at least one dimension. For example, the parameter can be resolved into a polar coordinate system along at least one rotation angle, such as pitch angle (tilt, rotation about the horizontal axis of the sensor), yaw angle (rotation about the vertical axis), or roll angle (rotation about the lateral axis). Additionally or alternatively, the parameter of the field of view, i.e., the field of view parameter, can be resolved into a Cartesian coordinate system along a position coordinate.

[0014] Additionally or alternatively, the field of view sensor can be configured to measure field of view parameters in two or three dimensions, which can be at least one of the following: distance to objects in the field of view, intensity, spectral characteristics, polarization parameters (e.g., degree of polarization, Stokes parameters), and / or light field parameters of light emitted and / or reflected by objects in the field of view.

[0015] The field of view sensor can be further configured to allow for the determination of the gaze direction. This can be achieved in multiple ways. In one simple example, the field of view sensor can include or be a directional sensor. This directional sensor is attached to the glasses, facing forward and aligned with the optical axis of the glasses. The directional light sensor can be optical or light based. The directional sensor can also be any kind of directional distance sensor, for example, radar or lidar. The directional sensor can be movable with the glasses. The system can also include a head orientation sensor aligned with the glasses or other equipment. The system can be mounted thereon. Due to the natural head movement of the user, the directional sensor can be able to sample the environment in different directions. In combination with the head orientation sensor, the system can obtain an angle resolved image of the lighting conditions.

[0016] When a user is reading content on a handheld electronic device (e.g., a smartphone or tablet) with an illuminated screen, the directional sensor can be configured to detect light emitted by the device. Due to head dynamics, the directional sensor can be configured to detect light emitted from the device from time to time. The corresponding tilt angle α indicates the gaze direction. At the same time, during the reading activity, the head orientation, e.g., the head pitch angle, can be equal to β on average. The angle β can typically be lower in absolute value than the gaze angle α. The eye angle can be found as α-β. In this way, by knowing the type of visual activity, the eye angle can be estimated from the gaze and head orientation depending on the subject of the visual activity.

[0017] The visual field sensor can use a directional sensor, i.e. a directional sensor aligned with the optical axis / axis of the glasses. Due to natural head movements combined with measurements of the head / device orientation sensor, a map of distances to surrounding objects can be created. This can also be performed by the processing unit, as introduced below. By knowing the type of visual task a priori, the user can identify the handheld device as an object located close to the user (e.g., by user input). Further analysis can be performed in a similar manner to the example above.

[0018] The directional sensor can be tilted downwards with respect to the optical axis of the glasses to collect more measurements from the handheld media. For example, for a typical gaze tilt during reading of a handheld media of 30°, it is typically advantageous to tilt the directional field of view sensor downwards at the same angle to increase the sampling density from the subject of visual activity (handheld media or device). This can be achieved by permanently pointing the field of view sensor downwards. Alternatively or additionally, the system can comprise at least two directional sensors. At least one of them can be pointed downwards by the required angle. The system can be configured to enable or disable the directional sensor based on the identified visual activity.

[0019] Alternatively or additionally, the system can be configured to change the orientation of the visual field sensor to optimize the density of data based on the visual activity / task being performed by the user. In one embodiment, the visual field sensor can be configured to sample the parameters of the visual field at different orientations using a scanner. Based on the identified activity, the density of the sampling can be adjusted to obtain more samples of the object of interest, such as the subject of the visual activity.

[0020] A particular visual task can be understood as a vision-related activity that is characterized by a relative consistency of the visual field, such as reading, writing, driving, using a handheld device, or watching television. A visual task can also be pre-selected during or after the performance of the task.

[0021] The system can be configured to perform measurements of a single activity, such as reading. In this case, the object captured by the visual field sensor can be known in advance as the reading medium / material (such as a book or a handheld device). Thus, the majority of the sensor measurements relate to the reading material. In this example, processing of the data can be performed using simple statistical methods aimed at discarding outliers, in particular using robust statistical processing. In a similar manner, the measurements of the head orientation sensor can be correlated to the head orientation of the reading activity. Thus, processing can be performed in a manner of reduced complexity, such as simple statistical methods.

[0022] The system can include user input, which allows a user to indicate a visual task and / or an object associated with the visual task. User input can be performed on the device itself or on an associated computing device, such as a mobile phone or mobile computer. Additionally, user input can be performed on a cloud interface.

[0023] The visual field sensor can be configured to identify objects in the user's visual field that are associated with a particular visual task, and further, the visual field sensor can be configured to derive a gaze direction of the user relative to the identified objects in the visual field.

[0024] The system may include a context sensor, which may be configured to measure at least one parameter related to an activity of the user.

[0025] The system may further comprise a statistical classifier. The statistical classifier may be part of the processing unit, as described below. The statistical classifier may be configured to identify a visual task and / or object of the user's visual field from at least one of the visual field sensor, the head orientation and / or position sensor, and the context sensor. The identification may be performed at least partially automatically, for example using methods of statistical analysis / modeling.

[0026] The context sensor can be adapted to measure at least one context parameter related to the user's visual task. The context sensor can be adapted such that the system can derive statistical characteristics of the measured context parameters and compare them with statistical characteristics of signature context parameters related to the particular visual task. These statistical characteristics of the measured context parameters can be stored on or in the memory unit. The memory unit can also include the (pre-stored) signature statistical characteristics of the context parameters.

[0027] The system may further comprise a memory unit such as the memory unit mentioned above. This memory unit may be configured to store a head orientation and / or position, in particular a head angle, and a gaze direction, in particular a gaze angle, both related to a particular visual task. The head angle and the gaze angle may be stored during the performance of the particular visual task. The stored head orientation and / or position, in particular the stored head angle, and the stored gaze direction, in particular the stored gaze angle, may form a basis for determining a distribution of optical parameters in a projection plane between the user's visual field and the retina.

[0028] As a result, information regarding the distribution of optical parameters can be stored for later customization of optical aids for the user.

[0029] The system may further comprise a processing unit, which may be configured to determine a corresponding difference between the head orientation and / or position, in particular the head angle, and the gaze direction, in particular the gaze angle, and to determine a distribution of the optical parameters in a projection plane between the user's visual field and the retina.

[0030] The processing unit may be configured to determine a corresponding difference between the stored head orientations and / or positions, in particular head angles, and the stored gaze directions, in particular gaze angles, and to determine a distribution of optical parameters in a projection plane between the user's field of view and retina.

[0031] As a result, the optical aids for the user can be quickly customized after simple use of the system.

[0032] The processing unit can be connected to a memory unit. Furthermore, the memory units can be interleaved so that the processing unit can have its own integrated memory. Calculations can then be performed on the processing unit immediately or after a measurement session has been performed by the user. Thus, the user can be offered a quick adaptation / customization of his optical aids. Alternatively, the results can be stored with the option of collecting data for a longer evaluation of the user to provide an optimal customization of the optical aids.

[0033] These signature statistical properties related to the context parameters can be provided to the memory unit in advance, during or after the measurement of the context parameters. Thus, the memory unit and the context sensor can directly communicate with each other. This also applies to the processing unit, which can perform a correlation / comparison of the respective statistical properties.

[0034] The context parameters can be metrics of the user's movements, e.g., intensity of movement, amount of acceleration, direction of acceleration, amount and / or direction of rotation. The context parameters can also be lighting conditions, such as light intensity, direction, spectral content, presence of flicker and its frequency. The context parameters can be the position and orientation of the user, estimated by positioning and navigation methods, such as global and local positioning systems, wireless signal quality, etc. The context sensor can include an imaging system configured to acquire images of the user's surroundings and / or the user himself, as well as images of the field of view.

[0035] The context sensor can be a wearable camera. Alternatively or additionally, the camera is attached to the outside of the user's body. For example, the camera can be a camera of a device such as a mobile phone, a handheld computer, a tablet, a laptop, and a desktop computer. Or the camera can be a separate camera module placed on a desktop.

[0036] The context sensor may be a microphone configured to measure acoustic vibrations (sounds) around the user. Intensity, spectral content, and patterns may be used as context parameters. The context sensor may comprise a detector of electromagnetic radiation in the radio frequency range, allowing detection of signals from wireless communication emitters. For example, GSM, GPS, WiFi, Bluetooth radio waves may be used.

[0037] Additionally or alternatively, the system can be configured to detect signals of wireless emitters. The system can include an electromagnetic receiver configured to receive the signal. Such signals can be transmitted using electromagnetic waves (radio waves and / or light) and / or mechanical waves. The system can be equipped with an electromagnetic transmitter configured to transmit a signal to request additional information from surrounding devices. For example, a car's Bluetooth communication module can be used to identify driving activities. Additionally, the radiation of a smartphone's or tablet's Bluetooth module can be used to identify activities using a handheld device. Bluetooth modules typically broadcast a numeric (MAC address) and text identifier of the device. Thus, a database can be used to associate a device with a particular activity. For example, a car can broadcast a text identifier of the car model and manufacturer. Meanwhile, a smartphone can broadcast by default the phone's manufacturer and model. This can be associated with the activity. Additional information such as the device's identifier or the device's location or device type can be requested by the device by transmitting a request signal by the transmitter. Characteristics of the signal such as signal strength, signal delay, signal reflection, etc. can be used to improve classification of visual activities.

[0038] The context sensor may comprise a positioning / location sensor configured to provide information about the user's position and movement (speed, acceleration and trajectory). The positioning sensor may be one of the global positioning systems, such as GPS, GLONASS, GNSS, or a local or indoor positioning system. The indoor positioning system may be implemented by scanning wireless devices around the system, such as WLAN or Bluetooth radiating devices. The classifier may use the user's position and movement to classify a corresponding activity, such as the user walking. Combining this information with motion data indicative of a characteristic walking pattern may allow the classifier to conclude that the user is walking.

[0039] The field of view sensor and the head orientation / position sensor can also be used as context sensors.

[0040] A context parameter measured by a context sensor can be used in combination with at least one other context parameter different from the first one and measured by the same or a different context sensor for automatic identification of a visual task. At least two context parameters from the same or different context sensors can be used together to identify an activity / task or an object associated therewith.

[0041] Visual tasks can be automatically identified based on at least one of visual field parameters measured by a visual field sensor, characteristic point clouds, head orientation, movement patterns, lighting conditions, and context sensor readings. Activity / task identification, or classification, can be performed using statistical analysis of data, for example by machine learning methods using classifiers trained based on data measured during known / labeled or tagged activities. Such methods can include logistic regression, naive Bayes classifiers, Fisher's linear discriminant, support vector machines, k-nearest neighbors, decision trees, random forests, neural networks, or other known methods or combinations of methods.

[0042] The field of view sensor data can be used in its original dimensionality and resolution, or can be reduced to improve the stability of the underlying classification algorithm. For example, a field of view sensor utilizing a directional sensor can build a map of objects in the field of view. Handheld reading materials, such as books, tablets, and smartphones, can be recognized as a cloud of points forming a plane of known size in a two- or three-dimensional map. When an object of matching shape and size, accompanied by a characteristic head tilt, is detected, the reading of the handheld media can be detected.

[0043] Additional sensors can improve the accuracy and specificity of the classification. For example, a sensor capable of detecting the polarization state of reflected light can be used to distinguish a liquid crystal-based display of a handheld electronic device from a paper-based medium such as a book. Additionally or alternatively, a directional sensor can be used to detect light emitted by the electronic device to accomplish the same. Additionally or alternatively, a motion sensor can be configured to detect head movement associated with reading to distinguish reading of handheld material from viewing of media content such as a movie on a handheld electronic device. Additionally or alternatively, a light sensor capable of detecting temporal changes in light caused by dynamic media content such as a movie can be used to enable distinction between reading and viewing activities.

[0044] The system may include a database of original or statistically processed measurements performed during known activities / tasks. Unknown activities / tasks may then be identified by comparing the measurements with those from the database. In a similar manner, identification of objects within the field of view may be performed automatically using statistical analysis / modeling methods. A database of signature measurements of known objects may be constructed. Further object identification may be performed by comparing the measurements of unknown objects with those of known objects stored in the database.

[0045] A user's field of view can be defined as the range of the user's vision. The user can be a patient or wearer of an optical aid, such as lenses, glasses, or any person undergoing correction or replacement of optical elements of the eye. An optical aid can also be a device whose primary purpose is not to compensate for visual insufficiency, but to enhance vision with elements beyond the capabilities of normal human vision. For example, such enhancements can be provided by virtual / augmented / mixed reality headsets or smart glasses, which modify the normal field of view, such as by adding artificial objects to the field of view, to provide special functions, such as displaying elements of a graphical user interface, highlighting objects in the field of view, etc. It is understood that such devices can still provide compensation for myopia, hyperopia, presbyopia, and other vision defects.

[0046] Gaze direction is defined by the direction from the common coordinate axis to the point seen by the eyes. Gaze direction can also be understood as gaze angle. In two-dimensional vision, if the visual task / activity can be assumed to be symmetrical, the common coordinate axis is the horizontal plane and the gaze angle is defined by a single pitch angle. The gaze angle can be composed of the head tilt angle (head pitch angle) and the eye tilt angle relative to the head angle.

[0047] The gaze direction / angle can be derived from the position of the object relative to the visual task in a common coordinate system, which can be a spherical coordinate system, which can have its origin at the base of the user's nose or another point.

[0048] The projection plane can be defined as a surface related to the function of the optical aid. For example, the projection plane can define a surface on which the optical aid to be used later is placed relative to the user's eye. The projection plane can be defined inside the volume of the optical aid as well as outside it. The projection plane can be a plane, a spherical surface, a toric surface, or any other surface between the user's retina and the field of view. The surface can be virtual / imaginary, for example, not associated with a real surface.

[0049] For example, the projection surface can be located outside the eye, if it is the spectacle surface where the lenses of the glasses are located. Or the surface can be the screen surface or optical surface of a virtual / augmented / mixed reality headset or glasses. It can then be fixed to the head coordinate system. The projection surface can also be located on the surface of the eye or inside the eye. This is the case for contact lenses or ophthalmic implants. The projection surface on the surface of the eye can be linked to the head coordinate system. On the other hand, the user's eye can move relative to the projection surface. This is the case for segmented bifocal or multifocal contact lenses. These stay in place even if the user's eye moves.

[0050] In one example, the contact lens as well as the ocular implant can move with the eye. The projection plane of the eye is fixed in the ocular coordinate system. A separate coordinate system can be used for each eye. Thus, the projection plane can be separate for each eye.

[0051] Furthermore, the projection process can be applied equally to eye-centered projection planes as well as head-centered projection planes.

[0052] In one example, the projection can take into account the individual characteristics of the user. These can include the shape and parameters of the eye structure, such as interpupillary distance, face / nose shape that can affect the position and angle of the eyeglass plane on the head, corneal curvature, range of pupil sizes, lens position, eye length or other dimensions.

[0053] Additionally or alternatively, the projection can incorporate further optical parameters of the user's eye that may be affected by the field of view: these can include rotation of the eye in the socket, adjustment of pupil size to the illumination level of the field of view, accommodation of the crystalline lens to focus the field of view, opening and closing of the eyelids.

[0054] The projection can be performed by ray tracing, where the path of light from an object in the field of view is traced based on the physical rules of light propagation. Preferably, light can be traced from the object until it reaches the user's retina. The light propagation from the object through the projection surface on its way to the retina can define the trajectory of the object on the projection surface. The projection can be formed by the light reaching the retina and forming an image on the retina.

[0055] The projection can be performed by a simplified method of mathematical and geometric transformations.

[0056] The mapping can be performed by geometric projection, i.e. relating the coordinates of the visual scene to the coordinates on the projection surface. For example, the position of the center of the smartphone display in the field of view can be converted to the position of a point in the eyeglass plane. Additionally or alternatively, limiting optics can be considered for the mapping. For example, the pupil size can affect the active area of ​​contact lenses, corneal implants, and / or intraocular lenses. If the pupil is constricted, light can reach the retina only from the central zone of the visual aid. On the other hand, when the pupil is dilated, the aperture of the visual aid increases and the peripheral optical zone of the lens is engaged. This relationship can be considered for customization of multifocal lenses whose refractive power changes depending on the distance from the center. For example, a user can use far vision outdoors with fully functioning eyelids, while near vision can be used indoors with relatively limited lighting. For both near and far activities, light passes through the central zone. Thus, a mapping with a constricted pupil can generate a mix of near and far vision (and the corresponding refractive power) in the central zone of the visual aid. Near-field activity associated with limited illumination can also be mapped onto concentric peripheral zones.

[0057] In this case, customization can be achieved by positioning optics that promote distance vision in the center, optics that match the constricted pupil conditions in outdoor settings, and optics that promote near vision in the periphery so that the near zone opens when the pupil dilates in low lighting conditions.

[0058] The customization can take into account the performance of the eye's optical system and the tolerance of defocus based on the shape of the eye. When the pupil constricts, the depth of focus can be increased. This can increase the range of distances that are formed in focus on the retina. Therefore, the requirements for the accuracy of the refractive power in the central zone of the visual aid can be lower than in the peripheral zone.

[0059] The mapping can combine measurements performed during multiple visual tasks / visual activities, assuming the user performs the measurements continuously, effectively combining typical everyday visual tasks.

[0060] The system can be a head-mounted wearable adapted to be worn by a user. In particular, the wearable can be a single module comprising all elements or sensor devices / units of the system. Thus, the field of view sensor and the head orientation and / or position sensor can be in the same housing.

[0061] Therefore, it is expected that the system will become more compact and consume less power.

[0062] The coordinate systems of each head orientation and / or position sensor and each field of view sensor can be aligned, so that coordinate transformations can be avoided, so that calculation steps can be reduced.

[0063] The coordinate system of each head orientation and / or position sensor and each visual field sensor may be the same or have the same reference point, so that only rotational information may be required to transform one into the other.

[0064] The field of view sensor and the head orientation and / or position sensor may be separate from each other.

[0065] As a result, the system can be provided in a modular fashion. For example, the visual field sensor can be operated or stored on a desk, shelf, board, or other storage location. Alternatively, the head orientation and / or position sensor can be head-mounted. Thus, the system can be provided in this modular fashion in order to avoid having bulky equipment on the head.

[0066] In a modular implementation of the system, the field of view sensor may be mounted on a different body part of the user than the head, for example the torso, whereas the head orientation and / or position sensor may be mounted on the head.

[0067] The measurements of the visual field sensor and the head orientation and / or position sensor can be synchronized in order to correctly link the head orientation and / or position to the visual field object. Synchronization can be performed by triggering or reading the measurements of both sensors at the same time, or in real time of the measurements within a predefined time, which can be (negligibly) small. Synchronization can be performed by recording the measurements of both sensors separately, but using information that can link the recorded measurements to time. For example, in a modular implementation, the visual field sensor and the head orientation and / or position sensor can be equipped with on-board clocks that can be related to a common point in time. The measurement data is recorded with a corresponding timestamp. In a processing stage, the measurements of both sensors can be linked to a common time system.

[0068] Context sensors are similar: they can also have independent clocks that can be synchronized in real time with other sensors or can be related to a common point in time.

[0069] The head orientation and / or position sensor may be coupled to the field of view sensor. The head orientation and / or position sensor may be adapted to provide position information of the field of view sensor and to convert from the coordinate system of the head orientation and / or position sensor to the coordinate system of the head orientation and / or position sensor. The conversion may be performed by the processing unit. Thus, the processing unit and the head orientation and / or position sensor may communicate with each other. This communication may be directly via a cable or indirectly via a communication means such as an antenna system driven short-range communication system such as Bluetooth or a wireless local area network (WLAN). Thus, the head orientation and / or position sensor may have an interface for connecting to a standard WLAN device. This interface may be shared by the head orientation and / or position sensor and / or the processing unit. The location of the processing unit may be in a single device together with at least the head orientation and / or position sensor. The field of view sensor may also be located in a single device. However, the processing unit may also be provided as a separate unit. For example, the processing unit may be provided via a network on an (external) server or via a cloud. Thus, processing by the processing unit may be performed on a device that is in communication only with at least one of the other elements of the system, such as an interface of the system for communicating or connecting a communication means to the system.

[0070] The projection surface may be associated with and / or coupled to an optical aid.

[0071] For example, the projection plane can be a plane on which an optical aid is subsequently placed or used. Thus, the projection plane can be the plane of the optical aid. The optical aid can be, for example, glasses, a lens, or the surface of an eye.

[0072] As a result, the refractive power and pupil diameter at a particular distance from the user's eye can be taken into account.

[0073] According to a second aspect, there is provided a use of the system according to the first aspect. A distribution of optical parameters on a projection surface is used for customizing an optical aid. The optical parameters can be at least one of refractive power, pupil diameter, depth of focus, spectral content of light, angular distribution of light, and polarization state of light. The distribution of optical parameters can include a distribution of optical parameters on the projection surface.

[0074] The distribution of optical parameters on the projection surface that is subsequently used for optical aids can include a combination of both pupil diameter and refractive power, so that the lighting and power requirements of an individual can be taken into account simultaneously.

[0075] The pupil diameter / size can be estimated from lighting conditions such as light intensity and spectral content using empirical formulas and / or models. Such formulas can include personalized coefficients as well as other parameters of the environment. The models can be general or personal. The pupil diameter / size can be further used to calculate the depth of focus. The depth of focus can be used to optimize the customization of optical aids.

[0076] If several activities are recorded that require various refractive powers with different focal depths, a combined solution can be found by combining refractive power and focal depth. For example, activity A is performed at a distance of 1 m with bright lighting. This results in a refractive power requirement of 1 D and a focal depth corresponding to a constricted pupil that can be 0.5 D. The range of refractive powers is therefore 0.75-1.25 D. For example, activity B is performed at a distance of 1.25 m in low lighting, so the required refractive power is 0.8 D and the focal depth corresponding to a constricted eye is approximately 0.1 D. The range is therefore 0.75-0.85 D. The customization of the optical aids should be able to provide optimal vision for most visual activities. The acceptable range of powers is therefore 0.75-0.85 D. This meets the requirements of both activities A and B.

[0077] According to a third aspect, a method for determining a distribution of optical parameters in a projection plane is provided. The method includes measuring, by a field of view sensor, a visual field of a user related to a particular visual task. This may include identifying, by the field of view sensor, an object related to the particular visual task in the visual field of the user. The method further includes determining, by the field of view sensor, a gaze direction of the user during the particular visual task. The method further includes measuring, by a head orientation and / or position sensor, an orientation and / or position of the user's head relative to the visual field during the particular visual task, for example, a user's head angle related to the gaze angle during the particular visual task. The method may include enabling a calculation of an orientation of the user's eyes relative to the user's head based on the gaze direction of the user and the orientation and / or position of the user's head to determine a distribution of optical parameters in a projection plane between the user's visual field and the retina. For example, the method may further include enabling a calculation of a corresponding difference between the head angle and the gaze angle to determine a distribution of optical parameters in a projection plane between the user's visual field and the retina.

[0078] According to a fourth aspect, there is provided a computer program product comprising program code portions for performing the method according to the second aspect, when the computer program product is executed on one or more processing units.

[0079] According to a fifth aspect, there is provided a computer program product according to the third aspect stored on one or more computer readable storage media.

[0080] According to a sixth aspect, there is provided an optical aid. The optical aid may be an adjustable optical aid. The optical aid may be / is adjustable based on the method according to the third aspect or using the system according to the first aspect.

[0081] Even though some of the above aspects are described with reference to a system, they may also be applied to a method, and similarly, aspects described above in relation to a method may be applicable in a corresponding manner to a system.

[0082] It will be apparent to those skilled in the art that the statements made herein may be implemented using hardware circuits, software means, or a combination thereof. The software means may relate to a programmed microprocessor, or a general computer, an ASIC (Application Specific Integrated Circuit), and / or a DSP (Digital Signal Processor).

[0083] For example, the sensor units herein, such as head orientation and / or position sensors, visual field sensors, processing units, and context sensors, may be implemented in part as a computer, logic circuit, Field Programmable Gate Array (FPGA), processor (e.g., microprocessor, microcontroller (μC), or array processor) / core / Central Processing Unit (CPU), FPU (Floating Point Unit), NPU (Numeric Processing Unit), ALU (Arithmetic Logical Unit), coprocessor (additional microprocessor to support the main processor (CPU)), GPGPU (General Purpose Computation on Graphics Processing Unit), multi-core processor (for parallel computation such as performing operations simultaneously on multiple main processors and / or graphics processors), or DSP.

[0084] Moreover, even if the details described herein are described as methods, it will be apparent to one skilled in the art that these details may be implemented or realized in a suitable device, system, computer processor, or memory connected to the processor. The memory may then comprise one or more programs that, when executed by the processor, perform the method. Thus, methods such as swapping and paging may be deployed.

[0085] It should also be understood that the terms used herein are for describing individual embodiments and are not intended to be limiting.Unless otherwise defined, all technical and scientific terms used herein have meanings corresponding to the common understanding of those skilled in the art in the relevant technical field of this disclosure.They should not be understood too broadly or too narrowly.If technical terms are used incorrectly in this disclosure and therefore do not reflect the technical ideas of this disclosure, they should be replaced with technical terms that convey accurate understanding to those skilled in the art in the relevant technical field of this disclosure.General terms used herein should be interpreted based on the definition in the dictionary or context.Overly narrow interpretations should be avoided.

[0086] For example, terms such as "comprising," "including," or "having" should be understood to mean the presence of stated features, numbers, operations, actions, components, parts, or combinations thereof, and not to preclude the presence or possible addition of one or more additional features, numbers, operations, actions, components, parts, or combinations thereof.

[0087] The term "and / or" includes both combinations of the relevant features as well as any combination of the listed features.

[0088] In this case, when a component is "connected to" or "in communication with" another component, this can mean that the component is directly connected to or has direct access to the other component. However, it should be noted that another component may exist between them. On the other hand, when a component is "directly connected to" or "directly accesses" another component, it should be understood that no further component exists between them.

[0089] Other objects, features, advantages, and applications will become apparent from the following description of non-limiting embodiments with reference to the accompanying drawings. Identical or similar components are always provided with identical or similar reference symbols. In the description of the present disclosure, detailed descriptions of known related functions or configurations are omitted only if they unnecessarily deviate from the present disclosure. All features described and / or illustrated in the drawings, alone or in any combination, form the subject matter disclosed therein, regardless of their grouping in the claims or their relationship / reference. Dimensions and proportions of components or parts shown in the drawings are not necessarily to scale. These dimensions and proportions may differ from the contents of the drawings and the embodiments implemented. In particular, in the drawings, the thickness of lines, layers, and / or regions may be exaggerated for clarity. [Brief description of the drawings]

[0090] [Figure 1] 1 is a schematic diagram of a scenario in which a system for determining the distribution of an optical parameter on a projection plane is used; [Diagram 2] 1 is a schematic diagram of a method for determining the distribution of an optical parameter in a projection plane; [Diagram 3] FIG. 2 is a schematic diagram of a point cloud in the coordinate system of a user's head. [Figure 4] FIG. 1 is a schematic diagram of the head coordinate system and its mapping to the spectacle plane of a subject in the sagittal plane. [Diagram 5]FIG. 2 is a schematic diagram of the requirements for power distribution in the form of a power map in the plane of the optical aid corresponding to the right eye. [Figure 6] FIG. 2 is a schematic diagram of a possible embodiment of a power distribution / profile of an optical aid, as an example of a progressive addition spectacle lens. [Figure 7] FIG. 2 is a schematic diagram of an example of a power profile. [Figure 8] FIG. 2 is a schematic diagram of the projection of the pupil diameter in the plane of the optical aid. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0091] The system and method will now be described in connection with embodiments. Particularly, but not limited thereto, specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure can be used in other embodiments that may differ from the details described below.

[0092] FIG. 1 shows a schematic scenario 100 in which a system for determining the distribution of optical parameters in a projection plane is used. At least a part of the system is arranged in an apparatus 110. The apparatus 110 may include a head orientation and / or position sensor. In particular, the head orientation and / or position sensor in FIG. 1 may be one-dimensional due to the sagittal view of the head 150 shown. The head orientation and / or position sensor measures the orientation of the head 150 in the sagittal plane as shown in FIG. 1. However, this can be extended to all planes with a respective sensor device inside the head orientation and / or position sensor of the apparatus 110. The head orientation and / or position sensor can therefore be calibrated to measure a head angle β=0 when the head is not tilted relative to the horizontal. This is specifically shown in FIG. 1.

[0093] If viewing an object requires a gaze angle (α) below the horizontal plane of the eye 170, the head tilt (β) (also referred to herein as head angle) only partially contributes to the gaze angle (α). The remaining part (γ) comes from reorienting the eye 170 (only the tilt of the eye 170) relative to the head tilt β. This is performed by the body itself to reduce the load on the neck 160. The distribution of the angular contribution between the head 150 and the eye 170 is individual and also depends on the individual position of the object 130. This can be activity and user specific. The object 130 in FIG. 1 is a handheld media, gazed upon by the user, represented by the head 150. The user can wear the device 110, in particular on the user's head or on the user's temple. In addition to this, the device 110 may be a head-mounted wearable. The device 110 may be integrated into or attachable to a spectacle frame.

[0094] In addition to the head orientation and / or position sensor, the device (e.g., a wearable device) can incorporate at least one distance sensor capable of measuring the distance to an object 130 in the field of view 120. The field of view 120 is indicated by an arrow and a star in FIG. 1. The distance sensor can be part of the field of view sensor described herein. Alternatively, the field of view sensor can be in the form of a distance sensor described with respect to FIG. 1. The head and body of a healthy individual are rarely completely at rest in an awake state. Therefore, a distribution of head tilt angles is expected during the observation period. By performing multiple measurements separated in time, the distance sensor can obtain the distance from the observation point (head view) to the object 130 in the field of view 120 in various directions. This can be the reference of the head coordinate system.

[0095] Sampling of the environment (field of view 120) can be performed by at least one directional distance sensor. The distance sensor can be a wearable distance sensor aligned with the user's head and / or integrated into the device 110. The distance sensor can have a scanning means, or an angular / spatial resolved sensor. However, the distance sensor can also rely only on the user's natural head movement to sample the environment in different directions, or it can be a combination of different sampling means in different directions. By relating the distance measurements to the orientation or position of the device 110, it is possible to build a two-dimensional or three-dimensional point cloud that represents the environment relative to the orientation and position of the user's head. The initial orientation or position of the device 110 can be obtained from inertial sensors (e.g., accelerometers, gyroscopes, magnetometers) or position sensors integrated into the device 110.

[0096] Additional context sensors can be used to automatically identify activities. For example, motion sensors can sample the user's movement intensity and statistical characteristics. For example, certain significant movements can be recognized, such as the movement of the head 150 while reading. Context sensors can also be included in the device 110.

[0097] Activities can be identified automatically with the aid of external sensors, or by direct user input performed through a user interface as part of the wearable, and / or the system, and / or additional devices such as a mobile phone or internet interface. The input identification activity can be performed in real time or at a later time. For example, a user can review the history of measurements and link the time series to specific activities through an interactive interface implemented as a web page or mobile application.

[0098] An example of such an input may be: from 10:00 to 10:30 an activity is reading, from 10:30 to 10:45 an activity is walking, from 10:45 to 11:45 an activity is driving, and so on.

[0099] Activity identification can also be performed as a combination of automatic and manual input. For example, the system can request user input only if the reliability or other metric of the performance of the automatic identification is below a certain threshold. In the above example, the system can automatically (confidently) identify reading and driving. However, the system may have some concerns about walking and so request user input. The system can be further configured to use user input for single episodes of activity and update the automatic identification of other episodes. In the above example, the user can manually specify a single episode that is walking from 10:30 to 10:45. The system can automatically update the activity classifier and re-evaluate all remaining episodes.

[0100] The head orientation and / or position sensor may comprise an accelerometer. In the simplest case, a single-axis accelerometer can be used, which allows the projection of an acceleration vector on a single axis to be measured. The single axis of the accelerometer is such that when the user is facing straight ahead (β=0), the projection of vector g (gravitational acceleration) on axis x is zero (g x = g sin β = 0, where g is the absolute value of the vector g), it is possible to align the device 110 horizontally so that the accelerometer measures zero acceleration. If the user's head 150 is tilted forward (β > 0), the projection g x The head inclination angle β is calculated from the measured projection as β=arcsin g x / g. The acceleration sensor can measure the acceleration along axis z acting on device 110 (in the coordinate system of the head orientation and / or position sensor). In the absence of significant acceleration of device 110 caused by movement (which is expected during significant visual activity), the accelerometer measures the force of gravity, i.e., the acceleration g.

[0101] The head vertical angle (pitch) β can be derived from measurements of gravity by an accelerometer (at least a single axis) mounted on the head 150 (e.g., on the glasses or the user's temple). In a more advanced configuration, the head orientation and / or position sensor can include a three-axis gyroscope, a three-axis accelerometer and a three-axis magnetometer (e.g., a compass). If the head orientation and / or position sensor is fixed to the user's head 150, it is then possible to estimate the absolute angle of the head orientation and / or position sensor and, correspondingly, the absolute orientation of the head 150.

[0102] Additionally or alternatively, a head position sensor may monitor the field of view or the position of the head relative to the field of view sensor.

[0103] The location of an object of interest 130 (an object associated with a particular visual activity) can be found by observing the field of view 120 with a field of view sensor relative to the head 150. For example, this can be done by a head-mounted camera, also called a point-of-view (POV) camera, a POV distance sensor, or a spatially resolved distance sensor (3D camera). By detecting the object of interest within the field of view, it is possible to indirectly derive the alignment angle (α, β, γ) and position (x, y, z) of the object within the field of view.

[0104] In combination with the distances measured by the distance sensor, the positions of the points can be obtained in the sagittal plane of the body to form a point cloud (points in FIG. 1 of the field of view 120) of the object 130 in the field of view 120. Furthermore, if the type of visual task is already given (e.g. if the user provides the information via a user interface), the recognition of the object 130 can be performed based on the expected field of view 120. Alternatively, the type of activity can be automatically recognized by comparing the statistics of the measured distances (obtained by the field of view sensor / distance sensor) with a dataset of statistical signatures of visual activity.

[0105] For example, the identified or recognized activity is a reading from a handheld device 130, as in the example shown in FIG. 1. In this case, the primary object of the visual activity is reading the handheld device 130. The handheld device 130 has a flat surface and would appear as a line in a sagittal projection at a comfortable arm's reach. Points corresponding to such a definition are marked with dashed lines (see FIG. 1). The angles corresponding to the points on the primary visual activity object 130 further define a set of gaze angles α used by the user to perform the corresponding visual task. The head tilt angle β is known from a head orientation and / or position sensor attached to the head 150. It is therefore possible to estimate the shift / angle of the eye 170, γ=α-β.

[0106] The density and scanning range of the point cloud can be increased by adding further distance sensors with different orientations and / or positions than the field of view sensor, or by using sensors that can acquire samples in multiple directions. For example, these sensors can have a single emitter and multiple sensitive zones / detectors with different sensitivities to distance in different directions. This can be achieved by the design of the sensor or by using additional elements, e.g. optical elements if the sensor is optically based.

[0107] For example, this can be implemented with a laser ranging sensor that has a 16x16 array of single-photon avalanche diodes (SPADs) and is configured to select the required area, thus implementing a single emitter and multiple detector strategy.

[0108] Another example may incorporate cameras or detector arrays positioned to detect light coming from different geometric positions and / or directions.

[0109] In a further example, the distance sensor can have at least one detector and multiple emitters configured to emit light in different directions and / or positions. In this case, the detector is configured to detect light emitted by at least one emitter and reflected from the field of view 120. The configuration / arrangement of active emitters can change from one point in time to another. This allows spatially resolved information to be collected.

[0110] In another example, at least one emitter can be configured to change the direction of the emitted light in order to probe the field of view 120 in different directions / positions. This can be achieved by a scanning element, which can be, for example, a scanning mirror, a scanning prism, or other movable optical element configured to change the optical path of the emitted light to emit the probing light in different directions. A detector can then be configured to detect the light reflected from the object probed by the emitter radiation. The detector signal can be linked to information about the probed direction / position in order to reconstruct the field of view 120. These directions can be known a priori from the scanner design, obtained in a calibration step, or obtained during the scan using additional feedback signals.

[0111] Alternatively, the field of view sensor can monitor the field of view when physically / mechanically separated from the head orientation and / or position sensor and the head. For example, the field of view sensor can be attached to the user's body (e.g., on the torso and / or chest). Or, the field of view sensor can be attached to the outside of the body (e.g., on a desk or on the dashboard of a car). The head orientation and / or position sensor and the field of view sensor can have a means to relate each other's coordinate systems, in particular their orientation and / or position. For example, this can be achieved by using an additional orientation and / or position sensor mechanically coupled to the field of view sensor.

[0112] Another approach could be to restrict the relative movement of the field of view sensor and the head, for example by mounting the field of view sensor on a specific part of the body different from the head, e.g. the chest, so that the relative movement of the field of view sensor and the head can only occur through head tilt, e.g. pitch, yaw, roll, which can be monitored with a head orientation and / or position sensor.

[0113] Details and aspects are described in relation to the embodiments described above or below. The embodiment shown in Figure 1 may include one or more optional additional features corresponding to the proposed concept or one or more aspects mentioned in relation to one or more embodiments described below (e.g., Figures 2-8).

[0114] FIG. 2 shows a schematic diagram of a method for determining the distribution of optical parameters in a projection plane. The method may include, as a first step, a step S210 of classifying a visual task. The method then includes a step S220 of measuring the user's visual field related to the specific visual task by a visual field sensor. This step may include identifying an object related to the specific visual task in the user's visual field. The method further includes a step S230 of determining the user's gaze direction during the specific visual task. The method further includes a step S240 of measuring the orientation and / or position of the user's head relative to the visual field during the specific visual task by a head orientation and / or position sensor. The method further includes a step S250 of enabling the calculation of the orientation of the user's eyes relative to the user's head based on the user's gaze direction and the orientation and / or position of the user's head in order to determine the distribution of optical parameters in a projection plane between the user's visual field and the retina.

[0115] In particular, the method can be implemented in two different ways: the first way is based on a mechanically coupled field of view sensor, such as the distance sensor described with respect to Fig. 1, and a head orientation and / or position sensor. The method shown in Fig. 2 can thus comprise at least one of the following (additional) steps according to the first way of implementing the method: A step S205 of acquiring a point cloud of one or more objects within the user's field of view; A step S210 of classifying the type of visual task; A step S220 of identifying, by the visual field sensor, at least one relevant object associated with a particular visual task within the visual field; and A step S230 of calculating at least one of the components of the gaze angle (pitch, yaw, and / or roll in a common coordinate system) corresponding to at least one relevant object of the visual task; A step S242 (S240) of measuring head orientation during visual activity with a head orientation and / or position sensor; A step S244 of calculating at least one component of the head angle (pitch, yaw, and / or roll in a common coordinate system) (S240); and Step S250 of calculating at least one angle between the head and the object (eye angle) as the difference between the gaze direction and the head orientation and / or position.

[0116] The objects of visual activity are often located in real space relative to the gravitational field, e.g., a piece of paper on a desk, a computer display, a television screen, a car dashboard, etc. Therefore, object recognition is easier to perform in a geocentric coordinate system.

[0117] The second way is based on a mechanically separated visual field sensor and a head orientation and / or position sensor. Thus, the method shown in FIG. 2 can include at least one of the following (additional) steps according to the second way of performing the method: a step S220 of identifying one or more objects in the user's field of view by a field of view sensor, and a step S230 of calculating the line of sight angle (in a common coordinate system); measuring head orientation during visual activity S240 by a head orientation and / or position sensor and calculating the head angle (in a common coordinate system); Calculate at least one angle between the head and the object (eye angle) as the difference between the gaze angle and the head angle S250.

[0118] Details and aspects are described in relation to the embodiments described above or below. The embodiment shown in Figure 2 may include one or more optional additional features corresponding to the proposed concept or one or more aspects mentioned in relation to one or more embodiments described above (e.g., Figure 1) or below (e.g., Figures 3-8).

[0119] FIG. 3 shows a schematic diagram of a point cloud in the coordinate system of the user's head. In particular, the sagittal plane is shown for understanding. The point cloud can be obtained by combining the measurements of the distance sensor in at least one direction with the measurements of the sensor's orientation and position. Measurements from multiple distance sensors (e.g., probing in different directions) can be combined into one map or form multiple maps. Once at least the head tilt pitch angle is measured, the point cloud is defined in the two-dimensional sagittal plane. With additional orientation sensors such as gyroscopes and / or magnetometers, the head yaw and roll angles can be added to define the point cloud in three-dimensional space. For example, by classifying the visual task or visual activity, the gaze angle can be extracted accordingly. In the sagittal plane, all points corresponding to each gaze angle are at the same distance from the head U, in particular, depending on the visual task. FIG. 3 shows a point cloud at a distance of about 0.33 m, which corresponds to a near vision (NV) task, such as reading a book or looking on a smartphone, in this example, 3D refraction. Another group is in the intermediate vision (IV) zone at about 1m (1D refraction), which could be viewing a desktop computer display, and a group in the far vision (FV) zone at about 2m (0.5D), which could be watching television.

[0120] The point cloud can form a pattern that is characteristic of the activity. The shape and / or location of the point cloud can be used to automatically classify the visual activity. Classification can be done in combination with user input of what type of visual task the user is performing, and / or in combination with pattern recognition from video captured during the visual task, and / or in combination with measurements of other sensors. For example, the visual field sensor is a camera. The processing involves searching for objects from a 2D image, for example identifying a book or a handheld device (smartphone or tablet), a computer screen. This involves understanding the user's activity from the camera image.

[0121] Details and aspects are described in relation to the embodiments described above or below. The embodiment shown in Figure 3 may include one or more optional additional features corresponding to the proposed concept or one or more aspects mentioned in relation to one or more embodiments described above (e.g., Figures 1-2) or below (e.g., Figures 4-8).

[0122] FIG. 4 shows a schematic of the head coordinate system and the mapping of the object to the eyeglass plane in the sagittal plane. If the activity is bilaterally symmetrical, one can imagine placing the object in the sagittal plane. Examples of such activities include reading handheld media such as a book, working on a desktop computer, working on a workbench, etc. In this case, the distance to the object can be monitored together with the pitch angle of the head, independent of yaw and roll. An example is the activity shown in FIG. 3.

[0123] The coordinates of each of the points associated with a particular visual task (here point A) are recalculated relative to the head coordinate system. In particular, the optical parameters such as the refractive power are mapped relative to a projection surface, which may be the spectacle surface.

[0124] Figure 4 specifically shows the following: P xz eyeglass face P yz sagittal plane P xy Pxz and P yz Vertical plane to P Eye pupil position A Point of interest A s Image of a point of interest on the surface of the glasses O nasal root O s Projection of O on the surface of the glasses O.O. s Distance between vertices OP distance: Monocular interpupillary distance adjusted for convergence

[0125] Additionally, panoscopic tilt (lens pitch), curvature angle (lens yaw) can be taken into account and specific optical aids can be customized.

[0126] For more general activities, bilateral symmetry cannot be assumed (e.g., while driving a car). In this case, head orientation monitoring can be performed in all three angular dimensions: pitch, yaw, and roll. The point cloud is not limited to the sagittal plane but is defined in 3D space. The illustrated geometric model can be further extended to allow depiction onto a projection plane.

[0127] Details and aspects are described in relation to the embodiments described above or below. The embodiment shown in Figure 4 may include one or more optional additional features corresponding to the proposed concepts or one or more aspects mentioned in relation to one or more embodiments described above (e.g., Figures 1-3) or below (e.g., Figures 5-8).

[0128] FIG. 5 shows a schematic representation of the requirements for the power distribution in the form of a power map in the plane of the optical aid corresponding to the right eye. For example, such a distribution can be obtained from the point cloud of FIG. 3 using the geometric transformation shown in FIG. 4. In this case, the near vision (NV) zone results in the requirement that the optical aid comprises a zone with a 3D refractive power to help the user see objects at a distance of 0.33 m. The intermediate vision (IV) zone, which allows viewing a desktop display, creates a zone corresponding to a zero pitch of refractive power of 1D (distance 1 m). Finally, the far vision zone (FV), with a refractive power of less than 1D (from 1 m to infinity), is located above the IV zone.

[0129] The NV zone is shown slightly to the right of the center. This is because when reading (converging), the eye rotates in a rotational direction toward the user's nose. Thus, FIG. 5 shows the customization of the lens of a right-eye eyeglass for a presbyopic user. The zones can be customized to suit the needs of the user. As can be seen in FIG. 5, the refractive powers can be distributed unevenly in each case, which can also make the transition of the zones smoother.

[0130] As a result, it is possible to provide a mapping of optimal lens power based on an individual's visual behavior.

[0131] Details and aspects are described in relation to the embodiments described above or below. The embodiment shown in Figure 5 may include one or more optional additional features corresponding to the proposed concepts or one or more aspects mentioned in relation to one or more embodiments described above (e.g., Figures 1-4) or below (e.g., Figures 6-8).

[0132] FIG. 6 shows a schematic representation of a possible embodiment of the power distribution / profile of an optical aid as an example of a progressive addition spectacle lens. The optical aid of FIG. 5 is a lens with a round shape. From this lens, a lens for mounting in spectacles can be cut along the dashed lines. The required power zone profile shown in FIG. 5 cannot be implemented with a lens. A customization step is therefore necessary to find a feasible design that takes into account the optical limitations of the spectacle lens and is as close as possible to the desired profile. Modern progressive addition lenses have blending regions (BR) that cannot be used for good vision due to high astigmatism. It is required to blend the refractive powers of the lenses for far and near vision. The refractive power changes gradually along the progressive zone from a distant reference point DRP (Distance Reference Point) for far vision to a near reference point NRP (Near Reference Point) for near vision. This progression is defined by a power profile. The power profile can be optimized together with other parameters to fit the required distribution.

[0133] Details and aspects are described in relation to the embodiments described above or below. The embodiment shown in Figure 6 may include one or more optional additional features corresponding to the proposed concepts or one or more aspects mentioned in relation to one or more embodiments described above (e.g., Figures 1-5) or below (e.g., Figures 7-8).

[0134] FIG. 7 shows a schematic example of a power profile implementing the design fit requirement power map from FIG. 5 with the layout of the progressive addition lens from FIG. 6. These measurements can correspond to the distance measurements in the sagittal plane according to FIG. 3. The refractive power in this case is calculated as the inverse of the distance to the object of the visual task. The eye pitch angle is calculated from the gaze angle and the measured head angle on FIG. 3. These measurements can be extended to different planes. In this example, pitch angles smaller than -5 degrees achieve distance vision starting from the DRP. At a pitch near 0, the power is equal to 1D (distance 1m, corresponding to the example desktop display in FIG. 3). By further increasing the pitch angle, the profile reaches an NRP with a power of +3D (0.33m), corresponding to the handheld media in FIG. 3.

[0135] Details and aspects are described in relation to the embodiments described above or below. The embodiment shown in Figure 7 may include one or more optional additional features corresponding to the proposed concepts or one or more aspects mentioned in relation to one or more embodiments described above (e.g., Figures 1-6) or below (e.g., Figure 8).

[0136] FIG. 8 shows a schematic projection of the pupil diameter in the plane of the optical aid. In particular, the light intensity / luminance and / or the spectral content of the light can be measured by a visual field sensor and converted to the user's pupil size using empirical formulas and models. Thus, the optical aid can also be designed for different light intensity exposures of the user. It is known that the eye adapts differently to different lighting conditions. For example, in particularly dark settings, the eye can only accommodate between 0.5 meters and 2 meters (correspondingly 2 to 0.5D). The depth of focus (the range of refractive powers that are imaged on the retina with sufficient quality) is inversely proportional to the pupil diameter. That is, in high illuminance settings, the pupil constricts and the range increases. The depth of focus varies from 0.1D to 0.5D. This can be taken into account in the design of the optical aid. In the example of FIG. 8, the pupil is larger for the lower zones. This means that in these zones the depth of focus is reduced. This can be used to define the precision requirements for the map of the optical aid's power, as shown in Figure 5. In this example, the optical aid design needs to provide a high precision power in the lower zone (used for near vision in this example). In this example, the upper zone is typically used with a reduced pupil size, which increases the depth of focus, which makes this region more resistant to defocus. Therefore, in this particular case, there is more flexibility in selecting the far power located in the upper zone.

[0137] Details and aspects are described in relation to the embodiments described above or below. The embodiment shown in Figure 8 may include one or more optional additional features corresponding to the proposed concepts or one or more aspects mentioned in relation to one or more embodiments described above (e.g., Figures 1-7).

[0138] The example spectacle surface in Figure 6 shows the case where the visual aid is separated from the eye, so eye movements can be related to changes in the optical power of the visual aid.

[0139] Another example of a visual aid can describe a contact lens, a corneal implant, and / or an intraocular lens moving with the eye. In this case, the projection plane is always aligned with the line of sight, and the head orientation is irrelevant. Nevertheless, the method allows objects in the peripheral vision to be mapped to the projection plane. The flowchart shown in FIG. 2 can represent various processes, operations, or steps. They can be substantially represented, for example, in a computer-readable medium and so executed by a computer or processor, whether or not such a computer or processor is explicitly shown. The methods disclosed herein or in the claims can be implemented by an apparatus having means for performing each of the operations of each of these methods.

[0140] It should be understood that the disclosure of multiple operations, processes, operations, steps, or functions disclosed in this specification or claims is not to be construed as being within a particular order unless expressly or implicitly stated otherwise, for example, for technical reasons. Thus, the disclosure of multiple operations or functions does not limit them to a particular order, unless such operations or functions are not interchangeable for technical reasons. Furthermore, in some embodiments, a single operation, function, process, operation, or step may each include or be divided into multiple sub-operations, multiple sub-functions, multiple sub-processes, multiple sub-operations, or multiple sub-steps. Such sub-operations may be included and made part of the disclosure of this single operation, unless expressly excluded.

[0141] The aspects and features mentioned and described in connection with one or more of the embodiments and figures detailed above may likewise be combined with one or more of the other embodiments to replace similar features of the other embodiments or to introduce additional features to the other embodiments.

[0142] Furthermore, the following claims are incorporated herein in the more detailed description. Each claim can be understood as a separate embodiment in itself. While each claim is understood as a separate embodiment in itself, it should be noted that: although a dependent claim may refer to a specific combination with one or more other claims in the claims, other embodiments may also include combinations of the dependent claim with the subject matter of claims that are dependent or independent of each other. Such combinations are expressly suggested herein, unless it is expressly stated that no particular combination is intended. Moreover, it is intended that the features of a claim be included in any other independent claim, even if the claim is not directly dependent on the independent claim.

Claims

1. 1. A system for determining a distribution of an optical parameter on a projection plane, comprising: a visual field sensor configured to measure a user's visual field associated with a particular visual task, the visual field sensor further configured to determine a gaze direction of the user during the particular visual task; a head orientation and / or position sensor configured to measure an orientation and / or position of the user's head relative to the field of view during the particular visual task; The system is configured to enable calculation of the orientation of the user's eyes relative to the user's head based on the user's gaze direction and the orientation and / or position of the user's head to determine a distribution of optical parameters on the projection plane, the projection plane being located between the user's field of view and the retina.

2. 2. The system of claim 1, wherein the field of view sensor is configured to identify objects in the user's field of view associated with the particular visual task and to derive a gaze direction of the user associated with the identified objects in the field of view.

3. The system of claim 1 or 2, further comprising a context sensor configured to measure at least one parameter related to the activity of the user.

4. 4. The system of claim 3, further comprising a statistical classifier, the statistical classifier comprising: The visual field sensor said head orientation and / or position sensor, and A system configured to identify a visual task and / or object in the field of view of the user from at least one of the context sensors, the identification being performed at least in part automatically.

5. The system according to any one of claims 1 to 4, The system further comprises a memory unit configured to store the head orientation and / or position and the gaze direction, both of which are associated with the particular visual task, wherein the stored head orientation and / or position and the stored gaze direction form a basis for determining a distribution of the optical parameters in the projection plane between the user's field of view and the retina.

6. A system according to any one of claims 1 to 5, The system further comprises a processing unit configured to determine a corresponding difference between the head orientation and / or position and the gaze direction, and to determine a distribution of the optical parameters in the projection plane between the user's field of view and the retina.

7. 7. The system of claim 6, wherein the processing unit is configured to determine a corresponding difference between the stored head orientation and / or position and the stored gaze direction, and to determine a distribution of the optical parameters in the projection plane between the field of view and the retina of the user.

8. 8. The system of claim 1, wherein the system is a head-mounted wearable adapted to be worn by the user or is disposed on a head-mounted wearable adapted to be worn by the user.

9. 10. The system of claim 8, wherein the wearable is a single module that comprises all elements of the system.

10. 10. A system according to claim 8 or 9, wherein the coordinate systems of each said head orientation and / or position sensor and each said field of view sensor are aligned.

11. A system according to any one of claims 1 to 10, wherein the visual field sensor and the head orientation and / or position sensor are separate from each other; and / or A system, wherein the projection plane is a plane on which optical aids are placed relative to the user's eyes.

12. Use of the system according to any one of claims 1 to 11, characterized in that the distribution of the optical parameters on the projection surface is used for customizing an optical aid, the optical parameters being: Refractive power Pupil diameter depth of focus Spectral content of light the angular distribution of light, and At least one of the polarization states of light.

13. 1. A method for determining a distribution of an optical parameter on a projection plane, comprising the steps of: Measuring the user's visual field associated with a particular visual task with a visual field sensor (S220); determining (S230) a gaze direction of the user during the particular visual task by the visual field sensor; Measuring (S240) the orientation and / or position of the user's head relative to the field of view during the particular visual task by a head orientation and / or position sensor; and (S250) enabling calculation of an orientation of the user's eyes relative to the user's head based on the user's gaze direction and the orientation and / or position of the user's head to determine a distribution of optical parameters on the projection plane, the projection plane being located between the user's field of view and retina.

14. A computer program product comprising program code portions for performing the method according to claim 13 when said computer program product is executed on one or more processing units, e.g. said computer program product being stored on one or more computer readable storage media.

15. Optical aid, the design of which is adjustable according to a method according to claim 13 or using a system according to any one of claims 1 to 11.

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