Systems and methods of object identification utilizing polarization

Abstract

Systems and methods for polarization-based object identification, implemented in accordance with various embodiments of the invention are illustrated. One embodiment includes an object identification system including an illumination system which illuminates an object; a polarization metasurface; an image sensor; and a polarization sensing system. Incident light from the illumination system reflects off the object as reflected light with one or more polarization states. The polarization metasurface receives the reflected light reflected from the object. The image sensor has a plurality of different regions configured to sense one or more different polarization states of light from the polarization metasurface. The polarization sensing system identifies the object based on the one or more polarization states.

Description

SYSTEMS AND METHODS OF OBJECT IDENTIFICATION UTILIZINGPOLARIZATIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The current application claims the benefit of and priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63 / 684,248, entitled “Systems and Methods of Object Identification Utilizing Polarization” filed August 16, 2024. The disclosure of U.S. Provisional Patent Application No. 63 / 684,248 is hereby incorporated by reference in its entirety for all purposes.FIELD OF THE INVENTION

[0002] The present invention generally relates to polarization-based identification. More particularly this specification is directed to polarization-optimizing configurations.BACKGROUND

[0003] Metasurfaces include a plurality of metasurface elements. Metasurface elements are diffractive optical elements in which individual waveguide elements have subwavelength spacing and have a planar profile. Metasurface elements have recently been developed for application in the UV-IR bands (300-10,000 nm). Compared to traditional refractive optics, metasurface elements may introduce phase shifts onto the light field and / or alter the polarization state of the light. Metasurface elements have thicknesses or cross-sectional dimensions on the order of the wavelength of light at which they are designed to operate, whereas traditional refractive surfaces have thicknesses that are 10-100 times (or more) larger than the wavelength of light at which they are designed to operate. Additionally, metasurface elements may have no variation in thickness along or parallel to the optical axis in the constituent elements and thus are able to shape light without any curvature, as typically included in refractive optics. Compared to traditional diffractive optical elements (DOEs), for example binary diffractive optics, metasurface elements have the ability to impart a range of phase shifts on an incident light field, at a minimum the metasurface elements can have phase shifts between 0-2TTwith at least 5 distinct values from that range, whereas binary DOEs are only able to impart two distinct functional values of phase shift and are often limited to phase shifts of either 0 or 1 TT. Compared to multi-level DOE’s, metasurface elements do not require height variation of its constituent elements along the optical axis, only the in-plane geometries of the metasurface element features vary.SUMMARY OF THE INVENTION

[0004] Many embodiments are directed to systems and methods for object identification utilizing polarization. One embodiment includes an object identification system including an illumination system which illuminates an object; a polarization metasurface; an image sensor; and a polarization sensing system. Incident light from the illumination system reflects off the object as reflected light with one or more polarization states. The polarization metasurface receives the reflected light reflected from the object. The image sensor has a plurality of different regions configured to sense one or more different polarization states of light from the polarization metasurface. The polarization sensing system identifies the object based on the one or more polarization states.

[0005] Some embodiments include an object identification system comprising: an illumination system which illuminates an object, wherein incident light from the illumination system reflects off the object as reflected light with one or more polarization states; a polarization metasurface which receives the reflected light reflected from the object; an image sensor with a plurality of different regions configured to sense one or more different polarization states of light from the polarization metasurface; and a polarization sensing system which identifies the object based on the one or more polarization states.

[0006] In some embodiments, the polarization metasurface directs the reflected light into the one or more different polarization states and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

[0007] In some embodiments, the polarization metasurface is a polarization separator which is configured to direct the one or more different polarization states of the reflected light in different directions; and the one or more different polarization states of the reflected light directed from the polarization metasurface are incident on the plurality ofdifferent regions of the image sensor.

[0008] In some embodiments, the light from the illumination system comprises nearinfrared light.

[0009] In some embodiments, the illumination system includes sunlight.

[0010] Some embodiments further comprise a filter which filters the reflected light that is captured by the polarization sensing system.

[0011] In some embodiments, the filter transmits near-infrared light.

[0012] In some embodiments, the illumination system includes a light output from a display device.

[0013] Some embodiments further comprise an ambient light sensor, wherein the light output from the display device is altered based on data from the ambient light sensor.

[0014] In some embodiments, the light output from the display device is altered by an increase in intensity of the light output or a specific color of light being produced by the light output of the display device.

[0015] In some embodiments, the illumination system produces a structured light output.

[0016] In some embodiments, the illumination system comprises a vertical cavity surface emitting laser (VCSEL) and a VCSEL metasurface which structures light from the VCSEL into the structured light output.

[0017] In some embodiments, the at least one VCSEL is configured into a VCSEL array.

[0018] In some embodiments, the VCSEL array is overlaid with a linear polarizer integrated into a diffuser.

[0019] In some embodiments, the VCSEL array comprises at least one of: a partialpolarization; an unpolarized background; and a preferential linear polarization.

[0020] In some embodiments, the linear polarizer is directionally-aligned with the preferential linear polarization.

[0021] In some embodiments, the VCSEL metasurface is: overlaid over the at least one VCSEL is configured into a VCSEL array; and used to project a polarization field onto the object.

[0022] In some embodiments, the polarization field is a spatially varying arbitrary polarization field.

[0023] In some embodiments, the structured light output is specific to the object.

[0024] In some embodiments, the structured light output comprises at least one dot pattern.

[0025] In some embodiments, the structured light output comprises a first dot pattern and a second dot pattern.

[0026] In some embodiments, the structured light output comprises a first dot pattern and a flood illumination pattern.

[0027] In some embodiments, the first dot pattern has a first polarization state and the second dot pattern has a second polarization state.

[0028] In some embodiments, the first and second dot patterns are projected simultaneously.

[0029] In some embodiments, the first dot pattern and the flood illumination pattern are projected simultaneously.

[0030] In some embodiments, the first and second dot patterns are projected in a sequence at two different times.

[0031] In some embodiments, the first and second polarization states are orthogonal.

[0032] In some embodiments, the object is a face.

[0033] In some embodiments, the polarization metasurface is configured to diffract light of a first polarization in a first direction and light of a second polarization in a second direction, and wherein the first polarization and the second polarization are different and the first direction and the second direction are different.

[0034] In some embodiments, the first polarization and the second polarization are arbitrary polarizations.

[0035] In some embodiments, the first polarization and the second polarization are orthogonal.

[0036] In some embodiments, the polarization metasurface is further configured to diffract light of a third polarization in a third direction, wherein the first polarization, the second polarization, and the third polarization are all different and the first direction, thesecond direction, and the third direction are all different.

[0037] In some embodiments, the polarization metasurface is further configured to diffract light of a fourth polarization in a fourth direction, wherein the first polarization, the second polarization, the third polarization, and the fourth polarization are all different and the first direction, the second direction, the third direction, and the fourth direction are all different.

[0038] In some embodiments, the polarization metasurface comprises an array of metasurface lenslets; and each of the metasurface lenslets are configured to direct light having a polarization state into different pixels of the image sensor.

[0039] In some embodiments, at least some of the metasurface lenslets are separated by spaces; and the spaces do not have a polarization metasurface element such that light impinging the spaces is not directed based on its polarization state.

[0040] Some embodiments further comprise a microlens array.

[0041] In some embodiments, the microlens array is a metasurface.

[0042] Some embodiments further comprise a refractive lens before the polarization metasurface.

[0043] In some embodiments, the illumination system comprises a first illuminator which provides light having a first static polarization state.

[0044] In some embodiments, the illumination system comprises a second illuminator which provides light having a second static polarization state.

[0045] In some embodiments, the first and second static polarization states are orthogonal.

[0046] In some embodiments, first and second illuminators provide sequenced illumination.

[0047] In some embodiments, the polarization metasurface directs the reflected light into the one or more different polarization states and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

[0048] In some embodiments, the first static polarization state from the illumination system is the same as at least one of the one or more different polarization states which the polarization metasurface directs onto the image sensor.

[0049] In some embodiments, identifying the object is performed based on relative polarization intensities determined from the reflected light detected by each of the plurality of different regions of the image sensor.

[0050] In some embodiments, the relative polarization intensities are interpreted as proportional to surface normal estimates relative to the image sensor.

[0051] In some embodiments, the surface normal estimates are determined from the relative polarization intensities to derive a shape of the object in three-dimensional (3D) space.

[0052] In some embodiments, the reflected light is interpreted as a Mueller polarimetric image; and the Mueller polarimetric image is used to identify the shape of the object.

[0053] Some embodiments include a method for object identification, the method comprising: receiving reflected light on a polarization metasurface, wherein the reflected light is: projected by an illumination system as incident light; reflected off on an object; and reflected with one or more polarization states; detecting, through an image sensor, the reflected light, wherein: the image sensor comprises a plurality of different regions; and each region of the plurality of different regions is configured to detect a given state of the one or more polarization states of the reflected light; and identifying the object using a polarization receiver, wherein identifying the object is performed based on detections of the reflected light.

[0054] In some embodiments, the polarization metasurface directs the reflected light into one or more different polarization states and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

[0055] In some embodiments, the polarization metasurface is a polarization separator which is configured to direct one or more different polarization states of the reflected light in different directions; and the one or more different polarization states of the reflected light directed from the polarization metasurface are incident on the plurality of different regions of the image sensor.

[0056] In some embodiments, the incident light from the illumination system comprises near-infrared light.

[0057] In some embodiments, the incident light comprises sunlight.

[0058] In some embodiments, a filter is used to filter the reflected light that is captured by the polarization receiver.

[0059] In some embodiments, the filter transmits near-infrared light.

[0060] In some embodiments, the illumination system includes a light output from a display device.

[0061] In some embodiments, the light output from the display device is altered based on data from an ambient light sensor.

[0062] In some embodiments, the light output from the display device is altered by an increase in intensity of the light output or a specific color of light being produced by the light output of the display device.

[0063] In some embodiments, the illumination system includes a structured light output.

[0064] In some embodiments, projecting the incident light comprises structuring light from a vertical cavity surface emitting laser (VCSEL) into the structured light output using a VCSEL metasurface, wherein the illumination system comprises the VCSEL and the VCSEL metasurface.

[0065] In some embodiments, the at least one VCSEL is configured into a VCSEL array.

[0066] In some embodiments, the VCSEL array is overlaid with a linear polarizer integrated into a diffuser.

[0067] In some embodiments, the VCSEL array comprises at least one of: a partialpolarization; an unpolarized background; and a preferential linear polarization.

[0068] In some embodiments, the linear polarizer is directionally-aligned with the preferential linear polarization.

[0069] In some embodiments, the VCSEL metasurface is overlaid over the at least one VCSEL is configured into a VCSEL array; and used to project a polarization field onto the object.

[0070] In some embodiments, the polarization field is a spatially varying arbitrary polarization field.

[0071] In some embodiments, the structured light output is specific to the object.

[0072] In some embodiments, the structured light output comprises at least one dot pattern.

[0073] In some embodiments, the structured light output comprises a first dot pattern and a flood illumination pattern.

[0074] In some embodiments, the structured light output includes a first dot pattern and a second dot pattern.

[0075] In some embodiments, the first dot pattern has a first polarization state and the second dot pattern has a second polarization state.

[0076] In some embodiments, the first and second dot patterns are projected simultaneously.

[0077] In some embodiments, the first dot pattern and the flood illumination pattern are projected simultaneously.

[0078] In some embodiments, the first and second dot patterns are projected in a sequence at two different times.

[0079] In some embodiments, the first and second polarization states are orthogonal.

[0080] In some embodiments, the object is a face.

[0081] In some embodiments, receiving the reflected light on the polarization metasurface comprises diffracting, from the reflected light, light of a first polarization in a first direction and light of a second polarization in a second direction, and the first polarization and the second polarization are different, and the first direction and the second direction are different.

[0082] In some embodiments, the first polarization and the second polarization are arbitrary polarizations.

[0083] In some embodiments, the first polarization and the second polarization are orthogonal.

[0084] In some embodiments, receiving the reflected light on the polarization metasurface further comprises diffracting, from the reflected light, light of a third polarization in a third direction; the third polarization is different from the first polarization and the second polarization; and the third direction is different from the first direction and the second direction.

[0085] In some embodiments, receiving the reflected light on the polarization metasurface further comprises diffracting, from the reflected light, light of a fourth polarization in a fourth direction; the fourth polarization is different from the first, second and third polarizations; and the third direction is different from the first, second and third directions.

[0086] In some embodiments, the polarization metasurface comprises an array of metasurface lenslets; and each of the metasurface lenslets are configured to direct a particular subset of the incident light, of a specific polarization state, into different pixels of the image sensor.

[0087] In some embodiments, at least some of the metasurface lenslets are separated by spaces; and the spaces do not have a polarization metasurface element such that light impinging the spaces is not directed based on its polarization state.

[0088] In some embodiments, the image sensor comprises a microlens array.

[0089] In some embodiments, the microlens array is a metasurface.

[0090] In some embodiments, the incident light enters a refractive lens before the polarization metasurface.

[0091] In some embodiments, a first subset of the incident light comes from a first illuminator of the illumination system which provides a first static polarization state.

[0092] In some embodiments, a second subset of the incident light comes from a second illuminator of the illumination system which provides a second static polarization state.

[0093] In some embodiments, the first and second static polarization states are orthogonal.

[0094] In some embodiments, first and second illuminators provide sequenced illumination.

[0095] In some embodiments, the polarization metasurface directs the reflected light into one or more different polarization states; and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

[0096] In some embodiments, the first static polarization state from the illumination system is the same as at least one of the one or more different polarization states whichthe polarization metasurface directs onto the image sensor.

[0097] In some embodiments, identifying the object is performed based on relative polarization intensities determined from the reflected light detected by each of the plurality of different regions of the image sensor.

[0098] In some embodiments, the relative polarization intensities are interpreted as proportional to surface normal estimates relative to the image sensor.

[0099] In some embodiments, the surface normal estimates are determined from the relative polarization intensities to derive a shape of the object in three-dimensional (3D) space.

[0100] In some embodiments, the reflected light is interpreted as a Mueller polarimetric image; and the Mueller polarimetric image is used to identify the shape of the object.

[0101] Some embodiments include a non-transitory computer-readable medium comprising instructions that, when executed, are configured to cause a processor to perform a process for: receiving, on a polarization metasurface, reflected light reflected off on an object, wherein the reflected light is: projected by an illumination system as incident light; and reflected with one or more polarization states; detecting, through an image sensor, the reflected light, wherein: the image sensor comprises a plurality of different regions; and each region of the plurality of different regions is configured to detect a given state of the one or more polarization states of the reflected light; and identifying the object using a polarization receiver, wherein identifying the object is performed based on detections of the reflected light.

[0102] In some embodiments, the polarization metasurface directs the reflected light into one or more different polarization states and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

[0103] In some embodiments, the polarization metasurface is a polarization separator which is configured to direct one or more different polarization states of the reflected light in different directions; and the one or more different polarization states of the reflected light directed from the polarization metasurface are incident on the plurality of different regions of the image sensor.

[0104] In some embodiments, the incident light from the illumination system comprisesnear-infrared light.

[0105] In some embodiments, the incident light comprises sunlight.

[0106] In some embodiments, a filter is used to filter the reflected light that is captured by the polarization receiver.

[0107] In some embodiments, the filter transmits near-infrared light.

[0108] In some embodiments, the illumination system includes a light output from a display device.

[0109] In some embodiments, the light output from the display device is altered based on data from an ambient light sensor.

[0110] In some embodiments, the light output from the display device is altered by an increase in intensity of the light output or a specific color of light being produced by the light output of the display device.

[0111] In some embodiments, the illumination system includes a structured light output.

[0112] In some embodiments, projecting the incident light comprises structuring light from a vertical cavity surface emitting laser (VCSEL) into the structured light output using a VCSEL metasurface, wherein the illumination system comprises the VCSEL and the VCSEL metasurface.

[0113] In some embodiments, the at least one VCSEL is configured into a VCSEL array.

[0114] In some embodiments, the VCSEL array is overlaid with a linear polarizer integrated into a diffuser.

[0115] In some embodiments, the VCSEL array comprises at least one of: a partialpolarization; an unpolarized background; and a preferential linear polarization.

[0116] In some embodiments, the linear polarizer is directionally-aligned with the preferential linear polarization.

[0117] In some embodiments, the VCSEL metasurface is: overlaid over the at least one VCSEL is configured into a VCSEL array; and used to project a polarization field onto the object.

[0118] In some embodiments, the polarization field is a spatially varying arbitrarypolarization field.

[0119] In some embodiments, the structured light output is specific to the object.

[0120] In some embodiments, the structured light output comprises at least one dot pattern.

[0121] In some embodiments, the structured light output comprises a first dot pattern and a flood illumination pattern.

[0122] In some embodiments, the structured light output includes a first dot pattern and a second dot pattern.

[0123] In some embodiments, the first dot pattern has a first polarization state and the second dot pattern has a second polarization state.

[0124] In some embodiments, the first and second dot patterns are projected simultaneously.

[0125] In some embodiments, the first dot pattern and the flood illumination pattern are projected simultaneously.

[0126] In some embodiments, the first and second dot patterns are projected in a sequence at two different times.

[0127] In some embodiments, the first and second polarization states are orthogonal.

[0128] In some embodiments, the object is a face.

[0129] In some embodiments, receiving the reflected light on the polarization metasurface comprises diffracting, from the reflected light, light of a first polarization in a first direction and light of a second polarization in a second direction, and

[0130] the first polarization and the second polarization are different, and the first direction and the second direction are different.

[0131] In some embodiments, the first polarization and the second polarization are arbitrary polarizations.

[0132] In some embodiments, the first polarization and the second polarization are orthogonal.

[0133] In some embodiments, receiving the reflected light on the polarization metasurface further comprises diffracting, from the reflected light, light of a third polarization in a third direction; the third polarization is different from the first polarizationand the second polarization; and the third direction is different from the first direction and the second direction.

[0134] In some embodiments, receiving the reflected light on the polarization metasurface further comprises diffracting, from the reflected light, light of a fourth polarization in a fourth direction; the fourth polarization is different from the first, second and third polarizations; and the third direction is different from the first, second and third directions.

[0135] In some embodiments, the polarization metasurface comprises an array of metasurface lenslets; and each of the metasurface lenslets are configured to direct a particular subset of the incident light, of a specific polarization state, into different pixels of the image sensor.

[0136] In some embodiments, at least some of the metasurface lenslets are separated by spaces; and the spaces do not have a polarization metasurface element such that light impinging the spaces is not directed based on its polarization state.

[0137] In some embodiments, the image sensor comprises a microlens array.

[0138] In some embodiments, the microlens array is a metasurface.

[0139] In some embodiments, the incident light enters a refractive lens before the polarization metasurface.

[0140] In some embodiments, a first subset of the incident light comes from a first illuminator of the illumination system which provides a first static polarization state.

[0141] In some embodiments, a second subset of the incident light comes from a second illuminator of the illumination system which provides a second static polarization state.

[0142] In some embodiments, the first and second static polarization states are orthogonal.

[0143] In some embodiments, first and second illuminators provide sequenced illumination.

[0144] In some embodiments, the polarization metasurface directs the reflected light into one or more different polarization states; and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

[0145] In some embodiments, the first static polarization state from the illumination system is the same as at least one of the one or more different polarization states which the polarization metasurface directs onto the image sensor.

[0146] In some embodiments, identifying the object is performed based on relative polarization intensities determined from the reflected light detected by each of the plurality of different regions of the image sensor.

[0147] In some embodiments, the relative polarization intensities are interpreted as proportional to surface normal estimates relative to the image sensor.

[0148] In some embodiments, the surface normal estimates are determined from the relative polarization intensities to derive a shape of the object in three-dimensional (3D) space.

[0149] In some embodiments, the reflected light is interpreted as a Mueller polarimetric image; and the Mueller polarimetric image is used to identify the shape of the object.

[0150] Additional embodiments and features are set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the specification or may be learned by the practice of the invention. A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings, which form a part of this disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0151] The description and claims will be more fully understood with reference to the following figures and data graphs, which are presented as exemplary embodiments of the invention and should not be construed as a complete recitation of the scope of the invention.

[0152] FIG. 1 A illustrates a system for object identification in accordance with several embodiments of the invention.

[0153] FIG. 1 B illustrates a schematic of an illumination system having a light source with an integrated polarizer and diffuser in accordance with some embodiments of the invention.

[0154] FIG. 1 C illustrates a schematic of an integrated polarizer and diffuser in accordance with certain embodiments of the invention.

[0155] FIG. 1 D illustrates a schematic of an integrated polarizer and diffuser in accordance with several embodiments of the invention.

[0156] FIG. 1 E illustrates a schematic of an integrated polarizer and diffuser in accordance with some embodiments of the invention.

[0157] FIG. 1 F illustrates a schematic of an integrated polarizer and diffuser in accordance with certain embodiments of the invention.

[0158] FIG. 2 illustrates a schematic of a polarization imaging-directed variant of systems implemented in accordance with certain embodiments of the invention.

[0159] FIGS. 3A - 3B illustrate a schematic of a polarization sorting optical metasurface microlens array (PSOMMA) configured in accordance with multiple embodiments of the invention.

[0160] FIG. 4A - 4B illustrate a PSOMMA-lenslet with various polarizations in accordance with numerous embodiments of the invention.

[0161] FIG. 5A illustrates a cross-sectional view of an imaging device including a polarization sorting capability implemented in accordance with various embodiments of the invention.

[0162] FIG. 5B is a schematic of a biometric identification system embedded in a smart device in accordance with multiple embodiments of the invention.

[0163] FIG. 6 illustrates a polarization system that performs object identification in accordance with a number of embodiments of the invention.

[0164] FIG. 7 illustrates a computation element that executes instructions to perform processes in accordance with certain embodiments of the invention.

[0165] FIG. 8 illustrates an illuminator implemented in accordance with numerous embodiments of the invention.

[0166] FIG. 9 illustrates a lighting system for object detection implemented in accordance with certain embodiments of the invention.

[0167] FIG. 10 illustrates a polarization receiver which includes a polarization separating metasurface which splits light into four different polarizations in accordancewith several embodiments of the invention.

[0168] FIG. 11 A illustrates a schematic of a system for interpreting a 3D structure of an object in accordance with some embodiments of the invention.

[0169] FIG. 11 B illustrates a schematic of the principle of operation for the system described in connection with Fig. 11A in accordance with certain embodiments of the invention.

[0170] FIG. 11 C illustrates a schematic of the system of Fig. 11A demonstrating depth and shape ambiguity in accordance with some embodiments of the invention.

[0171] FIG. 11 D illustrates a schematic of a system where the illumination is structured illumination in accordance with several embodiments of the invention.

[0172] FIG. 11 E illustrates a system of dynamic structured illumination in accordance with numerous embodiments of the invention.

[0173] FIG. 11 F illustrates a system of wavelength filtering and choice of illumination in accordance with certain embodiments of the invention.

[0174] FIG. 11 G illustrates a schematic of the system described in connection with Fig. 11A including complex polarimetric information in a 3D reconstruction algorithm in accordance with a number of embodiments of the invention.

[0175] FIG. 11 H illustrates a detail of glossy reflection distribution for polarized light (and diffuse reflection for unpolarized light) in accordance with several embodiments of the invention.DETAILED DESCRIPTION

[0176] Various embodiments of the invention concern approaches to object identification, including but not limited to application of near-infrared (NIR) and / or polarized metasurfaces to refine object visibility. In doing so, systems implemented in accordance with various embodiments may determine improved noise reduction, obtain better resolution, and / or manage lighting. These approaches may be used for enabling downstream applications, including but not limited to biometric authentication.

[0177] Systems and methods for object identification may, in some embodiments, be based around illumination through varying wavelengths including but not limited to nearinfrared (NIR) illumination. FIG. 1A illustrates a system for object identification in accordance with several embodiments of the invention. The system incorporates, but is not limited to an illuminator 104, an object 102, and at least one sensor 106. The illuminator 104 may be configured to illuminate an object 102 with light 104a. The light 104a can be reflected by the object 102 into reflected light 106a. The reflected light 106a may be sensed by the at least one sensor 106.

[0178] In various embodiments of the invention, the sensor(s) 106 may be directed to polarization. For example, sensor(s) 106 may include, but are not limited to: polarization sensors, non-polarization sensors with polarization filters, and / or sensors coupled with polarization sorting elements. As such, the polarization signature of the reflected light 106a may be altered based on certain properties of the object such as material configuration and topography. The (e.g., polarization) sensors 106 may be linearly- polarized to polarize pixels across RGB spectrum. Additionally or alternatively, in some cases, the sensor(s) may or may not include infrared detection functionality.

[0179] Various illuminators 104 and illumination sources may be utilized in accordance with miscellaneous embodiments of the invention, these may include but are not limited to transducers / energy sources like light-emitting diodes (LEDs), vertical-cavity surfaceemitting lasers (VCSELs), and / or miscellaneous sources of (e.g., polarized, nonpolarized) light 104a. When polarized, the light 104a may have one or more polarization states, including but not limited to linear, elliptical, circular, and orthogonal polarization states. In some embodiments, illumination sources 104 may further include configurations and combinations that output light 104a with one or more polarization states. Some examples include, but are not limited to:• Structured light: This may create a structured light pattern on the subject / object 102 for inference of (e.g., three-dimensional / 3D) shape of subject and detection of spoofs. The light may include a large total track length to access high 3D resolution.• Coherent laser speckle: This may use a coherent laser illumination and image the speckle statistics to infer material property. Coherent laser speckle may be placed under the display.• NIR Illumination: including LEDs or VCSELs, and in some embodiments, LEDs may be coupled to polarization filters and / or sorting elements to configure or restrict light output to specific polarization states.• In some embodiments, the illumination sources may be under a display element, such as an OLED phone screen.• In some embodiments, the illumination sources may include display elements: e.g., organic LED phone screens.

[0180] Systems for object 102 identification implemented in accordance with some embodiments may include, but are not limited to, time-of-flight (ToF) based systems which utilize time-of-flight imaging to infer 3D shapes. Such systems may include components to compensate for the relatively coarse resolution and large power draw. The polarization sensor 106 may be a linearly-polarized image sensor which polarizes pixels across RGB spectrum and does not have infrared detection functionality.

[0181] In order to improve on limitations of the sensor operations, various embodiments of the invention may incorporate metasurface lenses and / or polarization filters. For example, in some embodiments, the sensor may be optically coupled to a metasurface polarization filter or a polarizing metasurface prior to incoming light being incident on image sensors. In some embodiments, the polarizing metasurface or metasurface polarization filter may be used with a VCSEL to project a spatially varying arbitrary polarization output field onto a scene or object. Such embodiments may further include two or more polarizing metasurface such that light from a light source passes through the two or more polarizing metsurfaces to produce two or more polarization state outputs, with the outputs being the same pattern or different patterns (i.e. diffuse illumination, or various dot patterns, etc.).

[0182] Additionally or alternatively, VCSELs implemented in accordance with numerous embodiments of the invention, may include (but are not limited to) partially and / or fully-polarized VCSEL arrays. In some embodiments, the VCSEL arrays may have certain (e.g., preferentially linear) polarizations and / or (un)polarized backgrounds. Systems and methods in accordance with some embodiments of the invention may further integrate diffusers and / or linear polarizers to achieve the above effect. Specifically,by integrating linear polarizers and diffusers over VCSEL arrays, systems and methods in accordance with various embodiments of the invention may linearly-polarize (e.g., partially-polarized, fully-polarized) VCSEL arrays. In many embodiments, the VCSEL arrays may be optimized when the linear polarizers are aligned to the same direction as preferential linear polarizations. Further, metasurfaces over the VCSELs may be applied to project arbitrary polarization fields onto a given scene (e.g., via the structured light output).

[0183] Further in some embodiments, the illuminator 104 may include a partially- polarized VCSEL array. Such partially-polarized VCSEL arrays may have an unpolarized background illumination with preferential linear polarization in a portion of the light output. In such cases, a linear polarizer can be added and aligned to the same direction of the VCSEL linear polarization output. In some embodiments, a linear polarizer can be integrated with the VCSEL array or with a LED. A diffuser can be added to the linear polarizer with the VCSEL or LED to produce a linear polarized diffuse illumination. The linear polarizer could be replaced with a circular or elliptical polarizer, or more than one polarizer could be used such that portions of the output light have different polarization states. In some embodiments, the output light can have two different polarization states. The two polarization states can be orthogonal or non-orthogonal. In any of these embodiments, the polarizer element can be a polarization metasurface. Further a metasurface, either the polarizer metsurface or an additional metasurface, may be included to direct the output light into one or more dot patterns.

[0184] In some examples, the light 104a from the illuminator 104 may be infrared light. The illuminator 104 may include polarization transmission optic. The illuminator 104 may include a structured light output. The illuminator 104 may include one or more VCSEL(s) and / or one or more metasurface(s). The metasurface can structure light from the VCSEL into the structured light output. The structured light output can be specific to an object that is being illuminated. The structured light output can be a dot pattern; or a first dot pattern and a second dot pattern; or a dot pattern and a flood illumination pattern. The first dot pattern can have a first polarization state and the second dot pattern can have a second polarization state. The first dot pattern and the second dot pattern can be projectedsimultaneously or sequentially at two different times. The first dot pattern and the second dot pattern can be orthogonal. The dot patent and the flood illumination pattern can be projected simultaneously or sequentially at two different times. In some embodiments, the object identification system can further include a refractive lens before the polarization metasurface.

[0185] In some embodiments, the illuminator 104 can be an illumination system comprising at least one illuminator. In some embodiments, a first illuminator can provide light having a first static polarization state. A second illuminator can provide light having a second static polarization state. The first and second polarization state can be orthogonal. The first and second illuminators can provide sequenced illumination. The polarization metasurface can direct the reflected light into one or more different polarization states and the image sensor senses at least one of the different polarization states to obtain a polarization signature, and the first static polarization state from the illumination system is the same as at least one of the one or more different polarization states which the polarization metasurface directs onto the image sensor.

[0186] In some examples, the light 104a from the illuminator 104 may take the form of light of varying wavelengths including but not limited to infrared light. The illuminator 104 may include polarization transmission optic. The sensor 106 may be an RGBI (RGB- infrared) imaging sensor, to capture the reflected light 106a off of the object 102. The RGBI sensor captures the intensity of the reflected light from the scene. A polarization and / or wavelength filter may be optically coupled to the sensor, such as, for example, a nanograting for linear polarization filtering. By synchronizing (spatially and / or temporally), the reflected light 106a with the light 104a from the illuminator 104, systems can infer the material properties and / or surface normals of the object 102. It has been discovered that the polarization-bidirectional reflectance function of the subject at a point is influenced by the orientation of the object 102 with respect to both the light 104a from the illuminator 104 and reflected light 106a, as well as the material properties (e.g., diffuse vs. specular reflection) of the object 102.

[0187] FIG. 1 B schematically illustrates an embodiment of a system 200 having an optical light source 110 with an integrated polarizer and diffuser 210. In illustrativeembodiments, integrated polarizer and diffuser 210 have a minimized gap or eliminated gap between polarizer and diffuser. In some embodiments, the integrated polarizer and diffuser 210 are disposed, relative to the light source 110, such that the polarizer is between the light source 110 and the diffuser. In some embodiments, the integrated polarizer and diffuser 210 are disposed, relative to the light source 110, such that the diffuser is between the light source 110 and the polarizer. An intervening element is between the light source 110 and outer element if a line drawn from the light source 110 and the outer element passes through the intervening element.

[0188] FIG. 1 C schematically illustrates an embodiment of an integrated polarizer and diffuser 210. The integrated optical apparatus 210 of FIG. 1 C includes an optically transparent substrate 310 having a first face 311 , and a second face 312 opposite the first face 311.

[0189] The integrated optical apparatus 210 of FIG. 1 C also includes a polarizer 330 apparatus mounted to the first face 311 of the substrate 310, and a diffuser 320 mounted to the second face 312 of the substrate 310. Such a polarizer 330 may be referred-to as an “integrated polarizer” 330, and such a diffuser 320 may be referred-to as an “integrated diffuser” 320. In illustrative embodiments, there is no gap between the polarizer 330 and the substrate 310, and no gap between the diffuser 320 and the substrate 310.

[0190] FIG. 1 D schematically illustrates another embodiment of an integrated polarizer and diffuser 210. In this embodiment, the polarizer 330 is disposed on the first face 311 of the substrate 310, and the diffuser 320 is disposed on the polarizer 330 such that the polarizer 330 is disposed between the substrate 310 and the diffuser 320.

[0191] FIG. 1 E schematically illustrates an embodiment of an integrated polarizer and diffuser 210. In this embodiment, diffuser 320 is disposed on the first face 311 of the substrate 310, and the polarizer 330 is disposed on the diffuser 320 such that the diffuser 320 is disposed between the substrate 310 and the polarizer 330.

[0192] FIG. 1 F schematically illustrates an embodiment of an integrated polarizer and diffuser 210. FIG. 1 F includes an inset showing details of the integrated polarizer 330.

[0193] Some embodiments of an integrated polarizer and diffuser 210 may be described as including a bilayer metasurface. In illustrative embodiments, the substrate310 has a thickness (between the first face 311 and second face 312) of around 0.3 mm. On one face, the metasurface operates as a flood illuminator with a target field of illumination (“FOI”) of about 65 degrees x 65 degrees, which is polarization insensitive. In some embodiments, each pillar has a circular cross-section. On the opposite face, is a set of simple plasmonic meta-wires grid nanobars which are configured to filter an undesired polarization state, based on its orientation. For example, some embodiments pass (or propagate) TM-polarized light (e.g., perpendicular to the nanobars) and block or absorb TE-polarized light (e.g., along or parallel to the nanobars).

[0194] In some embodiments, the polarizer 330 is configured to propagate light with a first polarization, and to eliminate light of a second polarization that is orthogonal to the first polarization. Embodiments of such a polarizer are described in U.S. provisional application 63 / 684,262, filed August 16, 2024, and titled “Functional Metasurfaces for Arbitrary Polarization Filtering,” as well as one or more later applications that claim priority to that provisional application.

[0195] A schematic of a polarization imaging-directed variant of systems implemented in accordance with certain embodiments of the invention is illustrated in FIG. 2. The polarization imaging system includes metasurface elements 202 which split incident light 206 into different polarizations. As illustrated, incident light 206 may include single and / or mixed polarization states (i.e., may be completely unpolarized, a single pure polarization state, or some mixed state). In the example embodiment disclosed below, the incident light 206 may include four polarizations: Poll , Pol2, Pol3, Pol4. In cases of the incident light 206 including an even number of distinct polarizations, the polarizations may be orthogonal polarizations and / or nonorthogonal polarizations. In other words, it is understood that it may be two or more polarizations, the polarizations may be orthogonal polarizations and / or nonorthogonal polarizations. In more mathematical terms, the incident light may be represented by a Stokes vector S, with each outgoing diffracted direction being associated with another Stokes vector Mi which may correspond to a row of a Mueller matrix (used to describe the linear relationship between polarization states of the incident light 206 and the outgoing light beams 206a). Each outgoing direction may be independently associated with the Mueller matrix Ui. When light is captured by theimage sensor, the total intensity of the light may be measured. The Mueller matrix Ui multiplied by the incident Stokes vector S gives an outgoing Stokes vector 0 / in each direction, / , such that 0 / = U *S. When the light is captured by the image sensor, the first entry of the Stokes vector 0 / corresponds to the intensity of the light. Since there are four indices 0, 1 , 2, 3, this corresponds to Oi[0] = (Ui * S)[0], [x] denotes the x'th element in a vector, starting count from 0. This is equivalent to taking the first row of the Mueller matrix Ui and calculating its dot product with the Stokes vector S ((Ui * S)[0] = sumj(U{i, (o,j)} * Sj)). This first row of the Mueller matrix Ui may be considered a Stokes vector Mi, since it also obeys the same algebra as the Stokes vector. The intensity in each outgoing diffracted direction is proportional to the dot product between Mi and S. The diffracted orders may not necessarily be the same polarization state that is being selected.

[0196] The metasurface elements 202 may split the incident light 206 into diffracted light 206a where two or more polarizations are diffracted in different directions, such as, for example, each of the four polarizations being directed in different directions. The diffracted light 206a in each direction may have an intensity which is proportional to the projection of that particular light’s polarization state onto the incident state. The diffracted light 206a may go into a set of multiple different image sensors 204. In FIG. 2, the diffracted light 206a goes into four different regions of a single image sensor, other combinations of regions and sensors may be used in accordance with various embodiments (e.g., two regions of two image sensors). While these image sensors 204 and the diffracted light 206a are illustrated in different horizontal positions, this is merely exemplary and the image sensors 204 may actually be at different quadrants with the diffracted light 206a sending each of the polarizations into the different quadrants.

[0197] The incident light 206 may be in an arbitrary polarization state. The metasurface elements may split the incident light into diffracted light where each of the four directions correspond to a different target polarization state, with intensity in that direction dictated by the overlap of the incident polarization state with the target polarization state.

[0198] While the metasurface elements 202 overcome the absorption loss and / or complexity of traditional polarization imaging systems (including traditional polarizers),systems in accordance with some embodiments may benefit from apertures and / or illumination sources of specific fields of view to keep sub images from overlapping on the image sensor(s) 204.

[0199] Various embodiments of the invention may utilize a polarization sorting optical metasurface microlens array (PSOMMA) in order to intermix the polarization states spatially, across an image sensor. In some embodiments, a PSOMMA may be the last element before the image sensor and each lenslet (including a PSOMMA) may direct a set of designed polarization states to individual subpixels and / or imaging units or regions of a sensor. Additionally or alternatively, there may be no need for using fields of view of the illumination sources (or additional apertures) in order to keep sub-images from overlapping on the image sensors. Finally, the image sensors and PSOMMAs can be incorporated with any existing optical imaging system which may include refractive optical elements.

[0200] FIGS. 3A and 3B illustrate schematics of a PSOMMA in accordance with multiple embodiments of the invention. In FIG. 3A, the PSOMMA includes two individual metasurface lenslets 302, however, the number of individual lenslets 302 utilized by given configurations may depend on the corresponding optical systems and, in general, can include any number of lenslets. Each lenslet may split the incident light into individual polarizations for each diffraction angle. Each lenslet may split light into at least two polarizations but in general can split light into any number of polarizations. As illustrated in FIG. 3A, a first lenslet L1 may split the incident light into groups of different polarizations 304: poll , pol2, pol3, and pol4. Further, a second lenslet L2 may split the incident light into groups of different polarizations 306: pol5, pol6, pol7, pol8. The light may be split into four different directions proportionally in each direction to that direction’s selected polarization state. Similarly, an nth lenslet Ln may split the incident light into groups of different polarizations 308: pol 4n-3, pol 4n-2, pol 4n-1 , and pol 4n. As shown here the specific polarization states can be unique (labeled poll , pol2... pol 4n) for each lenslet but (additionally or alternatively) the same two or more polarization states could be utilized at each lenslet. For example, the first lenslet L1 and the second lenslet L2 may both splitthe incident light into the same four different polarizations: poll , pol2, pol3, pol4. Additionally or alternatively, the phase function of each lenslet can be uniquely specified.

[0201] As illustrated in FIG. 3B, PSOMMAs configured in accordance with miscellaneous embodiments of the invention can be coupled with image sensors 308 with any number of pixels (labeled p1 , p2, p3... p4n). The pixels may be a plurality of image sensing units. In such a case, the action of the PSOMMA may be to diffract each polarization state to one or more specific pixel. In various embodiments of the invention, the complete polarization state of a scene can be reconstructed on a pixel-by-pixel basis by designing the polarization state that a given pixel readout corresponds to. While the drawings here are shown in one dimension, it is understood that the same principle applies to higher-dimensional (such as, two-dimensional) lenslets and / or pixel arrays. Further, the incident light illustrated in FIG. 3B has a 0° chief ray angle (CRA), but the CRA of incident light implemented in accordance with various embodiments of the invention may vary between (or even across) individual lenses. Thus, the incident light may be collimated but may be incident on the metasurface lenslets at other angles. In some embodiments, metasurfaces may be used to provide microlens array functionality and designed such that lenslets may be optimized to accept different incoming light angles (e.g., non-zero CRAs) across image sensor fields, minimizing the effects that would otherwise be caused for a lens designed for zero-CRA functionality. Additionally or alternatively, in certain embodiments, physical microlens shifts may be provided, which match the CRA(s) of the microlens(es) and the image sensor(s). In this approach, the periodicity of microlens array may be decreased all over the sensor(s) and can partially cancel the microlens CRA(s).

[0202] In certain embodiments, microlens arrays may provide microlens functionality (e.g., focusing light at image sensors) using metasurfaces in a manner which provides a microlens shift as with the physical microlens shift. The metasurfaces may be locally designed in such a way that they can match the azimuth and / or elevation angles of the (primary) refractive lenses so to produce CRA matching across the sensors and / or with different incoming imaging light angles. This is complicated for conventional physical microlenses but may be achieved by leveraging metasurfaces with microlensfunctionality. In some embodiments, the metasurfaces may be utilized to provide collimation functionality to make the received light from a primary refractive lens or entrance pupil collimated and / or directed to the center of a sensor region.

[0203] FIG. 4A illustrates a PSOMMA with two polarizations at each lenslet in accordance with a number of embodiments of the invention. In accordance with various embodiments of the invention, lenslets may be over groups of two or more pixels. The PSOMMA includes multiple lenslets 402 (L1 , L2... LN, LN+1 ), where each of the lenslets may split the incoming light into two (or more) polarizations (pol). Examples include, as illustrated, L1 splitting the incident light into poll in one direction and pol2 in another direction, and / or L2 splitting the incident light into pol3 and pol4. Each lenslet may be over just two pixels. For example, as illustrated, L1 may be over pixels p1 and p2, directing the poll light into p1 and pol2 light into p2. In numerous embodiments, the polarization for a set of two lenslets may be repeated across the image sensor(s) 404. For example, L1 may split the light into poll and pol2, L2 splits the light into pol3 and pol4 and that pattern may repeat over the entire image sensor 404 or one or more portions of the image sensor 404, such that LN splits the light into poll and pol2 and LN+1 splits the light into pol3 and pol4. In some embodiments, the polarization is split into only two states across the image sensor(s) 404. For example, in PSOMMAs described in connection with FIG. 4A, poll may equal pol3 and pol2 may equal pol4. Thus, L1 and L2 may both split light into the same polarizations, poll and pol2. Finally, it is understood that the polarization states for each lenslet may be completely unique and independent and not just limited to linear polarization states. For example, poll may be right hand circularly polarized light and pol2 may be left hand circularly polarized light. Furthermore, poll may be S polarized light while pol2 may be P polarized light.

[0204] FIG. 4B illustrates a PSOMMA with two polarizations at each lenslet in accordance with miscellaneous embodiments of the invention. This configuration is similar to the configuration described in connection with FIG. 4A. However, in this configuration, a PSOMMA 406 includes a first lenslet L1 which directs a first polarization light poll into a first imaging unit p1 of an image sensor 408 and a second polarization light pol2 into a second imaging unit p2 of the image sensor 408. Similarly, the PSOMMA406 includes a second lenslet L2 which directs a first polarization light poll into the first imaging unit p1 and a second polarization light pol2 into the second imaging unit p2. Thus, the same imaging units p1 , p2 may be shared by the first lenslet L1 and the second lenslet L2. Examples of other PSOMMA embodiments are described in U.S. Pat. App. No. 18 / 194,359, entitled “Polarization Sorting Metasurface Microlens Array Device” and filed Mar. 31 , 2023, which is hereby incorporated by reference in its entirety for all purposes.

[0205] In some applications, the result of the material property and shape inference is used in an algorithm to determine when the object is an authentic access request for a biometric authentication system, and / or if the object was an attempt to spoof such a system (known as a presentation attack). Object identification systems in accordance with certain embodiments may be utilized for biometric identification (e.g., for a smart device). Examples of methods for utilizing polarization states for biometric identification are described in U.S. Pat. Pub. No. 2023 / 0196842, entitled “Spoof-Resistant Facial Recognition Through Illumination and Imaging Engineering” and filed Dec. 16, 2022, which is hereby incorporated by reference in its entirety for all purposes. In some biometric-based identification configurations, illuminators may be placed under display devices. Further polarization sensor(s) in accordance with multiple embodiments of the invention may have windows in the displays. Additionally or alternatively, illuminators may project spatially-varying patterns of polarization on the objects, the “unit tile” of which may include various dots patterns on the object(s). In this configuration, the dots may form a tetrahedron on the Poincare sphere. Systems and methods in accordance with numerous embodiments of the invention may minimize surface area of displays, that can be cut out to form clear windows. The polarization sensor(s) may include polarization separating metasurfaces which may reduce overall exposure time and operating power. Systems and methods in accordance with miscellaneous embodiments of the invention may project polarization patterns on objects in singular exposures (i.e., without a temporally-varying sequence), which reduces the time for sufficient data collection for downstream algorithms. In some embodiments, temporally varying dot projection patterns may be used and may provide higher spatial bandwidth.

[0206] In some cases, temporally-varying projection patterns may be advantageous,as a way to further mitigate against biometric replay attacks. Temporally-varying projection patterns may have higher spatial bandwidth as well.

[0207] FIG. 5A illustrates a cross-sectional view of an imaging device including a polarization sorting capability implemented in accordance with various embodiments of the invention. Imaging devices described in reference to this figure may correspond to the imaging devices described in connection with FIG. 5A. Imaging devices may include but are not limited to arrays of microlenses 516a, 516b which direct light into polarization sorting metasurfaces. The polarization sorting metasurfaces may include various regions as described above, such as a first region 518a configured to sort a first polarization light in a first direction and a second polarization light in a second direction and a second region 518b configured to sort the second polarization light in a first direction and the first polarization light in a second direction. Imaging devices may include one or more image sensors, configured to receive light from polarization sorting metasurfaces. The image sensor depicted in FIG. 5A includes a first pixel 520a configured to receive the first polarization light from the first region 518a; a second pixel 520b configured to receive the second polarization light from the first region 518a and the second region 518b; and a third pixel 520c configured to receive the first polarization light from the second region 518b. As illustrated, the positioning of the first region 518a and the second region 518b may be offset from the first pixel 520a, the second pixel 520b and the third pixel 520c. As illustrated in FIG. 5A there may be more microlenses and regions of the polarization sorting metasurface adjacent to what is illustrated in FIG. 5A (e.g., x microlenses for every pixel of the image sensor). In many exemplary embodiments, the back focal length 522 of the sensors may be set to 5 pm.

[0208] FIG. 5B is a schematic of a biometric identification system embedded in a smart device in accordance with multiple embodiments of the invention. Smart devices 502 may include but are not limited to imaging devices as described above in reference to FIG. 5A. The smart devices 502 may include, but are not limited to, camera(s) 506, display device(s) 504, polarization receiver(s) 508, and / or display devices. Images from the (e.g., front facing) cameras 506 may be utilized in conjunction with (polarization) signatures detected by the polarization receiver(s) 508 to perform identifications including but notlimited to biometric authentications of users.

[0209] Smart devices 502 may (additionally or alternatively) include display device(s) 504 which can be utilized to display images and output light. In some cases, the light may be used as illumination light and may or may not include NIR light. A smart device 502 may include at least one sensor (e.g., polarization receiver 508). Sensors may be configured to receive light including but not limited to ambient light. In this disclosure ambient light may refer to light including but not limited to natural light and / or artificial light. Artificial light can be from a light source such as an illuminator. Ambient light can provide a level of light that helps a person see the general environment and / or help an image sensor capture the general environment. In dim-to-no ambient light situations, the light from the display device 504 may be utilized to illuminate the user and create reflected light with a certain polarization signature (which may be detected by the polarization receiver 508). The polarization signature(s) may be utilized to perform biometric authentication of the users. The polarization receivers 508 may include NIR filters which filter all light besides certain wavelengths (e.g., corresponding to NIR light or near-NIR wavelengths). NIR light may be considered exemplary in various embodiments, but other light wavelengths may be utilized in many embodiments, such as, for example, visible and / or infrared light. In the latter cases, smart devices 502 may include proximity sensors that the display device 504 uses to turn on illuminators (e.g., inducing the display device 504 to emit (e.g., RGB, infrared) light from all of the display pixels in order to illuminate the a target with specific-wavelength light).

[0210] As mentioned, the smart device 502 may include one or more illuminators (e.g., located under the display device 504 of FIG. 5B). The illuminators may be configured to output dot patterns / sequences (spatially and temporally). A metasurface may be implemented in the illuminator to generate the dot patterns. In some embodiments, PSOMMA and / or metasurface microlens sensors can be incorporated into the illuminator. In certain embodiments, the microlens array is a metasurface. Examples of PSOMMA and / or metasurface microlens sensors embodiments are described in FIGS. 2 through 4C. In some embodiments, the illuminator can include various static and sequential polar illumination. The projection polarization pattern may be optimized for functions under-the-display, which maintains a high polarization spatial bandwidth.

[0211] In situations where there is adequate ambient light (e.g., light from outdoor situations), light from the outdoors may be utilized in addition or alternative to light from the display device(s) 504. In this case, the ambient light may reflect off the target object(s), including but not limited to users, to create polarization signatures which may be detected (by the polarization receiver 508). In various cases, personalized ambient light sensors may be used to detect the ambient light reflected.

[0212] As mentioned above, in multiple embodiments, various combinations of cameras 506, 508 may be used. For example, a front facing camera 506 may be a red, green, and blue (RGB) camera and the polarization receiver 508 may (additionally or alternatively) be an infrared camera. The infrared camera may incorporate (but is not limited to) a set of infrared camera pixels that can be polarization-sensitive, via (but not limited to) a polarization sorting mechanism (e.g., as described in connection with FIGS. 3A, 3B, 4A and 4B) and / or a set of gratings which select for polarizations incident on the sensor. In accordance with miscellaneous embodiments of the invention, polarization receivers 508 and / or illuminators can be placed under display devices 504. Additionally or alternatively, windows may be placed in the display devices 504 to allow improved transmission. The illuminator discussed above can exist either entirely under the display device 504, or a window can be made in the display device 504 to allow transmission. In general, instead of NIR light, other light sources may be used, up to and including visible light. However, it may be advantageous to have light which is invisible to the human eye and has a compatible and mature sensing technology.

[0213] Further, in certain embodiments, smart devices 502 may include an ambient light sensor which may be utilized to determine ambient light characteristics to determine whether the display device 504 and / or illuminator is to be utilized. In some embodiments, the light from the display device 504 can be altered by an increase in intensity of a light output or the display device produces a specific color of light.

[0214] In numerous embodiments, the polarization receivers 508 may be omitted and the (front facing) camera 506 may be utilized for detecting the polarization signature of the users. For example, this may be used with the front facing camera 506 on the smartdevice 502. In this instance, a polarization sorter and / or filter may be placed over the pixels. In some cases, the polarization receivers 508 may be optimized for one wavelength (e.g., visible), have certain wavelength (e.g., red) filters across all pixels, and / or may utilize multiple colors where metasurface(s) may be above each pixel and optimized for a specific color.Example Computation Element

[0215] An example of a polarization system that performs object identification in accordance with a number of embodiments of the invention is illustrated in FIG. 6. The system 600 includes a communications network 660. The communications network 660 is a network such as the Internet that allows devices connected to the network 660 to communicate with other connected devices. Server systems 610, 640, and 670 are connected to the network 660. Each of the server systems 610, 640, and 670 is a group of one or more servers communicatively connected to one another via internal networks that execute processes that provide cloud services to users over the network 660. One skilled in the art will recognize that polarization systems 600 may exclude certain components and / or include other components that are omitted for brevity without departing from this invention.

[0216] For purposes of this discussion, cloud services are one or more applications that are executed by one or more server systems to provide data and / or executable applications to devices over a network. The server systems 610, 640, and 670 are shown each having three servers in the internal network. However, the server systems 610, 640 and 670 may include any number of servers and any additional number of server systems may be connected to the network 660 to provide cloud services. In accordance with various embodiments of this invention, polarization systems 600 for object identification in accordance with certain embodiments of the invention may be provided by a process being executed on a single server system and / or a group of server systems communicating over network 660.

[0217] Users may use personal devices 680 and 620 that connect to the network 660 to perform processes for (e.g., biometric) object identification in accordance with variousembodiments of the invention, as shown above. In this embodiment, the personal devices 680 are shown as desktop computers that are connected via a conventional “wired” connection to the network 660. However, the personal device 680 may be a desktop computer, a laptop computer, a smart device, an imaging device, an entertainment gaming console, or any other device that connects to the network 660 via a “wired” connection. The mobile device 620 connects to network 660 using a wireless connection. A wireless connection is a connection that uses Radio Frequency (RF) signals, Infrared signals, or any other form of wireless signaling to connect to the network 660. In the example of this figure, the mobile device 620 is a mobile telephone. However, mobile device 620 may be a mobile phone, Personal Digital Assistant (PDA), a tablet, a smartphone, or any other type of device that connects to network 660 via wireless connection without departing from this invention.

[0218] As can readily be appreciated the specific computing system used for identification is largely dependent upon the requirements of a given application and should not be considered as limited to any specific computing system(s) implementation.

[0219] FIG. 7 illustrates an example of a computation element that executes instructions to perform processes including but not limited to object (e.g., biometric, polarization) detection in accordance with certain embodiments of the invention. The computation elements 700 may be implemented in systems including but not limited to the imaging and smart devices described above with respect to FIGS. 5A - 5B. The computation elements 700 in accordance with many embodiments of the invention can include (but are not limited to) one or more mobile devices, cameras, and / or computers. The computation elements 700 may be configured to include (but are not limited to) at least one processor 705, peripherals 710, a network interface 715, and memory 720. One skilled in the art will recognize that the computation element may exclude certain components and / or include other components that are omitted for brevity without departing from this invention.

[0220] The processor 705 can include (but is not limited to) a processor, microprocessor, controller, or a combination of processors, microprocessor, and / or controllers that perform instructions stored in the memory 720 to manipulate data storedin the memory. Processor instructions can configure the processor 705 to perform processes in accordance with certain embodiments of the invention. In various embodiments, processor instructions can be stored on non-transitory machine-readable and / or computer-readable mediums.

[0221] Peripherals 710 can include any of a variety of components for capturing data, such as (but not limited to) cameras, displays, and / or sensors (e.g., RGB image sensors, polarization image sensors). In a variety of embodiments, peripherals can be used to gather input data and / or provide output data. The computation element 700 can, additionally or alternatively, utilize network interface(s) 715 to transmit and receive data over a network, including but not limited to polarization signature data from an object. Doing so may, in various embodiments of the invention, be based upon the instructions performed by processor 705.

[0222] Memory 720 may be used to store data including but not limited to polarization signature data, sensory data produced by the peripherals 710, and / or outputs generated by performing processes in accordance with some embodiments of the invention. Memory 720 may, additionally alternatively, store polarization signature assessment data 725 and object categorization data 730. The polarization signature assessment data 625 and / or object categorization data 630 may, in accordance with several embodiments of the invention, be used to perform object recognition based on polarization signature data from an object. For example, in biometric authentication applications, the polarization signature assessment data 625 may be used to assess whether the received polarization signature of a user corresponds to an authentic 3D individual. Additionally or alternatively, the object categorization data 630 may include assessments based on the polarization signature assessment data 625. Then the object categorization data 630 may be used to compare previous images of users with current images of the users.

[0223] When (1 ) the received polarization signature is assessed to be an authentic 3D individual and (2) the current image of the user substantially matches the previous image of the user, then systems and methods in accordance with various embodiments may determine the biometric verification success. Otherwise, the biometric verification may be deemed a failure. As suggested above, biometric verification may be applied to variouspurposes, including but not limited to unlocking user devices. Examples of this biometric verification process are described in U.S. Pat. Pub. No. 2023 / 0196842, entitled “Spoof- Resistant Facial Recognition Through Illumination and Imaging Engineering” and filed Dec. 16, 2022, which is hereby incorporated by reference in its entirety for all purposes. Biometric authentication as described above is merely exemplary; other spoof resistance object detection may be performed utilizing computation elements configured in accordance with miscellaneous embodiments of the invention.

[0224] FIG. 8 illustrates an example illuminator implemented in accordance with numerous embodiments of the invention. The illuminator may include but is not limited to a light source 808 and a metasurface. In accordance with some embodiments, potential light sources 808 may include but are not limited to VCSELs, and / or arrays of light emitters (diodes) with or without fixed polarization. In accordance with many embodiments, the illuminator 808 is an LED or array of LEDs, all or some of which have polarization metasurfaces 802, 804 and / or polarization filters above them to limit and / or define output light to have one or more polarization states. In some embodiments, PSOMMA sensors and / or metasurface microlens array sensors can be incorporated into the illuminator. In certain embodiments, the microlens array is a metasurface. Examples of PSOMMA and / or metasurface microlens sensors embodiments are described in Figs. 2 through 4C. In some embodiments, the illuminator can include various static and sequential polar illuminationThe metasurface 704 diffracts the light into a projection pattern. FIG. 8 illustrates an example projection pattern outputted by a first metasurface element 802 and a second metasurface element 804. A first half 802a of the projection pattern, output by the first metasurface element 802, may be polarized in a first way (e.g., counterclockwise). A second half 804a of the projection pattern, output by a second metasurface element 802 may be polarized in a second way (e.g., counterclockwise).

[0225] FIG. 9 illustrates an example lighting system for object detection implemented in accordance with certain embodiments of the invention. The lighting system may correspond to the illuminator and projection pattern(s) described in connection with FIG. 8. Specifically, the illuminator 900 may illuminate a scene with light 902 with a fixed polarization, producing at least one projection pattern. The light 902 may be reflected byone or more objects of the scene as reflected light 904, which may contain a polarization signature. The reflected light 904 may be detected by a polarization receiver 906. Further examples of lighting systems and features of such lighting systems are described in U.S. Pat. Pub. No. 2019 / 0064532, entitled “Transmissive Metasurface Lens Integration” and filed Aug. 31 , 2018, which is hereby incorporated by reference in its entirety for all purposes.

[0226] The polarization receiver 906 may include a polarization separating metasurface 908. The polarization separating metasurface 908 separates the reflected light 904 into a first polarization light 910a which goes in a first direction and a second polarization light 910b which goes in a second direction. The first polarization light 910a is detected by a first detector 912a and the second polarization light 910b is detected by a second detector 912b. The first polarization light 910a and the second polarization light 910b may be orthogonal. The first polarization light 910a and the second polarization light 910b may have arbitrary polarizations. The first detector 912a and the second detector 912b may be photo detectors (e.g., single-photon avalanche diodes). The sum or difference of the amount of light detected by the first detector 912a and the second detector 912b can be computed and utilized for object detection as described throughout. In some examples, the polarization separating metasurface 908 may split light into three or more different polarizations. FIG. 10 illustrates an example of a polarization receiver which includes a polarization separating metasurface 1004 which splits light into four different polarizations. As illustrated, the polarization separating metasurface 1004 splits light into four streams of light 1006 each having a different polarization. Each of the streams of light 1006 is detected by a detector 1002. A complete polarization measurement may be performed by utilizing the intensity on each detector 1002.

[0227] In some embodiments, the polarization separating metasurface 908 may comprise an array of metasurface lenslets. Each of the metasurface lenslets can direct light having a polarization state into different pixels of the image sensor. Some of the metasurface lenslets are separated by spaces. These spaces may not have a polarization metasurface element such that light impinging those spaces is not directed based on its polarization state.

[0228] It is understood that when utilizing the polarization receiver 1000 described in connection with FIG. 10, a transmitter that outputs four different sets of fixed polarizations (e.g. a VCSEL array which outputs four different sets of fixed polarizations) may be utilized. In some embodiments, the transmitter outputs unpolarized light. The scene can be independently probed with a specific polarization to make a compact Mueller polarimeter.Structured Polarimetric Imaging Systems for 3D and Object Recognition

[0229] Various embodiments of the invention include illuminating, imaging, and interpreting a scene into a 3D or textural map. A polarized illumination (or a sequence of polarized illuminations) may be projected and then the reflected illumination may be interpreted to produce polarimetric scenes which may be utilized to produce 3D information. Because the polarized illumination source has a known displacement relative to the imaging system, and because light reflected from the polarized source which preserves polarization has a more specular nature (“glossy”), using the known source location and a priori specular reflection distribution can build a more accurate 3D shape of the structure. In particular, this enables 3D reconstruction for objects which are not traditionally associated with being glossy, such as human facial features or skin.

[0230] FIGS. 11 A - 11 H conceptually illustrate systems for interpreting 3D structures of objects in accordance with many embodiments of the invention. The system reconstructs the 3D structure of the object 1006 in a scene from a single image of the scene. The object 1006 may be illuminated and imaged from a particular configuration of a camera 1002 and an illumination 1004The system uses an illumination 1004which illuminates the object 1006 with light rays (1 , 2, 3). The light rays (1 , 2, 3) are reflected by the object 1006 and sensed by the camera 1002. The camera 1002 can include a polarization sensor or a non-polarization sensor with a polarization filter or polarization sorting element couple to it. However, it has been discovered that under normal view, most materials are diffused (the relative intensity of light is independent of the viewing angle and the surface normal), intensity variations are an unreliable source of 3D shapes(surface normal). It may also be advantageous to identify (e.g., segment) different materials / objects within a scene.

[0231] FIG. 11 B is a schematic of the principle of operation for the system described in connection with FIG. 11A. The illumination 1004 may be provided by a light source emitting polarized light to illuminate the object 1006. The polarized light may be partially polarized light. In some embodiments, PSOMMA sensors and / or metasurface microlens array sensors can be incorporated into the illuminator. In certain embodiments, the microlens array is a metasurface. Examples of PSOMMA and / or metasurface microlens sensors embodiments are described in Figs. 2 through 4C. In some embodiments, the illuminator can include various static and sequential polar illumination. Three example rays 1008 are traced to the camera 1002, which lies at distance d from the illumination 1004. Ray 1 shows a near-specular reflection, which is high intensity. Specular scattering or reflection may occur off of a surface of the object 1006 which may produce reflected rays 1010. The reflected rays 1010 are captured by the camera 1002 as an image. The relative polarization intensities across the image then correspond to the surface normal relative to the camera 1002 and the illumination 1004, which can be used to reconstruct the 3D shape. In some embodiments, the illumination 1004 may or may not be a pure polarization state. In some embodiments, the illumination 1204 may be a pure polarization.

[0232] FIG. 11 C is a schematic of the system of FIG. 11A demonstrating depth and shape ambiguity. The reflected rays 1010 may be captured by the camera 1002. There may be multiple combinations of surface normal and distance from camera 1002. It has been discovered that this can be resolved by closely inspecting the polarization content of the reflected ray via polarimetry, which will have a different signature for different polarization angles, owing to the well-known Fresnel reflection coefficients at different angles. Furthermore, the illumination may be a sparse illumination so that the ambiguity is not of a continuous nature, but rather a discrete set of possible ambiguities, which is more easily resolved. The sparse illumination may be a structured illumination such as a dot pattern and / or flood illumination.

[0233] FIG. 11 D is a schematic of a system where the illumination is a structured illumination 1004a. The dot pattern of the structured light illumination 1004a is illustrated by the grey dots on the object 1006. Structure illumination may be useful in resolving depth information. The structured light may be produced by a dot pattern projector. Examples of dot pattern projectors are described in International Patent App. No. PCT / US2024 / 017901 entitled “Line Pattern Projector Incorporating One or More Metasurfaces” and filed Feb. 29, 2024; U.S. Pat. App. Pub. No. 20220385042 entitled “Single Element Dot Pattern Projector” and filed May 25, 2022; U.S. Pat. App. Pub. No. 20240296575 entitled “Structured Light Depth Sensors Incorporating Metasurfaces” and filed March 5, 2024; the disclosures of which are hereby incorporated by reference in their entirety for all purposes. As disclosed in PCT / US2024 / 017901 , the dot pattern projectors may include metasurfaces. While a dot pattern is illustrated, other structured illumination has been contemplated such as a line pattern projector.

[0234] The structured illumination 1004a may have a specific pattern. For example, when the object 1006 is a face, the structured illumination patterns may match the profile of the face. The structured illumination 1004a may be designed for periorbital vs. broader facial illumination patterns and paired imaging. Also, the structured illumination 1004a may be temporal such as including blinking or facial expression changes or exposure of teeth.

[0235] FIG. 11 E is a schematic of a system including a dynamic structured illumination 1004b. In the dynamic structured illumination 1004b a first linear polarization is used to illuminate the object (1 ) and then subsequently a second circular polarization illuminates the object (2, shown offset for clarity). While a linear polarization and a circular polarization are illustrated, additional polarizations can improve the robustness of the analysis. By including multiple polarizations in the illumination, instead of a traditional Stokes polarimetric image of the scene, a Mueller polarimetric image of the scene can be derived, which describes each field point by a Mueller matrix (instead of a Stokes vector). This richness of information can improve the robustness of the 3D or textural reconstruction measured previously.

[0236] FIG. 11 F is a schematic of a system including wavelength filtering and choice of illumination. The wavelength filtering and choice of illumination may improve surface identification and signal-to-noise ratio. The illumination source may be the dominant source of light which is perceived by the camera 1002. The camera 1002 may include a wavelength filter 1602. By including the wavelength filter 1602, different sources of illumination may be accommodated with a single camera. The wavelength filter 1602 may reduce the amount of environmental noise. In an active illumination sequence, the reflected light from the environment-only illuminated scene may be used as additional information.

[0237] FIG. 11 G is a schematic of the system described in connection with FIG. 11 B including complex polarimetric information in a 3D reconstruction algorithm. Intensity variations of the polarized signal may occur as surface normal varies which may be utilized to perform 3D reconstruction. However, it has been further discovered that upon reflection, the nature of the polarization may change due to Fresnel reflection. This is equivalent to the Mueller matrix (for a given angle) of having terms coupling the incident polarization parameter to other polarizations. In the illustrated case, the reflected light has a small amount of circular polarization, despite being illuminated by linear polarization, and the reflected polarization state is analyzed by the polarimetric camera.

[0238] FIG. 11 H is a detail of glossy reflection distribution for polarized light (and diffuse reflection for unpolarized light). Within the language of Mueller calculus, the glossy BRDF represents a polarization-preserving Mueller matrix element (Mu, in this example) which is centered around the specular reflection angle, while the Mueller matrix element Mw is Lambertian (diffuse). The Mueller BRDF can also help distinguish / segment different materials more clearly.

[0239] While the above description contains many specific embodiments of the invention, these should not be construed as limitations on the scope of the invention, but rather as an example of one embodiment thereof. It is therefore to be understood that the present invention may be practiced in ways other than specifically described, without departing from the scope and spirit of the present invention. Thus, embodiments of the present invention should be considered in all respects as illustrative and not restrictive.Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their equivalents.

[0240] Although only a few embodiments of the invention have been described in detail, it should be appreciated that the invention may be implemented in many other forms without departing from the spirit or scope of the invention. For example, embodiments such as enumerated below are contemplated:

[0241] Clause 1. An object identification system comprising: an illumination system which illuminates an object, wherein incident light from the illumination system reflects off the object as reflected light with one or more polarization states; a polarization metasurface which receives the reflected light reflected from the object; an image sensor with a plurality of different regions configured to sense one or more different polarization states of light from the polarization metasurface; and a polarization sensing system which identifies the object based on the one or more polarization states.

[0242] Clause 2. The object identification system of clause 1 , wherein the polarization metasurface directs the reflected light into the one or more different polarization states and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

[0243] Clause 3. The object identification system of clause 1 or 2, wherein: the polarization metasurface is a polarization separator which is configured to direct the one or more different polarization states of the reflected light in different directions; and the one or more different polarization states of the reflected light directed from the polarization metasurface are incident on the plurality of different regions of the image sensor.

[0244] Clause 4. The object identification system of clauses 1 , 2, or 3, wherein the light from the illumination system comprises near-infrared light.

[0245] Clause 5. The object identification system of any of clauses 1 -4, wherein the illumination system includes sunlight.

[0246] Clause 6. The object identification system of any of clauses 1 -5, further comprising a filter which filters the reflected light that is captured by the polarization sensing system.

[0247] Clause 7. The object identification system of any of clauses 1 -6, wherein the filter transmits near-infrared light.

[0248] Clause 8. The object identification system of any of clauses 1 -7, wherein the illumination system includes a light output from a display device.

[0249] Clause 9. The object identification system of any of clauses 1 -8, further comprising an ambient light sensor, wherein the light output from the display device is altered based on data from the ambient light sensor.

[0250] Clause 10. The object identification system of any of clauses 1-9, wherein the light output from the display device is altered by an increase in intensity of the light output or a specific color of light being produced by the light output of the display device.

[0251] Clause 11 . The object identification system of any of clauses 1 -10, wherein the illumination system produces a structured light output.

[0252] Clause 12. The object identification system of any of clauses 1-11 , wherein the illumination system comprises a vertical cavity surface emitting laser (VCSEL) and a VCSEL metasurface which structures light from the VCSEL into the structured light output.

[0253] Clause 13. The object identification system of any of clauses 1 -12, wherein the at least one VCSEL is configured into a VCSEL array.

[0254] Clause 14. The object identification system of any of clauses 1 -13, wherein the VCSEL array is overlaid with a linear polarizer integrated into a diffuser.

[0255] Clause 15. The object identification system of any of clauses 1 -14, wherein the VCSEL array comprises at least one of: a partial-polarization; an unpolarized background; and a preferential linear polarization.

[0256] Clause 16. The object identification system of any of clauses 1 -15, wherein the linear polarizer is directionally-aligned with the preferential linear polarization.

[0257] Clause 17. The object identification system of any of clauses 12-16, wherein the VCSEL metasurface is: overlaid over the at least one VCSEL is configured into a VCSEL array; and used to project a polarization field onto the object.

[0258] Clause 18. The object identification system of clause 17, wherein the polarization field is a spatially varying arbitrary polarization field.

[0259] Clause 19. The object identification system of any of clauses 11-18, wherein the structured light output is specific to the object.

[0260] Clause 20. The object identification system of any of clauses 11-19, wherein the structured light output comprises at least one dot pattern.

[0261] Clause 21. The object identification system of any of clauses 11-20, wherein the structured light output comprises a first dot pattern and a second dot pattern.

[0262] Clause 22. The object identification system of any of clauses 11-21 , wherein the structured light output comprises a first dot pattern and a flood illumination pattern.

[0263] Clause 23. The object identification system of any of clause 21 , wherein the first dot pattern has a first polarization state and the second dot pattern has a second polarization state.

[0264] Clause 24. The object identification system of any of clause 21 , wherein the first and second dot patterns are projected simultaneously.

[0265] Clause 25. The object identification system of clause 22, wherein the first dot pattern and the flood illumination pattern are projected simultaneously.

[0266] Clause 26. The object identification system of clause 21 , wherein the first and second dot patterns are projected in a sequence at two different times.

[0267] Clause 27. The object identification system of clause 23, wherein the first and second polarization states are orthogonal.

[0268] Clause 28. The object identification system of any of clauses 1-27, wherein the object is a face.

[0269] Clause 29. The object identification system of any of clauses 1-28, wherein the polarization metasurface is configured to diffract light of a first polarization in a first direction and light of a second polarization in a second direction, and wherein the first polarization and the second polarization are different and the first direction and the second direction are different.

[0270] Clause 30. The object identification system of clause 29, wherein the first polarization and the second polarization are arbitrary polarizations.

[0271] Clause 31. The object identification system of clause 29, wherein the first polarization and the second polarization are orthogonal.

[0272] Clause 32. The object identification system of clause 29, wherein the polarization metasurface is further configured to diffract light of a third polarization in a third direction, wherein the first polarization, the second polarization, and the third polarization are all different and the first direction, the second direction, and the third direction are all different.

[0273] Clause 33. The object identification system of clause 32, wherein the polarization metasurface is further configured to diffract light of a fourth polarization in a fourth direction, wherein the first polarization, the second polarization, the third polarization, and the fourth polarization are all different and the first direction, the second direction, the third direction, and the fourth direction are all different.

[0274] Clause 34. The object identification system of any of clauses 1-33, wherein: the polarization metasurface comprises an array of metasurface lenslets; and each of the metasurface lenslets are configured to direct light having a polarization state into different pixels of the image sensor.

[0275] Clause 35. The object identification system of clause 34, wherein: at least some of the metasurface lenslets are separated by spaces; and the spaces do not have a polarization metasurface element such that light impinging the spaces is not directed based on its polarization state.

[0276] Clause 36. The object identification system of any of clauses 1-35, further comprises a microlens array.

[0277] Clause 37. The object identification system of clause 36, wherein the microlens array is a metasurface.

[0278] Clause 38. The object identification system of any of clauses 1-37, further comprises a refractive lens before the polarization metasurface.

[0279] Clause 39. The object identification system of any of clauses 1-38, wherein the illumination system comprises a first illuminator which provides light having a first static polarization state.

[0280] Clause 40. The object identification system of clause 39, wherein the illumination system comprises a second illuminator which provides light having a second static polarization state.

[0281] Clause 41 . The object identification system of clause 40, wherein the first and second static polarization states are orthogonal.

[0282] Clause 42. The object identification system of clause 40, wherein first and second illuminators provide sequenced illumination.

[0283] Clause 43. The object identification system of clause 39, wherein the polarization metasurface directs the reflected light into the one or more different polarization states and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

[0284] Clause 44. The object identification system of clause 43, wherein the first static polarization state from the illumination system is the same as at least one of the one or more different polarization states which the polarization metasurface directs onto the image sensor.

[0285] Clause 45. The object identification system of clause 43, wherein identifying the object is performed based on relative polarization intensities determined from the reflected light detected by each of the plurality of different regions of the image sensor.

[0286] Clause 46. The object identification system of clause 45, wherein the relative polarization intensities are interpreted as proportional to surface normal estimates relative to the image sensor.

[0287] Clause 47. The object identification system of clause 46, wherein the surface normal estimates are determined from the relative polarization intensities to derive a shape of the object in three-dimensional (3D) space.

[0288] Clause 48. The object identification system of claim 48, wherein: the reflected light is interpreted as a Mueller polarimetric image; and the Mueller polarimetric image is used to identify the shape of the object.

[0289] Clause 49. A method for object identification, the method comprising: receiving reflected light on a polarization metasurface, wherein the reflected light is: projected by an illumination system as incident light; reflected off on an object; and reflected with one or more polarization states; detecting, through an image sensor, the reflected light, wherein: the image sensor comprises a plurality of different regions; and each region of the plurality of different regions is configured to detect a given state of the one or morepolarization states of the reflected light; and identifying the object using a polarization receiver, wherein identifying the object is performed based on detections of the reflected light.

[0290] Clause 50. The method of clause 49, wherein the polarization metasurface directs the reflected light into one or more different polarization states and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

[0291] Clause 51. The method of clause 49 or 50, wherein: the polarization metasurface is a polarization separator which is configured to direct one or more different polarization states of the reflected light in different directions; and the one or more different polarization states of the reflected light directed from the polarization metasurface are incident on the plurality of different regions of the image sensor.

[0292] Clause 52. The method of clauses 49, 50, or 51 , wherein the incident light from the illumination system comprises near-infrared light.

[0293] Clause 53. The method of any of clauses 49-52, wherein the incident light comprises sunlight.

[0294] Clause 54. The method of any of clauses 49-53, wherein a filter is used to filter the reflected light that is captured by the polarization receiver.

[0295] Clause 55. The method of clause 54, wherein the filter transmits near-infrared light.

[0296] Clause 56. The method of any of clauses 49-55, wherein the illumination system includes a light output from a display device.

[0297] Clause 57. The method of clause 56, wherein the light output from the display device is altered based on data from an ambient light sensor.

[0298] Clause 58. The method of clause 57, wherein the light output from the display device is altered by an increase in intensity of the light output or a specific color of light being produced by the light output of the display device.

[0299] Clause 59. The method of any of clauses 49-58, wherein the illumination system includes a structured light output.

[0300] Clause 60. The method of clause 59, wherein projecting the incident light comprises structuring light from a vertical cavity surface emitting laser (VCSEL) into the structured light output using a VCSEL metasurface, wherein the illumination system comprises the VCSEL and the VCSEL metasurface.

[0301] Clause 61. The method of clause 60, wherein the at least one VCSEL is configured into a VCSEL array.

[0302] Clause 62. The method of clause 61 , wherein the VCSEL array is overlaid with a linear polarizer integrated into a diffuser.

[0303] Clause 63. The method of clause 62, wherein the VCSEL array comprises at least one of: a partial-polarization; an unpolarized background; and a preferential linear polarization.

[0304] Clause 64. The method of clause 63, wherein the linear polarizer is directionally-aligned with the preferential linear polarization.

[0305] Clause 65. The method of any of clauses 60-64, wherein the VCSEL metasurface is: overlaid over the at least one VCSEL is configured into a VCSEL array; and used to project a polarization field onto the object.

[0306] Clause 66. The method of clause 65, wherein the polarization field is a spatially varying arbitrary polarization field.

[0307] Clause 67. The method of any of clauses 60-66, wherein the structured light output is specific to the object.

[0308] Clause 68. The method of any of clauses 60-67, wherein the structured light output comprises at least one dot pattern.

[0309] Clause 69. The method of any of clauses 60-68, wherein the structured light output comprises a first dot pattern and a flood illumination pattern.

[0310] Clause 70. The method of clause 68, wherein the structured light output includes a first dot pattern and a second dot pattern.

[0311] Clause 71. The method of clause 70, wherein the first dot pattern has a first polarization state and the second dot pattern has a second polarization state.

[0312] Clause 72. The method of clause 70, wherein the first and second dot patterns are projected simultaneously.

[0313] Clause 73. The method of clause 69, wherein the first dot pattern and the flood illumination pattern are projected simultaneously.

[0314] Clause 74. The method of clause 70, wherein the first and second dot patterns are projected in a sequence at two different times.

[0315] Clause 75. The method of clause 71 , wherein the first and second polarization states are orthogonal.

[0316] Clause 76. The method of any of clauses 49-75, wherein the object is a face.

[0317] Clause 77. The method of any of clauses 49-76, wherein: receiving the reflected light on the polarization metasurface comprises diffracting, from the reflected light, light of a first polarization in a first direction and light of a second polarization in a second direction, and the first polarization and the second polarization are different, and the first direction and the second direction are different.

[0318] Clause 78. The method of clause 77, wherein the first polarization and the second polarization are arbitrary polarizations.

[0319] Clause 79. The method of clause 77, wherein the first polarization and the second polarization are orthogonal.

[0320] Clause 80. The method of clause 77, wherein: receiving the reflected light on the polarization metasurface further comprises diffracting, from the reflected light, light of a third polarization in a third direction; the third polarization is different from the first polarization and the second polarization; and the third direction is different from the first direction and the second direction.

[0321] Clause 81. The method of clause 80, wherein: receiving the reflected light on the polarization metasurface further comprises diffracting, from the reflected light, light of a fourth polarization in a fourth direction; the fourth polarization is different from the first, second and third polarizations; and the third direction is different from the first, second and third directions.

[0322] Clause 82. The method of any of clauses 49-81 , wherein: the polarization metasurface comprises an array of metasurface lenslets; and each of the metasurface lenslets are configured to direct a particular subset of the incident light, of a specific polarization state, into different pixels of the image sensor.

[0323] Clause 83. The method of clause 82, wherein: at least some of the metasurface lenslets are separated by spaces; and the spaces do not have a polarization metasurface element such that light impinging the spaces is not directed based on its polarization state.

[0324] Clause 84. The method of any of clauses 49-83, wherein the image sensor comprises a microlens array.

[0325] Clause 85. The method of clause 84, wherein the microlens array is a metasurface.

[0326] Clause 86. The method of any of clauses 49-85, wherein the incident light enters a refractive lens before the polarization metasurface.

[0327] Clause 87. The method of any of clauses 49-86, wherein a first subset of the incident light comes from a first illuminator of the illumination system which provides a first static polarization state.

[0328] Clause 88. The method of clause 87, wherein a second subset of the incident light comes from a second illuminator of the illumination system which provides a second static polarization state.

[0329] Clause 89. The method of clause 88, wherein the first and second static polarization states are orthogonal.

[0330] Clause 90. The method of clause 88, wherein first and second illuminators provide sequenced illumination.

[0331] Clause 91. The method of clause 88, wherein: the polarization metasurface directs the reflected light into one or more different polarization states; and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

[0332] Clause 92. The method of clause 91 , wherein the first static polarization state from the illumination system is the same as at least one of the one or more different polarization states which the polarization metasurface directs onto the image sensor.

[0333] Clause 93. The method of any of clauses 49-92, wherein identifying the object is performed based on relative polarization intensities determined from the reflected light detected by each of the plurality of different regions of the image sensor.

[0334] Clause 94. The method of clause 93, wherein the relative polarization intensities are interpreted as proportional to surface normal estimates relative to the image sensor.

[0335] Clause 95. The method of clause 94, wherein the surface normal estimates are determined from the relative polarization intensities to derive a shape of the object in three-dimensional (3D) space.

[0336] Clause 96. The method of clause 95, wherein: the reflected light is interpreted as a Mueller polarimetric image; and the Mueller polarimetric image is used to identify the shape of the object.

[0337] Clause 97. A non-transitory computer-readable medium comprising instructions that, when executed, are configured to cause a processor to perform a process for: receiving, on a polarization metasurface, reflected light reflected off on an object, wherein the reflected light is: projected by an illumination system as incident light; and reflected with one or more polarization states; detecting, through an image sensor, the reflected light, wherein: the image sensor comprises a plurality of different regions; and each region of the plurality of different regions is configured to detect a given state of the one or more polarization states of the reflected light; and identifying the object using a polarization receiver, wherein identifying the object is performed based on detections of the reflected light.

[0338] Clause 98. The non-transitory computer-readable medium of clause 97, wherein the polarization metasurface directs the reflected light into one or more different polarization states and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

[0339] Clause 99. The non-transitory computer-readable medium of clause 97 or 98, wherein: the polarization metasurface is a polarization separator which is configured to direct one or more different polarization states of the reflected light in different directions; and the one or more different polarization states of the reflected light directed from the polarization metasurface are incident on the plurality of different regions of the image sensor.

[0340] Clause 100. The non-transitory computer-readable medium of clauses 97, 98, or 99, wherein the incident light from the illumination system comprises near-infrared light.

[0341]

[0342] Clause 101. The non-transitory computer-readable medium of any of clauses 97-100, wherein the incident light comprises sunlight.

[0343] Clause 102. The non-transitory computer-readable medium of any of clauses 97-101 , wherein a filter is used to filter the reflected light that is captured by the polarization receiver.

[0344] Clause 103. The non-transitory computer-readable medium of clause 102, wherein the filter transmits near-infrared light.

[0345] Clause 104. The non-transitory computer-readable medium of any of clauses 97-103, wherein the illumination system includes a light output from a display device.

[0346] Clause 105. The non-transitory computer-readable medium of clause 104, wherein the light output from the display device is altered based on data from an ambient light sensor.

[0347] Clause 106. The non-transitory computer-readable medium of clause 104, wherein the light output from the display device is altered by an increase in intensity of the light output or a specific color of light being produced by the light output of the display device.

[0348] Clause 107. The non-transitory computer-readable medium of any of clauses 97-106, wherein the illumination system includes a structured light output.

[0349] Clause 108. The non-transitory computer-readable medium of clause 107, wherein projecting the incident light comprises structuring light from a vertical cavity surface emitting laser (VCSEL) into the structured light output using a VCSEL metasurface, wherein the illumination system comprises the VCSEL and the VCSEL metasurface.

[0350] Clause 109. The non-transitory computer-readable of clause 108, wherein the at least one VCSEL is configured into a VCSEL array.

[0351] Clause 110. The non-transitory computer-readable of clause 109, wherein the VCSEL array is overlaid with a linear polarizer integrated into a diffuser.

[0352] Clause 111. The non-transitory computer-readable of clause 110, wherein the VCSEL array comprises at least one of: a partial-polarization; an unpolarized background; and a preferential linear polarization.

[0353] Clause 112. The non-transitory computer-readable of clause 111 , wherein the linear polarizer is directionally-aligned with the preferential linear polarization.

[0354] Clause 113. The non-transitory computer-readable of clause 108, wherein theVCSEL metasurface is: overlaid over the at least one VCSEL is configured into a VCSEL array; and used to project a polarization field onto the object.

[0355] Clause 114. The non-transitory computer-readable of clause 113, wherein the polarization field is a spatially varying arbitrary polarization field.

[0356] Clause 115. The non-transitory computer-readable medium of clause 108, wherein the structured light output is specific to the object.

[0357] Clause 116. The non-transitory computer-readable medium of clause 108, wherein the structured light output comprises at least one dot pattern.

[0358] Clause 117. The non-transitory computer-readable medium of clause 108, wherein the structured light output comprises a first dot pattern and a flood illumination pattern.

[0359] Clause 118. The non-transitory computer-readable medium of clause 116, wherein the structured light output includes a first dot pattern and a second dot pattern.

[0360] Clause 119. The non-transitory computer-readable medium of clause 118, wherein the first dot pattern has a first polarization state and the second dot pattern has a second polarization state.

[0361] Clause 120. The non-transitory computer-readable medium of clause 118, wherein the first and second dot patterns are projected simultaneously.

[0362] Clause 121. The non-transitory computer-readable medium of clause 117, wherein the first dot pattern and the flood illumination pattern are projected simultaneously.

[0363] Clause 122. The non-transitory computer-readable medium of clause 118, wherein the first and second dot patterns are projected in a sequence at two different times.

[0364] Clause 123. The non-transitory computer-readable medium of clause 119, wherein the first and second polarization states are orthogonal.

[0365] Clause 124. The non-transitory computer-readable medium of any of clauses 97-123, wherein the object is a face.

[0366] Clause 125. The non-transitory computer-readable medium of any of clauses 97-124, wherein: receiving the reflected light on the polarization metasurface comprises diffracting, from the reflected light, light of a first polarization in a first direction and light of a second polarization in a second direction, and the first polarization and the second polarization are different, and the first direction and the second direction are different.

[0367] Clause 126. The non-transitory computer-readable medium of clause 125, wherein the first polarization and the second polarization are arbitrary polarizations.

[0368] Clause 127. The non-transitory computer-readable medium of clause 125, wherein the first polarization and the second polarization are orthogonal.

[0369] Clause 128. The non-transitory computer-readable medium of clause 125, wherein: receiving the reflected light on the polarization metasurface further comprises diffracting, from the reflected light, light of a third polarization in a third direction; the third polarization is different from the first polarization and the second polarization; and the third direction is different from the first direction and the second direction.

[0370] Clause 129. The non-transitory computer-readable medium of clause 110, wherein: receiving the reflected light on the polarization metasurface further comprises diffracting, from the reflected light, light of a fourth polarization in a fourth direction; the fourth polarization is different from the first, second and third polarizations; and the third direction is different from the first, second and third directions.

[0371] Clause 130. The non-transitory computer-readable medium of any of clauses 110-129, wherein: the polarization metasurface comprises an array of metasurface lenslets; and each of the metasurface lenslets are configured to direct a particular subset of the incident light, of a specific polarization state, into different pixels of the image sensor.

[0372] Clause 131. The non-transitory computer-readable medium of any of clauses 112-130, wherein: at least some of the metasurface lenslets are separated by spaces;and the spaces do not have a polarization metasurface element such that light impinging the spaces is not directed based on its polarization state.

[0373] Clause 132. The non-transitory computer-readable medium of any of clauses 85-131 , wherein the image sensor comprises a microlens array.

[0374] Clause 133. The non-transitory computer-readable medium of clause 114, wherein the microlens array is a metasurface.

[0375] Clause 134. The non-transitory computer-readable medium of any of clauses 85-133, wherein the incident light enters a refractive lens before the polarization metasurface.

[0376] Clause 135. The non-transitory computer-readable medium of any of clauses85-134, wherein a first subset of the incident light comes from a first illuminator of the illumination system which provides a first static polarization state.

[0377] Clause 136. The non-transitory computer-readable medium of clause 117, wherein a second subset of the incident light comes from a second illuminator of the illumination system which provides a second static polarization state.

[0378] Clause 137. The non-transitory computer-readable medium of clause 118, wherein the first and second static polarization states are orthogonal.

[0379] Clause 138. The non-transitory computer-readable medium of clause 118, wherein first and second illuminators provide sequenced illumination.

[0380] Clause 139. The non-transitory computer-readable medium of clause 118, wherein: the polarization metasurface directs the reflected light into one or more different polarization states; and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

[0381] Clause 140. The non-transitory computer-readable medium of clause 121 , wherein the first static polarization state from the illumination system is the same as at least one of the one or more different polarization states which the polarization metasurface directs onto the image sensor.

[0382] Clause 141. The non-transitory computer-readable medium of any of clauses 85-140, wherein identifying the object is performed based on relative polarizationintensities determined from the reflected light detected by each of the plurality of different regions of the image sensor.

[0383] Clause 142. The non-transitory computer-readable medium of clause 123, wherein the relative polarization intensities are interpreted as proportional to surface normal estimates relative to the image sensor.

[0384] Clause 143. The non-transitory computer-readable medium of clause 124, wherein the surface normal estimates are determined from the relative polarization intensities to derive a shape of the object in three-dimensional (3D) space.

[0385] Clause 144. The non-transitory computer-readable medium of clause 125, wherein: the reflected light is interpreted as a Mueller polarimetric image; and the Mueller polarimetric image is used to identify the shape of the object.

Claims

AMENDED CLAIMS received by the International Bureau on 9 December 2025WHAT IS CLAIMED IS:1 . An object identification system comprising: an illumination system which illuminates an object, wherein incident light from the illumination system reflects off the object as reflected light with one or more polarization states; a polarization metasurface which receives the reflected light reflected from the object; an image sensor with a plurality of different regions configured to sense one or more different polarization states of light from the polarization metasurface; and a polarization sensing system which identifies the object based on the one or more polarization states.

2. The object identification system of claim 1 , wherein the polarization metasurface directs the reflected light into the one or more different polarization states and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

3. The object identification system of claim 1 , wherein: the polarization metasurface is a polarization separator which is configured to direct the one or more different polarization states of the reflected light in different directions; and the one or more different polarization states of the reflected light directed from the polarization metasurface are incident on the plurality of different regions of the image sensor.

4. The object identification system of claim 1 , wherein the light from the illumination system comprises near-infrared light.

5. The object identification system of claim 1 , wherein the illumination system includes sunlight.

6. The object identification system of claim 1 , further comprising a filter which filters the reflected light that is captured by the polarization sensing system.

7. The object identification system of claim 6, wherein the filter transmits near-infrared light.

8. The object identification system of claim 1 , wherein the illumination system includes a light output from a display device.

9. The object identification system of claim 8, further comprising an ambient light sensor, wherein the light output from the display device is altered based on data from the ambient light sensor.

10. The object identification system of claim 9, wherein the light output from the display device is altered by an increase in intensity of the light output or a specific color of light being produced by the light output of the display device.

11. The object identification system of claim 1 , wherein the illumination system produces a structured light output.

12. The object identification system of claim 11 , wherein the illumination system comprises a vertical cavity surface emitting laser (VCSEL) and a VCSEL metasurface which structures light from the VCSEL into the structured light output.

13. The object identification system of claim 12, wherein the at least one VCSEL is configured into a VCSEL array.

14. The object identification system of claim 13, wherein the VCSEL array is overlaid with a linear polarizer integrated into a diffuser.

15. The object identification system of claim 14, wherein the VCSEL array comprises at least one of: a partial-polarization; an unpolarized background; and a preferential linear polarization.

16. The object identification system of claim 15, wherein the linear polarizer is directionally-aligned with the preferential linear polarization.

17. The object identification system of claim 12, wherein the VCSEL metasurface is: overlaid over the at least one VCSEL is configured into a VCSEL array; and used to project a polarization field onto the object.

18. The object identification system of claim 17, wherein the polarization field is a spatially varying arbitrary polarization field.

19. The object identification system of claim 11 , wherein the structured light output is specific to the object.

20. The object identification system of claim 11 , wherein the structured light output comprises at least one dot pattern.

21. The object identification system of claim 11 , wherein the structured light output comprises a first dot pattern and a second dot pattern.

22. The object identification system of claim 11 , wherein the structured light output comprises a first dot pattern and a flood illumination pattern.

23. The object identification system of claim 21 , wherein the first dot pattern has a first polarization state and the second dot pattern has a second polarization state.

24. The object identification system of claim 21 , wherein the first and second dot patterns are projected simultaneously.

25. The object identification system of claim 22, wherein the first dot pattern and the flood illumination pattern are projected simultaneously.

26. The object identification system of claim 21 , wherein the first and second dot patterns are projected in a sequence at two different times.

27. The object identification system of claim 23, wherein the first and second polarization states are orthogonal.

28. The object identification system of claim 1 , wherein the object is a face.

29. The object identification system of claim 1 , wherein the polarization metasurface is configured to diffract light of a first polarization in a first direction and light of a second polarization in a second direction, and wherein the first polarization and the second polarization are different and the first direction and the second direction are different.

30. The object identification system of claim 29, wherein the first polarization and the second polarization are arbitrary polarizations.

31. The object identification system of claim 29, wherein the first polarization and the second polarization are orthogonal.

32. The object identification system of claim 29, wherein the polarization metasurface is further configured to diffract light of a third polarization in a third direction, wherein thefirst polarization, the second polarization, and the third polarization are all different and the first direction, the second direction, and the third direction are all different.

33. The object identification system of claim 32, wherein the polarization metasurface is further configured to diffract light of a fourth polarization in a fourth direction, wherein the first polarization, the second polarization, the third polarization, and the fourth polarization are all different and the first direction, the second direction, the third direction, and the fourth direction are all different.

34. The object identification system of claim 1 , wherein: the polarization metasurface comprises an array of metasurface lenslets; and each of the metasurface lenslets are configured to direct light having a polarization state into different pixels of the image sensor.

35. The object identification system of claim 34, wherein: at least some of the metasurface lenslets are separated by spaces; and the spaces do not have a polarization metasurface element such that light impinging the spaces is not directed based on its polarization state.

36. The object identification system of claim 1 , further comprises a microlens array.

37. The object identification system of claim 36, wherein the microlens array is a metasurface.

38. The object identification system of claim 1 , further comprises a refractive lens before the polarization metasurface.

39. The object identification system of claim 1 , wherein the illumination system comprises a first illuminator which provides light having a first static polarization state.

40. The object identification system of claim 39, wherein the illumination system comprises a second illuminator which provides light having a second static polarization state.

41. The object identification system of claim 40, wherein the first and second static polarization states are orthogonal.

42. The object identification system of claim 40, wherein first and second illuminators provide sequenced illumination.

43. The object identification system of claim 39, wherein the polarization metasurface directs the reflected light into the one or more different polarization states and the image sensor senses at least one of the one or more different polarization states to obtain a polarization signature.

44. The object identification system of claim 43, wherein the first static polarization state from the illumination system is the same as at least one of the one or more different polarization states which the polarization metasurface directs onto the image sensor.

45. The object identification system of claim 43, wherein identifying the object is performed based on relative polarization intensities determined from the reflected light detected by each of the plurality of different regions of the image sensor.

46. The object identification system of claim 45, wherein the relative polarization intensities are interpreted as proportional to surface normal estimates relative to the image sensor.

47. The object identification system of claim 46, wherein the surface normal estimates are determined from the relative polarization intensities to derive a shape of the object in three-dimensional (3D) space.

8. The object identification system of claim 47, wherein: the reflected light is interpreted as a Mueller polarimetric image; and the Mueller polarimetric image is used to identify the shape of the object.

Images