Capture device having camera and infinity mirror

Abstract

The invention pertains to a capture device (1) comprising an infinity mirror (4) configured to create an infinity optical effect to a person (2) and a camera (3) for capturing an image of an eye (20) of the person. The invention further pertains to an ocular examination system for examining the eye and to an ocular recognition system for identifying a person based on visual inspection of the eye, the ocular examination system and the ocular recognition system comprising such a capture device. The invention further pertains to a humanoid robot comprising the examination system and / or the ocular recognition system, wherein at least one eyeball of the of the humanoid robot at least partially comprises the capture device.

Description

[0001] 240809W059340

[0002] 1

[0003] Capture Device having Camera and Infinity Mirror

[0004] The present invention pertains to devices comprising an infinity mirror and a camera. The camera is arranged to capture images of an eye of a person while the person’s gaze is guided by the infinity mirror. While the infinity mirror ensures that the eye is in a defined position relative to the camera, the camera images of the eye can be used, e.g., for medical eye inspection, for identification and / or for guiding and correcting a head pose of the person.

[0005] An infinity mirror is a configuration of two or more parallel or angled mirrors, which are arranged to create a series of reflections that appear, given the correct positioning of an observer, to recede like a tunnel to infinity. In a self-contained infinity mirror, a set of point-source lights are placed around the periphery of a first mirror, that can be fully or partially reflective, and a second, partially reflective mirror is placed in a parallel alignment a short distance in front of the first mirror. When an outside observer looks into the surface of the partially reflective mirror, the lights appear to recede into infinity, creating the appearance of a tunnel of great depth that is lined with lights. A 3D illusion is produced due to two parallel reflective surfaces which can bounce a beam of light back and forth a - theoretically infinite - number of times. The reflections also appear to diminish in intensity because the front mirror is semi-transparent so that the beam intensity decreases with the number of reflections becoming progressively dimmer each time. The appearance of the tunnel changes with the observer’s position. This effect may be used to guide the observer to a certain position, i.e. the position at which the tunnel is straight with its “end” being in the centre of the infinity mirror.

[0006] Camera-based eye examination techniques require a patient to look into a certain desired direction for a certain duration in a relaxed manner. It would be desirable to provide a solution that allows guiding a patient to hold his or her head still in a certain position and orientation while looking in the desired direction, in order to allow performingthe camera-based eye examination. 240809W059340

[0007] 2

[0008] It is known to identify a person using various ocular-based technologies, such as retinal scans, iris recognition or eye vein verification. It would be desirable to provide a solution that allows guiding a person to hold his or her head in a certain position and orientation that allows performing the ocular-based identification.

[0009] It is known to estimate a gaze direction of an eye from reflections of light patterns on the eye, e.g. based on corneal reflections. It would be desirable to provide a solution that allows guiding a person to correct his or her gaze direction, for instance to facilitate eye examination or ocular-based identification.

[0010] It is an object of the present invention to provide an improved capture device for capturing images of a face of a user, particularly of an eye of the user.

[0011] It is a particular object of the present invention to provide such a capture device that guides the gaze of the user at close distance, maintains a relaxed state of the eye and avoids squinting.

[0012] It is another object of the present invention to provide such a capture device that allows users to position themselves correctly in front of the device.

[0013] It is another object of the present invention to provide an ocular examination system that allows users to position themselves correctly to have their eyes examined.

[0014] It is another object of the present invention to provide an ocular recognition system that allows users to position themselves correctly to be identified based on features of their eyes.

[0015] At least one of these objects is achieved by the appended claims.

[0016] A first aspect of the invention pertains to a capture device for imaging a person’s face or a part thereof. In particular, the capture device may be configured for imaging an eye of the person or a part of the person’s face including one or both eyes and / or the area around the eyes (such as the eyebrows or the glabella). The capture device comprises a camera for capturing an image of the eye, and an infinity mirror 240809W059340

[0017] 3 comprising a front side with a first surface, a back side with a second surface, wherein the first and second surfaces are at least partially reflecting and arranged in parallel, and one or more light sources arranged relative to the first and second surface for creating an infinity optical effect. According to this aspect of the invention, a beam splitter is arranged along an optical path and configured to split the optical path into a first and a second sub-path, wherein the infinity mirror is arranged at the first sub-path and the camera is arranged at the second sub-path.

[0018] The capture device may comprise further cameras in addition to the camera imaging the eye - especially if the capture device is configured for imaging other parts of the person’s body than the eye.

[0019] A second aspect of the invention pertains to a capture device for determining a gaze direction of an eye of a person, the capture device comprising a camera for capturing an image of the eye, a controlling and processing unit, and an infinity mirror comprising a front side with a first surface, a back side with a second surface, wherein the first and second surfaces are at least partially reflecting and arranged in parallel, and one or more light sources arranged relative to the first and second surface for creating an infinity optical effect, wherein the one or more light sources are arranged relative to the first and second surfaces of the infinity mirror to create a structured light pattern. According to this aspect of the invention, the controlling and processing unit is configured

[0020] - to detect, in the captured image, a pattern of glints on the at least one eye, the pattern of glints constituting a reflection of at least a part of the structured pattern;

[0021] - to derive, based on the detected pattern of glints, a gaze direction of the at least one eye; and

[0022] - to provide a feedback signal based on the derived gaze direction.

[0023] According to some embodiments, the controlling and processing unit is configured to determine whether an orientation of the derived gaze direction relative to an optical axis of the infinity mirror is outside a predetermined range, wherein, if the 240809W059340

[0024] 4 gaze direction is outside the predetermined range, the feedback signal comprises instructions to correct the gaze direction.

[0025] According to some embodiments, the feedback signal comprises a visual guiding output providing instructions to the person howto correct the gaze, the visual guiding output being provided by means of the infinity mirror.

[0026] According to some embodiments, the visual guiding output is provided by controlling the one or more light sources, in particular wherein controlling the one or more light sources comprises creating different structured patterns.

[0027] According to some embodiments, the controlling and processing unit is configured to determine whether an orientation of the derived gaze direction relative to an optical axis of the infinity mirror is indicative of a posture of the person’s head being outside a predetermined range, the posture including at least one of neck flexion, neck rotation and lateral bending, wherein, if the posture is outside the predetermined range, the feedback signal comprises instructions to correct the posture.

[0028] Accordingto some embodiments, the camera is arranged and configured to capture an image of the face of the person or of a part of the face comprising the eye, and the controlling and processing unit is configured to determine the posture of the person’s head also based on the image of the face.

[0029] According to some embodiments, the feedback signal comprises an acoustical guiding output.

[0030] Accordingto some embodiments, the capture device comprises a beam splitterthat is arranged along an optical path and configured to split the optical path into a first and a second sub-path, wherein the infinity mirror is arranged at the first sub-path and the camera is arranged at the second sub-path.

[0031] According to some embodiments, the capture device is configured to allow the person to look along the optical path and the first sub-path at the front side of the 240809W059340

[0032] 5 infinity mirror.

[0033] Accordingto some embodiments, the first surface is semi-transparent, in particular wherein the first surface has a reflectance of at least 90%, particularly at least 94%, and / or has a transmission of at least 2.5%, particularly at least 3.5%.

[0034] Accordingto some embodiments, the second surface is non-transparent and / or has a reflectance of at least 94%, particularly at least 98%.

[0035] Accordingto some embodiments, the front side and the back side are connected by side walls.

[0036] According to some embodiments, the front side and the back side are surfaces of a glass block. In some embodiments, the glass block is cuboidal. According to some embodiments, the glass block comprises one or more cavities, and the one or more light sources are arranged in the cavities, particularly wherein each cavity houses one light source.

[0037] According to some embodiments, the first surface and the second surface have an elongated shape, particularly a rectangular or oval shape, a width of each surface being larger than a height of each surface, the width being parallel to an axis connecting the eyes of the person.

[0038] Accordingto some embodiments, the light sources are light emitting diodes (LEDs).

[0039] According to some embodiments, the light sources comprise a plurality of light sources that are circumferentially arranged around the optical path.

[0040] Accordingto some embodiments, at least one light source is positioned between the front side and the back side, particularly between the first and second surfaces.

[0041] Accordingto some embodiments, at least one light source is positioned between the front side and the eye.

[0042] According to some embodiments, the light sources comprise a plurality of light 240809W059340

[0043] 6 sources that are arranged in one or more arrays of light sources, particularly arrays of point-like light sources.

[0044] According to some embodiments, the front side and the back side are surfaces of a glass block, particularly wherein the glass block is cuboidal; and the glass block comprises one or more cavities, and the one or more arrays of light sources are arranged in the cavities, particularly wherein each cavity houses one light source or one array of light sources.

[0045] Accordingto some embodiments, one array of light sources is configured as a bottom array, wherein the light sources of the bottom array are arranged in a line that is parallel to the front side and below the front side.

[0046] According to some embodiments, one array of light sources is configured as a top array, wherein the light sources of the top array are arranged in a line that is parallel to the front side and above the front side.

[0047] According to some embodiments, one or more arrays, particularly two arrays, are configured as side arrays, wherein light sources of each side array are arranged in a line that is parallel to the first surface.

[0048] Accordingto some embodiments, the arrays are configured and arranged relative to the first and second surfaces to create an inner appearance that is visible to the person when looking along the optical path into the infinity mirror, particularly wherein the inner appearance comprises an appearance of a tunnel tapering in infinity.

[0049] According to some embodiments, the infinity mirror is configured to create an inner appearance that is visible to the person when looking along the optical path into the infinity mirror, wherein the inner appearance is entirely observable by the person when the person is aligned relative to the capture device in a predefined manner. For instance, aligning the person in the predefined manner can comprise the person obtaining a desired pose, particularly a centred pose relative to the capture device. 240809W059340

[0050] 7

[0051] According to some embodiments, the inner appearance is or comprises the appearance of a tunnel tapering in infinity, and all sides of the tunnel are observable when the person is aligned relative to the capture device in the predefined manner.

[0052] According to some embodiments, the capture device is provided in a spherical or hemispherical housing, wherein the infinity mirror is observable from the outside through a circular opening in the housing. For instance, the housing may have the appearance of an eyeball, the circular hole appearing as an iris of the eyeball.

[0053] Accordingto some embodiments, the capture device is part of a humanoid robot, the robot comprising at least a head, particularly wherein the housing of the capture device has the appearance of an eyeball of the humanoid robot.

[0054] According to some embodiments, the first surface and the second surface have a circular shape, particularly wherein the light sources are arranged in a circular array around the infinity mirror.

[0055] According to some embodiments, the first surface and the second surface have a central opening, the camera being positioned behind the back side of the infinity mirror and arranged to capture the images of the eye through the central openings.

[0056] A third aspect of the invention pertains to an ocular examination system for examining an eye of a person, particularly for visual examination of the retina. The ocular examination system comprises a controlling and processing unit and the capture device according to the first or second aspect of the invention. The controlling and processing unit is configured to execute a data acquisition functionality to generate eye data based on at least one captured image of the eye.

[0057] According to some embodiments, the ocular examination system comprises a display device having a display and being configured to display a representation of the eye data on the display.

[0058] Accordingto some embodiments, the eye data comprises image data of the retina. 240809W059340

[0059] 8

[0060] According to some embodiments, the controlling and processing unit is configured to execute an analysis functionality to interpret the eye data to detect one or more indicators for a condition of the retina and to generate analysis data based on the indicators.

[0061] According to some embodiments, the ocular examination system comprises an interface configured to output eye data and / or analysis data to a user.

[0062] A fourth aspect of the invention pertains to a humanoid robot comprising the ocular examination system accordingto the third aspect, wherein at least one eyeball of the of the humanoid robot at least partially comprises the capture device, particularly wherein the infinity mirror is observable from the outside through a circular hole in the eyeball that appears as an iris of the eyeball.

[0063] A fifth aspect of the invention pertains to an ocular recognition system for identifying a person based on visual inspection of an eye of the person. The system comprises a controlling and processing unit and the capture device according to the first or second aspect of the invention. The controlling and processing unit is configured

[0064] - to receive at least one captured image of the eye;

[0065] - to generate eye data based on the at least one captured image of the eye;

[0066] - to compare the generated eye data with stored eye data from an eye data base;

[0067] - to determine an identity of the person based on the stored and generated eye data; and

[0068] - to provide information about the person.

[0069] According to some embodiments, the information about the person comprises the identity of the person.

[0070] According to some embodiments, the controlling and processing unit is configured to determine the information about the person based on the determined identity.

[0071] According to some embodiments, the controlling and processing unit is configured to access a person database to determine the information about the person. 240809W059340

[0072] 9

[0073] According to some embodiments, the information about the person comprises at least one of a right, an entitlement and a qualification of the person, particularly a right of access.

[0074] A sixth aspect of the invention pertains to a humanoid robot comprising the ocular recognition system according to the fifth aspect, wherein at least one eyeball of the humanoid robot at least partially comprises the capture device, particularly wherein the infinity mirror is observable from the outside through a circular hole in the eyeball that appears as an iris of the eyeball.

[0075] Optionally, the humanoid robot may also comprise the ocular examination system accordingto the third aspect.

[0076] The invention in the following will be described in detail by referring to exemplary embodiments that are accompanied by figures, in which:

[0077] Fig. 1 shows an exemplary embodiment of a device for capturing images of a person’s face;

[0078] Fig. 2 shows an exemplary embodiment of an infinity mirror as part of the device of Fig. 1 ;

[0079] Fig. 3 illustrates the capturing of an image of a person’s face usingthe device of Fig. 1 ;

[0080] Figs. 4a-b show two exemplary embodiments of a capture device according to a first aspect of the invention;

[0081] Figs. 5a-b show two exemplary embodiments of an infinity mirror as part of the capture devices of Figs. 4a-b;

[0082] Fig. 6 shows another exemplary embodiments of an infinity mirror as part of the capture devices of Figs. 4a-b;

[0083] Fig. 7 show a first example of the inner appearance of an exemplary embodiment of an infinity mirror;

[0084] Figs. 8a-c show a second example of the inner appearance of an exemplary 240809W059340

[0085] 10 embodiment of an infinity mirror;

[0086] Figs. 9a-b show a third example of the inner appearance of an exemplary embodiment of an infinity mirror;

[0087] Fig. 10 shows an exemplary embodiment of a capture device according to a second aspect of the invention;

[0088] Figs. 11 a-b show two exemplary embodiments of a capture device that are embodied as artificial eyeballs;

[0089] Fig. 12 shows a humanoid robot comprising one or two of the capture devices of Figs. 9a-b;

[0090] Fig. 13 shows an exemplary embodiment of an ocular examination system accordingto the invention; and

[0091] Fig. 14 shows an exemplary embodiment of an ocular recognition system accordingto the invention.

[0092] Figure 1 shows an exemplary embodiment of a device 10 configured to capture images of the face of a person, for instance to measure the skin of the person. The device 10 comprises a set of illumination elements 11 a-d for illuminating the skin with measuring light and a set of cameras 12a and 12b for capturing an image of the skin by detecting at least a part of the measuring light which is reflected at the skin. The device 10 also comprises a pedestal 16 to place the device 10 on a table or desk to provide flexible measuring conditions. For instance, the height of the stand can be fixed or adjustable.

[0093] Further, the device 10 comprises an infinity mirror 4. The infinity mirror 4 is shown in Figure 2 in more detail. The infinity mirror 4 (configured as a self-contained infinity mirror) comprises at least two mirror surfaces 41 ,42 which are arranged opposite apart from each other. A light source 43 is arranged for emitting light 44. The mirror 4 also comprises a front side 45 to look inside the infinity mirror 4. Here, the two mirror surfaces 41 ,42 are built as separate mirrors 41 ,42. 240809W059340

[0094] 11

[0095] Optionally, the infinity mirror can be provided by a single optical element which comprises the two mirror surfaces 41 ,42. For example, the two mirror surfaces 41 ,42 are provided by coated boundary surfaces of a glass element having a defined width.

[0096] The infinity mirror 4 is arranged at the device 10 and placed and oriented relative to the device 10 so that an insight axis 46 and an insight distance for the person is defined to provide suitable and repeatable measuring of, e.g., the skin of the person by defined looking inside the infinity mirror 4.

[0097] At least one of the mirror surfaces is built as a semi-transparent mirror 42 and is arranged on the front side 45. The infinity mirror 4 comprises the front side and an opposite back side 47. The front side 45 and back side 47 may be connected by side walls 48. The front side 45 is arranged opposite of the back side 47. A light source 43 emits illumination light inside the infinity mirror 4. The semi-transparent mirror 42 can be built to be 50% reflective and 50% transmissive, i.e. a portion of 50% of the light emitted by the light source 43 is transmitted to the outside of the infinity mirror 4 and a remaining portion of 50% of the emitted light is reflected back to the other mirror 41.

[0098] The backside mirror surface 41 is built as a (totally) reflective mirror 41 and is arranged on the back side 47 of the infinity mirror.

[0099] The light emitted by the light source 43 is reflected multiple times at the mirrors 41 , 42. Due to part-reflections on the semi-transparent mirror 42 the corresponding transmitted components create a light pattern emitted from the semi-transparent mirror. A portion of the light escapes through the front mirror 42. Each time a part of the light escapes through the front mirror 42, less amount of light is reflected towards the back mirror 41. Due to this effect, a user of the device 10 sees progressively dimmer “illusion” light sources behind the real light source 43 when looking into the infinity mirror on side of the front mirror 42.

[0100] In some embodiments, a number of point-like light sources, such as light emitting diodes (LEDs) is arranged around the perimeter of the infinity mirror 4 to provide 240809W059340

[0101] 12 circumferential illumination inside of the infinity mirror 4. The mirrors 41 and 42 are preferably arranged with a relative distance to each other out of a range of 20 mm to 30 mm. The configuration of the infinity mirror 4 provides an optical effect to an observer, as if the observer would be looking into an illuminated tunnel which comprises an infinite end of the tunnel in the centre; in other words: the tunnel is tapering in infinity (shown in Figure 7). The decreasing intensity with every order of reflection enhances the tunnel-like appearance of the created light pattern. The axis of the infinity mirror is defined as the line perpendicular to its plane-parallel surfaces, intersecting them at their midpoint. Depending on the viewing angle relative to this axis, an observer sees deeper or less deep into the tunnel. The effect of the tunnel guides the observer gradually and intuitively to centred position parallel to the infinity mirror surfaces. Such an appearance inside of the infinity mirror 4 occurs in case the user of the device 10 is in a desired position and orientation relative to the infinity mirror 4 and looks inside the mirror 4 according to a corresponding viewing direction (insight axis 46). If the position is not correct, the person cannot see the end of the tunnel.

[0102] Such design provides a defined alignment of a person in front of the device 10. A measurement of the person by means of the illumination elements and cameras can be performed when the person sees the tunnel inside of the infinity mirror 4 entirely, i.e. the person sees the side walls and the infinite end of the tunnel basically in the centre of the infinity mirror 4. This additionally provides repositioning of the person in front of the device 10 in identical position and orientation. This provides a big advantage when a later progress measurement of the person's face should be performed, e.g. after a particular treatment of the person's face. Hence, comparison of before / after states of the face becomes comparatively direct and with low effort.

[0103] Furthermore, the infinity mirror 4 provides that the person to be measured can be guided relative to the device 10 in short distance. Also, squinting of the person is avoided due to the optical effect of the infinity mirror 4, i.e. looking into infinity. In other words, compared to other approaches of positioning a person with short 240809W059340

[0104] 13 distance relative to a device to capture an image of the face of the person, the use of an infinity mirror provides removal of squinting of the person for capturing the image. This results in providing image data which represents the person in more realistic manner, i.e. true-to-life.

[0105] The insight axis 46 is defined by the surface the front mirror 42, wherein the insight axis 46 is perpendicular to and intersects a centre point of the surface of the front mirror 42.

[0106] The insight distance, i.e. a desired distance between the person to be measured and the device 10, is defined by the configuration of the infinity mirror, in particular by the relative arrangement of the at least two mirrors and the LEDs.

[0107] A visual output at the device 10 can be provided to show the person a measure concerning an alignment deviation relative to the capture position. As for example, the output may comprise coloured markings the colour of which switches in case the person approaches or reaches the capture position in one or each direction relative to the device 10. In a preferred embodiment, the visual feed back is given by switching the colour of the infinity mirror LEDs, so that the created tunnel appears in a different colour as soon as the viewer has reached its desired positioning relative to the device. In further preferred embodiment, only the colour of few LEDs are switched so that the viewer receives not only feedback about her or his viewing angle but also about the distance to the device or the head posture.

[0108] Figure 3 shows a crosscut of the device 10 with the infinity mirror 4 and a person 2 to be captured in a top view direction. As can be seen, by the particular arrangement of the optical axes of the cameras 12a and 12b, the face of the person 2 can be captured from two direction in a way so that the face can entirely be covered by the generated image data. In particular, the entire region of interest e.g. for facial cosmetic treatment can be covered, e.g. the front side, left and right face half and neck.

[0109] Furthermore, the infinity mirror 4 provides positioning of the person 2 according to the insight distance 49. The insight distance 49 is given by the (interior) design of the 240809W059340

[0110] 14 infinity mirror, e.g. by a distance between the front 42 and the backside mirror 41 and an arrangement of the light source 43 relative thereto.

[0111] In the shown embodiment, the infinity mirror 4 is designed so that the insight distance 49 is comparatively short to provide close positioning of the person 2 relative to the device 10. Such close positioning becomes suitable because the infinity mirror 4 provides looking of the person into infinity and thus squinting can be avoided despite the short insight distance 49.

[0112] However, this setup is insufficient for optimal imaging of a human eye. Although the infinity mirror fixes the gaze of the person to be imaged and also reduces blinking while imaging, cameras are still off-axis with the gaze of the person. Hence, eyes are imaged at an inclined angle. To overcome this problem, the invention includes an optical setup with bringing gaze of the person to be imaged in accordance with the camera axis, facilitating and improving imaging of human eyes for medical and / or security purposes.

[0113] Figures 4a and 4b illustrate two exemplary embodiments of a capture device 1 for imaging an eye of a person 2 accordingto a first aspect of the invention. For instance, such a capture device may be used as part of an ocular examination system for examining the eye or eyes of the person 2, e.g., for visual examination of the retina. Also, such a capture device may be used as part of an ocular recognition system, i.e., for identifying the person 2 based on visual inspection of the person’s eye or eyes.

[0114] The capture device 1 comprises an infinity mirror 4, a camera 3 and a beam splitter 5. The beam splitter 5 is arranged at the insight axis 46 and configured to split an optical path defined by the insight axis 46 into a first sub-path 51 and a second subpath 52. The beam splitter 5 can be of any kind, including polarizing beam splitters (PBS). In Figure 4a, the first sub-path 51 coincided with the insight axis 46, and in Figure 4b, the second sub-path 52 coincided with the insight axis 46.

[0115] The infinity mirror 4, which, e.g., may be configured as described above with respect to Figure 2, is arranged at the first sub-path 51 , so that the first surface 45 is directed 240809W059340

[0116] 15 towards the beam splitter 5 and, thus, can be viewed by the person 2 looking along the insight axis 46. The camera 3 is arranged at the second sub-path 52 and configured for capturing an image including at least the person’s eye when the person 2 looks along the insight axis 46 into the infinity mirror 4. For instance by positioning a suitable optical arrangement (not shown here) between the camera 3 and the beam splitter 5, the field of view of the camera 3 may be widened or narrowed to capture images of either only the eye or a part of the face (e.g., the area surrounding the eye 20 including eyebrow and / or glabella) or the whole face of the person 2. Optionally, the arrangement may be adaptable by the user depending on the required field of view.

[0117] Figures 5a and 5b show two exemplary embodiments of an infinity mirror 4. Figure 5a shows a first embodiment of the infinity mirror 4, the mirror comprising two plan parallel mirror surfaces 41 , 42. A back mirror surface 41 - particularly being fully reflective (R=1 ) - is arranged at the back side 47 of the infinity mirror 4, and a front mirror surface 42 - being only partly reflective (R<1 ) - is arranged at the front side 45 of the infinity mirror 4. Light sources 71 , 72 may be arranged in front of the front side 45 (from the viewpoint of the person looking at the infinity mirror), and / or between the two mirror surfaces 41 , 42. The space between the two mirror surfaces 41 , 42 is either a vacuum, or filled with air or similar gas(es), so that the refractive index n of that space is either 1 or close to 1 (n « 1). The material of the mirror surfaces 41 , 42 may be one of glass, PMMA or polycarbonate, so that their refractive index n is between 1 .4 and 1.6 (n » 1.5). Figure 5b shows a second embodiment of the infinity mirror 4, the mirror comprising a solid glass block 6, wherein the reflective surfaces of the infinity mirror are the surfaces on the front side 45 and the back side 47 of the glass block 6. Light sources 71 , 72 may be arranged in front of the front side 45 (from the viewpoint of the person looking at the infinity mirror), and / or between the front side 45 and the back side 47. The glass block 6 may comprise one or more cavities 61 for housing the light sources 72 that are arranged between the front side 45 and the back side 47. The reflective surface at the front side 45 has a reflectivity below 1 (R<1 ), whereas the reflective surface at the back side 47 may be fully reflective (R=1 ). 240809W059340

[0118] 16

[0119] Instead of glass, other transparent material may be used for the block 6, such as PMMA or polycarbonate. Depending on the chosen material the refractive index n of the block 6 is between about 1 .4 and 1 .6 (n « 1 .5).

[0120] Figure 6 illustrates an exemplary embodiment of an infinity mirror 4 with four arrays of light sources arranged around the mirror. The infinity mirror 4 has a rectangular shape, the longer side being parallel (along the insight axis 46) to a line connecting the eyes of a person when looking into the mirror 4. The light sources are arranged in two side arrays 73, 74, a bottom array 75 and a top array 76. Each array 73-76 comprising a row of light sources that are arranged in parallel to the edges of the front side 75 of the infinity mirror 4. As described with respect to Figures 5a and 5b, the light sources of the arrays 73-76 may be positioned in front of the front side 75 or between the front side 45 and the back side 47. If the infinity mirror 4 comprises a glass block (as described with respect to Figure 5b), all or some of the light sources may be positioned in cavities of the glass block.

[0121] Figure 7 shows an inner appearance created by exemplary embodiments of an infinity mirror, wherein the inner appearance involves an optical effect of infinity (“infinity optical effect”). The appearance of a tunnel tapering in infinity is created by an exemplary embodiment of an infinity mirror, wherein arrays of light sources are arranged around the mirror (e.g., as shown in Figure 6). As already described above with respect to Figure 2, a configuration of the infinity mirror with a number of LEDs being arranged around the perimeter of the infinity mirror to provide circumferential illumination provides an optical effect to an observer, as if the observer would be looking into an illuminated tunnel which comprises an infinite end of the tunnel in the centre (“infinity optical effect”). Such an appearance inside of the infinity mirror 4 occurs in case the user of the capture device 1 is in a desired pose (position and orientation) relative to the infinity mirror.

[0122] Figures 8a-c show another example of an inner appearance from three different poses of the observer’s eyes relative to the infinity mirror. In Figure 8a, the observer’s pose is far away (i.e., left) from a desired (i.e., centred) pose, in Figure 8b, the pose is 240809W059340

[0123] 17 closer to the desired pose, and in Figure 8c, the observer has reached the desired pose. The appearance of a tunnel serves as a guiding system for guiding the user to obtain the desired pose.

[0124] Figures 9a and 9b show an alternative guiding system of the infinity mirror. The two central lines of lights in Figure 9a have the same length and thereby indicate a good (i.e., central) position. The additional lines in Figure 9b indicate a bad position in terms of height. Being above the central line, the additional lines here indicate that the head is too high with respect to the target. The central line and the additional lines may have different colours to indicate their importance to the user. For instance, the central lines may be green, and the additional lines may be orange or red.

[0125] Figure 10 illustrates an exemplary embodiment of a of a capture device 1 for imaging an eye 20 of a person according to a second aspect of the invention. The capture device 1 comprises a camera 3 for capturing an image of at least one eye 20 of the person, optionally an image of the whole face or a part of the face of the person. The capture device 1 further comprises an infinity mirror 4 with a first, fully reflective surface 41 , and a second semi-reflective surface 42, wherein one or more light sources 70 are arranged at or around the infinity mirror 4 and relative to the first and second surfaces 41 , 42 to create a structured pattern of light in the infinity mirror 4. This structured pattern of light effects a corresponding pattern of glints 25 as corneal reflections in the (at least one) eye 20, when the person looks into the infinity mirror 4. As shown here, the camera 3 may be provided with its imaging axis 36 deviating from the insight axis 46. Alternatively, the camera 3 may be provided behind a beam splitter as shown in Figures 4a and 4b, so that the imaging axis 36 coincides with the insight axis 46, allowing a frontal view at the eye.

[0126] A controlling and processing unit (not shown here) of the capture device 1 detects the pattern of glints 25 in the images captured by the camera 3 and automatically derives a gaze direction of the eye 20 based on the positions of the pupil and the pattern of glints 25. Estimating a gaze direction based on pupil centre and corneal reflections is generally known in the art, and disclosed, e.g., in: E. D. Guestrin and M. 240809W059340

[0127] 18

[0128] Eizenman, “General theory of remote gaze estimation using the pupil center and corneal reflections,” in IEEE Transactions on Biomedical Engineering, vol. 53, no. 6, pp. 1124-1133, June 2006.

[0129] Optionally, a pose of the head may be estimated based on the derived gaze direction. For instance, further information, such as images of the face, can be used to support the estimation of the pose. A signal with feedback to adapt the pose of the head relative to the capture device 1 can then be provided - e.g., to the person or to an operator of the capture device 1 .

[0130] Figures 11 a-b show two exemplary embodiments of a capture device according to a third aspect of the invention. The capture device is provided in (or configured as) an artificial eyeball 80 - e.g. of a humanoid robot. The eyeball 80 may serve as a housing for some or all the components of the capture device, and e.g., can be spherical or half-spherical. The infinity mirror preferably can be adapted to the round shape of the eyeball 80: as shown here, both the front side 45 and the back side 47 with their reflective surfaces may have a circular shape. Also, the light sources may be arranged in a circular array 77 around the infinity mirror. For instance, the front side 45 may be provided at the front of the eyeball, thus appearing as the iris of the humanoid robot’s eye. Aside from being provided in the form of an eyeball, the capture device optionally may be configured according to the first or second aspect of the invention.

[0131] As shown in Figure 11 a, the camera 3 may be arranged behind the infinity mirror, on- axis with the insight axis 46. In this case, all reflective surfaces of the infinity mirror need to be semi-transparent to allow the camera 3 capturing images of an eye through these surfaces. The camera may be positioned inside the eyeball 80 or behind the eyeball, e.g., in a humanoid robot’s head. Alternatively, the camera may be arranged as shown in Figures 4a, 4b or 10, i.e., together with a beam splitter or off- axis. The camera may even be provided entirely outside of the eyeball 80.

[0132] Another alternative is shown in Figure 11 b. Here, both the front side 45 and the back 240809W059340

[0133] 19 side 47 have a central opening 88. Such an opening can be a hole in the reflective surfaces or a transparent, non-reflective part (or a more transparent, less reflective part) of the otherwise reflective surfaces. The camera 3 is positioned behind the opening in the back side 47 for capturing images of an eye through both of these openings 88. The opening88 in the front side 45 may be circular, thus appearing as a pupil of the eyeball 80, with the semi-reflective surface of the front side 45 appearing as the iris.

[0134] Figure 12 shows a humanoid robot 8 having two eyes, wherein one or both eyeballs 80 of the robot 8 are configured as the capture device of Figures 11 a or 11 b, i.e., comprising an infinity mirror and a camera, e.g., for examining one eye or both eyes (in particular simultaneously) of a person, orfor identifyingthe person based on eye-feature recognition.

[0135] Figure 13 shows an exemplary embodiment of an ocular examination system 90. The system comprises a capture device 1 for imaging an eye 20 of a person 2. For instance, the capture device 1 can be one of the exemplary embodiments disclosed above - particularly with respect to one of Figures 4a, 4b and 6. The capture device 1 comprises at least one camera and an infinity mirror. A controlling and processing unit9 of the ocular examination system 90 is configured to execute a data acquisition functionality to receive digital images (image data) of the eye captured by the camera of the capture device 1 and to generate eye data based on the digital images - for instance by extracting data related to the eye or parts thereof (eye data) from the image data. For instance, if the retina is to be examined, the eye data optionally may comprise only image data related to the retina. In the shown example, the ocular examination system 90 comprises a display unit 95 for displaying a representation of the eye data on a display, e.g., to an ophthalmologist or other physician.

[0136] Optionally, the controlling and processing unit 9 may be configured to execute an analysis functionality to automatically interpret the eye data in order to detect one or more indicators for a condition of the eye, e.g., of the retina, and to generate analysis data based on the indicators, which then may be provided to the ophthalmologist - 240809W059340

[0137] 20 e.g., by means of the display unit 95. The controlling and processing unit 9 also may be configured to access a medical database 96- e.g., via an Internet connection -to perform the analysis functionality.

[0138] Figure 14 shows an exemplary embodiment of an ocular recognition system 91 . The ocular recognition system 91 allows identifying a person 2 based on visual inspection of one or both eyes 20 of the person. The system comprises a capture device 1 for imaging an eye 20 (or both) of the person 2. For instance, the capture device 1 can be one of the exemplary embodiments disclosed above - particularly with respect to one of Figures 4a, 4b and 6. The capture device 1 comprises at least one camera and an infinity mirror. A controlling and processing unit 9 of the ocular recognition system 91 is configured to execute a data acquisition functionality to receive digital images (image data) of the eye captured by the camera of the capture device 1 and to generate eye data based on the digital images - for instance by extracting data related to the eye or parts thereof (eye data) from the image data. The controlling and processing unit 9 then compares the generated eye data with stored eye data from an eye data base 97. This eye data base 97 may be provided as part of the ocular recognition system 91 or be accessed remotely, e.g., via a local network or via an Internet connection. Based on the comparison of the generated and the stored eye data, an identity of the person 2 can be determined - or it is determined that the person’s identity is unknown. Information about the person 2 is then provided. This provision of information may include displaying it by means of a display unit 95 of the ocular recognition system 91. Additionally or alternatively, the information may be provided to an external device of a human supervisor, or to an automated system, such as, e.g., a door or a computer system, to allow or deny access to that system based on the provided information. In particular, the provided information may comprise the identity of the person, i.e. a name or identification number, and the human supervisor or the automated system decide whether or not access is granted. Alternatively, the information about the person 2 does not comprise the identity but only information that is relevant for granting or denying the access, such as a right of access or an entitlement granted to the person or a qualification of the person 2. The 240809W059340

[0139] - 21 - information about the person may be provided in the eye data base 97 or may be determined by the controllingand processingunit9 based on the determined identity by accessing a separate database. Like the eye database 97, this person database 98 may be provided as part of the ocular recognition system 91 or be accessed remotely, e.g., via a local network or via an Internet connection.

[0140] Both, the ocular examination system 90 of Figure 13, and the ocular recognition system 91 of Figure 14 optionally may be provided in the humanoid robot 8 of Figure 12, wherein at least the capture devices are provided in the robot’s eyeballs.

[0141] Although the invention is illustrated above, partly with reference to some preferred embodiments, it must be understood that numerous modifications and combinations of different features of the embodiments can be made. All of these modifications lie within the scope of the appended claims.

Claims

240809W05934022Claims1. Capture device (1) for imaging a face of a person (2) or a part of the face, particularly an eye (20) of the person, the capture device comprising- a camera (3) for capturing an image of the eye (20), and- an infinity mirror (4) comprising a front side (45) with a first surface (42), a back side (47) with a second surface (41 ), wherein the first and second surfaces are at least partially reflecting and arranged in parallel, and one or more light sources (71-76) arranged relative to the first and second surface for creating an infinity optical effect, characterized by a beam splitter (5) that is arranged along an optical path and configured to split the optical path into a first and a second sub-path (51 , 52), wherein the infinity mirror (4) is arranged at the first sub-path (51 ) and the camera (3) is arranged at the second sub-path (52).

2. Capture device (1 ) for determining a gaze direction of an eye (20) of a person (2), the capture device (1 ) comprising- a camera (3) for capturing an image of the eye (20);- a controlling and processing unit; and- an infinity mirror (4) comprising a front side (45) with a first surface (42), a back side (47) with a second surface (41 ), wherein the first and second surfaces are at least partially reflecting and arranged in parallel, and one or more light sources (71-76) arranged relative to the first and second surface for creating an infinity optical effect, wherein the one or more light sources (71-76) are arranged relative to the first and second surfaces (41 , 42) of the infinity mirror (4) to create a structured light pattern, characterized in that the controlling and processing unit is configured240809W05934023- to detect, in the captured image, a pattern of glints (25) on the at least one eye (20), the pattern of glints constituting a reflection of at least a part of the structured pattern;- to derive, based on the detected pattern of glints (25), a gaze direction of the at least one eye (20); and- to provide a feedback signal based on the derived gaze direction.

3. Capture device (1) according to claim 2, wherein the controlling and processing unit is configured to determine whether an orientation of the derived gaze direction relative to an optical axis (46) of the infinity mirror (4) is outside a predetermined range, wherein, if the gaze direction is outside the predetermined range, the feedback signal comprises instructions to correct the gaze direction.

4. Capture device (1) according to claim 2 or claim 3, wherein the feedback signal comprises a visual guiding output providing instructions to the person howto correct the gaze, the visual guiding output being provided by means of the infinity mirror (4).

5. Capture device (1 ) according to claim 4, wherein the visual guiding output is provided by controllingthe one or more light sources (71-76), in particular wherein controlling the one or more light sources comprises creating different structured patterns.

6. Capture device (1) according to claim 2 or claim 3, wherein the controlling and processing unit is configured to determine whether an orientation of the derived gaze direction relative to an optical axis (46) of the infinity mirror (4) is indicative of a posture of the person’s head being outside a predetermined range, the posture including at least one of neck flexion, neck rotation and lateral bending, wherein, if the posture is outside the predetermined range, the feedback signal comprises instructions to correct the posture.

7. Capture device (1) according to claim 6, wherein240809W05934024- the camera (3) is arranged and configured to capture an image of the face of the person (2) or of a part of the face comprising the eye (20); and- the controlling and processing unit is configured to determine the posture of the person’s head also based on the image of the face.

8. Capture device (1) according to any one of claims 2 to 7, wherein the feedback signal comprises an acoustical guiding output.

9. Capture device (1) according to any one of claims 2 to 8, comprising a beam splitter (5) that is arranged along an optical path and configured to split the optical path into a first and a second sub-path (51 , 52), wherein the infinity mirror (4) is arranged at the first sub-path (51 ) and the camera (3) is arranged at the second sub-path (52).

10. Capture device (1) according to any one of the preceding claims, configured to allow the person to look along the optical path and the first sub-path (51) at the front side (45) of the infinity mirror (4).

11. Capture device (1) according to any one of the preceding claims, wherein the first surface (42) is semi-transparent, in particular wherein the first surface- has a reflectance of at least 90%, particularly at least 94%, and / or- has a transmission of at least 2.5%, particularly at least 3.5%.

12. Capture device (1) according to any one of the preceding claims, wherein the second surface (41 )- is non-transparent; and / or- has a reflectance of at least 94%, particularly at least 98%.

13. Capture device (1) according to any one of the preceding claims, wherein the front side (45) and the back side (47) are connected by side walls.

14. Capture device (1) according to any one of the preceding claims, wherein the front side (45) and the back side (47) are surfaces of a glass block (6).240809W0593402515. Capture device (1) according to claim 14, wherein the glass block (6) is cuboidal.

16. Capture device (1) according to claim 14 or claim 15, wherein the glass block (6) comprises one or more cavities (61 ), and the one or more light sources (71-76) are arranged in the cavities, particularly wherein each cavity houses one light source.

17. Capture device (1) according to any one of the preceding claims, wherein the first surface (42) and the second surface (41 ) have an elongated shape, particularly a rectangular or oval shape, a width of each surface (41 , 42) being larger than a height of each surface (41 , 42), the width being parallel to an axis connecting the eyes of the person (2).

18. Capture device (1) according to any one of the preceding claims, wherein the light sources (71-76) are light emitting diodes.

19. Capture device (1) according to any one of the preceding claims, wherein the light sources (71-76) comprise a plurality of light sources that are circumferentially arranged around the optical path.

20. Capture device (1) according to any one of the preceding claims, wherein at least one light source (72) is positioned between the front side (45) and the back side (47), particularly between the first and second surfaces (41 , 42).

21. Capture device (1) according to any one of the preceding claims, wherein at least one light source (71) is positioned between the front side (45) and the eye (20).

22. Capture device (1) according to any one of the preceding claims, wherein the light sources (71-76) comprise a plurality of light sources that are arranged in one or more arrays (73-76) of light sources, particularly arrays of point-like light sources.240809W0593402623. Capture device (1) according to claim 22, wherein- the front side (45) and the back side (47) are surfaces of a glass block (6), particularly wherein the glass block is cuboidal; and- the glass block (6) comprises one or more cavities (61 ), and the one or more arrays (73-76) of light sources are arranged in the cavities, particularly wherein each cavity houses one light source or one array of light sources.

24. Capture device (1) according to claim 22 or claim 23, wherein- one array of light sources is configured as a bottom array (75), wherein the light sources of the bottom array (75) are arranged in a line that is parallel to the front side (45) and below the front side (45); and / or- one array of light sources is configured as a top array (76), wherein the light sources of the top array (76) are arranged in a line that is parallel to the front side (45) and above the front side (45).

25. Capture device (1) according to any one of claims 22 to 24, wherein one or more arrays, particularly two arrays, are configured as side arrays (73, 74), wherein light sources of each side array (73, 74) are arranged in a line that is parallel to the first surface.

26. Capture device (1) according to any one of claims 22 to 25, wherein the arrays (73-76) are configured and arranged relative to the first and second surfaces (41 , 42) to create an inner appearance that is visible to the person (2) when looking alongthe optical path into the infinity mirror (4), particularly wherein the inner appearance comprises an appearance of a tunnel tapering in infinity.

27. Capture device (1) according to any one of the preceding claims, wherein the infinity mirror (4) is configured to create an inner appearance that is visible to the person (2) when looking alongthe optical path into the infinity mirror (4),240809W05934027 wherein the inner appearance is entirely observable by the person (2) when the person is aligned relative to the capture device (1) in a predefined manner.

28. Capture device (1) according to claim 27, wherein- the inner appearance is or comprises the appearance of a tunnel tapering in infinity, and- all sides of the tunnel are observable when the person (2) is aligned relative to the capture device (1 ) in a predefined manner.

29. Capture device (1) according to any one of the preceding claims, the capture device being provided in a spherical or hemispherical housing, wherein the infinity mirror (4) is observable from the outside through a circular opening in the housing.

30. Capture device (1) according to claim 29, wherein the housing has the appearance of an eyeball (80), the circular hole appearing as an iris of the eyeball.

31. Capture device (1) according to claim 29 or claim 30, the capture device being part of a humanoid robot (8), the robot comprising at least a head, particularly wherein the housing has the appearance of an eyeball (80) of the humanoid robot.

32. Capture device (1) according to any one of claims 29 to 31 , wherein the first surface (42) and the second surface (41) have a circular shape, particularly wherein the light sources are arranged in a circular array (77) around the infinity mirror (4).

33. Capture device (1) according to any one of claims 29 to 31 , wherein the first surface (42) and the second surface (41 ) have a central opening (88), the camera (3) being positioned behind the back side (47) of the infinity mirror (4) and arranged to capture the images of the eye (20) through the central openings.240809W0593402834. Ocular examination system (90) for examining an eye (20) of a person (2), particularly for visual examination of the retina, the system comprising- a controlling and processing unit (9), and- the capture device (1 ) of any one of claims 1 to 33, wherein the controlling and processing unit (9) is configured to execute a data acquisition functionality to generate eye data based on at least one captured image of the eye (20).

35. Ocular examination system (90) accordingto claim 34, comprising a display device (95) having a display and being configured to display a representation of the eye data on the display.

36. Ocular examination system (90) according to claim 34 or claim 35, wherein the eye data comprises image data of the retina.

37. Ocular examination system (90) according to any one of claims 34 to 36, wherein the controlling and processing unit (9) is configured to execute an analysis functionality to interpret the eye data to detect one or more indicators for a condition of the retina and to generate analysis data based on the indicators.

38. Ocular examination system (90) according to any one of claims 34 to 37, comprising an interface (96) configured to output eye data and / or analysis data to a user.

39. Humanoid robot (8), comprisingthe ocular examination system (90) of any one of claims 23 to 27, wherein at least one eyeball (80) of the of the humanoid robot at least partially comprises the capture device (1 ), particularly wherein the infinity mirror (4) is observable from the outside through a circular hole in the eyeball (80) that appears as an iris of the eyeball (80).

40. Ocular recognition system (91 ) for identifying a person (2) based on visual inspection of an eye (20) of the person, the system comprising240809W05934029- a controlling and processing unit (9); and- the capture device (1 ) of any one of claims 1 to 33, wherein the controlling and processing unit (9) is configured- to receive at least one captured image of the eye (20);- to generate eye data based on the at least one captured image of the eye (20);- to compare the generated eye data with stored eye data from an eye data base (97);- to determine an identity of the person (2) based on the stored and generated eye data; and- to provide information about the person (2).

41. Ocular recognition system (91) according to claim 40, wherein the information about the person (2) comprises the identity of the person.

42. Ocular recognition system (91 ) according to claim 40 or claim 41 , wherein the controlling and processing unit (9) is configured to determine the information about the person (2) based on the determined identity.

43. Ocular recognition system (91 ) according to claim 42, wherein the controlling and processing unit (9) is configured to access a person database (98) to determine the information about the person (2).

44. Ocular recognition system (91 ) according to any one of claims 40 to 43, wherein the information about the person (2) comprises at least one of a right, an entitlement and a qualification of the person, particularly a right of access.

45. Humanoid robot (8), comprisingthe ocular recognition system (91) of any one of claims 40 to 44, wherein at least one eyeball (80) of the of the humanoid robot at least partially comprises the capture device (1 ), particularly wherein the infinity mirror (4) is observable from the outside through a circular hole in the eyeball (80) that appears as an iris of the eyeball (80).

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