Method and system for 3D volumetric display

Abstract

A method and system for generating a 3D volumetric image. The method and system comprise rotating about a rotation axis a light modulating surface comprising separately controllable light modulating regions located across the light modulating surface and controlling separately the modulation of the light modulating regions to generate the 3D volumetric image upon rotation of the light modulating surface about the rotation axis. A characteristic of two or more selected light modulating regions of the light modulating surface is then varied in accordance with respective spacings of the two or more selected light modulating regions from the rotation axis.

Description

METHOD AND SYSTEM FOR 3D VOLUMETRIC DISPLAYPRIORITY DOCUMENTS

[0001] The present application claims priority from United States Provisional Patent Application No. 63 / 667,936 titled “METHOD AND SYSTEM FOR 3D VOLUMETRIC DISPLAY” and fded on 5 July 2024, the content of which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to volumetric three-dimensional (3D) displays. In a particular form, the present disclosure relates to volumetric 3D display based on a swept rotating surface.BACKGROUND

[0003] Swept surface displays are conventionally based upon a fast-moving screen or surface that moves to create an equivalent swept volume. In these displays, a 3D scene is parsed into multiple 2D image slices that are projected onto the moving surface with each of the projected 2D image slices varying depending on the location of the moving surface. These multiple projected 2D images then have the combined effect of creating a perception of the 3D scene located in the contained swept volume through persistence of vision. This 3D scene may then be viewed from multiple directions with respect to the display essentially creating a 3D rendered object.

[0004] These swept surface displays provide a number of significant advantages over a 2D display and accordingly these 3D displays have found many uses ranging from medical, training, engineering and communication applications to entertainment and gaming platforms or indeed any application involving the visualization of 3D information or data. As would be appreciated, similar to 2D displays, rendered 3D scene quality parameters such as brightness and resolution are also important in 3D display systems.SUMMARY

[0005] In one aspect, the present disclosure provides a method for generating a 3D volumetric image, comprising: rotating about a rotation axis a light modulating surface comprising separately controllable light modulating regions located across the light modulating surface; and controlling separately a modulation of the light modulating regions to generate the 3D volumetric image upon rotation of the light modulating surface about the rotation axis; wherein at least one characteristic of two or more selected light modulating regions of the light modulating surface is varied inaccordance with respective spacings of the two or more selected light modulating regions from the rotation axis.

[0006] In another form, the at least one characteristic that is varied comprises a refresh rate of the two or more selected light modulating regions.

[0007] In another form, respective refresh rates of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the rotation axis.

[0008] In another form, the light modulating surface is divided in two or more radial refresh rate zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial refresh rate zone are controlled to have a same zone refresh rate and wherein respective zone refresh rates of two or more selected radial refresh rate zones are controlled to be proportional to respective zone radial distances of the two or more radial refresh rate zones from the rotation axis.

[0009] In another form, a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same column refresh rate, and wherein respective column refresh rates of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the rotation axis.

[0010] In another form, the at least one characteristic that is varied comprises a level of spatial dithering of the two or more selected light modulating regions.

[0011] In another form, the level of spatial dithering is controlled to assist in creating the generated 3D volumetric image with substantially uniform spatial density.

[0012] In another form, the light modulating surface is divided in two or more radial level of spatial dithering zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial level of spatial dithering zone are controlled to have a same zone level of spatial dithering and wherein respective zone levels of spatial dithering of two or more selected radial level of spatial dithering zones are controlled to be proportional to respective zone radial distances of the two or more radial level of spatial dithering zones from the rotation axis.

[0013] In another form, the at least one characteristic that is varied comprises a luminance of the two or more selected light modulating regions.

[0014] In another form, a plurality of light modulating regions forming a column on the light modulating surface having a same radial distance from the rotation axis are controlled to have a same luminance, and wherein respective luminances of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the rotation axis.

[0015] In another form, the luminance of an individual light modulating region is controlled by varying a supply current to the individual light modulation region.

[0016] In another form, the luminance of an individual light modulating region is controlled by varying a duty cycle of the light modulation region.

[0017] In another form, the light modulating surface is divided in two or more radial duty cycle zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial duty cycle zone are controlled to have a same zone duty cycle and wherein respective zone duty cycles of two or more selected radial duty cycle zones are controlled to be proportional to respective zone radial distances of the two or more radial duty cycle zones from the rotation axis, wherein the respective zone duty cycles of the two or more radial duty cycle zones are controlled to generally increase as the zone radial distances increase from the rotation axis.

[0018] In another form, the at least one characteristic that is varied comprises a level of dilation of the two or more selected light modulating regions that is varied.

[0019] In another form, respective levels of dilation of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the rotation axis.

[0020] In another form, the light modulating surface is divided in two or more radial level of dilation zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial level of dilation zone are controlled to have a same zone level of dilation and wherein respective zone levels of dilation of two or more selected radial level of dilation zones are controlled to be proportional to respective zone radial distances of the two or more radial level of dilation zones from the rotation axis.

[0021] In another form, the at least one characteristic that is varied comprises a temporal dithering of the two or more selected light modulating regions.

[0022] In another form, the temporal dithering of a selection of individual light modulating regions is controlled to assist in creating the generated 3D volumetric image with substantially uniform perceived color appearance.

[0023] In another form, the at least one characteristic that is varied comprises a surface density of the two or more selected light modulating regions that is varied, wherein the surface density is based on a spacing between light modulation regions of the light modulating surface.

[0024] In another form, respective zone surface densities of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the rotation axis, wherein the respective zone surface densities of the two or more selected radial surface density zones are controlled to generally increase as the zone radial distances increase from the rotation axis.

[0025] In another form, the light modulating surface is divided in two or more radial surface density zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial surface density zone are controlled to have a same zone surface density and wherein respective zone surface densities of two or more selected radial surface density zones are controlled to be proportional to respective zone radial distances of the two or more radial surface density zones from the rotation axis.

[0026] In another form, the at least one characteristic to be varied comprises a modulator dimension of the two or more selected light modulating regions, wherein the modulator dimension is based on a size of the light modulation region.

[0027] In another form, respective modulator dimensions of the two or more selected light modulating regions of the light modulating surface are controlled to increase with respective radial distances of the two or more selected light modulating regions from the rotation axis.

[0028] In another form, the light modulating surface is divided in two or more radial modulator dimension zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial modulator dimension zone are controlled to have a same zone modulator dimension and wherein respective zone modulator dimensions of two or more selected radial modulator dimension zones are controlled to increase as the zone radial distances increase from the rotation axis.

[0029] In another form, the light modulating surface comprises opposed emission light modulation subsurfaces mounted to a rotatable support member, and wherein the at least one characteristic to be varied comprises a thickness of the support member corresponding to the location of the two or more selectedlight modulation regions, and wherein the thickness is configured to increase with increasing distance from the rotation axis.

[0030] In another form, the at least one characteristic to be varied comprises a light modulation characteristic.

[0031] In a second aspect, the present disclosure provides a three dimensional (3D) volumetric display system comprising: a 3D display comprising a light modulating surface comprising separately controllable light modulation regions located across the light modulating surface, the light modulating surface configured to rotate about a rotation axis; and an emission controller comprising one or more data processors configured to separately control the modulation of the light modulating regions to generate a 3D volumetric image upon rotation of the light modulating surface about the rotation axis; wherein at least one characteristic of two or more selected light modulating regions of the light modulating surface is varied in accordance with respective spacings of the two or more selected light modulating regions from the rotation axis.

[0032] In another form, the at least one characteristic comprises a light modulation characteristic and wherein the emission controller is configured to dynamically adjust the light modulation characteristic in accordance with radial distance.

[0033] In another form, the light modulation characteristic comprises at least one of: refresh rate, level of spatial dithering, luminance, level of dilation, or temporal dithering.

[0034] In a third aspect, the present disclosure provides an article of manufacture including a non- transitory computer-readable medium, having stored thereon program instructions that, upon execution by a three dimensional (3D) volumetric display system comprising one or more data processors, cause the display system to perform the operations in accordance with the first aspect.BRIEF DESCRIPTION OF DRAWINGS

[0035] Embodiments of the present disclosure will be discussed with reference to the accompanying drawings wherein:

[0036] FIG. 1 is a figurative top perspective view of a light modulating surface for generating a 3D volumetric image in accordance with some embodiments;

[0037] FIG. 2 is a flow diagram of an example method for generating a 3D volumetric image in accordance with some embodiments;

[0038] FIG. 3 A is a system overview diagram of an example 3D volumetric display system in accordance with some embodiments;

[0039] FIG. 3B is a system overview diagram of the 3D display component of the 3D volumetric display system illustrated in FIG. 3A in accordance with some embodiments;

[0040] FIG. 3C is a system overview diagram of the emission controller component of the 3D volumetric display system illustrated in FIG.3A in accordance with some embodiments;

[0041] FIGS. 4A and 4B are top and perspective views of a rotating light modulating surface comprising separately controllable light modulating regions in accordance with some embodiments;

[0042] FIG. 5 is a plot of the refresh rate, circumference and the resulting substantially constant volumetric density as a function of spacing or distance from the rotation axis in accordance with some embodiments;

[0043] FIG. 6 shows a top view of a light modulation surface divided into a plurality of radial refresh rate zones each comprising a plurality of light modulating regions where each radial refresh rate zone is controlled to have a different refresh rate in accordance with some embodiments;

[0044] FIG. 7 shows a skeletal image of a hand showing the variation in pixel density resulting from the level of spatial dithering varying as a function of spacing or distance from the rotation axis in accordance with some embodiments;

[0045] FIG. 8A is a front view of a light modulating surface comprising a 64x64 matrix of individual light modulating elements;

[0046] FIG. 8B is a front view of the light modulating surface shown in FIG. 8A showing the rows that are illuminated for a duty cycle of 2 / 64;

[0047] FIG. 9 is a front view of an emission surface similar to that shown in FIGS. 8 A and 8B but where the duty cycle of a light modulating element is varied based on the spacing from the axis of rotation in accordance with some embodiments;

[0048] FIG. 10 is atop view showing a rotating emission surface at successive time steps comprising four zones where the duty cycle of light emission is varied based on the spacing from the axis of rotation in accordance with some embodiments;

[0049] FIG. 11 is a figurative view showing the effect of changing the level of dilation for a single voxel in accordance with some embodiments;

[0050] FIG. 12 is a top perspective view showing a generated 3D volumetric image in the form of mesh of a 3D object showing four radial zones (Zone 1 to Zone 4) where the level of dilation increases for a given radial zone as the distance from the axis of rotation increases in accordance with some embodiments;

[0051] FIG. 13A shows a color palette comprising the secondary colors of a voxel that may be generated by temporal dithering of a light modulating region capable of emitting the primary colors of red, green and blue in successive update cycles in accordance with some embodiments;

[0052] FIG. 13B shows a figurative view showing temporal dithering involving successive voxels of primary colors and voxel clusters of secondary colors being combined to form a new voxel cluster having a tertiary color in accordance with some embodiments;

[0053] FIG. 14 is a front view of a light modulating surface comprising two or more light modulation regions where the spacing between individual light modulation regions (or surface density) varies in accordance with the spacing of an individual selected light modulation region from the rotation axis in accordance with some embodiments;

[0054] FIG. 15 is a front view of a light modulation surface comprising two or more light modulation regions where the size of individual light modulation regions varies in accordance with the spacing of an individual selected light modulation region from the rotation axis in accordance with some embodiments;

[0055] FIG. 16 is a perspective view of a 3D volumetric display comprising opposed light modulation surfaces mounted to a support member configured to rotate about a central rotation axis;

[0056] FIG. 17 is a perspective view of a 3D volumetric display similar to that illustrated in FIG. 16 but where the gap or separation between the opposed light modulation surfaces increases with spacing from the central rotation axis to form a wedge shape in accordance with some embodiments;

[0057] FIG. 18 is a flowchart indicating options for varying a characteristic of light modulating regions in accordance with their spacing from the rotation axis in accordance with some embodiments;

[0058] FIGS. 19A-19F show perspective views of various 3D volumetric displays in accordance with some embodiments;

[0059] FIGS. 20A and 20B, are figurative views of a 3D volumetric display comprising a non-planar light modulating surface comprising two curved surfaces in accordance with some embodiments;

[0060] FIG. 21 shows a figurative view of a 3D volumetric display comprising a non-planar light modulating surface similar to the display illustrated in FIGS. 20A and 20B but comprising three curved surfaces in accordance with some embodiments; and

[0061] FIGS. 22A and 22B show perspective views of a 3D volumetric display showing the reduction in occlusion when using a transparent substrate in accordance with some embodiments.

[0062] In the following description, like reference characters designate like or corresponding parts throughout the figures.DESCRIPTION OF EMBODIMENTS

[0063] A 3D volumetric display differs from a traditional screen by creating a three-dimensional representation of an object in physical space rather than a flat image. Unlike typical displays that simulate depth through visual effects, a 3D volumetric display utilizes the emission of light from defined regions in (x,y,z) space to generate 3D imagery. A true volumetric display enables viewers to perceive a 3D image or object by creating a representation of the image or object within a physical 3D space or swept volume. It allows observers to view the 3D image or object from any angle, focus on specific details, and experience perspective, where objects closer to the viewer appear larger than those farther away.

[0064] Techniques are disclosed for generation of a 3D volumetric image based on a rotating light modulating surface comprising separately controllable light modulation elements. The disclosed techniques are particularly beneficial for compensating for visual artifacts introduced by the rotating surface configuration.

[0065] It is instructive to first review the general principles of operation of a volumetric swept surface 3D display system based on a rotating surface. Consider FIG. 1 which shows a figurative top perspective view of a light modulatingsurface 110 comprising separately controllable light modulation elements 120 that are located or spread across a light modulating surface 120 where the light modulation surface 110 rotates anticlockwise (in this example) about rotation axis A. Shown in FIG. 1 are eleven separate slices 110A, . . . , 11 OF, . . . , 11 OK (ie, 110A-K) corresponding to the position of the light modulating surface 110 at successive time steps as the modulation surface rotates about rotation axis A.

[0066] Throughout this specification, the term "light modulating element" is defined to be the smallest controllable light modulating arrangement or structure that forms part of a light modulating surface in a 3D volumetric display system where a light modulating element is capable of modulating light to a specific intensity and / or color to generate a 3D image.

[0067] A light modulating element may be implemented in various forms, including, but not limited to: a light emitting diode (LED) typically having a size ranging between 1 mm - several millimeters, and further including variations such as mini LEDs (100 pm to 1 mm) and micro LEDs (smaller than 100 pm) or more generally a semiconductor based light emitting structure (eg, quantum dot, laser diode).

[0068] In other examples, a light modulating element may be implemented as an opto-electronic arrangement such as a micro-electro-mechanical system (MEMs) (eg, digital micromirror devices having a potential modulation rate in the tens of kHz), liquid crystal modulator (having a potential modulation rate in tens of kHz), or an opto-electronic spatial light modulator (having a potential modulation in the tens of MHz), where the light modulating element is configured to selectively block or unblock light.

[0069] Furthermore, a “light modulating region” of a light modulating surface is defined to be a collection of one or more co-located light modulating elements that may be controlled as a collection of light modulating elements to modulate light for the light modulating region to a selected specific intensity and / or color. As an example, in accordance with the present disclosure separate light modulating elements may comprise individual red, green and blue LEDs and a corresponding light modulating region may comprise a collection of the individual red, green and blue LEDs that may be controlled as a collection to emit light (in this example) for the light modulating region at a specific intensity and color (eg, an RGB LED pixel). In other examples, a light modulating region may be equivalent to an individual light modulation element in the example where the individual light modulation element is controlled independently of neighboring light modulation elements.

[0070] As would be appreciated, various types of light modulating elements or light modulating regions may be combined to form a light modulating surface. In one example, where the light modulating elements comprise light emitting elements (eg, LEDs), the light modulating surface may be characterized as a light emitting surface.

[0071] Consider by way of example light modulating region 121 as depicted in FIG. 1 in a light emitting state in this example. As can be seen, light modulating region 121 on rotation of light modulating surface 110 as it forms successive slices 110A-K will describe a circular path around the rotation axis A. When the emission surface 110 is rotated at high speed, the illuminated light modulating region 121 will be visually extruded through space as a result of an observer’s “persistence of vision” to create a volumetric pixel at a physical location in 3D space defined in two dimensions by the size and shape of the lightmodulating region 121 and in a third dimension by the path or arc that the light modulating region 121 traverses over a predetermined time period corresponding to the duration that the light modulating region 121 is illuminated.

[0072] Persistence of vision is the visual phenomenon that occurs when the human eye sees a trail of light behind a moving emissive object. As an example, when a glowing ember on a burning stick is waved around at night, it leaves a trail of light behind it. This light trail is visible due to persistence of vision.

[0073] Throughout this description when referring to the coordinates within a volumetric display reference is made to the X, Y and Z directions. The X direction is the axial direction (ie, along the rotation axis), the Y direction is the radial direction extending from the outer edge of the rotating emission surface toward the axis of rotation, and the Z direction is the swept or circumferential direction of a voxel, ie the circular path or arc around the axis of rotation that whose radius of curvature increases in size for a given rotation angle the farther the voxel is located from the axis of rotation.

[0074] In the geometry shown in FIG. 1, the X direction corresponds to the vertical direction, the Y direction corresponds to the horizontal direction, and the Z direction extends along a circular path in the direction of rotation which will depend on location of the voxel with respect to the axis of rotation. As would be appreciated, any type of 3 -dimensional coordinate system may be employed such as cartesian, cylindrical, spherical or mixed coordinate systems depending on requirements. As would be further appreciated, there will be a set of mathematical transformations to allow quantities expressed in one coordinate system to be expressed in a different coordinate system following the mathematical transformation should this be required.

[0075] Throughout this description, a volumetric picture element, or “voxel” is the smallest element that can be displayed on a volumetric display in accordance with the present disclosure which will be defined by the spatial dimensions (ie, the X and Y directions as depicted in FIG. 1) of the smallest available light modulating region and the distance that the light modulating region can move during a single on / off or update cycle in the Z direction.

[0076] Furthermore, throughout this description, a grouping or collection of two or more nearby voxels is defined to be a voxel cluster. An example of a voxel cluster is shown in the inset of FIG. 1 which depicts light modulation region 121 being activated or illuminated for four successive update cycles and in this example forming a substantially cube shaped voxel cluster 125 (ie, having curved sides in the circumferential Z direction). As the number of successive update cycles increases, the voxel cluster will adopt a more rectangular prism configuration (again having curved sides). As would be appreciated, a voxel cluster may also comprise voxels located spatially near to a voxel as well as temporally. As anexample, a voxel cluster may be formed comprising light modulating region or in this case voxel 121 and the nearest voxels located interior and exterior to voxel 121 with respect to the rotation axis. In another example, the voxel cluster of the previous example may include all of the voxels formed from activating the voxel cluster for two or successive update cycles to temporally extend the initial voxel cluster.

[0077] In order to create a 3D image, individual light modulation regions (eg, light modulation region 121) are each controlled to generate light for a predetermined amount of time as the entire light modulating surface 110 rotates in the process forming voxel and voxel cluster combinations and as a result generating a corresponding 3D volumetric image resulting from an observer’s persistence of vision. As an example, a light modulating surface may comprise an array of hundreds or, thousands, millions, or billions of individual light modulation regions that may be selectively turned on and off thousands, tens of thousands, hundreds of thousands or millions of times per second which combined with a high rotation rate of the light modulating surface can provide a correspondingly high resolution 3D volumetric image.

[0078] Voxels and voxel clusters have various characteristics that combine to determine the visual and perceived characteristics of any generated 3D volumetric image or volumetric scene. In various examples, the light modulation characteristics of a voxel or voxel cluster may be controlled by using software, hardware or a combination of both. As an example, the light modulation characteristics may be initially defined by the hardware configuration or characteristics but then further controlled or modified in real-time in accordance with commands to the hardware originating from a data processor or computing system generating commands in accordance with software.

[0079] Referring now to TABLE 1, there are shown some example voxel characteristics of a 3D volumetric display system. As would be appreciated, these voxel characteristics depend in part on the characteristics of the light modulation regions of the light modulating surface.TABLE 1 - EXAMPLE VOXEL CHARACTERISTICS

[0080] In various examples, an individual voxel may be configured or controlled to emit at a color from a limited selection of colors (eg, red, green and blue) and a voxel cluster may be generated having a primary, secondary, tertiary, quaternary, quinary color etc by combining nearby voxels of different colors. For example, consider 4 nearby voxels comprising RED, BLUE, RED, BLUE light modulation regions respectively, these when combined would generate a voxel cluster that would be perceived as having the color magenta. Similarly, GREEN and BLUE voxels when combined would generate a voxel cluster having the color cyan.

[0081] Referring now to TABLE 2, there are shown some example voxel cluster characteristics that may be controlled and an indication whether the voxel cluster characteristic is controllable by hardware and software.TABLE 2 - EXAMPLE VOXEL CLUSTER CHARACTERISTICS

[0082] In this manner, a 3D representation of an object in physical space defined by the swept volume may be generated by emission of light from a defined region in the swept volume to generate the overall 3D image. This allows a viewer to view the 3D image from any angle relative to the swept volume and experience a true perspective where objects or features closer to the viewer within the swept volume will appear larger than features farther away from the viewer.

[0083] While volumetric 3D display systems of the type described above have some advantages over swept surface display based on a projection arrangement (eg, a display based on a reciprocating screen), an issue with rotating emissive volumetric displays is the non-uniformity of the generated 3D image or volumetric scene resulting from the adoption of a rotating emission surface.

[0084] Referring now to FIG. 2, there is shown a flow diagram of a method 200 for generating a 3D volumetric image according to an illustrative embodiment. By way of overview, method 200 comprises (at block 210) rotating a light modulating surface comprising controllable light modulating regions located across or on the emission surface and (at block 220) controlling the emission of the light modulating regions separately to generate the 3D volumetric image upon rotation of the light modulating surface about the rotation axis through persistence of vision as described above. In accordance with the present disclosure, at least one characteristic of two or more selected light modulating regions of the light modulating surface is varied in accordance with (or based on) the respective spacings or distances the two or more selected light modulating regions are from the rotation axis.

[0085] Referring now to FIG. 3A, there is shown a system overview diagram of an example 3D volumetric display system 300 for generating a 3D volumetric image according to an illustrative embodiment. In various examples, system 300 may be configured to implement or carry out method 200 as illustrated in FIG. 1 . 3D volumetric display system 300 in this example comprises a 3D display 310 and a light modulation controller 350.

[0086] Referring now to FIG. 3B, there is shown a system overview diagram of the 3D display 310 component of the 3D volumetric display system 300 shown in FIG. 3A according to some embodiments. In this example, 3D display 310 comprises a rotating light modulating surface 320 comprising a light modulating subsystem 330 and a motor subsystem 340. In this embodiment, the rotating light modulating surface 320 comprises the light modulating surface 331 and associated driver electronics 332 for controlling the modulation of the individual light modulating regions that are located over or across the light modulating surface 331 in accordance with control signals from the light modulation controller 350.

[0087] In one example, the light modulating subsystem or surface 330, 331 comprises an LED matrix formed from an array of light-emitting diodes (LEDs) most commonly arranged in a grid format, consisting of one or more rows and / or columns. These matrices can be designed with LEDs of varying sizes, including mini, micro, and standard sizes, to suit different application requirements. The spacing between the LEDs, known as the pitch, can also be selected for a desired resolution and visual effect.

[0088] The performance of an LED matrix, particularly the maximum refresh rate for any region within the matrix, is typically determined by the driver electronics 332 and in this example the number of controller chips assigned to a region of light modulating surface 331. Each controller chip manages aspecific portion of the matrix, and in general the refresh rate of a light modulating surface 331 will be influenced by the number, processing capacity and efficiency of these controller chips.

[0089] In one example, the light modulating surface 331 comprises an LED matrix consisting of 128 rows and 64 columns having a refresh rate of approximately 7.5 kHz. In another example, the light modulating surface 331 comprises an LED matrix consisting of 64 rows and 64 columns, having the same number of controller chips but with a maximum refresh rate of the order 15 kHz. In another example, where the number of LEDs remains the same, but the LED matrix consists of 1,024 rows and only 4 columns the maximum refresh rate may also be in the order of 15 kHz. In yet another example, the LED matrix may only have one column but 4,096 rows and half the number of controller chips as compared to the previous case in which case the refresh rate may be approximately 7.5 kHz. In another example, the LED matrix might not be rectangular or square, but may be round or another shape and in those cases, the numbers of LEDs on each row and column might vary across the matrix. In one example, the individual light emitting elements of the LED matrix actually comprise individual red, green and blue LEDs forming sub pixels that may be controlled to generate various colors. In another example, the 2D LED matrix comprises combined color LEDs. In another example, the 2D LED matrix comprises a mixture of individual color LEDs and combined color LEDs.

[0090] In one example, the light modulating surface 331 or LED matrix may be substantially planar. In another example, light modulating surface 331 or LED matrix may be curved or comprise curved regions.

[0091] Motor subsystem 340 comprises a motor 341 and associated motor driver electronics 342 operable to rotate light modulating surface 331 at a selected angular velocity which may be varied in accordance with a control signal from light modulation controller 350.

[0092] In one example, motor driver electronics 342 may comprise a motor controller, a positional feedback system, and a power supply. The motor controller rotates the light modulating surface 331 at a rate that is sufficient to achieve a required volumetric refresh rate high enough to create a coherent volumetric image that is substantially free from flicker and able to display moving animated scenes at a rate that is acceptable to the human eye. The positional feedback system functions to communicate the precise positioning of the rotating light modulating surface 331 to the light modulating controller 350 so that the correct images may be rendered on the display based on the anticipated position of the light modulation surface 331 at a given time step.

[0093] Referring now to FIG. 3C, there is shown a system overview diagram of the light modulation controller 350 component of the 3D volumetric display system 300 shown in FIG. 3A according to some embodiments. Emission controller 350 typically includes at least one processor 360 which communicates with a number of peripheral devices via bus subsystem 355. These peripheral devices may include astorage subsystem 390, including, for example, a memory subsystem 391 and a fde storage subsystem 395, user interface input / output devices 380, and a network interface subsystem 370. The input and output devices 380 allow user interaction with 3D volumetric display system 300.

[0094] Network interface subsystem 370 provides an interface to outside networks and is coupled to corresponding interface devices in other computing devices. User interface input devices 380 may include a keyboard, pointing devices such as a mouse, trackball, touchpad, or graphics tablet, a scanner, a touchscreen incorporated into the display, audio input devices such as voice recognition systems, microphones, and / or other types of input devices. In general, use of the term "input device" is intended to include all possible types of devices and ways to input information into light modulation controller 350 or onto a communication network.

[0095] User interface output devices 380 may include a 2D display subsystem, a printer, or non -visual displays such as audio output devices. The 2D display subsystem may include a cathode ray tube (CRT), a flat-panel device such as a liquid crystal display (UCD), a projection device, or some other mechanism for creating a visible image. The 2D display subsystem may also provide non-visual display such as via audio or haptic output devices. In general, use of the term "output device" is intended to include all possible types of devices and ways to output information from light modulation controller 350 to the user or to another machine or computing device.

[0096] Storage subsystem 390 stores programming and data constructs that provide the functionality of some or all implementations in accordance with the present disclosure. For example, the storage subsystem 390 may include the logic to perform selected aspects of method 200 of FIG. 2 and / or method 1800 of FIG. 18.

[0097] These software modules are generally executed by processor 360 alone or in combination with other processors (eg, driver subsystems of 3D display 310). Memory 391 used in the storage subsystem 390 can include a number of memories including a main random access memory (RAM) 392 for storage of instructions and data during program execution and a read only memory (ROM) 392 in which fixed instructions are stored. A file storage subsystem 395 can provide persistent storage for program and data files, and may include a hard disk drive, a floppy disk drive along with associated removable media, a CD-ROM drive, an optical drive, or removable media cartridges. The modules implementing the functionality of certain implementations may be stored by file storage subsystem 395 in the storage subsystem 390, or in other computing systems accessible by the processor(s) 360.

[0098] Bus subsystem 355 provides a mechanism for letting the various components and subsystems of light modulation controller 350 communicate with each other as intended. Although bus subsystem 355 isshown schematically as a single bus, alternative implementations of the bus subsystem may use multiple buses.

[0099] Light modulation controller 350 can be of varying types including a workstation, server, computing cluster, blade server, server farm, GPU, ASIC, microprocessor or any other data processing system or computing device. Due to the ever-changing nature of computers and networks, the description of controller 350 depicted in FIG. 3C is intended only as a specific example for purposes of illustrating some implementations. Many other configurations of controller 350 are possible having more or fewer components than that depicted in FIG 3C.

[0100] Light modulation controller 350 may run any suitable operating system including, but not limited to, any embedded operating system, any real-time operating system, any open source operating system, any proprietary operating system, any operating systems for mobile computing devices, or any other operating system capable of running on controller 350 and performing the operations described in this disclosure. In an embodiment, the operating system may be run on one or more cloud machine instances.

[0101] As will be appreciated in light of this disclosure, the various computer-implemented methods of the present disclosure, are implemented in software, such as a set of high level instructions (eg, HTML, XML, C, C++, object oriented C, BASIC, Python, etc.) or low level instructions (eg, assembly language, processor instruction set) encoded on any computer readable medium or computer program product (eg, hard drive, server, disc, or other suitable non-transitory memory or set of memories), that when executed by one or more processors, cause the various methodologies provided in this disclosure to be carried out.

[0102] Referring now to FIGS. 4A and 4B, there are shown top and top perspective views of a rotating light modulating surface 410 comprising separately controllable light modulation regions 420 in this example in the form of a 2D LED matrix, grid or array in accordance with some embodiments.

[0103] As can be seen from FIG. 4B, the light modulation regions or LEDs at the outside edge 431 of the light modulating surface travel farther per unit time than the LEDs 432 located closer to the axis of rotation. As the entire LED array comprising the light modulating surface 410 has a constant refresh rate, then the voxel or voxel clusters rendered or generated at the outer edge of the display will be more spaced out in 3D space when compared to voxels or voxel clusters that are rendered near the axis of rotation. This results in a non-uniformity of rendering which in turn results in the visual quality of the generated 3D volumetric image or scene varying according to its distance from the rotation axis within the 3D volume containing the 3D volumetric image.

[0104] In accordance with the present disclosure, and in one example, the characteristic of the two or more selected light modulating regions of the light modulating surface that is controlled to vary in accordance with or based on the respective spacings from the rotation axis comprises a light modulation characteristic of the two or more light modulation regions.

[0105] Consider in one example a light modulating surface comprising a 2D matrix of LEDs, the density of voxels or volumetric density VD in a volumetric display is measured in voxels, cm-3and may be defined as:VD = RD X LEDX X LEDY Equation 1

[0106] where LEDX is the number of LEDs per centimetre in the X direction of the emission surface, LEDY is the number of LEDs per centimetre in the Y direction of the light modulating surface and RD is the radial density defined in Equation 2 below.

[0107] A 3D volumetric display system based on a rotating light modulating surface comprising a 2D LED matrix, with a fixed LED matrix refresh rate and constant LED spacing on the X and Y axis will, as discussed with reference to FIGs 4A and 4B, have a non-uniform voxel rendering ability because as the distance of the light emission region (ie, the LED) from the rotation axis increases, the LED has to travel farther between each successive on and off state governed by the refresh rate of the LED. A similar principle will apply to any light modulating surface where light modulating regions across the surface have a constant refresh or update rate.

[0108] Define D to be the radial distance from the rotation axis in centimetres, Vpsto be the refresh rate of the volume in Hz and RR to be the refresh rate of the matrix in Hz. The radial density RD may then be defined as:Equation 2

[0109] Consider an emission surface having a width (ie, D) of 12 centimetres, a volumetric refresh rate (ie, Vps) of 15 Hz and an LED refresh rate (ie, RR) of 7200 Hz then the radial density will be as follows:RD = 6.369 voxels, cm Equation 3

[0110] and the volumetric density in accordance with Equation 1 will be as follows:VD = 57.51 voxels, cm3Equation 4

[0111] The volumetric density calculated above is only correct at the outermost part of the display (the part that is 12 cm from the axis of rotation in this example) because VD is dependent on D through the dependence of RD on D (see Equation 2). Accordingly, the value for VD will vary with the radial distance from the axis of rotation D .

[0112] Accordingly, in one example, the characteristic or light modulation characteristic that is controlled to vary in accordance with a spacing or distance from the rotation axis is a refresh rate of a light modulation region. By varying the refresh rate of a light modulation region (eg, an LED) within a volumetric display based on the distance of the light modulation region from the axis of rotation, then more voxels per rotation may be rendered towards the outer parts of the display to generate a uniform density of voxels or spatial density within the whole display.

[0113] In one example, the refresh rate of individual selected light emission regions is controlled to assist in creating the generated 3D volumetric image with a substantially uniform spatial density within the swept volume.

[0114] As would be appreciated, generally a 3D volumetric image will have regions of different spatial density in accordance with the image being generated, eg, some regions may be intended to be rendered more densely than other regions in the generated image. In this context, the requirement to be able to generate a 3D volumetric image with a substantially uniform spatial density means that a 3D volumetric image intended to have a uniform spatial density throughout the generated image would, following generation of the image in accordance with the present disclosure, have a uniform spatial density throughout the generated image.

[0115] Referring now to TABLE 3, it can be seen that varying the refresh rate as indicated in the “Refresh Rate” columns of the table results in a constant volumetric density across the generated 3D volumetric image.TABLE 3 - VARIATION OF REFRESH RATE AS A FUNCTION OF DISTANCE FROMROTATION AXIS

[0116] This is also shown in FIG. 5 which shows a plot 500 of the refresh rate RR 510, circumference 520 (ie, the total distance traversed by a light emission region in one full rotation) and the resulting substantially constant volumetric density VD 530 as a function of spacing or distance from the rotation axis D. This means that 3D voxels displayed inside the volume will look substantially the same, regardless of the 3D position of an individual voxel within the swept volume.

[0117] In one example, the respective refresh rates of two or more selected light modulation regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulation regions from the axis of rotation.

[0118] In another example, a plurality of light modulating regions forming a column on the light modulating surface (ie, a vertically extending region) having the same radial distance from the rotation axis are controlled to have the same column refresh rate, and wherein the respective column refresh rates of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0119] In another example, the light modulating surface is divided in two or more radial refresh rate zones each having a zone radial distance from the rotation axis and the light modulation regions within a radial refresh rate zone are controlled to have the same zone refresh rate and wherein the respective zone refresh rates of two or more selected radial refresh rate zones are controlled to be proportional to respective zone radial distances of the two or more radial refresh rate zones from the axis of rotation.

[0120] In various examples, the zone radial distance for a radial refresh rate zone may be the distance or spacing from the rotation axis to a central point or location of the radial refresh rate zone, the distance or spacing from the rotation axis to an interior boundary (with respect to the rotation axis) of the radial refresh rate zone, the distance or spacing from the rotation axis to an exterior boundary (with respect to the rotation axis) of the radial refresh rate zone, or the distance or spacing from the rotation axis to a defined location of the radial refresh rate zone.

[0121] Referring now to FIG. 6, there is shown atop view 600 of a light modulating surface 610 divided into a plurality of radial refresh rate zones each comprising a plurality of light modulation regions where each radial refresh rate zone is controlled to have a different refresh rate within the refresh rate zone. In this example, light modulating surface 610 is divided into four refresh rate zones each with a constant or defined refresh rate across the radial refresh rate zone but varying with respect to other zones. Zone 4, which is farthest from the rotation axis, has the fastest refresh rate. Moving towards the rotation axis, Zone 3, Zone 2 and Zone 1 each has a fast, medium and slow refresh rate respectively.

[0122] As would be appreciated, the size and number of radial refresh rate zones may be varied as required depending on the image generation task with the minimum number of zones being two, and the maximum number being the number of individual light modulation elements (eg, LEDs) extending between the axis of rotation and the outer edge of the light modulating surface.

[0123] As would be appreciated, the radial refresh rate zones toward the outer parts of the emission surface 610 have a higher refresh rate and, as a result, can render more voxels per second, leading to a spatial density that is more similar to that to the inner portions of the emission surface resulting in a generated 3D volumetric image having a substantially uniform spatial density.

[0124] In another example, the characteristic or light modulation characteristic that is varied comprises a level of spatial dithering of the light modulation region, where the level of spatial dithering modifies the number of voxels that are used to represent a generated 3D image. As would be appreciated, the emission characteristic of a light emission region may comprise multiple different modifications that together characterize the emission properties of an individual light emission region forming the emission surface.

[0125] Spatial dithering is a technique employed in generating 3D volumetric images that enhances the perceived number of colors and brightness by arranging voxels so that the human eye blends them to create the perception of intermediate colors and varying brightness levels. In various examples, spatial dithering manipulates the voxel arrangement to vary voxel characteristics such as transparency and color intensity across the display volume as a result achieving smoother gradients and reducing the appearance of banding in areas with color or intensity shifts.

[0126] In a typical implementation, the volumetric display's rendering algorithm calculates which light modulating regions and as a result which voxels to activate and at what intensity based on the 3D data input. In various examples, the spatial dithering algorithm may use a fixed ordered pattern or in some cases it can use an error diffusion algorithm to enhance the perceived image quality by spreading the quantization error of a light modulating region (or voxel or voxel cluster) to its neighboring light modulating regions (or voxels or voxel clusters). By selectively modulating certain voxels and leaving others unmodulated in a controlled pattern, spatial dithering can simulate intermediate colors and shades in regions where the display may not have sufficient resolution to depict them directly.

[0127] As an example, if a gradual transition from light blue to a darker blue is required in a generated 3D volumetric image, and there may not be enough distinct blue shades available due to limited color depth of the light modulating surface, spatial dithering may be employed to simulate additional shades of blue using patterns of spatially arranged voxels. From a distance, these voxels will blend optically to a viewer of the generated 3D volumetric images in the process creating the perception of the desired gradient.

[0128] As would be appreciated, the level of spatial dithering may be varied by changing the type of spatial dithering algorithm as well by varying the amount or intensity of spatial dithering using a particular spatial dithering algorithm typically by varying the spatial dithering algorithm’s tuning parameters.

[0129] As would be appreciated, there are many types of spatial dithering algorithms, each having their own tradeoffs in terms of visual quality and processing overhead. In one example spatial dithering algorithm, error propagation is employed to enhance the image quality. Consider a voxel grid, where each voxel has a 16 bit intensity. In this approach, spatial dithering commences by quantizing each voxel cell from 16 bit color down to 1 bit color. In this example, each color component is processed independently during this conversion process. For best color representation, error diffusion (similar to a ID Floyd-Steinberg) may be used. For example, after quantization, the remainder error is spread to a voxel on the next slice (eg, X, Y, Z+l) and quantized again in a future pass. In one approach to minimizing voxel blurring, the majority of the error is spread in the direction that is smallest in distance.

[0130] In one example, the level of dithering is controlled to assist in creating the generated 3D volumetric image with substantially uniform spatial density.

[0131] In another example, respective levels of dithering of the two or more selected light modulating regions of the light modulating surface as referred to above are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0132] In another example, a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same level of spatial dithering. In this example, respective levels of dithering of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0133] In another example, the light modulating surface is divided in two or more radial levels of spatial dithering zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial level of spatial dithering zone are controlled to have the same zone level of spatial dithering and wherein respective zone levels of spatial dithering of two or more selected radial level of spatial dithering zones are controlled to be proportional to respective zone radial distances of the two or more radial levels of spatial dithering zones from the axis of rotation.

[0134] In yet another example, the respective zone levels of spatial dithering of the two or more selected radial levels of spatial dithering zones are controlled to generally increase apparent spatial density as the zone radial distances increase from the axis of rotation. In other examples, the respective zone levels of spatial dithering of the two or more selected radial levels of spatial dithering zones are controlled to generally increase the apparent luminance, brightness or color appearance as the zone radial distances increase from the axis of rotation.

[0135] Referring now to FIG. 7, there is shown a skeletal image of a hand 700 showing the variation in pixel density resulting from the level of spatial dithering varying as a function of spacing or distance from the rotation axis.

[0136] In accordance with the present disclosure the level of spatial dithering effect (ie, either the type or strength or degree of spatial dithering) is varied in proportion to the distance that a light modulation region of the light modulation surface is from the rotation axis of the light modulation surface.

[0137] In the example, shown in FIG. 7 the level of dithering controlled with distance from the axis of rotation to generally increase the spatial density resulting in the generated 3D volumetric image or rendered object (in this example a skeletal image of a hand) having a substantially uniform spatial density upon rotation of the light modulating surface. In this example, the left side of the image 700 represents the outer side of the swept volume where an individual light modulation region of the light modulating surface would be traveling farther per unit time as compared to a light modulation region closer to the rotation axis and as a result may require the 3D volumetric image to be generated with more apparent density to appear to have a uniform spatial density when compared to the inner part of the lightmodulating surface where the light modulation region would be moving more slowly. As would be appreciated, even though it is not shown in FIG. 7, the spatial dithering will also apply in the Z direction.

[0138] In some examples, the perceived brightness of a voxel or voxel cluster in a generated 3D volumetric image may be affected by the duration that a respective light modulation region or regions are illuminated for. Generally, a voxel that is associated with a light modulation region that is only illuminated for a shorter time will not appear as bright as an equivalently sized voxel where the light modulating region is illuminated for a longer time.

[0139] In one example, where a 3D volumetric image has been generated based on a rotating light modulating or emission surface employing a variable refresh rate that is based on the spacing from the rotation axis it may be desirable to account for perceived changes in brightness that may be associated with the different refresh rates to generate a 3D volumetric image with substantially uniform perceived brightness throughout the 3D volumetric image.

[0140] As would be appreciated, generally a 3D volumetric image will have regions of different brightness in accordance with the image being generated, eg, some regions may be intended to be darker than other regions in the generated image. In this context, the requirement for a substantially uniform perceived brightness means that a 3D volumetric image intended to have uniform brightness throughout the generated image would, following generation of the image in accordance with the present disclosure, have a uniform perceived brightness throughout the generated image.

[0141] In one example, the characteristic or light modulation characteristic that is varied comprises a luminance of the light modulation region that is controlled to vary based on the spacing of the individual selected light emission region from the rotation axis. Luminance in the context of volumetric displays refers to the measurable amount of light that is emitted from a light modulating region, perceived by the viewer as brightness.

[0142] In one example, the luminance of individual light modulating regions is controlled to assist in creating the generated 3D volumetric image with substantially uniform perceived brightness. In one example, the luminance of individual light modulating regions is controlled to compensate for modifications that may have been applied in order to generate a 3D volumetric image with substantially uniform spatial density.

[0143] In one example, respective luminances of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0144] In one example, a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same luminance, and wherein respective luminances of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0145] In one example, the light modulating surface is divided into two or more radial luminance zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial luminance zone are controlled to have the same zone luminance and wherein respective zone luminances of two or more selected radial luminance zones are controlled to be proportional to respective zone radial distances of the two or more radial luminance zones from the axis of rotation.

[0146] In one example, the respective zone luminances of the two or more selected luminance zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0147] In one example, where the luminance of a light modulation region is proportional to the supply current driving the light modulation region then the luminance of the light modulating region may be controlled by varying a supply current to light modulating region.

[0148] In one example, controlling the supply current comprises controlling the resistance of a current supply path to a light modulation region. In one example, the resistance may be controlled by introducing resistors into the current supply path of individual light modulation regions of the light modulating surface based on the spacing of the individual light modulation regions from the rotation axis but otherwise supplying a constant voltage to the light modulation regions. As would be appreciated, a higher resistance results in a lower current resulting in dimmer light modulation regions, while a lower resistance allows more current to flow as a result increasing the brightness of the light modulation region.

[0149] In another example, controlling the supply current comprises the use of a current regulator which is an electronic component operable to maintain a constant preset current level regardless of voltage fluctuations or other variations in the current supply electrical circuit.

[0150] In one example, the light modulation region comprises an LED noting that the brightness of an LED is directly proportional to the current flowing through it. In another example, different types of LEDs having different brightness outputs either due to their current handling capability or their efficiency may be adopted in accordance with the present disclosure.

[0151] In another example, the luminance of a light modulation region of the light modulating surface is controlled by varying the duty cycle of a light modulation region.

[0152] Referring now to FIG. 8A, there is shown a front view 800 of a light modulation surface 810 comprising a 64x64 uniform matrix of individual light modulation regions. As shown in FIG. 8 A, light modulating surface 810 in this example is refreshed every 1 / 14, 400th of a second. As would be appreciated, at any one point in time it appears to the human eye that the whole light modulating surface comprising the uniform matrix of light modulation regions is being illuminated, however, in actuality only one or several lines of the light modulating surface 810 are turned on at the same point in time.

[0153] This is shown in FIG. 8B which shows the actual rows 811A, 81 IB of light modulation regions of light modulating surface 810 that are illuminated on light modulating surface 810 that are being refreshed in 1 / 14,400th of a second with a duty cycle of 2 / 64.

[0154] In one example, the light modulating surface is divided in two or more radial duty cycle zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial duty cycle zone are controlled to have the same zone duty cycle and wherein respective zone duty cycles of two or more selected radial duty cycles zones are controlled to be proportional to respective zone radial distances of the two or more radial duty cycle zones from the axis of rotation. In one example, the respective zone duty cycles of the two or more selected radial duty cycle zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0155] Referring now to FIG. 9, there is shown a front view 900 of a light modulating surface 910 similar to that shown in FIGS. 8 A and 8B but where the duty cycle of a light modulation region is varied based on the spacing from the axis of rotation.

[0156] In the example shown in FIG. 9, light modulating surface 910 comprises three radial duty cycle zones where the duty cycle of light modulation regions are varied. As can be seen from inspection, the light modulation regions of rows 911A and 91 IB comprise light modulation regions falling within Zones 1, 2 and 3 corresponding to duty cycles of 2 / 32, 4 / 16 and 8 / 8 respectively. Similarly, the light modulation regions of rows 911C and 91 ID comprise light modulation regions falling within Zones 2 and 3 corresponding to duty cycles 4 / 16 and 8 / 8 respectively. Finally, the light modulation regions of rows 91 IE-911H only fall in Zone 3 corresponding to a duty cycle of 8 / 8.

[0157] Moving from the axis of rotation to the outer edge of light modulating surface 910, the number of rows illuminated increases in successive duty cycle zones, ie, the number of rows in Zone 3 is greater than Zone 2 which in turn is greater than Zone 1. As more lines are simultaneously illuminated in Zone 3, the display will appear brighter to an observer in Zone 3, and in the context of a rotating emission surface this will compensate for the effective reduction of brightness for light emission regions at greater spacing from the axis of rotation and increase the uniformity of perceived brightness in the generated volumetric 3D image.

[0158] In one example, where emission surface 910 is a matrix of column and row LEDs illumination of the matrix of LEDs is controlled by one or more ROW and COLUMN controllers (eg, semiconductor-based switching devices). In this example, the number of ROW and COLUMN controllers increasie moving from Zone 1 to Zone 3 so that more LED rows can be illuminated concurrently in Zone 3.

[0159] As would be appreciated, this would also increase the current draw for a zone in line with the number of controllers and number of rows that are being concurrently activated or caused to emit.

[0160] Referring now to LIG. 10, there is shown atop view 1000 of a rotating light modulating surface 1010 at successive time steps comprising four duty cycle zones where the duty cycle of light emission is varied based on the distance of the duty cycle zone from the axis of rotation.

[0161] In LIG. 10, the different zones represent LED matrices with 64 rows, where each duty cycle zone of the display has a different duty cycle. In duty cycle zone 1 (ie, closest to the axis of rotation), for every complete LED matrix image refresh, only one scanline is displayed at a time. In duty cycle zone 2, there are two concurrent scanlines, in zone 3, there are 3 and in zone 4 there are 4 concurrent scanlines, ie the zone duty cycle increases with the zone spacing from the rotation axis. The net result of more concurrent scanlines is that the generated 3D volumetric image is brighter but draws more current.

[0162] In another example the characteristic or light modulation characteristic that is varied comprises a level of dilation for the light emission region that is controlled to vary based on the spacing of the individual selected light emission region from the rotation axis.

[0163] Referring now to LIG. 11, there is a figurative view 1100 showing the effect of changing the level of dilation for a single voxel 1110A in accordance with some embodiments. As can be seen by inspection, dilation may be in the X, Y or Z directions (1110C, 1110D and 1110B respectively) or in both X and Y directions (1110E) , X and Z direction (not shown), Y and Z direction (not shown), or all three X, Y and Z directions (1110E).

[0164] Considering the light emission region 1111 that corresponds to voxel 1110A, it can be seen that dilation of light emission region 1111 in the X or Y direction is equivalent to the dilation of voxel 1110A when considering the rotation of light emission region 1111.In one example, the level of dilation of individual light modulating regions is controlled to assist in creating the generated 3D volumetric image with substantially uniform perceived brightness.

[0165] In one example, the level of dilation of individual light modulating regions is controlled to compensate for modifications to generate a 3D volumetric image with substantially uniform spatial density.

[0166] In one example, the respective levels of dilation of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0167] In one example, a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same level of dilation, and respective levels of dilation of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0168] In one example, the light modulating surface is divided in two or more radial level of dilation zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial level of dilation zone are controlled to have the same zone level of dilation and wherein respective zone levels of dilation of two or more selected radial level of dilation zones are controlled to be proportional to respective zone radial distances of the two or more radial level of dilation zones from the axis of rotation.

[0169] In one example, the respective zone levels of dilation of the two or more selected level of dilation zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0170] In various examples, varying the level of dilation of a light emission region (and equivalent voxel) to create an associated cluster of voxels functions to increase the brightness but with a lower perceived resolution. In accordance with the present disclosure, the level of dilation may be increased with increasing spacing from the axis of rotation.

[0171] This variation may be done continuously or in another example the emission surface is divided in two or more radial levels of dilation zones as described above.

[0172] By varying the level of dilation and as a result the size of a voxel cluster with respect to its position from the axis of rotation this provides yet another option to create a uniform perceived brightness throughout the generated volumetric image.

[0173] Referring now to FIG. 12, there is shown atop perspective view 1200 showing a generated 3D volumetric image 1210 in the form of mesh of a 3D object (ie, a torus) showing four radiallevel of dilation zones (Zone 1 to Zone 4) where the level of dilation increases for a given radial zone as the distance from the axis of rotation increases according to some embodiments. As can be seen, as the level of dilation is increased to the voxels within a mesh object within a LED volumetric display, the perceived brightness of the object (all other things being equal) will increase, but the resolution will be reduced.

[0174] Referring now to FIG. 13A, there is shown the color palette 1300 comprising the secondary colors of a voxel that may be generated by temporal dithering of a light modulation region capable of emitting the primary colors of red, green and blue in successive update cycles (eg, 3 bit color LED). As can be seen by inspection, primary colors red, green and blue may be generated as well as secondary colors cyan, magenta, yellow and white. By alternating between various color sequences over time, temporal dithering can simulate a broader color spectrum, resulting in the appearance of richer, more vibrant colors as the human eye blends the component colors together.

[0175] Referring now to FIG. 13B, there is shown a figurative view 1300 showing temporal dithering involving successive voxels of primary colors 1355 (eg, red) and voxel clusters of secondary colors 1358 (eg, yellow) being combined to form a new voxel having a tertiary color (eg, orange) according to some embodiments. As can be seen, by adjusting the number of overlapping light modulating regions, voxels or voxel clusters of primary and secondary colors, additional tertiary colors may be formed which may then be overlapped to again form quaternary colors etc. Additionally, by combining different ratios and mixtures of component colors it is possible to modify the perceived hue, saturation, and brightness of the resulting voxel cluster.

[0176] In one example application, a light modulating surface comprising a 2D matrix of LEDs displaying 3-bit color values may be adopted to generate a 3D volumetric image. Although a 3 -bit color palette is greatly reduced as compared to 24-bit color palette the 3-bit colors may be advantageously displayed at a frame or update rates in the kHz to MHz range which assists in the generation of a 3D volumetric image based on a rotating light modulating surface comprising this type of 2D LED matrix light modulating surface.

[0177] As discussed previously, and referring once again to FIGS. 4A and 4B, for a given time step the distance between the update of successive light modulation regions is smaller closer to the rotation axis as compared to light modulating regions moving towards the outer edge of the light modulating surface at greater distances from the rotation axis. In the context of temporal dithering, this implies that there are more “slices” available for color mixing closer to the rotation axis as compared to the reducing number of slices that are available moving towards the outer edge of the emission surface farther from the rotation axis.

[0178] Accordingly, closer to the rotation axis there is a greater scope to apply temporal dithering by combining temporally different ratios and mixtures of primary and secondary colors to modify the perceived hue, saturation (ie, the intensity or purity of a color) and brightness of the resulting voxel cluster formed given the available slices that may be modified as compared to the reduced number of slices farther from the rotation axis. In some examples, this results in a reduced ability to render colors depending on the location on the light modulating surface with respect to the rotation axis resulting in potential reduced color consistency.

[0179] In accordance with the present disclosure, where the refresh rate is increased based on the distance from the rotation axis, this effectively increases the number of available slices available for temporal dithering farther away from the rotation axis to be comparable to those available in those regions closer to the rotation axis effectively improving the ability to uniformly and consistently generate colors throughout the generated 3D volumetric image independent of where a region may be located with respect to the rotation axis.

[0180] In one example, the characteristic or light modulation characteristic that is varied in accordance with distance from the rotation axis is the temporal dithering of the light modulating region.

[0181] In one example, the temporal dithering of individual light modulating regions is controlled to assist in creating the generated 3D volumetric image with substantially uniform perceived color appearance.

[0182] In one example, the temporal dithering of individual light modulating regions is controlled to compensate for modifications of individual light modulating regions required to generate a 3D volumetric image with substantially uniform spatial density.

[0183] For the various examples described so far, the at least one characteristic of the light modulation regions that has been varied in accordance with a spacing from the rotation axis may be characterised as a light modulation characteristic and comprises characteristics such as the refresh rate, a level of spatial dithering, luminance, level of dilation or even the ability to adopt temporal dithering uniformly across the light modulating surface based on the varying refresh rates. In other examples, the characteristic that varies may be characterised as a spatial configuration characteristic of the light modulation surface relating in various examples to the positioning, spacing, density, size or configuration of light modulating regions which may vary based on the distance or spacing from the rotation axis. These will be described below.

[0184] In one example, the characteristic of two or more selected light modulating regions of the light modulating surface that is controlled to vary in accordance with the respective spacings from the rotation axis comprises a spatial configuration characteristic of the light modulating surface.

[0185] In one example, the characteristic or spatial configuration characteristic that is varied comprises a surface density based on a spacing between light modulation regions of the light modulating surface. In one example, the surface density is controlled to assist in creating the generated 3D volumetric image with substantially uniform spatial density.

[0186] In one example, respective surface densities of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0187] In one example, a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same column surface densities, and wherein respective column surface densities of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0188] In one example, the light modulating surface is divided in two or more radial surface density zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial surface density zone are controlled to have the same zone surface density and wherein respective surface densities of two or more selected radial surface density zones are controlled to be proportional to respective zone radial distances of the two or more radial surface density zones from the axis of rotation.

[0189] In another example, the respective zone surface densities of the two or more selected radial surface density zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0190] Referring now to FIG. 14, there is shown a front view 1400 of a light modulating surfacel410 comprising two or more light modulation regions 1411 where the spacing between individual light modulation regions 1411 (or surface density) varies in accordance with the distance of an individual selected light modulation region from the rotation axis.

[0191] In the example shown in FIG. 14, light modulating surface 1410 comprises four radial surface density zones (in this example columns) where the spacing between individual light emission regions 1411 (ie, surface density) on the light modulating surface 1410 is approximately constant (ie, thesame zone surface density) within a given radial surface density zone but where the spacing for a particular radial zone decreases (ie, the zone surface density of light emission regions increases) moving from Zone 1, which is proximate to the axis of rotation, to Zone 4 which is at the outer edge of the light modulating surface 1410. As depicted in FIG. 14, the spacing between individual light emission regions 1411 within a zone may include some variation (ie, not perfectly uniform spacing) but overall the zone surface density (eg, relating to an average spacing between light emission regions 1411) will increase moving farther away from the axis of rotation.

[0192] In other examples, the light modulating surface 1410 may be divided into two, three, five, six, seven, eight, nine, ten, or greater than 10 zones.

[0193] In another example, light modulating surface 1410 is not divided into radial zones but the surface density of light emission regions 1411 increases continuously moving from the rotation axis to the outer edge of the light modulating surface 1410. In another example, the surface density may increase continuously but there may be a radial zone where there is no variation in spacing between light emission regions 1411.

[0194] By varying the spacing or surface density of the light emission regions across the light modulating surface with respect to the distance from the axis of rotation, it is possible to vary the spatial (or apparent) density of a voxel formed by a rotating light modulation region within the generated 3D volumetric image with respect to its distance from the axis of rotation and as a result control uniformity of spatial density.

[0195] As an example, consider the case where light modulation regions comprise individual LEDs. In this example, where the LEDs are more closely spaced across the light modulating surface or denser the resulting voxel density increases accordingly. In such a display, an option to configure the voxel spatial density to be substantially uniform is to vary the LED spacing as described above.

[0196] In another example, the characteristic or spatial configuration characteristic that is varied comprises the modulator dimension based on the size of a light modulator region. In one example, the modulator dimension is controlled to assist in creating the generated 3D volumetric image with substantially uniform spatial density.

[0197] In one example, respective modulator dimensions of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0198] In one example, a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same column modulator dimensions, and wherein respective column modulator dimensions of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0199] In one example, the light modulating surface is divided in two or more radial modulator dimension zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial modulator dimension zone are controlled to have the same zone modulation dimension and wherein respective zone modulator dimensions of two or more selected radial modulator dimension zones are controlled to be proportional to respective zone radial distances of the two or more radial modulator dimension zones from the axis of rotation.

[0200] In another example, the respective zone modulator dimensions of the two or more selected radial modulator dimension zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0201] Referring now to FIG. 15, there is shown a front view 1500 of a light modulating surface1510 comprising two or more light emission regions 1511 where the modulator dimension of individual light modulation regions 1511 varies in accordance with the spacing of an individual selected light emission region from the rotation axis.

[0202] In the example shown in FIG. 15, light modulating surface 1510 comprises four radial modulator dimension zones (in this example columns) where the size of individual light emission regions1511 on the light modulating surface 1510 is approximately constant within a given radial zone but where the size of individual light emission regions for a particular zone (ie, zone modulator dimension) increases moving from Zone 1, which is proximate to the axis of rotation, to Zone 4 which is at the outer edge of the light modulating surface 1510. As depicted in FIG. 15, the size or modulator dimension of individual light modulation regions 1511 within a radial modulator dimension zone may include some variation (ie, not perfectly uniform size) but overall the zone modulator dimension (eg, an average size of light modulation regions 1511) will increase moving farther away from the axis of rotation.

[0203] In other examples, the light modulating surface 1510 may be divided into two, three, five, six, seven, eight, nine, ten, or greater than 10 zones.

[0204] In another example, light modulating surface 1510 is not divided into zones but the size of light emission regions 1511 (ie, modulator dimension) increases continuously moving from the rotation axis to the outer edge of the light modulating surface 1510. In another example, the size or modulatordimension may increase continuously but there may be a radial zone where the size does not change and then commence to increase continuously again.

[0205] By varying the size or modulator dimension of light emission regions across the light modulating surface with respect to the distance from the axis of rotation, it is possible to vary the spatial (or apparent) density of a voxel formed by a rotating light modulation region within the generated 3D volumetric image with respect to its distance from the axis of rotation and as a result control uniformity of spatial density.

[0206] As an example, for the case where light modulation regions comprise individual LEDs, where the LEDs are larger (ie, having a larger modulator dimension) the proportion of the light modulating surface that is capable of emitting increases (ie, less gaps between LEDs) resulting in an increase in the apparent voxel density. In such a display, an option to configure the apparent voxel spatial density to be substantially uniform is to vary the LED sizing as described above. Another consideration that may be taken into account is that for a transparent substrate, the modulator dimension will affect the degree of occlusion. Accordingly, in some examples, having smaller LEDs near the axis of rotation (ie, smaller modulator dimension) may be desired in order to reduce the amount of occlusion close to the rotation axis.

[0207] As would be appreciated, in various examples both the spacing between, and size of, individual light emission regions may be varied to configure the voxel spatial density as a function of spacing or distance from the axis of rotation to assist in generating a 3D volumetric image with substantially uniform perceived brightness and spatial density arising from the rotating light modulating surface.

[0208] Referring now to FIG. 16, there is shown a perspective view of a 3D volumetric display 1600 having a light modulating surface comprising opposed light modulation sub-surfaces 1610A, 1610B mounted on the opposite sides of a support member 1650 configured to rotate about a central rotation axis.

[0209] As shown in FIG. 16, and considering the example where the light modulation subsurfaces 1610A, 1610B are formed of respective LED matrices mounted to the opposite sides of the rotating support member 1650 in the form of a substrate, the support member 1650 will have a required thickness or depth to accommodate the electronic components and connecting arrangements for the respective LED matrices. As a result of the thickness of the support member 1650, there is caused a cylindrical “dead zone” 1655 in the middle of the display that has a diameter equal to this thickness where a component of any generated volumetric 3D image cannot be displayed.

[0210] In one example, the light modulating surface comprises opposed emission light modulation sub-surfaces mounted to a rotatable support member such as shown above. In this case, the characteristic or spatial configuration characteristic that is varied comprises a thickness of the support member which is configured to increase with increasing distance from the rotation axis.

[0211] Referring now to FIG. 17, there is shown a perspective view of a 3D volumetric display 1700 similar to display 1600 but where the gap or separation between the opposed light modulation subsurfaces 1710A, 1710B increases with spacing from the central rotation axis to form a wedge shape in accordance with some embodiments, ie where the thickness of the support member is configured to increase with increasing distance from the rotation axis.

[0212] In this example, the various electronic components required for light modulation subsurfaces 1710A, 1710B are preferentially located on the outer edge of the light modulation sub-surfaces 1710A, 1710B, allowing the support member 1750 to taper towards the axis of rotation to form a central column of LEDs (as an example) that is located on, or very close to the center of rotation, as a result substantially eliminating the central dead zone shown in FIG. 16.

[0213] Referring now to FIG. 18, there is shown a flowchart 1800 indicating the options for varying at least one characteristic of light modulating regions in accordance with their spacing from the rotation axis according to some embodiments. In various examples, block 1810 may correspond to block 220 shown in FIG. 2.

[0214] At blocks 1820 and 1850, the characteristic of the two or more selected light modulating regions that may be controlled to vary may comprise a light modulation characteristic and / or a spatial modulation characteristic of the light modulating regions. In various examples, the light modulation characteristic 1820 may comprise any combination of the refresh rate (at block 1821), level of spatial dithering (at block 1822), luminance (at block 1823), level of dilation (at block 1824), or temporal dithering (at block 1825) in accordance with the present disclosure. Furthermore, in various examples, the spatial configuration characteristic 1850 may comprise any combination of surface density of light modulating regions (at block 1851), modulation dimension (ie, size of modulator) (at block 1852) or configuration of the support member (at block 1853).

[0215] Referring now to FIGS 19A-19E, there are shown perspective views of various 3D volumetric displays in accordance with some embodiments.

[0216] FIG. 19A shows a 3D volumetric display 1910 comprising a single light modulation surface 1911 rotating about rotation axis A located at an interior edge of light modulation surface 1911 forming in this example a cylindrical swept volume 1915. In various examples, light modulation surface1911 may comprise opposed light modulation sub-surfaces. While in this example, or indeed the examples discussed below, the rotation axis A is shown as horizontal, it will be appreciated that the rotation axis could be vertical or indeed adopt any orientation which would then define the orientation of the associated swept volume 1915 in which the 3D volumetric image will be generated.

[0217] FIG. 19B shows a 3D volumetric display 1920 comprising two light modulation surfaces 1921a, 1921b located either side of the central rotation axis A forming a cylindrical swept volume 1925.

[0218] FIG. 19C shows a 3D volumetric display 1930 comprising six two-sided modulation surfaces 193 la-193 If spaced in an equiangular configuration with respect to each other and rotating about central rotation axis A forming a cylindrical swept volume 1935. As would be appreciated, the number of individual light modulation surfaces may be varied as required.

[0219] In various examples, to reduce perceived flicker in a volumetric display, the rate of movement of any hardware component moving within the swept volume should be sufficient to blur the moving components from the perspective of a viewer viewing the display. In one example, a volumetric refresh rate of approximately 30 volumes per second may be sufficient to provide a substantially flicker free experience. In a display with a light modulating surface comprising two LED matrices (eg, two “blades”) located on opposed sides of the rotation axis (eg, FIG. 19B), rotating the light modulating surface at 900 rpm equates to a 15 Hz rotation, and a 30 Hz volumetric refresh rate.

[0220] In the same display, a light modulating surface comprising a cross shaped arrangement of four LED matrices (ie, four blades) but keeping the rotational speed at 15 Hz would resulting in the volumetric refresh rate of the display doubling to 60 volumes per second (ie 60 Hz), creating a smoother playback experience. If this arrangement added additional slices interlaced with the existing slices, it would double the resolution in the Z direction but also require twice the additional CPU capacity to generate the extra data, and additional bandwidth to transmit the data to the display. Similarly, a light modulating surface comprising a star shaped arrangement of six LED matrices (ie, six blades) with the same rotational speed of 15 Hz would result in a volumetric refresh rate of 90 volumes per second but with a correspondingly increased CPU load and bandwidth requirement.

[0221] Another consideration when varying the number of blades that are substantially out of phase rotationally is that unless they are transparent, generally more blades will result in more physical occlusion and block other parts of the swept volume from view.

[0222] FIG 19D shows a 3D volumetric display 1940 comprising a non -planar emission surface 1941 that rotates about rotation axis A forming a cylindrical swept volume 1945.

[0223] FIG. 19E shows a 3D volumetric display 1950 comprising four 3D volumetric displays 1920A-D configured to tile an enlarged swept volume in a 2X2 array. As would be appreciated, the array could be extended in any direction to create an extended swept volume having a required HEIGHT x WIDTH x DEPTH requirement.

[0224] FIG. 19F shows an interleaved 3D volumetric display 1970 comprising two of the 3D volumetric displays 1920 shown in FIG. 19B and configured to counter rotate with respect to each other and forming an extended swept volume 1955 from the combined swept volumes of component volumetric displays 1920.

[0225] Referring now to FIG. 20A, there is shown a figurative view of a 3D volumetric display 2000 comprising a non-planar light modulating surface 2010 comprising two curved surfaces 2011, 2015 according to some embodiments of the present disclosure.

[0226] In this example, the curved surfaces of 2011, 2015 of light modulating surface follow an Archimedean spiral and the rotation axis is horizontal as indicated. Such an arrangement may be advantageous as the curved surface potentially provide more control over which parts of the display may be occluded. As shown, display 2000 is adapted to display a human face 2030 in a natural speaking orientation.

[0227] FIG. 20B depicts the volumetric display 2000 of FIG. 20A and shows which modulating regions may be illuminated at a point in time corresponding to face 2030 illustrated in FIG. 20A. As can be seen, the direction of the light modulating regions 2035 would be directed to a person that might be interacting with face 2030 such as in a video teleconference call.

[0228] Referring now to FIG. 21, there is shown a figurative view of a 3D volumetric display 2100 comprising a non-planar light modulating surface similar to display 2000 illustrated in FIGS. 20A and 20B but comprising three curved surfaces. In this example, rotating light modulating surface 2110 at 10 Hz (corresponding to 600 RPM) would equate to a volumetric refresh rate of 30 Hz.

[0229] Referring now to FIG. 22A, there is shown a 3D volumetric display 2200 comprising light modulating surfaces arranged in a cross-shaped configuration. In this example, the light modulating surfaces comprise 2D LED matrices formed on an opaque substrate and as can be seen the light modulating surface will physically occlude part of the swept volume that is farthest from the viewer. This is because regardless of how fast the light modulation surfaces are rotating, the LEDs that are on the lower half of the far side of the display will be occluded as the display rotates as the blade or panel that is offset by 90 degrees occludes the view.

[0230] In a 3D volumetric display with an opaque LED matrix, each viewer only sees data rendered on the side of LED matrix that is facing them at any given time. In such a setup, it is possible to omit writing volumetric data to a single side of a dual sided LED matrix so that the produced effect is that only one person can see a particular item that is within or near their side of the display. An example of a use case for such a technique would be a representation of a game of battleships, where each player would only be required view their own ships, and not those of their opposition. Referring now to FIG. 22B, there is shown a 3D volumetric display 2250 similar to 3D volumetric display 2200 shown in FIG. 22A but instead the 2D LED matrices are formed on a transparent substrate in accordance with some embodiments. In various examples, the substrate may be formed from materials including, but not limited to glass, acrylic, polycarbonate, lattice, or other transparent materials.

[0231] As can be seen from FIG. 22B, by varying the transparency of the substrate that the LED matrices are formed on, the occlusion caused by the LED matrix substrates themselves may be greatly reduced and the uniformity of volume transparency throughout the volume be controlled. As would be appreciated, the use of a transparent substrate or support member for the light modulating surface may be advantageously adopted to reduce occlusion where this may be a requirement.

[0232] In various embodiments a method and system for generating a 3D volumetric image in accordance with the present disclosure comprises a light modulation surface having light modulation regions able to adopt refresh rates in the following ranges including, but not limited to: less than 1 kHz, 1 kHz - 5 kHz, 5 kHz - 10 kHz, 10 kHz - 20 kHz, 20 kHz - 30 kHz, 30 kHz - 40 kHz, 40 kHz - 50 kHz, 50 kHz - 60 kHz, 60 kHz - 70 kHz, 70 kHz - 80 kHz, 80 kHz - 90 kHz, or 90 kHz - 100 kHz.

[0233] In other examples, the refresh rates may be in the following ranges including, but not limited to: less than 100 kHz, 100 kHz - 200 kHz, 200 kHz - 300 kHz, 300 kHz - 400 kHz, 400 kHz - 500 kHz, 500 kHz - 600 kHz, 600 kHz - 700 kHz, 700 kHz - 800 kHz, 800 kHz - 900 kHz, 900 kHz - 1 MHz, or greater than 1 MHz.

[0234] In various embodiments a method and system for generating a 3D volumetric image in accordance with the present disclosure comprises the 3D volumetric image being generated with a volumetric refresh rate in the following ranges including, but not limited to: less than 5 Hz, 5 Hz - 10 Hz, 10 Hz - 20 Hz, 20 Hz - 30 Hz, 30 Hz - 40 Hz, 40 Hz - 50 Hz, 50 Hz - 60 Hz, 60 Hz - 70 Hz, 70 Hz - 80 Hz, 80 Hz - 90 Hz, 90 Hz - 100 Hz, or greater than 100 Hz.

[0235] In various examples, a method and system for generating a 3D volumetric image in accordance with the present disclosure may comprise a light modulating surface having a maximum refresh rate and an overall volumetric refresh rate combination including, but not limited to the ranges shown in Table 4.TABLE 4 -EXAMPLE MAXIMUM REFRESH RATE ANDVOLUMETRIC REFRESH RATE COMBINATIONS

[0236] Embodiments of the present disclosure are capable of addressing one or more of the following disadvantages of rotating volumetric displays including but not limited to:• Uneven Voxel Density: Rotating volumetric displays often have varying voxel densities due to the radial nature of the rotation. Methods adopted in accordance with the present disclosure may operate to achieve uniform voxel density across different radial zones, leading to consistent visual quality.• Non-Uniform Color Representation: Color consistency can be a challenge due to varying refresh rates across different radial sections of a rotating volumetric display. Methods adopted in accordance with the present disclosure may operate to maintain consistent color output, ensuring accurate and uniform color representation throughout the display.• Inconsistent Brightness: Due to the varying distances from the axis of rotation, perceived brightness levels can differ across a rotating volumetric display. Methods adopted in accordance with the present disclosure may operate to achieve uniform brightness by adjusting LED intensity and managing refresh rates.• Limited Viewing Angles: A rotating volumetric display can have inconsistent viewing angles depending on rotation speed and voxel distribution. Methods adopted in accordance with the present disclosure may operate to broaden viewing angles and maintain visual consistency from different perspectives.• Inconsistent 3D rendering quality: In a non-uniform rotating volumetric display, different areas might show varying levels of clarity, resulting in blurred or distorted visuals. This inconsistency disrupt the overall image, making it difficult to rely on the display for precise visualization. Methods adopted in accordance with the present disclosure may operate to improve uniformity in detailed 3D scenes.• Increased eye strain: Inconsistent depth perception can lead to eye strain, especially during prolonged use. This discomfort may deter users from engaging with the display for extended periods. Methods adopted in accordance with the present disclosure may operate to maximize the spatial density within a volumetric display, allowing for more detailed images that cause less eye strain.• Collaboration: When different angles produce inconsistent visuals, it becomes challenging for multiple users to collaborate around the same rotating volumetric display. Methods adopted in accordance with the present disclosure may operate to enable a uniform viewing experience for multiple people simultaneously.• Performance: When displays with larger diameters are designed, increasing the rotational speed can be challenging. Methods adopted in accordance with the present disclosure may operate to use multiple transparent LED matrices to increase the number of volumes generated per rotation allowing for a smoother animation rate at lower rotational speeds.

[0237] Methods and systems for generating a 3D volumetric image in accordance with the present disclosure may be used in many applications including, but not limited to:• Medical Imaging: Surgical planning, diagnostic visualization, and medical education.• Advertising and Marketing: Attention-grabbing displays, product showcases, and interactive promotions.• Architecture and Construction: Architectural visualization, construction planning, and virtual walkthroughs.• Education and Training: Interactive learning, simulations, and training exercises.• Entertainment and Gaming: Immersive gaming experiences, live performances, and interactive exhibits.• Engineering and Design: Collaborative design reviews, virtual prototyping, and engineering simulations.• Defence and Aerospace: Military training, situational awareness, and virtual testing of defense systems.• Home entertainment: Al assistants, exercise classes, cooking guide, Yoga glasses, weather reports.• Sport replay: Playback and analysis of 3D captured sporting events, basketball, tennis, golf swings, UFC.• Communication: Live 3D video communication with two-way 3D streaming including the translation between different languages.

[0238] It is appreciated that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software or instructions, middleware, platforms, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Those of ordinary skill in the art may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0239] The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two, including cloud based systems. For a hardware implementation, processing may be implemented within one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, or other electronic units designed to perform the functions described herein, or a combination thereof. Various middleware and computing platforms may be used.

[0240] Software modules, also known as computer programs, computer codes, or instructions, may contain a number a number of source code or object code segments or instructions, and may reside in any computer readable medium such as a RAM memory, flash memory, ROM memory, EPROM memory, registers, hard disk, a removable disk, a CD-ROM, a DVD-ROM, a Blu-ray disc, or any other form of computer readable medium. In some aspects the computer-readable media may comprise non- transitory computer-readable media (e.g., tangible media). In addition, for other aspects computer- readable media may comprise transitory computer- readable media (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media. In another aspect, the computer readable medium may be integral to the processor. The processor and the computer readable medium may reside in an ASIC or related device. The software codes may be stored in a memory unit andthe processor may be configured to execute them. The memory unit may be implemented within the processor or external to the processor, in which case it can be communicatively coupled to the processor via various means as is known in the art.

[0241] EMBODIMENTS

[0242] Clause 1. A method for generating a 3D volumetric image, comprising: rotating about a rotation axis a light modulating surface comprising separately controllable light modulating regions located across the light modulating surface; and controlling separately the modulation of the light modulating regions to generate the 3D volumetric image upon rotation of the light modulating surface about the rotation axis; wherein a characteristic of two or more selected light modulating regions of the light modulating surface is varied in accordance with respective spacings of the two or more selected light modulating regions from the rotation axis.

[0243] Clause 2. The method of clause 1, wherein the characteristic of the two or more selected light modulating regions of the light modulating surface that is controlled to vary in accordance with the respective spacings from the rotation axis comprises a light modulation characteristic.

[0244] Clause 3. The method of clause 2, wherein the light modulation characteristic comprises a refresh rate of a light modulating region.

[0245] Clause 4. The method of clause 3, wherein the refresh rate of individual light modulation regions is controlled to assist in creating the generated 3D volumetric image with a substantially uniform spatial density.

[0246] Clause 5. The method of clause 3, wherein respective refresh rates of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0247] Clause 6. The method of clause 3, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same column refresh rate, and wherein respective column refresh rates of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0248] Clause 7. The method of clause 3, wherein the light modulating surface is divided in two or more radial refresh rate zones each having a zone radial distance from the rotation axis and the lightmodulating regions within a radial refresh rate zone are controlled to have the same zone refresh rate and wherein respective zone refresh rates of two or more selected radial refresh rate zones are controlled to be proportional to respective zone radial distances of the two or more radial refresh rate zones from the axis of rotation.

[0249] Clause 8. The method of clause 7, wherein the respective zone refresh rates of the two or more selected radial refresh rate zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0250] Clause 9. The method of any one of clauses 2 to 8, wherein the light modulation characteristic comprises a level of spatial dithering of the light modulation region.

[0251] Clause 10. The method of clause 9, wherein the level of spatial dithering is controlled to assist in creating the generated 3D volumetric image with substantially uniform spatial density.

[0252] Clause 11. The method of clause 9, wherein respective levels of dithering of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0253] Clause 12. The method of clause 9, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same level of spatial dithering, and wherein respective levels of dithering of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0254] Clause 13. The method of clause 9, wherein the light modulating surface is divided in two or more radial level of spatial dithering zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial level of spatial dithering zone are controlled to have the same zone level of spatial dithering and wherein respective zone levels of dithering of two or more selected radial level of spatial dithering zones are controlled to be proportional to respective zone radial distances of the two or more radial level of spatial dithering zones from the axis of rotation.

[0255] Clause 14. The method of clause 9, wherein the respective zone levels of dithering of the two or more selected radial level of spatial dithering zones are controlled to generally increase apparent spatial density as the zone radial distances increase from the axis of rotation.

[0256] Clause 15. The method of any one of clauses 2 to 14, wherein the light modulation characteristic comprises a luminance of the light modulation region.

[0257] Clause 16. The method of clause 15, wherein the luminance of individual light modulating regions is controlled to assist in creating the generated 3D volumetric image with substantially uniform perceived brightness.

[0258] Clause 17. The method of clause 16, wherein the luminance of individual light modulating regions is controlled to compensate for modifications of the individual light modulating regions required to generate a 3D volumetric image with substantially uniform spatial density.

[0259] Clause 18. The method of clause 15, wherein respective luminances of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0260] Clause 19. The method of clause 15, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same luminance, and wherein respective luminances of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0261] Clause 20. The method of clause 15, wherein the light modulating surface is divided in two or more radial luminance zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial luminance zone are controlled to have the same zone luminance and wherein respective zone luminances of two or more selected radial luminance zones are controlled to be proportional to respective zone radial distances of the two or more radial luminance zones from the axis of rotation.

[0262] Clause 21. The method of clause 15, wherein the respective zone luminances of the two or more selected luminance zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0263] Clause 22. The method of any one of clauses 15 to 21, wherein the luminance of an individual light modulating region is controlled by varying a supply current to the individual light modulation region.

[0264] Clause 23. The method of any one of clauses 15 to 21, wherein the luminance of an individual light modulating region is controlled by varying a duty cycle of the light modulation region.

[0265] Clause 24. The method of clause 23, wherein the light modulating surface is divided in two or more radial duty cycle zones each having a zone radial distance from the rotation axis and the lightmodulating regions within a radial duty cycle zone are controlled to have the same zone duty cycle and wherein respective zone duty cycles of two or more selected radial duty cycles zones are controlled to be proportional to respective zone radial distances of the two or more radial duty cycle zones from the axis of rotation.

[0266] Clause 25. The method of clause 14, wherein the respective zone duty cycles of the two or more selected radial duty cycle zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0267] Clause 26. The method of any one of clauses 2 to 25, wherein the light modulation characteristic comprises a level of dilation for a light modulation region.

[0268] Clause 27. The method of clause 26, wherein the level of dilation of individual light modulating regions is controlled to assist in creating the generated 3D volumetric image with substantially uniform perceived brightness.

[0269] Clause 28. The method of clause 27, wherein the level of dilation of individual light modulating regions is controlled to compensate for modifications of the individual light modulating regions required to generate a 3D volumetric image with substantially uniform spatial density.

[0270] Clause 29. The method of clause 26, wherein respective levels of dilation of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0271] Clause 30. The method of clause 26, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same level of dilation, and wherein respective levels of dilation of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0272] Clause 31. The method of clause 26, wherein the light modulating surface is divided in two or more radial level of dilation zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial level of dilation zone are controlled to have the same zone level of dilation and wherein respective zone levels of dilation of two or more selected radial level of dilation zones are controlled to be proportional to respective zone radial distances of the two or more radial level of dilation zones from the axis of rotation.

[0273] Clause 32. The method of clause 26, wherein the respective zone levels of dilation of the two or more selected level of dilation zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0274] Clause 33. The method of any one of clauses 2 to 32, wherein the light modulation characteristic comprises a temporal dithering of the light modulating region.

[0275] Clause 34. The method of clause 33, wherein the temporal dithering of individual light modulating regions is controlled to assist in creating the generated 3D volumetric image with substantially uniform perceived color appearance.

[0276] Clause 35. The method of clause 34, wherein the temporal dithering of individual light modulating regions is controlled to compensate for modifications of the individual light modulations required to generate a 3D volumetric image with substantially uniform spatial density.

[0277] Clause 36. The method of any one of clauses 1 to 35, wherein the characteristic of the two or more selected light modulating regions of the light modulating surface that is controlled to vary in accordance with the respective spacings from the rotation axis comprises a spatial configuration characteristic of the light modulating surface.

[0278] Clause 37. The method of clause 36, wherein the spatial configuration characteristic comprises a surface density based on a spacing between light modulation regions of the light modulating surface.

[0279] Clause 38. The method of clause 37, wherein the surface density is controlled to assist in creating the generated 3D volumetric image with substantially uniform spatial density.

[0280] Clause 39. The method of clause 37, wherein respective surface densities of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0281] Clause 40. The method of clause 37, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same column surface densities, and wherein respective column surface densities of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0282] Clause 41. The method of clause 37, wherein the light modulating surface is divided in two or more radial surface density zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial surface density zone are controlled to have the same zone surface density and wherein respective zone surface densities of two or more selected radial surface density zones are controlled to be proportional to respective zone radial distances of the two or more radial surface density zones from the axis of rotation.

[0283] Clause 42. The method of clause 41, wherein the respective zone surface densities of the two or more selected radial surface density zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0284] Clause 43. The method of any one of clauses 36 to 42, wherein the spatial configuration characteristic comprises a modulator dimension based on a size of the light modulation region.

[0285] Clause 44. The method of clause 43, wherein the modulator dimension is controlled to assist in creating the generated 3D volumetric image with substantially uniform spatial density.

[0286] Clause 45. The method of clause 43, wherein respective modulator dimensions of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0287] Clause 46. The method of clause 43, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same column modulator dimensions, and wherein respective column modulator dimensions of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0288] Clause 47. The method of clause 43, wherein the light modulating surface is divided in two or more radial modulator dimension zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial modulator dimension zone are controlled to have the same zone modulator dimension and wherein respective zone modulator dimensions of two or more selected radial modulator dimension zones are controlled to be proportional to respective zone radial distances of the two or more radial modulator dimension zones from the axis of rotation.

[0289] Clause 48. The method of clause 47, wherein the respective zone modulator dimensions of the two or more selected radial modulator dimension zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0290] Clause 49. The method of any one of clauses 36 to 48, wherein the light modulating surface comprises opposed emission light modulation sub-surfaces mounted to a rotatable support member, and wherein the spatial configuration characteristic comprises a thickness of the support member which is configured to increase with increasing distance from the rotation axis.

[0291] Clause 50. The method of any one of clauses 1 to 49, wherein the 3D volumetric image is generated with a volumetric refresh rate of greater than 30 Hz.

[0292] Clause 51. A three dimensional (3D) volumetric display system comprising: a 3D display comprising a light modulating surface comprising separately controllable light modulation regions located across the light modulating surface, the light modulating surface configured to rotate about a rotation axis; and an emission controller comprising one or more data processors configured to separately control the modulation of the light modulating regions to generate the 3D volumetric image upon rotation of the light modulating surface about the rotation axis; wherein a characteristic of two or more selected light modulating regions of the light modulating surface is varied in accordance with respective spacings of the two or more selected light modulating regions from the rotation axis.

[0293] Clause 52. The display system of clause 51, wherein the characteristic of the two or more selected light modulating regions of the light modulating surface that is controlled to vary in accordance with the respective spacings from the rotation axis comprises a light modulation characteristic.

[0294] Clause 53. The display system of clause 52, wherein the light modulation characteristic comprises a refresh rate of a light modulating region.

[0295] Clause 54. The display system of clause 53, wherein the refresh rate of individual light modulation regions is controlled to assist in creating the generated 3D volumetric image with a substantially uniform spatial density.

[0296] Clause 55. The display system of clause 53, wherein respective refresh rates of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0297] Clause 56. The display system of clause 53, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same column refresh rate, and wherein respective column refresh rates of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0298] Clause 57. The display system of clause 53, wherein the light modulating surface is divided in two or more radial refresh rate zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial refresh rate zone are controlled to have the same zone refresh rate and wherein respective zone refresh rates of two or more selected radial refresh rate zones are controlled to be proportional to respective zone radial distances of the two or more radial refresh rate zones from the axis of rotation.

[0299] Clause 58. The display system of clause 57, wherein the respective zone refresh rates of the two or more selected radial refresh rate zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0300] Clause 59. The display system of any one of clauses 52 to 58, wherein the light modulation characteristic comprises a level of spatial dithering of the light modulation region.

[0301] Clause 60. The display system of clause 59, wherein the level of spatial dithering is controlled to assist in creating the generated 3D volumetric image with substantially uniform spatial density.

[0302] Clause 61. The display system of clause 59, wherein respective levels of dithering of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0303] Clause 62. The display system of clause 59, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same level of spatial dithering, and wherein respective levels of dithering of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0304] Clause 63. The display system of clause 59, wherein the light modulating surface is divided in two or more radial level of spatial dithering zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial level of spatial dithering zone are controlled to have the same zone level of spatial dithering and wherein respective zone levels of dithering of two or more selected radial level of spatial dithering zones are controlled to be proportional to respective zone radial distances of the two or more radial level of spatial dithering zones from the axis of rotation.

[0305] Clause 64. The display system of clause 59, wherein the respective zone levels of dithering of the two or more selected radial level of spatial dithering zones are controlled to generally increase apparent spatial density as the zone radial distances increase from the axis of rotation.

[0306] Clause 65. The display system of any one of clauses 52 to 64, wherein the light modulation characteristic comprises a luminance of the light modulation region.

[0307] Clause 66. The display system of clause 65, wherein the luminance of individual light modulating regions is controlled to assist in creating the generated 3D volumetric image with substantially uniform perceived brightness.

[0308] Clause 67. The display system of clause 66, wherein the luminance of individual light modulating regions is controlled to compensate for modifications of the individual light modulating regions required to generate a 3D volumetric image with substantially uniform spatial density.

[0309] Clause 68. The display system of clause 65, wherein respective luminances of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0310] Clause 69. The display system of clause 65, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same luminance, and wherein respective luminances of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0311] Clause 70. The display system of clause 65, wherein the light modulating surface is divided in two or more radial luminance zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial luminance zone are controlled to have the same zone luminance and wherein respective zone luminances of two or more selected radial luminance zones are controlled to be proportional to respective zone radial distances of the two or more radial luminance zones from the axis of rotation.

[0312] Clause 71. The display system of clause 65, wherein the respective zone luminances of the two or more selected luminance zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0313] Clause 72. The display system of any one of clauses 65 to 71, wherein the luminance of an individual light modulating region is controlled by varying a supply current to the individual light modulation region.

[0314] Clause 73. The display system of any one of clauses 65 to 71, wherein the luminance of an individual light modulating region is controlled by varying a duty cycle of the light modulation region.

[0315] Clause 74. The display system of clause 73, wherein the light modulating surface is divided in two or more radial duty cycle zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial duty cycle zone are controlled to have the same zone duty cycle and wherein respective zone duty cycles of two or more selected radial duty cycles zones are controlled to be proportional to respective zone radial distances of the two or more radial duty cycle zones from the axis of rotation.

[0316] Clause 75. The display system of clause 74, wherein the respective zone duty cycles of the two or more selected radial duty cycle zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0317] Clause 76. The display system of any one of clauses 52 to 75, wherein the light modulation characteristic comprises a level of dilation for a light modulation region.

[0318] Clause 77. The display system of clause 76, wherein the level of dilation of individual light modulating regions is controlled to assist in creating the generated 3D volumetric image with substantially uniform perceived brightness.

[0319] Clause 78. The display system of clause 77, wherein the level of dilation of individual light modulating regions is controlled to compensate for modifications of the individual light modulating regions required to generate a 3D volumetric image with substantially uniform spatial density.

[0320] Clause 79. The display system of clause 76, wherein respective levels of dilation of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0321] Clause 80. The display system of clause 76, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same level of dilation, and wherein respective levels of dilation oftwo or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0322] Clause 81. The display system of clause 76, wherein the light modulating surface is divided in two or more radial level of dilation zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial level of dilation zone are controlled to have the same zone level of dilation and wherein respective zone levels of dilation of two or more selected radial level of dilation zones are controlled to be proportional to respective zone radial distances of the two or more radial level of dilation zones from the axis of rotation.

[0323] Clause 82. The display system of clause 76, wherein the respective zone levels of dilation of the two or more selected level of dilation zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0324] Clause 83. The display system of any one of clauses 52 to 82, wherein the light modulation characteristic comprises a temporal dithering of the light modulating region.

[0325] Clause 84. The display system of clause 83, wherein the temporal dithering of individual light modulating regions is controlled to assist in creating the generated 3D volumetric image with substantially uniform perceived color appearance.

[0326] Clause 85. The display system of clause 84, wherein the temporal dithering of individual light modulating regions is controlled to compensate for modifications of the individual light modulations required to generate a 3D volumetric image with substantially uniform spatial density.

[0327] Clause 86. The display system of any one of clauses 51 to 85, wherein the characteristic of the two or more selected light modulating regions of the light modulating surface that is controlled to vary in accordance with the respective spacings from the rotation axis comprises a spatial configuration characteristic of the light modulating surface.

[0328] Clause 87. The display system of clause 86, wherein the spatial configuration characteristic comprises a surface density based on a spacing between light modulation regions of the light modulating surface.

[0329] Clause 88. The display system of clause 87, wherein the surface density is controlled to assist in creating the generated 3D volumetric image with substantially uniform spatial density.

[0330] Clause 89. The display system of clause 87, wherein respective surface densities of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0331] Clause 90. The display system of clause 87, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same column surface densities, and wherein respective column surface densities of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0332] Clause 91. The display system of clause 87, wherein the light modulating surface is divided in two or more radial surface density zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial surface density zone are controlled to have the same zone surface density and wherein respective zone surface densities of two or more selected radial surface density zones are controlled to be proportional to respective zone radial distances of the two or more radial surface density zones from the axis of rotation.

[0333] Clause 92. The display system of clause 91, wherein the respective zone surface densities of the two or more selected radial surface density zones are controlled to generally decrease as the zone radial distances increase from the axis of rotation.

[0334] Clause 93. The display system of any one of clauses 86 to 92, wherein the spatial configuration characteristic comprises a modulator dimension based on a size of the light modulation region.

[0335] Clause 94. The display system of clause 93, wherein the modulator dimension is controlled to assist in creating the generated 3D volumetric image with substantially uniform spatial density.

[0336] Clause 95. The display system of clause 93, wherein respective modulator dimensions of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the axis of rotation.

[0337] Clause 96. The display system of clause 93, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same column modulator dimensions, and wherein respectivecolumn modulator dimensions of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the axis of rotation.

[0338] Clause 97. The display system of clause 93, wherein the light modulating surface is divided in two or more radial modulator dimension zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial modulator dimension zone are controlled to have the same zone modulator dimension and wherein respective zone modulator dimensions of two or more selected radial modulator dimension zones are controlled to be proportional to respective zone radial distances of the two or more radial modulator dimension zones from the axis of rotation.

[0339] Clause 98. The display system of clause 97, wherein the respective zone modulator dimensions of the two or more selected radial modulator dimension zones are controlled to generally increase as the zone radial distances increase from the axis of rotation.

[0340] Clause 99. The display system of any one of clauses 86 to 98, wherein the light modulating surface comprises opposed emission light modulation sub-surfaces mounted to a rotatable support member, and wherein the spatial configuration characteristic comprises a thickness of the support member which is configured to increase with increasing distance from the rotation axis.

[0341] Clause 100. The display system of any one of clauses 51 to 59, wherein the 3D volumetric image is generated with a volumetric refresh rate of greater than 30 Hz.

[0342] Clause 101. A three dimensional (3D) volumetric display system comprising means to carry out the method of any one of clauses 1 to 50.

[0343] Clause 102. An article of manufacture including a non-transitory computer-readable medium, having stored thereon program instructions that, upon execution by a three dimensional (3D) volumetric display system comprising one or more data processors, cause the display system to perform the operations of any one of clauses 1 to 50.

[0344] Clause 103. A method for generating a 3D volumetric image, comprising: rotating about a rotation axis a light modulating surface comprising separately controllable light modulating regions; and controlling separately the modulation of the light modulating regions to generate the 3D volumetric image upon rotation of the light modulating surface about the rotation axis; wherein at least one characteristic of two or more selected light modulating regions is varied in accordance with respective spacings of the two or more selected light modulating regions from the rotation axis.

[0345] Clause 104. The method of clause 103, wherein the characteristic comprises a refresh rate of the light modulating regions.

[0346] Clause 105. The method of clause 104, wherein the refresh rate is controlled to be proportional to the radial distance from the rotation axis.

[0347] Clause 106. The method of clause 104 or 105, wherein the light modulating surface is divided into two or more radial refresh rate zones, each having a zone refresh rate proportional to its radial distance from the rotation axis.

[0348] Clause 107. The method of clause 104, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same refresh rate.

[0349] Clause 108. The method of any one of clauses 103 to 107, wherein the characteristic comprises a level of spatial dithering of the light modulating regions.

[0350] Clause 109. The method of clause 108, wherein the level of spatial dithering increases with radial distance from the rotation axis to maintain uniform spatial density.

[0351] Clause 110. The method of clause 108, wherein the light modulating surface is divided into radial spatial dithering zones, each having a level of dithering proportional to radial distance from the rotation axis.

[0352] Clause 111. The method of any one of clauses 103 to 110, wherein the characteristic comprises a luminance of the light modulating regions.

[0353] Clause 112. The method of clause 111, wherein the luminance is controlled by varying supply current to the light modulating regions.

[0354] Clause 113. The method of clause 111, wherein the luminance is controlled by varying duty cycle of the light modulating regions.

[0355] Clause 114. The method of clause 113, wherein the light modulating surface is divided into radial duty cycle zones, with duty cycle increasing with radial distance from the rotation axis.

[0356] Clause 115. The method of any one of clauses 111 to 114, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same luminance.

[0357] Clause 116. The method of any one of clauses 103 to 115, wherein the characteristic comprises a level of dilation for the light modulating regions.

[0358] Clause 117. The method of clause 116, wherein the level of dilation is proportional to the radial distance from the rotation axis.

[0359] Clause 118. The method of clause 116 or 117, wherein the light modulating surface is divided into radial dilation zones with different dilation levels.

[0360] Clause 119. The method of any one of clauses 103 to 118, wherein the characteristic comprises temporal dithering of the light modulating regions.

[0361] Clause 120. The method of clause 119, wherein the temporal dithering is controlled to achieve a uniform perceived color appearance.

[0362] Clause 121. The method of any one of clauses 103 to 120, wherein the characteristic comprises a surface density of the light modulating regions based on spacing between regions.

[0363] Clause 122. The method of clause 121, wherein the surface density increases with radial distance from the rotation axis.

[0364] Clause 123. The method of clause 121 or 122, wherein the light modulating surface is divided into radial surface density zones with surface density proportional to radial distance.

[0365] Clause 124. The method of any one of clauses 103 to 123, wherein the characteristic comprises a modulator dimension based on size of the light modulating regions.

[0366] Clause 125. The method of clause 124, wherein the modulator dimension increases with radial distance from the rotation axis.

[0367] Clause 126. The method of clause 24, wherein the light modulating surface is divided into radial modulator dimension zones, each with increasing modulator size with radial distance.

[0368] Clause 127. The method of any one of clauses 103 to 126, wherein the light modulating surface comprises opposed emission light modulation sub-surfaces mounted to a rotatable support member.

[0369] Clause 128. The method of clause 27, wherein the support member has a thickness that increases with radial distance from the rotation axis.

[0370] Clause 129. A three-dimensional (3D) volumetric display system comprising: a light modulating surface comprising separately controllable light modulating regions, configured to rotate about a rotation axis; and an emission controller configured to control modulation of the light modulating regions to generate a 3D volumetric image upon rotation; wherein at least one characteristic of two or more selected light modulating regions is varied in accordance with respective spacings of the two or more selected light modulating regions from the rotation axis.

[0371] Clause 130. The system of clause 129, wherein the emission controller is configured to dynamically adjust light modulation characteristics based on radial distance.

[0372] Clause 131. The system of clause 129 or 130, wherein the emission controller supports modulation control for at least one of: refresh rate, spatial dithering, luminance, dilation, or surface density as a function of radial distance from the rotation axis.

[0373] Clause 132. A non-transitory computer-readable medium having stored thereon program instructions that, upon execution by a 3D volumetric display system comprising one or more processors, cause the display system to perform the method of any one of clauses 103 to 128.

[0374] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that such prior art forms part of the common general knowledge.

[0375] It will be understood that the terms “comprise” and “include” and any of their derivatives (e.g. comprises, comprising, includes, including) as used in this specification, and the claims that follow, is to be taken to be inclusive of features to which the term refers, and is not meant to exclude the presence of any additional features unless otherwise stated or implied.

[0376] In some cases, a single embodiment may, for succinctness and / or to assist in understanding the scope of the disclosure, combine multiple features. It is to be understood that in such a case, these multiple features may be provided separately (in separate embodiments), or in any other suitable combination. Alternatively, where separate features are described in separate embodiments, these separate features may be combined into a single embodiment unless otherwise stated or implied. This also applies to the claims which can be recombined in any combination. That is a claim may be amended to include a feature defined in any other claim. Further a phrase referring to “at least one of’ a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.

[0377] It will be appreciated by those skilled in the art that the disclosure is not restricted in its use to the particular application or applications described. Neither is the present disclosure restricted in its preferred embodiment with regard to the particular elements and / or features described or depicted herein. It will be appreciated that the disclosure is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope as set forth and defined by the following claims.

Claims

CLAIMS1. A method for generating a 3D volumetric image, comprising: rotating about a rotation axis a light modulating surface comprising separately controllable light modulating regions located across the light modulating surface; and controlling separately a modulation of the light modulating regions to generate the 3D volumetric image upon rotation of the light modulating surface about the rotation axis; wherein at least one characteristic of two or more selected light modulating regions of the light modulating surface is varied in accordance with respective spacings of the two or more selected light modulating regions from the rotation axis.

2. The method of claim 1, wherein the at least one characteristic that is varied comprises a refresh rate of the two or more selected light modulating regions.

3. The method of claim 2, wherein respective refresh rates of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the rotation axis.

4. The method of claim 2, wherein the light modulating surface is divided in two or more radial refresh rate zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial refresh rate zone are controlled to have a same zone refresh rate and wherein respective zone refresh rates of two or more selected radial refresh rate zones are controlled to be proportional to respective zone radial distances of the two or more radial refresh rate zones from the rotation axis.5 The method of claim 2, wherein a plurality of light modulating regions forming a column on the light modulating surface having the same radial distance from the rotation axis are controlled to have the same column refresh rate, and wherein respective column refresh rates of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the rotation axis.

6. The method of any one of claims 1 to 5, wherein the at least one characteristic that is varied comprises a level of spatial dithering of the two or more selected light modulating regions.

7. The method of claim 6, wherein the level of spatial dithering is controlled to assist in creating the generated 3D volumetric image with substantially uniform spatial density.

8. The method of claim 6 or 7, wherein the light modulating surface is divided in two or more radial level of spatial dithering zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial level of spatial dithering zone are controlled to have a same zone level of spatial dithering and wherein respective zone levels of spatial dithering of two or more selected radial level of spatial dithering zones are controlled to be proportional to respective zone radial distances of the two or more radial level of spatial dithering zones from the rotation axis.

9. The method of any one of claims 1 to 8, wherein the at least one characteristic that is varied comprises a luminance of the two or more selected light modulating regions.

10. The method of claim 9, wherein a plurality of light modulating regions forming a column on the light modulating surface having a same radial distance from the rotation axis are controlled to have a same luminance, and wherein respective luminances of two or more selected columns are controlled to be proportional to respective radial distances of the two or more selected columns from the rotation axis.

11. The method of claim 9 or 10, wherein the luminance of an individual light modulating region is controlled by varying a supply current to the individual light modulation region.

12. The method of claim 9 or 10, wherein the luminance of an individual light modulating region is controlled by varying a duty cycle of the light modulation region.

13. The method of claim 12, wherein the light modulating surface is divided in two or more radial duty cycle zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial duty cycle zone are controlled to have a same zone duty cycle and wherein respective zone duty cycles of two or more selected radial duty cycle zones are controlled to be proportional to respective zone radial distances of the two or more radial duty cycle zones from the rotation axis, wherein the respective zone duty cycles of the two or more radial duty cycle zones are controlled to generally increase as the zone radial distances increase from the rotation axis.

14. The method of any one of claims 1 to 13, wherein the at least one characteristic that is varied comprises a level of dilation of the two or more selected light modulating regions that is varied.

15. The method of claim 14, wherein respective levels of dilation of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the rotation axis.

16. The method of claim 14, wherein the light modulating surface is divided in two or more radial level of dilation zones each having a zone radial distance from the rotation axis and the light modulatingregions within a radial level of dilation zone are controlled to have a same zone level of dilation and wherein respective zone levels of dilation of two or more selected radial level of dilation zones are controlled to be proportional to respective zone radial distances of the two or more radial level of dilation zones from the rotation axis.

17. The method of any one of claims 1 to 16, wherein the at least one characteristic that is varied comprises a temporal dithering of the two or more selected light modulating regions.

18. The method of claim 17, wherein the temporal dithering of a selection of individual light modulating regions is controlled to assist in creating the generated 3D volumetric image with substantially uniform perceived color appearance.

19. The method of any one of claims 1 to 18, wherein the at least one characteristic that is varied comprises a surface density of the two or more selected light modulating regions that is varied, wherein the surface density is based on a spacing between light modulation regions of the light modulating surface.

20. The method of claim 19, wherein respective zone surface densities of the two or more selected light modulating regions of the light modulating surface are controlled to be proportional to respective radial distances of the two or more selected light modulating regions from the rotation axis, wherein the respective zone surface densities of the two or more selected radial surface density zones are controlled to generally increase as the zone radial distances increase from the rotation axis.

21. The method of claim 19, wherein the light modulating surface is divided in two or more radial surface density zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial surface density zone are controlled to have a same zone surface density and wherein respective zone surface densities of two or more selected radial surface density zones are controlled to be proportional to respective zone radial distances of the two or more radial surface density zones from the rotation axis.

22. The method of any one of claims 1 to 21, wherein the at least one characteristic to be varied comprises a modulator dimension of the two or more selected light modulating regions, wherein the modulator dimension is based on a size of the light modulation region.

23. The method of claim 22, wherein respective modulator dimensions of the two or more selected light modulating regions of the light modulating surface are controlled to increase with respective radial distances of the two or more selected light modulating regions from the rotation axis.

24. The method of claim 22, wherein the light modulating surface is divided in two or more radial modulator dimension zones each having a zone radial distance from the rotation axis and the light modulating regions within a radial modulator dimension zone are controlled to have a same zone modulator dimension and wherein respective zone modulator dimensions of two or more selected radial modulator dimension zones are controlled to increase as the zone radial distances increase from the rotation axis.

25. The method of any one of claims 1 to 24, wherein the light modulating surface comprises opposed emission light modulation sub-surfaces mounted to a rotatable support member, and wherein the at least one characteristic to be varied comprises a thickness of the support member corresponding to the location of the two or more selected light modulation regions, and wherein the thickness is configured to increase with increasing distance from the rotation axis.

26. The method of any one of claims 1 to 25, wherein the at least one characteristic to be varied comprises a light modulation characteristic.

27. A three dimensional (3D) volumetric display system comprising: a 3D display comprising a light modulating surface comprising separately controllable light modulation regions located across the light modulating surface, the light modulating surface configured to rotate about a rotation axis; and an emission controller comprising one or more data processors configured to separately control the modulation of the light modulating regions to generate a 3D volumetric image upon rotation of the light modulating surface about the rotation axis; wherein at least one characteristic of two or more selected light modulating regions of the light modulating surface is varied in accordance with respective spacings of the two or more selected light modulating regions from the rotation axis.

28. The display system of claim 27, wherein the at least one characteristic comprises a light modulation characteristic and wherein the emission controller is configured to dynamically adjust the light modulation characteristic in accordance with radial distance.

29. The display system of claim 28, wherein the light modulation characteristic comprises at least one of: refresh rate, level of spatial dithering, luminance, level of dilation, or temporal dithering.

30. An article of manufacture including a non -transitory computer-readable medium, having stored thereon program instructions that, upon execution by a three dimensional (3D) volumetric display system comprising one or more data processors, cause the display system to perform the operations of any one of claims 1 to 26.

Images