Method and apparatus for holographic display

Abstract

A device for displaying visual media includes a light source, a spatial light modulator having a respective top and a respective bottom surface and an optical filter arrangement. The optical filter arrangement includes a plurality of filter elements configured in a layer having a relative top surface, a relative bottom surface and a relative outline, where the bottom surface of the layer of the plurality of filter elements is located proximal to the top surface of the spatial light modulator and each filter element is associated with a color of X colors. Additionally, for each color of the X colors the device includes a set of filter elements associated with a predetermined portion of an area within the outline, where each filter element of the set of filter elements is spatially located within the optical filter arrangement according to a predetermined spatial distribution to form a color-specific filter overlay.

Description

Attorney Docket No.: SWV0005WO METHOD AND APPARATUS FOR HOLOGRAPHIC DISPLAY Inventors: Edward Buckley & Silviu Crisan FIELD OF THE DISCLOSURE

[0001] The subject disclosure relates to optical color filters and associated applications for spatial light modulators, holographic displays and projection systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

[0003] FIG.1 illustrates a schematic block diagram of an embodiment of an ecosystem for implementing three-dimensional (3D) display, three-dimensional (3D) projection and augmented reality (AR) devices, in accordance with various aspects described herein;

[0004] FIG.2A illustrates a high frequency optical color filter arrangement, in accordance with various aspects described herein;

[0005] FIG.2B illustrates the pupil of a user as an oval shape relative to a high frequency optical color filter arrangement, in accordance with various aspects described herein;

[0006] FIG.2C illustrates the spatio-temporally averaged perception of a user along an eye path for a high frequency optical color filter arrangement, in accordance with various aspects described herein;

[0007] FIG.3A illustrates a low frequency optical color filter arrangement, in accordance with various aspects described herein;

[0008] FIG.3B illustrates the pupil of a user as an oval shape relative to a low frequency optical color filter arrangement, in accordance with various aspects described herein;

[0009] FIG.3C illustrates the spatio-temporally averaged perception of a user along an eye path for a low frequency optical color filter arrangement, in accordance with various aspects described herein;

[0010] FIG. 4A illustrates an example implementation of an optical color filter arrangement having blue noise spectral properties, in accordance with various aspects described herein;

[0011] FIG.4B is an optical color filter arrangement illustrated in the Fourier domain, in accordance with various aspects described herein;Attorney Docket No.: SWV0005WO

[0012] FIG.4C illustrates a reconstructed hologram for an optical color filter arrangement having blue noise spectral properties, in accordance with various aspects described herein;

[0013] FIG. 5A illustrates an example implementation of an optical color filter arrangement with red noise spectral properties, in accordance with various aspects described herein;

[0014] FIG.5B is an optical color filter arrangement having red noise spectral properties illustrated in the Fourier domain, in accordance with various aspects described herein;

[0015] FIG.5C illustrates a reconstructed hologram for an optical color filter arrangement having red noise spectral properties, in accordance with various aspects described herein;

[0016] FIG.6 illustrates a hexagonal tessellation for an optical color filter arrangement, in accordance with various aspects described herein;

[0017] FIG. 7A illustrates an example optical color filter arrangement tessellated with Voronoi shapes, in accordance with various aspects described herein;

[0018] FIG.7B illustrates another example optical color filter arrangement tessellated with Voronoi shapes, in accordance with various aspects described herein;

[0019] FIG.7C illustrates another example optical color filter arrangement tessellated with Voronoi shapes, in accordance with various aspects described herein;

[0020] FIG. 8A illustrates a starting approximation for allocation of colors in an optical color filter arrangement, in accordance with various aspects described herein;

[0021] FIG.8B illustrates the spectrum of an optical color filter arrangement after a starting approximation of color allocation in the optical color filter arrangement, in accordance with various aspects described herein;

[0022] FIG. 8C illustrates a modified allocation of colors in an optical color filter arrangement, in accordance with various aspects described herein;

[0023] FIG. 8D illustrates a spectrum for an optical color filter arrangement with a modified allocation of colors in the optical color filter arrangement, in accordance with various aspects described herein;

[0024] FIG.9 is a flowchart illustrating an example method for mapping color channels for display by a spatial light modulator, in accordance with various aspects described herein;

[0025] FIG. 10 is a flowchart illustrating another example method for mapping color channels for display by a spatial light modulator, in accordance with various aspects described herein;

[0026] FIG.11 is a flowchart illustrating an example method for mapping color channels for display by a spatial light modulator, in accordance with various aspects described herein;Attorney Docket No.: SWV0005WO

[0027] FIG. 12A illustrates an example dither mask derived from a set of gray scale dot patterns, in accordance with various aspects described herein;

[0028] FIG.12B illustrates an example of using a dither mask designed for blue noise on an input image, in accordance with various aspects described herein;

[0029] FIG. 12C illustrates an example of using a dither mask designed with a signal window in the frequency domain on an input image, in accordance with various aspects described herein;

[0030] FIG.12D illustrates an example hologram dithering process with a signal window in a frequency domain , in accordance with various aspects described herein;

[0031] FIG.12E illustrates an example of using a dither mask and inverse dither mask, in accordance with various aspects described herein; and

[0032] FIG.12F illustrates an example use of mask-based dithering to quantize a hologram, in accordance with various aspects described herein. DETAILED DESCRIPTION

[0033] One or more examples are now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the various examples. It is evident, however, that the various examples can be practiced without these details.

[0034] FIG. 1 is a schematic block diagram of an embodiment of an ecosystem for implementing three-dimensional (3D) display, three-dimensional (3D) projection and / or augmented reality (AR) devices. In an example, 3D / AR module 104 includes an optical engine 104-3 for displaying / projecting visual media, such as, but not limited to, images, with an associated 3D / AR device, a processor 104-2, such as a holographic processor, for processing visual media, such as, but not limited to, images, for display / projection using optical engine 104-3 and a wireless transceiver 104-1 for enabling communication with a wireless access network (WAN), such as WAN 108.

[0035] In an example of implementation, 3D / AR module 104 is adapted for use on an 3D / AR device, such as, but not limited to, augmented reality glasses, a virtual reality headset, a head-up display, a 3D projector device and / or a 3D display device. In a related example, 3D / AR module 104 is adapted to receive media, such as, but not limited to, one or more of images, partial images, audiovisual content, or two-dimensional (2D) and / or three-dimensional (3D) graphics for use with the 3D / AR device. In another related example, 3D / AR module 104Attorney Docket No.: SWV0005WO is adapted to receive 3D content in the form of a point cloud, and / or RGBZ data, a single 2D image together with an associated depth value, or a set of 2D images, with each image of the set of 2D images having an associated display depth value. In a further related example, media can be provided to the 3D / AR module 104 from one or more of a third party resource, such as third party media resource 106, over a wireless LAN, such as WAN 108, where WAN 108 can be one or more of a local wireless LAN, the World Wide Web or a cellular network.

[0036] In yet another related example, 3D / AR module 104 can be wirelessly coupled to a mobile device, such as mobile device 102. In the example, mobile device 102 can be adapted to provide media for 3D / AR module 104 and / or to provide processing functionality for use with 3D / AR module 104.

[0037] In various examples, a 3D display / projection device and / or an augmented reality device can integrate one or more spatial light modulator devices, such as spatial modulator devices based on one or more integrated circuits. In an example, a spatial light modulator can be used as a holographic display, with the spatial light modulator configured to render one or more diffraction patterns on its active area. In an example of implementation and operation, a diffraction pattern can be rendered on a spatial light modulator and subsequently illuminated by one or more illumination sources to provide a reconstructed hologram perceptible by a user. In a related example, a diffraction pattern rendered using a spatial light modulator can also be referred to as a hologram pattern. In another related example, a reconstructed hologram perceptible to a user based on an illuminated diffraction pattern rendered on a spatial light modulator can comprise visual media. In an example, visual media includes, but is not limited to, a two-dimensional image, a two-dimensional graphic, a set of two-dimensional images, a set of two-dimensional graphics, a three-dimensional object, a three-dimensional scene and / or a three-dimensional graphic. In an example, a spatial light modulator comprises an array of light modulating unit cells, where each light modulating unit cell is individually addressable to program / select one of a plurality of optical states of the light modulating unit cell. In an example, the optical state of a light modulating unit cell influences the interaction of the light modulating unit cell with incident light. In a related example, programming an optical state of a light modulating unit cell can be done by the applying heat, applying an electric field, or applying one or more magnetic fields to the light modulating unit cell. In a related example, the pitch between adjacent light modulating unit cells (distance between the center of adjacent light modulating unit cells) is equal to or smaller than a wavelength of light modulated by one of the light modulating unit cells of the spatial light modulator.Attorney Docket No.: SWV0005WO

[0038] In a specific example of implementation and operation, visual media can be displayed by a spatial light modulator chip in combination with an illumination source, by illuminating a diffraction pattern, as rendered on the spatial light modulator chip, with the diffraction pattern to modulate a wavefront of light generated by the illumination source. In various examples, a wavefront modulated by a spatial light modulator enables a viewer to perceive visual media, including, but not limited to, digital 2D images and / or digital 3D scenes that are encoded in one or more diffraction patterns. In related examples, visual media can be created for display in color to enhance vibrancy and depth. Accordingly, presenting media in a single color (monochrome) may diminish the immersive quality of the user's experience.

[0039] In a specific example of implementation and operation, integrating separate spatial light modulator chips into a single device can enable generation of visual media in full color. In an example of implementation relevant to a red, green, blue (RGB) display, an integrated spatial light modulator integrated circuit (IC) can be configured to interact with red light, another spatial light modulator IC can be configured to interact with green light and another spatial light modulator IC can be configured to interact with blue light. In an example, modulated wavefronts of a plurality of discrete spatial light modulator (SLM) ICs, such as an SLM IC configured for red light, an SLM IC configured for green light and an SLM IC configured for blue light, can be combined to display / project visual media in color. In a related example, multiple SLM ICs can be integrated into a single device, with each SLM IC configured to interact with a different wavelength or a different range of wavelengths. In another example, an active area of a SLM can be divided into multiple regions and each region can be illuminated using light of a different wavelength or of a different range of wavelengths.

[0040] In various examples, implementing 3D / AR devices with multiple spatial light modulator chips can result in larger and bulkier devices with associated higher costs. For example, AR glasses can be implemented with multiple components integrated into one or more temples, accordingly, requiring three ICs in a temple can negatively impact compactness, weight and cost of the AR glasses. Accordingly, integrating a single spatial light modulator chip in one or in each of the temples of the AR glasses can be advantageous.

[0041] 3D / AR devices implemented using a spatial light modulator chip can be configured to include an optical color filter arrangement associated with the spatial light modulator chip. In an example, implementing an optical color filter arrangement can involve providing a set of subareas, where each subarea is configured to be one of: 1) transmissive for red light while absorbing green and blue light; 2) transmissive for green light while absorbing red and blue light; or 3) transmissive for blue light while absorbing red and green light. In a related example,Attorney Docket No.: SWV0005WO an optical color filter arrangement that includes multiple sub-areas, can be configured so that a subarea of the multiple subareas is transmissive to a wavelength or range of wavelengths different from a wavelength or a range of wavelengths of any other sub-area of the set of sub- areas. In another related example, an optical color filter arrangement can be implemented atop or in close proximity to an active area of a spatial light modulator. In yet another example of implementation and operation, each subarea of the set of subareas can comprise filter elements that are substantially transparent to a same wavelength or to a same range of wavelengths, where the filter elements that are substantially transparent to a same wavelength or to a same range of wavelengths are spatially distributed across an optical color filter arrangement, according to a predefined spatial distribution. In an example, the spatial distribution of the filter elements that are substantially transparent to a same wavelength or to a same range of wavelengths, includes forming a filter overlay that is associated with a color that is associated with the wavelength or the range of wavelengths the filter elements of the filter overlay are transmissive to. In various examples of implementation, a color-specific filter overlay can exhibit a regular or irregular pattern across the optical color filter arrangement.

[0042] Optical color filter arrangements designed for use with spatial light modulators (SLMs), such as, but not limited to, spatial light modulators used as holographic displays, can have undesirable tradeoffs. In an example, an SLM IC can be designed for direct view applications (for example, where a user views the SLM IC directly). In another example, an SLM can be designed for non-direct view applications, where the SLM plane can be replicated onto a user's pupil to form an eye box (for example, using an optical engine / optical module, or using an optical engine in combination with an optical combiner). In another example of a non- direct view application, a magnified version of the SLM plane is replicated onto a user’s pupil forming a larger eye box. In the examples, a user perceives the SLM plane on the user's pupil. In most examples, SLMs implemented using an optical color filter arrangement are best when the color-specific overlays implemented in the optical color filter arrangement are not configured as relatively larger, contiguous spatial blobs. In an example, the spatial distribution of the filter elements associated with a color-specific filter overlay of the optical color filter arrangement can be designed to have a relatively high spatial frequency, to provide improved color balance (such as white light balance) and to ensure that color artifacts are not visible when a user's eye is under motion while viewing visual media.

[0043] In various examples, the color-specific overlays of an optical color filter arrangement can be implemented as one or more grating structures, with the grating structure configured to provide replicas of the desired visual media for display. In some examples, anAttorney Docket No.: SWV0005WO optical color filter arrangement can be implemented using color-specific filter overlays, with each having a relatively high spatial frequency potentially resulting in a compromised perceived field of view (FOV) for a user. In a specific example, replicas formed from desired visual media for display can be filtered out. In a specific related example, replicas can be filtered out in Fourier space. In alternative examples, replicas formed based on an optical filter arrangement with color-specific filter overlays having relative medium spatial frequency can result in blurred visual media, such as, but not limited to, blurred images due to replicas that partially overlap with the desired visual media for display. In other examples, optical color filter arrangements with color-specific filter overlays having a relatively low spatial frequency can be implemented to mitigate reduced FOV and / or mitigate blurred visual media, such as blurred images, for a user.

[0044] In various examples, a Fourier space refers to the domain obtained by applying the Fourier transform to, for example, an image, where the Fourier transform is a mathematical operation for decomposing the image into constituent frequencies. In an example, a representative image can be converted into a Fourier space, thus the color-specific filter overlays of an associated optical color filter arrangement will necessarily be implemented with a relatively low spatial frequency to prevent the formation of Fourier replicas that either 1) compromise the field of view (if very high frequency); and / or 2) compromise image quality due to a blurred image (if medium spatial frequency).

[0045] FIG.2A illustrates an example high frequency “stripe” color filter arrangement. In an example of implementation, each of filter elements for color 158-1, color 158-2 and color 158-3 for a color model, such as a red, green, blue (RGB) color model, are implemented as narrow stripes repeated at a high relative frequency to overlay a spatial light modulator (SLM) chip. In an example, the high spatial frequency filter design of FIG.2A can provide relatively good image quality, because Fourier replicas can be separated from desired visual media, such as, but not limited to, a desired image, sufficiently that the Fourier replicas can be filtered out. In an example, Fourier replicas are filtered out in the Fourier domain. In an example, filtering out of Fourier replicas can result in a reduced field of view (FOV) for a user. In a specific example, for an “RGB stripe” optical color filter arrangement implemented with color-specific filter overlays having an associated frequency, the relative FOV can be reduced by a factor of 3 by filtering out Fourier replicas.

[0046] FIG.2B illustrates the pupil of a user relative to a high frequency stripe color filter arrangement associated with a spatial light modulator (SLM). In the example, with a stripe color filter arrangement a user’s eye or pupil can intercept with each of filter elements of colorAttorney Docket No.: SWV0005WO 158-1, color 158-2 and color 158-3 at any given temporal location, such as under an eye movement (100 degrees / sec 152) illustrated in FIG.2B. Referring again to FIG.2B, the oval shape representative of a user’s pupil (pupil relative location 156) as illustrated overlaps multiple repeated filter stripes color 158-1, color 158-2 and color 158-3 of the high frequency stripe color filter arrangement.

[0047] FIG.2C illustrates the spatio-temporally averaged perception of a user along an eye path for a high frequency stripe color filter arrangement as illustrated in FIG. 2A. In the example, a user’s pupil under an eye movement (for example, at 100 deg / sec) can perceive replicas that do not overlay, not even partially, with the desired image.

[0048] FIG.3A illustrates a low frequency stripe color filter arrangement. In an example, a “RGB stripe” optical color filter arrangement with lowest spatial frequency possible is implemented having only one stripe for red (color 208-1), one stripe for green (color 208-2) and one stripe for blue (color 208-3). In an example of operation, a color filter arrangement implemented with a low spatial frequency can be used to substantially eliminate Fourier replicas. In an example, a color filter arrangement implemented using a single, relative fat, stripe for red, one for green and one for blue, such as the optical color filter arrangement of FIG.3A, effectively provides Fourier replicas that substantially overlay with the desired image.

[0049] FIG.3B illustrates the pupil of a user as an oval shape relative to a low frequency stripe color filter arrangement. In an example, the oval shape representative of a user’s pupil (pupil relative location 206) is illustrated as overlapping a maximum of two stripes of the low frequency stripe color filter arrangement. In an example, when a low frequency red, green, blue (RGB) (respectively color 208-1, color 208-2 and color 208-3) color filter arrangement is used, an observer’s / user’s pupil can intercept a maximum of two of the three colors of a color filter arrangement at any given temporal location. In an example, when only two colors can be intercepted, relatively poor color quality / performance is observed, along with undesirable eye motion artifacts. In an example, relatively poor color quality / performance associated with a low frequency stripe color filter arrangement can result in a dominant color that will be perceived by a user as a pervasive glow across desired visual media, such as, but not limited to, a desired image.

[0050] FIG.3C illustrates the spatio-temporally averaged perception of a user along an eye path for a low frequency stripe color filter arrangement. As illustrated in FIG. 3C, the low frequency color filter arrangement effectively eliminates perceptible replicas, however FIG. 3C illustrates a color (such as yellow) glowing across the image instead of a desired white color balance.Attorney Docket No.: SWV0005WO

[0051] In an example of operation, an “RGB stripe” optical color filter arrangement having color-specific filter overlays configured with relatively high spatial frequency can be used to provide a desired white color balance across visual media, such as, but not limited to, an image, but necessarily includes perceptible image replicas. In an example, image replicas can be effectively filtered, such as filtered in the Fourier domain, but filtering in this manner can reduce an observer’s effective field of view (FOV). In an alternative example, when the “width” of the stripes in a given color filter arrangement is increased, image replicas can substantially overlap with a desired image to effectively eliminate them from perception by a user, however a dominant color glow can persist over the desired image, instead of a proper / desired white color balanced image.

[0052] Considering the optical color filter arrangements illustrated in FIGs 2A & 3A, an alternative optical color filter arrangement having color-specific filter overlays configured with a spatial frequency somewhere between the high spatial frequency of FIG. 2A and the low frequency of FIG.3 can be used, however a blurred image can result, because image replicas are shifted relative to a desired image, so they do not precisely overlay the desired image. Additionally, the alternative optical color filter arrangement with color-specific overlays having a relatively medium spatial frequency can still exhibit a dominant color glow (i.e., not sufficiently white light color balanced) on visual media for display, such as an image, although the color glow can be attenuated relative to the color filter arrangement described in FIG.3A- 3C.In an example of implementation and operation, each individual filter element of the set of filter elements out of which the optical color filter arrangement is composed can be located atop a single light modulating unit cell of an array of light modulating unit cells associated with a spatial light modulator (SLM). In another example, one or more of the individual filter elements of an optical color filter arrangement can be located atop two or more light modulating unit cells of an array of light modulating unit cells of an SLM.

[0053] In an example, implementing a spatial light modulator with an optical color filter arrangement reduces the resolution for each color channel of the set of color channels of visual media intended for display. In an example of implementation and operation, an optical color filter arrangement can be configured using Bayer filter mosaics. In a related example, an optical color filter arrangement can be configured so that each SLM light modulating unit cell is overlayed with a color filter (red, green, or blue), where the typical pattern or mosaic includes twice as many green filter elements as red or blue filter elements (RGGB), reflecting the human vision's higher sensitivity to green light. In a related example, each SLM light modulating unitAttorney Docket No.: SWV0005WO cell can capture a single color, inherently reducing the resolution of each color channel of the visual media for display.

[0054] In an example, a color filter arrangement can be engineered to achieve a predefined barycentric color density. In the example above, a color filter arrangement based on RGGB filter mosaics provides filter elements in multiples of 4, providing benefits that include improved downstream computation requirements and potentially improved filter layout options. In an example of implementation and operation, an optical color filter arrangement is implemented using X colors, with each color of the X colors assigned a same percentage of the area of the optical color filter arrangement. In another example, an optical color filter arrangement is implemented using X colors, with a different percentage of the area of the optical color filter arrangement assigned to at least one color of the X colors than is assigned to any other colors of the X colors. In a related example, an optical color filter arrangement implemented using red, green and blue (RGB) optical filter elements, a higher percentage of the area of the optical color filter arrangement can be assigned to the color green.

[0055] FIG. 4A illustrates an example implementation of an optical color filter arrangement with each of the spatial distributions of the filter elements associated with a color- specific filter overlay having blue noise spectral properties; or simply saying an optical color filter arrangement with the color-specific overlays having blue noise spectral properties. In the example, 2 / 4 of the filter elements are allocated to the color green (color 308-2), ¼ of the filter elements are allocated to the color red (color 308-1) and ¼ of the filter elements are allocated to the color blue (color 308-3). In an example of operation, when a hologram pattern associated with a color channel of the visual media for display is sampled fora given color filter arrangement (i.e. which light modulating unit cells of a spatial light modulator (SLM) are allocated for red, green and blue, respectively), can influence image quality of the reconstructed hologram. In an example of implementation and operation, a color filter arrangement will include a color-specific overlay for each color represented in the color filter arrangement. For example, the filter elements allocated to color 308-2 will be arranged spatially within the color filter arrangement to provide a color-specific filter overlay for color 308-2. The filter elements of color 308-1 and the filter elements of color 308-3 will also be spatially arranged so that each set of filter elements associated with a color provides a respective color-specific filter overlay, with color 308-2, color 308-1 and color 308-3 together making up the optical color filter arrangement illustrated in FIG.4A.

[0056] In another example, an optical color filter arrangement can comprise X color- specific filter overlays with the spatial distribution of the filter elements associated with a color-Attorney Docket No.: SWV0005WO specific filter overlay configured for high spatial frequency, where the spatial distribution of the filter elements associated with each of the X colors is random, but spatially uniform with minimal clustering or repetition.

[0057] In an example, an optical color filter arrangement can be engineered to provide color-specific filter overlays having spectral properties associated with blue noise (blue noise spectral properties), where the blue noise spectral properties are sufficient to attenuate or eliminate color artifacts in visual media that is displayed using an associated spatial light modulator (SLM) . Referring to FIG.4A, an example optical filter arrangement, can result in image replicas sufficiently close to a desired image, eliminating the need for filtering or removal of image replicas that would reduce the field of view; however, the image replicas do not perfectly overlay the desired image. Accordingly, in some examples, image replicas can still overlay with a desired image, but with sufficient shift relative to the desired image to result in blurring of the desired image. In a related example, an optical color filter arrangement comprising color-specific filter overlays can be engineered for the color-specific filter overlays to have a sufficiently high spatial frequency to avoid and / or mitigate color artifacts, such as, but not limited to, non-white color balancing.

[0058] FIG. 4B is a color filter arrangement illustrated in the Fourier domain. In an example, sampling a hologram pattern associated with a color channel of visual media for display according to an optical color filter arrangement can introduce noise. In an alternative example, a color filter arrangement engineered to provide blue noise spectral properties can result in the sample noise being located in a predetermined area in Fourier domain, providing an opportunity to effectively filter out the noise. FIG.4C illustrates a computer simulation of a reconstructed hologram for a spatial light modulator (SLM) having an optical color filter arrangement engineered to provide color-specific filter overlays exhibiting blue noise spectral properties. In the example, the image is blurry, due to image replicas not overlaying a desired image with sufficient precision.

[0059] FIG. 5A illustrates an example implementation of a color filter arrangement with the color-specific filter overlays having red noise spectral properties. In an example of implementation and operation, an optical color filter arrangement can be engineered to exhibit red noise (i.e. low-pass) spectral properties. In a related example, an optical color filter arrangement can be engineered so that ½ of the active area of a spatial light modulator (SLM), or in other words ½ of the light modulating unit cells of the spatial light modulator, is allocated to the color green (color 408-2), ¼ of the active area of the SLM is allocated to the color red (color 408-1) and ¼ of the active area of the SLM is allocated to the color blue (color 408-3).Attorney Docket No.: SWV0005WO

[0060] FIG. 5B illustrates an optical color filter arrangement having red noise spectral properties illustrated in the Fourier domain. In an example, a substantial spatial frequency of the color-specific filter overlays of an optical color filter arrangement, such as that illustrated in FIG.5A, is too low to prevent color artifacts (such as non-white color balance) at the SLM plane. FIG.5C illustrates a computer simulation of a reconstructed hologram for a spatial light modulator with an optical color filter arrangement engineered to provide red noise spectral properties. In the example, image replicas are within sufficient proximity to a desired image to effectively avoid a reduction of a user’s field of view (FOV), with little or no blurring in reconstruction. In an example or operation, an optical color filter arrangement engineered with color filter overlays thaving red noise spectral properties will necessarily have a spatial frequency too low to prevent color artifacts in the SLM plane.

[0061] In an explanatory example, relatively large color filter elements can result in undesirable color artifacts at the SLM plane. In another explanatory example, relatively small or narrow color filter elements can result in Fourier replicas, blurring a desired image in reconstruction. In an example, a color filter element would preferably be engineered to provide a relatively large area-to-perimeter ratio, for Fourier replicas to be projected in relatively close proximity to a desired image. In another example, a color filter element having a relatively large area-to-perimeter ratio, while having a shape enabling efficient tiling over a spatial light modulator (SLM) would also be preferable. In an example, a hexagon shape filter element has a relatively large area-to-perimeter ratio, while potentially enabling efficient overlay on a spatial light modulator (SLM).

[0062] FIG. 6 illustrates a hexagonal tessellation of an optical filter arrangement (i.e. a tessellation of hexagonal shaped filter elements.) In an example, hexagonal filter element(s) 406 can be implemented as individual color filter elements of an optical color filter arrangement 400 overlaying light modulating unit cells of a spatial light modulator (SLM). In various examples, an SLM having a rectangular shape cannot be perfectly tiled or filled solely with hexagonal filter elements, because a rectangle cannot be entirely covered by whole hexagons without gaps or overlaps. In the example of FIG.14, hexagonal tessellation can be implemented to tile 3 filter colors (color 408-1, color 408-2 and color 408-3, respectively) associated with a red, green, blue (RGB) color model in a two-dimensional filter arrangement using hexagonal filter elements. In an example, a rectangular shaped SLM cannot be completely overlaid by the tessellation of hexagonal filter elements without leaving horizontal edge(s) 402 and vertical edge(s) 404 with unfiltered regions, and / or overlapping horizontal edge(s) 402 and / or vertical edge(s) 404. In an example, a spatial light modulator is configured with hexagonal shaped lightAttorney Docket No.: SWV0005WO modulating unit cells (from a top view perspective) in order for whole hexagons to work as filter elements.. In another example, some or all light modulating unit cells of an SLM can be configured in an irregular matrix structure, with adjacent light modulating unit cells not directly aligned to each other in either horizontal and / or vertical directions. In an example, light modulating unit cells of a spatial light modulator can be configured in a predetermined configuration engineered to align an optical color filter arrangement with a tessellation of hexagonal filter elements to an active area of the SLM.

[0063] FIG. 7A illustrates an example optical color filter arrangement tessellated with Voronoi shaped filter elements to provide a Voronoi diagram. In various examples, forming a Voronoi diagram 410-1 can begin with an initial set of regularly distributed seed points (seeds) in a two dimensional (2D) space, such as a square or rectangular shape of an active area of an SLM. In an example, each seed point of a plurality of seed points “grows” in all directions at an identical rate to form associated Voronoi cells. In an example, Voronoi shapes in a Voronoi diagram can comprise polygons. In various examples applicable herein, a Voronoi diagram tessellated with Voronoi shaped filter elements may overlay one or more light modulating unit cells associated with a spatial light modulator.

[0064] FIG.7B illustrates another example optical color filter arrangement tessellated with Voronoi shapes. In an example of implementation, forming Voronoi diagram 410-2 begins with an initial set of irregularly distributed seed points in a square / rectangular shape outlining a two- dimensional (2D) space, where the shape of the two-dimensional (2D) shape substantially matches an associated rectangular shaped active area of spatial light modulator. In an example, each seed point is associated with a region (a Voronoi cell) containing all seed points closer to the seed point than to any other and a centroid (or geometric center) of each Voronoi cell is determined. In an illustrative example, each seed point is “moved” to the centroid of its respective Voronoi cell, with the moving step repeated until convergence or until a specified number of iterations is reached. In the example, each seed point of the set of seed points can be distributed across a space, such as the square or rectangular shape of an associated SLM.

[0065] FIG.7C illustrates another example optical color filter arrangement tessellated with Voronoi shapes. In an example, an optical color filter arrangement can be engineered to tessellate a rectangular spatial light modulator (SLM) with Voronoi shapes optimized to fill the space relatively uniformly. In the example, the Voronoi shapes, such as Voronoi polygons or cells, are configured to partition the space into regions based on growth starting from each of a plurality of seed points in all directions at the same rate. As with the examples illustrated above with reference to FIGs 15A and 15B, each Voronoi cell is associated with one of theAttorney Docket No.: SWV0005WO input seed points and all the points within a given region are closer to an associated seed point than to any other seed point in the set, where each Voronoi cell is associated with a specific seed point. In an example, the boundary of a given Voronoi cell consists of points that are substantially equidistant to the two nearest seed points. The resulting shape resembles a polygon, where the polygons collectively form Voronoi diagram 410-3.

[0066] In an example of implementation and operation, an iterative method (such as Lloyd’s algorithm) can be used to optimize a formation of Voronoi cells of a Voronoi diagram, where the Voronoi cells represent filter elements of an optical filter arrangement. In an example, an optical filter arrangement comprising N Voronoi cells can be adapted to near optimally fill a rectangular outline, with each Voronoi cell substantially resembling any other Voronoi cell in the Voronoi diagram as to area and / or shape. In a related example, an optical filter arrangement, including the shape, size and position of the filter elements, can be fixed for a given outline, such as the rectangular outline of a spatial light modulator. In an example, a color, such as each of red, green and blue (RGB) of an RGB color model, can be assigned to each of these Voronoi shapes. In a specific example of implementation, color assignments for each of the Voronoi cells can be adapted to provide multiple tessellation patterns (i.e. color- specific filter overlays) within an optical filter arrangement, where each tessellation pattern (i.e. color-specific filter overlay) is associated with a color channel of a set of color channels out of which visual media intended for display is composed of, so that such that one or more of the tessellation patterns exhibits predetermined spectral properties, such as blue noise spectral properties.

[0067] FIG. 8A illustrates a starting approximation for allocation of colors in an optical color filter arrangement. In an example, an optical color filter arrangement can be representative of a Voronoi diagram, with each Voronoi cell of the Voronoi diagram representing a filter element of the optical color filter arrangement. In an example of implementation and operation, color allocation of each Voronoi cell of a set of Voronoi cells comprising an optical filter arrangement can begin by generating a starting approximation based on each color of a plurality of color channels associated with visual media intended for display overlaying a desired portion of the active area of a spatial light modulator. In an example, each color of the plurality of color channels associated with the visual media intended for display covers a substantially similar or equal percentage of the area of the optical filter arrangement. In another related example, the allocation of color to each Voronoi cell of an optical filter arrangement can begin by generating a starting approximation based on a barycentric color distribution. In an example, starting approximation 500 can be based on a red,Attorney Docket No.: SWV0005WO green, green, blue (RGGB) color model adapted to provide 2 green (color 508-2) filter elements for each combined red (color 508-1#) and blue (color 508-3) filter element.

[0068] FIG.8B illustrates the spectrum of an optical color filter arrangement after a starting approximation of color allocation in the optical color filter arrangement. In an example, the spectrum is the representation of the optical filter arrangement in the frequency domain. In an example, an optical color filter arrangement with a non-optimized color allocation can represent more noise in the lower frequencies.

[0069] FIG. 8C illustrates a modified allocation of colors in an optical color filter arrangement, such as a Voronoi based color filter arrangement. Referring to FIG.8A, an initial starting approximation of color allocation is used as a starting point for an iterative process implemented using an optimization technique, such as a simulated annealing algorithm, to allocate a color to each of the filter elements of the optical color filter arrangement. In an example, an optimization technique can be adapted to achieve color-specific overlays exhibiting one or more relatively high spatial frequencies. In another specific example, a simulated annealing algorithm adapted for allocating color to filter elements can be applied iteratively until a final optical color filter arrangement 520 is achieved. In a related example, color-specific overlays of the final optical color filter arrangement 520 can be used to provide predetermined blue-noise spectral properties. Referring to the examples of FIG.8A and 8C, an optical color filter arrangement comprises a color-specific overlay for green (color 508-2), one for red (color 508-1) and one for blue (color 508-3).

[0070] FIG. 8D illustrates the spectrum of the optical filter arrangement 520 of FIG.8C. (522). In the example of FIG.8D, the spectrum reflects improved reconstruction image quality, with SLM colors “blue-noise distributed” in each color channel, so that color and eye-motion performance compare favorably to an image generated using a blue-noise mask arrangement.

[0071] In an example of implementation, a color filter arrangement can be adapted to uniformly fill a rectangular outline, such as a rectangular active area of a spatial light modulator (SLM). In a related example, each filter element comprising the color filter arrangement can be adapted to have a Voronoi shape, with the aggregate Vornoi shaped filter elements together optimized to fill a rectangular space as uniformly as possible. In another related example, filter elements comprising a color filter arrangement can be allocated to provide a desired barycentric color density. Finally, a color assigned to each Voronoi shape of a color filter arrangement relative to a desired barycentric color density, can be chosen to provide an optical color filter arrangement exhibiting blue noise spectral properties.Attorney Docket No.: SWV0005WO

[0072] In an example of operation, a color filter implemented using Voronoi shaped filter elements and exhibiting blue noise spectral properties can provide attenuated generation of visual artifacts associated with eye motion when using modulation associated with a spatial light modulator, while improving image quality requirements in a reconstruction plane associated with the SLM. In an example, “close-to-hexagonal shape” color filter elements can be sued to provide relatively close placement of Fourier replicas resulting in improved attenuation of visual artifacts.

[0073] FIG.9 is a flowchart illustrating an example method for mapping color channels for display by a spatial light modulator. The method begins with visual media data being received at a holographic device comprising a holographic processor and one or more spatial light modulators at step 1000. The method then continues at steps 1002 and 1004 by generating an interference-based light pattern based on the visual media data, where the interference-based light pattern is configured to map color channels to the light pattern based on a filter arrangement comprised of a plurality of polygonal filter elements adapted to uniformly fill a space defined by a rectangular spatial light modulator.

[0074] FIG. 10 is a flowchart illustrating another example method for mapping color channels for display by a spatial light modulator. The method begins with visual media data being received at a holographic device comprising a holographic processor and one or more spatial light modulators at step 1020. The method then continues at steps 1022 and 1024 by generating an interference-based light pattern based on the visual media data, where the interference-based light pattern based on a filter arrangement having a predetermined barycentric color density and is further configured to generate color artifact noise at a frequency favorable to color artifact avoidance.

[0075] FIG.11 is a flowchart illustrating an example method for mapping color channels for display by a spatial light modulator. The method begins at step 1040 by generating a starting approximation for a filter arrangement. The starting approximation filter arrangement can be based on a “best guess” for generating a 2D filter arrangement to provide a compromise between color quality (such as color balance) and eliminating eye motion artifacts. The method continues at step 1042, by optimizing placement of each filter element iteratively until blue- noise spectral threshold is achieved. FIG.12A illustrates an example dither mask for processing derived from a set of dot patterns, each dot pattern representing a different gray scale. Dither masks can be used in image processing to create an illusion of color depth in images with a limited number of pixel states. In various relevant examples, a dither mask, such as dither mask 602 can be used in a dithering process to introduce a controlled form of noise into an image soAttorney Docket No.: SWV0005WO that quantization errors appear to be relatively random, rather than structured. In an example of implementation and operation, an example dither mask can be used to quantize pixel values in a traditional 2D image for distributing quantization errors to provide, in further example, for an example image to have a smoothed appearance. In an example, a small static dither mask (for example, 128 x 128 pixels) can be used to provide a set of threshold values for dithering a traditional 2D image, where the traditional 2D image has a size larger than 128 x 128 pixels. In an example, a dither mask for quantizing traditional 2D images can be derived from a set of dot patterns, each dot pattern representing a different gray scale, where the dot patterns for each of the desired gray scales are designed using simulated annealing to have blue noise properties (blue noise contains more energy at higher frequencies and less energy at lower frequencies, making it less noticeable for human vision). In an example of implementation, a dithering process can be configured for use in hardware by comparing pixel values of, for example, a traditional 2D image, to threshold values in a dither mask, enabling relatively low computational requirements. In an example, where dither can be enabled for two available states, an upper state and a lower state, when a pixel value of, for example, a traditional 2D image, is larger than a corresponding threshold value of the dither mask, such that the pixel is quantized to the upper state. In the example, when the pixel value of, for example a traditional 2D image, is smaller than the corresponding threshold value in the dither mask, the pixel is quantized to the lower state. In a related example, a smaller dither mask (for example, 128 x 128 pixels) can be tiled across an image, with the image having a size larger than the dither mask, enabling the dithering of a relatively large image with a smaller dither mask. In an example, a smaller dither mask can enable a reduced memory size requirement in a given hardware implementation. In another related example, dithering by comparison of pixel values of a traditional 2D image to threshold values in a dither mask, can enable serial pixel quantization, further enabling a relatively relaxed hardware design.

[0076] FIG.12B illustrates the use of a dither mask on a traditional 2D input image, where the dither mask can be designed to have blue noise properties. In an example, dithering using a dither mask with blue noise properties can be suitable for traditional 2D images because the quantization noise can be moved into high spatial frequencies where it is easier for the human visual system to integrate. In an example, a given dither mask can be configured so that quantization noise for a 2D image can be moved into relatively high spatial frequencies, where it can be easier for a human visual system to integrate for visual interpretation. In a specific relevant example of operation, a dither mask can be adapted for use to quantize holograms. In a specific related example, while a dither mask used to quantize traditional 2D images canAttorney Docket No.: SWV0005WO incorporate blue-noise properties, a dither mask used to quantize hologram patterns can be designed to incorporate appropriate properties in frequency domain, where quantization noise can be moved to a region outside a desired signal window in frequency domain. Quantizing hologram patterns using a dither mask enables relatively low computational requirements in hardware, as the process can be a relatively simple comparison operation in hardware.

[0077] FIG.12C illustrates the use of a dither mask designed with a desired signal window in frequency domain. The dither mask of FIG. 1C can be designed for quantizing hologram patterns, where quantization noise can be moved outside a desired signal window in frequency domain. In an example, a dither mask optimized to quantize hologram patterns can be nonoptimal for quantizing traditional 2D images, because a dither mask optimized to quantize hologram patterns does not incorporate blue noise properties.

[0078] FIG.12D illustrates the use of a dither mask on a hologram pattern, with the dither mask designed for a desired signal window in a frequency domain. In the example of FIG.1D, a Fast Fourier Transform of a dithered hologram pattern includes a relatively well-defined signal window in frequency domain, where quantization noise can be largely moved outside the well-defined signal window. In an example, a dither mask designed to quantize hologram patterns can have a size requirement that can be substantially the same size as the hologram pattern to be quantized. In an example, a real-valued hologram pattern can be normalized so that each pixel of the real-valued hologram pattern maintains a value between -1 and 1 (with - 1 and 1 included). In a related example, a dither mask can be provided to quantize the pixel values of a normalized real-valued hologram pattern, where each pixel of the normalized real- valued hologram pattern maintains a value between -1 and 1 (with -1 and 1 included), to either -1 or to 1, where the dither mask can be designed to provide a well-defined signal window in frequency domain with quantization noise largely moved outside the well-defined signal window. In an example, a dither mask optimized for quantizing hologram patterns has the same size as the hologram patterns to be quantized. In an example, an augmented reality device, such as augmented reality glasses, are adapted with one or more mask based dithering methods for the dithering of hologram patterns that are to be rendered on one or more spatial light modulators that are integrated as part of the augmented reality device. In a related example, a dither mask can be precomputed and stored on one or more memory devices of the augmented reality device, where the dither mask can be designed to provide a well-defined signal window with quantization noise largely moved outside the well-defined signal window.

[0079] FIG. 12E illustrates an example use of a dither mask optimized for quantizing hologram patterns, where the size of the dither mask can be smaller than the size of theAttorney Docket No.: SWV0005WO hologram patterns to be quantized. In an example, the pixels of a hologram pattern are quantized to either -1 or 1. In an example, a dither mask can be adapted to quantize the pixels of a hologram pattern to either -1 or 1, where the dither mask can be smaller than the hologram pattern to be quantized and where the dither mask can be designed to provide a relatively well- defined signal window in frequency domain with quantization noise largely moved outside the well-defined signal window in frequency domain. The threshold values in the dither mask maintain a value between -1 and 1 (with -1 and 1 included). In an example, a hologram pattern can be divided into four quadrants. Top left and bottom right quadrants are quantized by tiling a dither mask, with the dither mask having a size smaller than the size of a given hologram pattern to be quantized, across each of these quadrants. In a specific example, for top right and bottom left quadrants, a sign-flip is applied to each value, and the dither mask is tiled across the sign-flipped top right and bottom left quadrants for quantization, resulting in an unfinished quantized hologram pattern for the top right and bottom left quadrants. In a related example of operation, a sign flip is applied to the unfinished quantized hologram patterns to provide a finished quantized hologram pattern for the top right and bottom left quadrant of the hologram pattern. In an example of implementation, a dithering operation implemented in quadrants enables a given pixel value of a continuous real-valued hologram Hr to be quantized to provide a binary hologram Hb pixel value, as illustrated in FIG. 9E, providing minimally acceptable quantization results on a hologram pattern.

[0080] In an alternative example of implementation and operation, a second dither mask can be used, where each location in the second dither mask has a threshold value at a corresponding location in the first dither mask but where the sign for each location is reversed as compared to the first dither mask. In a related example, the second dither mask can be derived from the first dither mask by applying a sign flip to each value of the first dither mask. In another related example, both the first and the second dither mask can be adapted to be the same “size”, but where the two masks are smaller than the size of the to-be-quantized hologram pattern. In a specific example, a hologram pattern can be divided into four quadrants, where the left and bottom right quadrants are quantized by tiling the first dither mask across each of these quadrants, with the second dither mask tiled across the top right and bottom left quadrants for quantization to implement an unfinished quantized hologram pattern for top right and bottom left quadrant. In the example, a sign flip can be applied to the unfinished hologram pattern for top right and bottom left quadrant, providing a finished quantized hologram pattern for the top right and bottom left quadrant of the hologram pattern. In an example of implementation, a dithering operation can be implemented in quadrants, so that a pixel valueAttorney Docket No.: SWV0005WO of a continuous real hologram Hr can be quantized to a binary hologram Hb pixel value, to provide serviceable quantization results for a hologram pattern.

[0081] FIG.12F illustrates an example use of mask-based dithering to quantize a hologram pattern. In the example, a 4096 x 4096 hologram pattern can be quantized using a 256 x 256 dither mask, providing a frequency domain signal window with quantization noise largely moved outside the well-defined signal window. In an example of implementation and operation, a memory device can be required for the dither mask (256 x 256 x 8 bits in this example), however the dithering operation requires almost no additional computation. In yet another related example, a comparison of values of a hologram pattern to threshold values in a dither mask can be processed in an arbitrary order.

[0082] An example method comprises receiving a hologram pattern, representing one of an image, a three-dimensional (3D) object, or a three-dimensional (3D) scene for display. In an example, the hologram pattern can be spatially divided into four subspace quadrants. In a related example, the hologram pattern can be quantized using a first and a second dither mask, where the values of the second dither mask are those of the first dither mask, but with the associated signs reversed. In an example, the first dither mask can be applied to two subspace quadrants of the four subspace quadrants, such as, for example, top left and bottom right subspace quadrants, while the second dither mask can be adapted for use with the remaining two subspace quadrants of the four subspace quadrants, such as, for example, top right and bottom left subspace quadrants resulting in an unfinished quantized hologram pattern for each of these two subspace quadrants. In an example, a sign flip can then be applied to each value of the unfinished quantized hologram of each of these two subspace quadrants to obtain a finished quantized hologram for all four quadrants. In a related example, each of the four subspace quadrants can be aligned to a common first axis and a common second axis, wherein the first axis and the second axis cross at a quadripoint of the four subspace quadrants.

[0083] It is noted that in addition to and / or in alternative to any of the previously described alternatives, the term “color filter pattern” can be used interchangeably with “color filter arrangement” or “optical color filter arrangement” when used to describe an array of optical color filters elements configured on top of light modulating unit cells of a spatial light modulator. Alternatively, the term “color filter pattern” can be used interchangeably with “color-specific filter overlay” or "filter overlay", when used to describe each sub-array of a plurality of sub-arrays that together comprise an array of optical color filters elements and where each sub-array of the plurality of sub-arrays further corresponds with a color of a set of color channels associated with visual media for display.Attorney Docket No.: SWV0005WO

[0084] It is further noted that terminologies as may be used herein such as bit stream, stream, signal sequence, etc. (or their equivalents) have been used interchangeably to describe digital information whose content corresponds to any of a number of desired types (e.g., data, video, speech, text, graphics, audio, etc. any of which may generally be referred to as ‘data’). As may be used herein, the terms “substantially” and “approximately” provide an industry- accepted tolerance for its corresponding term and / or relativity between items. For some industries, an industry-accepted tolerance is less than one percent and, for other industries, the industry-accepted tolerance is 10 percent or more. Other examples of industry-accepted tolerance range from less than one percent to fifty percent. Industry-accepted tolerances correspond to, but are not limited to, component values, integrated circuit process variations, temperature variations, rise and fall times, thermal noise, dimensions, signaling errors, dropped packets, temperatures, pressures, material compositions, and / or performance metrics. Within an industry, tolerance variances of accepted tolerances may be more or less than a percentage level (e.g., dimension tolerance of less than + / - 1%). Some relativity between items may range from a difference of less than a percentage level to a few percent. Other relativity between items may range from a difference of a few percent to magnitude of differences.

[0085] As may also be used herein, the term(s) “configured to”, “operably coupled to”, “coupled to”, and / or “coupling” includes direct coupling between items and / or indirect coupling between items via an intervening item (e.g., an item includes, but is not limited to, a component, an element, a circuit, and / or a module) where, for an example of indirect coupling, the intervening item does not modify the information of a signal but may adjust its current level, voltage level, and / or power level. As may further be used herein, inferred coupling (i.e., where one element is coupled to another element by inference) includes direct and indirect coupling between two items in the same manner as “coupled to”.

[0086] As may even further be used herein, the term “configured to”, “operable to”, “coupled to”, or “operably coupled to” indicates that an item includes one or more of power connections, input(s), output(s), etc., to perform, when activated, one or more its corresponding functions and may further include inferred coupling to one or more other items. As may still further be used herein, the term “associated with”, includes direct and / or indirect coupling of separate items and / or one item being embedded within another item.

[0087] As may be used herein, the term “compares favorably”, indicates that a comparison between two or more items, signals, etc., indicates an advantageous relationship that would be evident to one skilled in the art in light of the present disclosure, and based, for example, on the nature of the signals / items that are being compared. As may be used herein, the termAttorney Docket No.: SWV0005WO “compares unfavorably”, indicates that a comparison between two or more items, signals, etc., fails to provide such an advantageous relationship and / or that provides a disadvantageous relationship. Such an item / signal can correspond to one or more numeric values, one or more measurements, one or more counts and / or proportions, one or more types of data, and / or other information with attributes that can be compared to a threshold, to each other and / or to attributes of other information to determine whether a favorable or unfavorable comparison exists. Examples of such a advantageous relationship can include: one item / signal being greater than (or greater than or equal to) a threshold value, one item / signal being less than (or less than or equal to) a threshold value, one item / signal being greater than (or greater than or equal to) another item / signal, one item / signal being less than (or less than or equal to) another item / signal, one item / signal matching another item / signal, one item / signal substantially matching another item / signal within a predefined or industry accepted tolerance such as 1%, 5%, 10% or some other margin, etc. Furthermore, one skilled in the art will recognize that such a comparison between two items / signals can be performed in different ways. For example, when the advantageous relationship is that signal 1 has a greater magnitude than signal 2, a favorable comparison may be achieved when the magnitude of signal 1 is greater than that of signal 2 or when the magnitude of signal 2 is less than that of signal 1. Similarly, one skilled in the art will recognize that the comparison of the inverse or opposite of items / signals and / or other forms of mathematical or logical equivalence can likewise be used in an equivalent fashion. For example, the comparison to determine if a signal X > 5 is equivalent to determining if -X < -5, and the comparison to determine if signal A matches signal B can likewise be performed by determining -A matches -B or not(A) matches not(B). As may be discussed herein, the determination that a particular relationship is present (either favorable or unfavorable) can be utilized to automatically trigger a particular action. Unless expressly stated to the contrary, the absence of that particular condition may be assumed to imply that the particular action will not automatically be triggered. In other examples, the determination that a particular relationship is present (either favorable or unfavorable) can be utilized as a basis or consideration to determine whether to perform one or more actions. Note that such a basis or consideration can be considered alone or in combination with one or more other bases or considerations to determine whether to perform the one or more actions. In one example where multiple bases or considerations are used to determine whether to perform one or more actions, the respective bases or considerations are given equal weight in such determination. In another example where multiple bases or considerations are used to determine whether to perform oneAttorney Docket No.: SWV0005WO or more actions, the respective bases or considerations are given unequal weight in such determination.

[0088] As may be used herein, one or more claims may include, in a specific form of this generic form, the phrase “at least one of a, b, and c” or of this generic form “at least one of a, b, or c”, with more or less elements than “a”, “b”, and “c”. In either phrasing, the phrases are to be interpreted identically. In particular, “at least one of a, b, and c” is equivalent to “at least one of a, b, or c” and shall mean a, b, and / or c. As an example, it means: “a” only, “b” only, “c” only, “a” and “b”, “a” and “c”, “b” and “c”, and / or “a”, “b”, and “c”.

[0089] As may also be used herein, the terms “processing module”, “processing circuit”, “processor”, “processing circuitry”, and / or “processing unit” may be a single processing device or a plurality of processing devices. Such a processing device may be a microprocessor, micro- controller, digital signal processor, microcomputer, central processing unit, field programmable gate array, programmable logic device, state machine, logic circuitry, analog circuitry, digital circuitry, and / or any device that manipulates signals (analog and / or digital) based on hard coding of the circuitry and / or operational instructions. The processing module, module, processing circuit, processing circuitry, and / or processing unit may be, or further include, memory and / or an integrated memory element, which may be a single memory device, a plurality of memory devices, and / or embedded circuitry of another processing module, module, processing circuit, processing circuitry, and / or processing unit. Such a memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, cache memory, and / or any device that stores digital information. Note that if the processing module, module, processing circuit, processing circuitry, and / or processing unit includes more than one processing device, the processing devices may be centrally located (e.g., directly coupled together via a wired and / or wireless bus structure) or may be distributedly located (e.g., cloud computing via indirect coupling via a local area network and / or a wide area network). Further note that if the processing module, module, processing circuit, processing circuitry and / or processing unit implements one or more of its functions via a state machine, analog circuitry, digital circuitry, and / or logic circuitry, the memory and / or memory element storing the corresponding operational instructions may be embedded within, or external to, the circuitry comprising the state machine, analog circuitry, digital circuitry, and / or logic circuitry. Still further note that, the memory element may store, and the processing module, module, processing circuit, processing circuitry and / or processing unit executes, hard coded and / or operational instructions corresponding to at least some of theAttorney Docket No.: SWV0005WO steps and / or functions illustrated in one or more of the Figures. Such a memory device or memory element can be included in an article of manufacture.

[0090] One or more embodiments have been described above with the aid of method steps illustrating the performance of specified functions and relationships thereof. The boundaries and sequence of these functional building blocks and method steps have been arbitrarily defined herein for convenience of description. Alternate boundaries and sequences can be defined so long as the specified functions and relationships are appropriately performed. Any such alternate boundaries or sequences are thus within the scope and spirit of the claims. Further, the boundaries of these functional building blocks have been arbitrarily defined for convenience of description. Alternate boundaries could be defined as long as the certain significant functions are appropriately performed. Similarly, flow diagram blocks may also have been arbitrarily defined herein to illustrate certain significant functionality.

[0091] To the extent used, the flow diagram block boundaries and sequence could have been defined otherwise and still perform the certain significant functionality. Such alternate definitions of both functional building blocks and flow diagram blocks and sequences are thus within the scope and spirit of the claims. One of average skill in the art will also recognize that the functional building blocks, and other illustrative blocks, modules and components herein, can be implemented as illustrated or by discrete components, application specific integrated circuits, processors executing appropriate software and the like or any combination thereof.

[0092] In addition, a flow diagram may include a “start” and / or “continue” indication. The “start” and “continue” indications reflect that the steps presented can optionally be incorporated in or otherwise used in conjunction with one or more other routines. In addition, a flow diagram may include an “end” and / or “continue” indication. The “end” and / or “continue” indications reflect that the steps presented can end as described and shown or optionally be incorporated in or otherwise used in conjunction with one or more other routines. In this context, “start” indicates the beginning of the first step presented and may be preceded by other activities not specifically shown. Further, the “continue” indication reflects that the steps presented may be performed multiple times and / or may be succeeded by other activities not specifically shown. Further, while a flow diagram indicates a particular ordering of steps, other orderings are likewise possible provided that the principles of causality are maintained.

[0093] The one or more embodiments are used herein to illustrate one or more aspects, one or more features, one or more concepts, and / or one or more examples. A physical embodiment of an apparatus, an article of manufacture, a machine, and / or of a process may include one or more of the aspects, features, concepts, examples, etc. described with reference to one or moreAttorney Docket No.: SWV0005WO of the embodiments discussed herein. Further, from figure to figure, the embodiments may incorporate the same or similarly named functions, steps, modules, etc. that may use the same or different reference numbers and, as such, the functions, steps, modules, etc. may be the same or similar functions, steps, modules, etc. or different ones.

[0094] Unless specifically stated to the contra, signals to, from, and / or between elements in a figure of any of the figures presented herein may be analog or digital, continuous time or discrete time, and single-ended or differential. For instance, if a signal path is shown as a single-ended path, it also represents a differential signal path. Similarly, if a signal path is shown as a differential path, it also represents a single-ended signal path. While one or more particular architectures are described herein, other architectures can likewise be implemented that use one or more data buses not expressly shown, direct connectivity between elements, and / or indirect coupling between other elements as recognized by one of average skill in the art.

[0095] The term “module” is used in the description of one or more of the embodiments. A module implements one or more functions via a device such as a processor or other processing device or other hardware that may include or operate in association with a memory that stores operational instructions. A module may operate independently and / or in conjunction with software and / or firmware. As also used herein, a module may contain one or more sub- modules, each of which may be one or more modules.

[0096] As may further be used herein, a computer readable memory includes one or more memory elements. A memory element may be a separate memory device, multiple memory devices, or a set of memory locations within a memory device. Such a memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, cache memory, a quantum register or other quantum memory and / or any other device that stores data in a non-transitory manner. Furthermore, the memory device may be in a form of a solid-state memory, a hard drive memory or other disk storage, cloud memory, thumb drive, server memory, computing device memory, and / or other non-transitory medium for storing data. The storage of data includes temporary storage (i.e., data is lost when power is removed from the memory element) and / or persistent storage (i.e., data is retained when power is removed from the memory element). As used herein, a transitory medium shall mean one or more of: (a) a wired or wireless medium for the transportation of data as a signal from one computing device to another computing device for temporary storage or persistent storage; (b) a wired or wireless medium for the transportation of data as a signal within a computing device from one elementAttorney Docket No.: SWV0005WO of the computing device to another element of the computing device for temporary storage or persistent storage; (c) a wired or wireless medium for the transportation of data as a signal from one computing device to another computing device for processing the data by the other computing device; and (d) a wired or wireless medium for the transportation of data as a signal within a computing device from one element of the computing device to another element of the computing device for processing the data by the other element of the computing device. As may be used herein, a non-transitory computer readable memory is substantially equivalent to a computer readable memory. A non-transitory computer readable memory can also be referred to as a non-transitory computer readable storage medium.

[0097] One or more functions associated with the methods and / or processes described herein can be implemented via a processing module that operates via the non-human “artificial” intelligence (AI) of a machine. Examples of such AI include machines that operate via anomaly detection techniques, decision trees, association rules, expert systems and other knowledge- based systems, computer vision models, artificial neural networks, convolutional neural networks, support vector machines (SVMs), Bayesian networks, genetic algorithms, feature learning, sparse dictionary learning, preference learning, deep learning and other machine learning techniques that are trained using training data via unsupervised, semi-supervised, supervised and / or reinforcement learning, and / or other AI. The human mind is not equipped to perform such AI techniques, not only due to the complexity of these techniques, but also due to the fact that artificial intelligence, by its very definition – requires “artificial” intelligence – i.e., machine / non-human intelligence.

[0098] One or more functions associated with the methods and / or processes described herein can be implemented as a large-scale system that is operable to receive, transmit and / or process data on a large-scale. As used herein, a large-scale refers to a large number of data, such as one or more kilobytes, megabytes, gigabytes, terabytes or more of data that are received, transmitted and / or processed. Such receiving, transmitting and / or processing of data cannot practically be performed by the human mind on a large-scale within a reasonable period of time, such as within a second, a millisecond, microsecond, a real-time basis or other high speed required by the machines that generate the data, receive the data, convey the data, store the data and / or use the data.

[0099] One or more functions associated with the methods and / or processes described herein can require data to be manipulated in different ways within overlapping time spans. The human mind is not equipped to perform such different data manipulations independently, contemporaneously, in parallel, and / or on a coordinated basis within a reasonable period ofAttorney Docket No.: SWV0005WO time, such as within a second, a millisecond, microsecond, a real-time basis or other high speed required by the machines that generate the data, receive the data, convey the data, store the data and / or use the data.

[0100] One or more functions associated with the methods and / or processes described herein can be implemented in a system that is operable to electronically receive digital data via a wired or wireless communication network and / or to electronically transmit digital data via a wired or wireless communication network. Such receiving and transmitting cannot practically be performed by the human mind because the human mind is not equipped to electronically transmit or receive digital data, let alone to transmit and receive digital data via a wired or wireless communication network.

[0101] One or more functions associated with the methods and / or processes described herein can be implemented in a system that is operable to electronically store digital data in a memory device. Such storage cannot practically be performed by the human mind because the human mind is not equipped to electronically store digital data.

[0102] One or more functions associated with the methods and / or processes described herein may operate to cause an action by a processing module directly in response to a triggering event -- without any intervening human interaction between the triggering event and the action. Any such actions may be identified as being performed “automatically”, “automatically based on” and / or “automatically in response to” such a triggering event. Furthermore, any such actions identified in such a fashion specifically preclude the operation of human activity with respect to these actions – even if the triggering event itself may be causally connected to a human activity of some kind.

[0103] While particular combinations of various functions and features of the one or more embodiments have been expressly described herein, other combinations of these features and functions are likewise possible. The present disclosure is not limited by the particular examples disclosed herein and expressly incorporates these other combinations.

Claims

Attorney Docket No.: SWV0005WO CLAIMS What is claimed is:

1. A device for displaying visual media comprises: a light source; a spatial light modulator having a respective top and a respective bottom surface; and an optical filter arrangement, wherein the optical filter arrangement includes a plurality of filter elements configured in a layer having a relative top surface, a relative bottom surface and a relative outline, wherein the bottom surface of the layer of the plurality of filter elements is located proximal to the top surface of the spatial light modulator, wherein each filter element of the plurality of filter elements is associated with a color of X colors, wherein for each color of X colors: a set of filter elements associated with the color are associated with a predetermined portion of an area within the outline; and each filter element of the set of filter elements associated with the color is spatially located within the optical filter arrangement according to a predetermined spatial distribution to form a color-specific filter overlay.

2. The device of claim 1, wherein the spatial light modulator comprises an array of light modulating unit cells, wherein each light modulating unit cell of the array of light modulating unit cells is individually addressable, and wherein a distance between a center of a first light modulating unit cell and a center of a second light modulating unit cell adjacent to the first light modulating unit cell is equal to or smaller than a wavelength of light modulated by the first or second light modulating unit cells.

3. The device of claim 1, wherein a filter element associated with a color of the X colors is substantially transparent to light in a predetermined range of wavelengths.

4. The device of claim 1, wherein the predetermined portion of an area within the outline associated with a color of the X colors is equal to a predetermined portion of an area within the outline associated with any other color of the X colors.Attorney Docket No.: SWV0005WO 5. The device of claim 1, wherein the predetermined portion of an area within the outline associated with a color of the X colors is greater than a predetermined portion of an area within the outline associated with any other color of the X colors.

6. The device of claim 1, wherein the spatial distribution of the set of filter elements of a filter overlay is selected to provide a spatial frequency substantially above a predetermined threshold.

7. The device of claim 1, wherein the spatial distribution of the set of filter elements of a filter overlay is adapted to exhibit blue noise spectral properties.

8. The device of claim 1, wherein each filter element of the plurality of filter elements is configured in a polygon shape.

9. The device of claim 6, wherein the polygon shape is a hexagon.

10. The device of claim 1, wherein the optical filter arrangement is representative of a Voronoi diagram, wherein each filter element of the optical filter arrangement is a Voronoi cell associated with the Voronoi diagram.

11. The device of claim 10, wherein the outline has a rectangular shape.

12. The device of claim 10, wherein the spatial distribution of the set of filter elements of the filter overlay is selected to provide a spatial frequency substantially above a predetermined threshold.

13. The device of claim 10, wherein the spatial distribution of the set of filter elements of the filter overlay is adapted to exhibit blue noise spectral properties.

14. The device of claim 1, wherein the X colors are selected from a list comprising at least one of red, green and blue.Attorney Docket No.: SWV0005WO 15. The device of claim 1, wherein the filter overlay comprises a regular pattern, wherein a regular pattern is a pattern that is repeated at least once within the outline.

16. The device of claim 1, wherein the filter overlay comprises an irregular pattern.

17. The device of claim 10, wherein the Voronoi diagram includes a plurality of Voronoi cells, wherein the plurality of Voronoi cells are configured to uniformly fill a shape defined by the outline.

18. The device of claim 10, wherein the Voronoi diagram comprises a predetermined number of Voronoi cells, wherein the Voronoi cells are configured to enable a predetermined color balance for perception by a user and wherein the Voronoi cells are further configured to enable Fourier replicas to substantially overlay a desired reconstructed visual media.

19. The device of claim 1, wherein the spatial light modulator and the optical filter arrangement have a same respective width and a same respective length.

20. The device of claim 1, wherein the optical filter arrangement is formed according to one or more photolithographic processes.

21. A method for execution by one or more processing modules of one or more computing devices, the method comprises: receiving a continuous hologram, wherein the continuous hologram is divided into an array of pixels using a quantization mask to quantize the pixel value of each pixel of the array of pixels to one of a plurality of states, wherein the quantization mask is configured to facilitate moving noise associated with a quantization process outside a predetermined signal window in a frequency domain.

22. The method of claim 21, further comprising: adapting the continuous hologram so that values of the continuous hologram lie between -1 and 1, with -1 and 1 included;Attorney Docket No.: SWV0005WO dividing the continuous hologram to provide four quadrants sharing a quadripoint, a first quadrant including a portion of the array of pixels, wherein each of a second quadrant, a third quadrant and a fourth quadrant respectively includes another equal size portion of the array of pixels; generating a first quantization mask, wherein each value of the first quantization mask lies between -1 and 1, with -1 and 1 included; reversing the sign of each value of the first quantization mask to provide a second quantization mask; using the first quantization mask over the second and the fourth quadrant for quantization of the second and the fourth quadrant of the continuous hologram; using the second quantization mask over the first and the third quadrant of the continuous hologram providing an unfinished quantized first quadrant and an unfinished quantized third quadrant; reversing the sign of each value of the unfinished quantized first quadrant and of the unfinished quantized third quadrant providing a finished quantized hologram for the first and third quadrant of the continuous hologram.

23. The method of claim 22, wherein the first and the second quantization mask have a size smaller than the size of any of the four quadrants, the method comprising: replicating the first quantization mask over the second quadrant and over the fourth quadrant for quantization of the second and the fourth quadrant of the continuous hologram providing a finished quantized hologram for the second and the fourth quadrant, replicating the second quantization mask over the first quadrant and over the third quadrant for quantization of the first and the third quadrant providing an unfinished quantized first quadrant and an unfinished quantized third quadrant; reversing the sign of each value of the unfinished quantized first quadrant and of the unfinished quantized third quadrant providing a finished quantized hologram for the first and the third quadrant of the continuous hologram.

24. The method of claim 21, the method comprising: adapting the continuous hologram so that values of the continuous hologram lie between -1 and 1, with -1 and 1 included; dividing the continuous hologram to provide four quadrants sharing a quadripoint, a first quadrant including a portion of the array of pixels, wherein each of a second quadrant , aAttorney Docket No.: SWV0005WO third quadrant and a fourth quadrant respectively includes another equal size portion of the array of pixels; generating a first quantization mask, wherein each value of the first quantization mask lies between -1 and 1, with -1 and 1 included; using the first quantization mask over the second and the fourth quadrant for quantization of the second and the fourth quadrant of the continuous hologram; reversing the sign of each value of the first quadrant and of the third quadrant of the continuous hologram providing a sign-reversed first quadrant and a sign-reversed third quadrant; using the first quantization mask over the sign-reversed first and the sign-reversed third quadrant of the continuous hologram providing a quantized sign-reversed first quadrant and a quantized sign-reversed third quadrant; reversing the sign of each value of the quantized sign-reversed first quadrant and of the quantized sign-reversed third quadrant providing a quantized hologram for the first and third quadrant of the continuous hologram.

25. The method of claim 24, wherein the first quantization mask has a size smaller than the size of any of the four quadrants, the method comprising: replicating the first quantization mask over the second quadrant and over the fourth quadrant for quantization of the second and the fourth quadrant of the continuous hologram providing a quantized hologram for the second and the fourth quadrant, reversing the sign of each value of the first quadrant and of the third quadrant of the continuous hologram providing a sign-reversed first quadrant and a sign-reversed third quadrant; replicating the first quantization mask over the sign-reversed first quadrant and over the sign-reversed third quadrant for quantization of the sign-reversed first and the sign-reversed third quadrant providing a quantized sign-reversed first quadrant and a quantized sign-reversed third quadrant; reversing the sign of each value of the quantized sign-reversed first quadrant and of the quantized sign-reversed third quadrant providing a quantized hologram for the first and the third quadrant of the continuous hologram.

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