[go: up one dir, main page]

WO2025149675A1 - Procédé et système d'affichage - Google Patents

Procédé et système d'affichage

Info

Publication number
WO2025149675A1
WO2025149675A1 PCT/EP2025/050702 EP2025050702W WO2025149675A1 WO 2025149675 A1 WO2025149675 A1 WO 2025149675A1 EP 2025050702 W EP2025050702 W EP 2025050702W WO 2025149675 A1 WO2025149675 A1 WO 2025149675A1
Authority
WO
WIPO (PCT)
Prior art keywords
initialising
array
complex
phase
display
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2025/050702
Other languages
English (en)
Inventor
Olivia-Jules CASAGRANDE GODAWATTA
Christian FIELDHOUSE
Alfred NEWMAN
Indi PRITCHARD
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Vividq Ltd
Original Assignee
Vividq Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Vividq Ltd filed Critical Vividq Ltd
Publication of WO2025149675A1 publication Critical patent/WO2025149675A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/08—Synthesising holograms, i.e. holograms synthesized from objects or objects from holograms
    • G03H1/0808—Methods of numerical synthesis, e.g. coherent ray tracing [CRT], diffraction specific
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
    • G03H1/2202—Reconstruction geometries or arrangements
    • G03H1/2205—Reconstruction geometries or arrangements using downstream optical component
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/08—Synthesising holograms, i.e. holograms synthesized from objects or objects from holograms
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/08—Synthesising holograms, i.e. holograms synthesized from objects or objects from holograms
    • G03H1/0841—Encoding method mapping the synthesized field into a restricted set of values representative of the modulator parameters, e.g. detour phase coding
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
    • G03H1/2294—Addressing the hologram to an active spatial light modulator
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/08—Synthesising holograms, i.e. holograms synthesized from objects or objects from holograms
    • G03H1/0808—Methods of numerical synthesis, e.g. coherent ray tracing [CRT], diffraction specific
    • G03H2001/0825—Numerical processing in hologram space, e.g. combination of the CGH [computer generated hologram] with a numerical optical element
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
    • G03H1/2294—Addressing the hologram to an active spatial light modulator
    • G03H2001/2297—Addressing the hologram to an active spatial light modulator using frame sequential, e.g. for reducing speckle noise
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H2210/00—Object characteristics
    • G03H2210/40—Synthetic representation, i.e. digital or optical object decomposition
    • G03H2210/44—Digital representation
    • G03H2210/441—Numerical processing applied to the object data other than numerical propagation
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H2223/00—Optical components
    • G03H2223/50—Particular location or purpose of optical element
    • G03H2223/55—Arranged at a Fourier plane

Definitions

  • the present invention relates to methods and apparatus for displaying computer generated holograms (CGH).
  • CGH computer generated holograms
  • target image data is typically initialised by multiplication with a complex phase array, forming an array of complex data used to compute a hologram for display.
  • phase arrays including random phase and linear or “flat” phase.
  • Linear phase profiles have been proposed as an alternative to random phase when initialising image data for display as a CGH.
  • the argument of the linear phase profile gives an inclined plane of phase values which passes through the origin.
  • Applying a linear phase profile induces a highly uneven amplitude distribution in Fourier space, the majority of the intensity is concentrated in one spot (referred to as a “spike” because it resembles a spike when the amplitude is plotted in the Fourier domain, having a concentrated spot of high intensity).
  • Such displays can avoid phase- induced image speckle entirely but bring their own problems.
  • Examples discussed herein propose a new technique for use when initialising images for CGH displays. Rather than initialising with a phase profile, this technique initialises images for CGH display with a complex array, which comprises a sum of weighted affine phase profiles.
  • a weighted affine phase profile is an affine phase profile multiplied by a real valued weight.
  • the values of the constants a and b determine the position of the spike in the Fourier domain.
  • the constant c acts as a phase offset and, together with the real valued weight, two additional, independent degrees of freedom per spike in the Fourier domain are provided. This provides more control over the amplitude of the sum of the phase profiles so that amplitude variation
  • the distribution of the intensity in the Fourier domain is concentrated in multiple discrete spots, referred to as "spikes". This results in multiple high points of intensity reaching the viewer's pupil, improving defocus.
  • the affine nature of the phase profiles results in a structured amplitude variation pattern in the displayed CGH image which may not even be noticed by a viewer at all. If it is visible, the deterministic repeating nature of the amplitude variation enables it to be reduced with lower computational complexity compared to prior random phase and flat phase approaches.
  • a method of displaying a computer generated hologram, CGH comprises: initialising an image array for display as a CGH using an initialising complex array to give an initialised array, wherein the initialising complex array comprises a sum of a plurality of weighted affine phase profiles, wherein each weighted affine phase profile comprises a real weight, a linear phase gradient and a phase offset, and corresponds to a spike in a Fourier domain; determining a modulation pattern, H, for display by a spatial light modulator using the initialised array, wherein the Fourier Transform of H, F(H), comprises multiple spikes; and displaying the modulation pattern using a spatial light modulator and an optical system.
  • the modulation pattern may be determined in many ways from the initialised array, depending on the properties of the final hologram and the spatial light modulator (SLM) used to display the CGH.
  • SLM spatial light modulator
  • Examples include encoding schemes involving quantising and optionally spatial filtering in an optical path after the SLM.
  • a non-exhaustive list includes a binary quantisation scheme, for instance when using a Digital Mirror Device (DMD), potentially in combination with a spatial filter as described in W02023/002175; amplitude-only schemes such as described in WO2023/180693, and phase-only schemes, such as Double Phase Amplitude Control, which is discussed on page 4 of WO2023/180693.
  • DMD Digital Mirror Device
  • amplitude-only schemes such as described in WO2023/180693
  • phase-only schemes such as Double Phase Amplitude Control, which is discussed on page 4 of WO2023/180693.
  • At least one of the plurality of weighted affine phase profiles has a non-zero phase offset. This may change the pattern of amplitude variation so that amplitude is less noticeable to a viewer.
  • the non-zero phase offset may be predetermined to reduce amplitude variation compared to the case where all of the plurality of weighted affine phase profiles have a zero phase offset.
  • At least two of the plurality of weighted affine phase profiles may have different real weights from each other. This may change the pattern of amplitude variation so that amplitude variation is less noticeable to a viewer.
  • the different real weights may be predetermined to reduce visible amplitude variation compared to the case where all of the plurality of weighted affine phase profiles have a same weight.
  • weighted affine phase profiles may be particularly advantageous when averaging over time, because two degrees of freedom may be exploited, namely the real weights and the phase offsets. These may (i) allow the position of amplitude peaks and troughs to be adjusted and/or (ii) reduce amplitude variation so that fewer time-sequential frames are required.
  • a set of initialised arrays When a set of initialised arrays is used, they may be formed from the same or different images for display; the amplitude variation introduced is independent of the image so the time-averaging works regardless of whether the image array is the same or different.
  • a same image array may be used for relatively slowly changing information (such as a vehicle heads up display) or relatively lower frame rate video or and different images may be used for relatively faster changing information and relatively higher frame rate video.
  • the respective initialising complex arrays may form a set of initialising complex arrays.
  • the set of initialising complex arrays may comprise at least two subsets of initialising complex arrays, where each subset comprises initialising complex arrays whose corresponding pluralities of spikes in the Fourier domain share geometric similarity. “Similarity” is used in its mathematical sense. In this way, each subset shares a distinct geometry.
  • At least one of the subsets may comprise at least two initialising complex arrays. By using at least two subsets, more time-averaged complex geometries can be implemented, while managing the complexity of the amplitude variation.
  • Examples of geometric similarities in the Fourier domain include: a square with vertices in the Fourier Domain made up of four spikes and four rotations; a fixed set of spikes in the Fourier Domain and cycling through different phase offsets; and a regular pentagon with vertices in the Fourier domain made up of five spikes and where the radius of the pentagon varies between frames.
  • a first initialising complex array from each subset may be used to determine a sequence of initialised arrays, followed by a second initialising complex array from each subset, and so on.
  • initialised arrays formed from the first complex initialising array in each subset may be displayed in sequence
  • initialised arrays formed from the second complex initialising array in each subset may then be displayed in sequence, and so on.
  • the method may comprise determining a plurality of initialised arrays for display sequentially in time, each initialised array determined using a respective initialising complex array, each respective initialising complex array (i) corresponding to a respective region of a Fourier plane and (ii) corresponding to a plurality of higher intensity spots in the respective region of the Fourier plane; and wherein the displaying comprises spatially filtering in a Fourier plane corresponding to the different respective regions.
  • the spikes in the Fourier domain result in the distribution of intensity in a Fourier plane being concentrated in multiple discrete spots of high intensity. These higher intensity spots generally correspond to spikes in the Fourier domain.
  • Fourier planes may be created within the optical system.
  • the initialised arrays may be formed from a same or different images.
  • a “region” of the Fourier plane as referred to here is a space containing a plurality of higher intensity spots, such as a filtered area of the Fourier plane.
  • Spatial filtering in a Fourier plane of an optical system is an effective way of reducing quantisation noise in some examples. By time multiplexing different regions of the Fourier plane in conjunction with the spatial filtering, a greater area of the Fourier plane can be used, increasing a visible eyebox.
  • the optical system may be configured such that a viewer’s pupil receives a plurality of spikes in the Fourier domain when viewing the image.
  • perceived defocus may be improved.
  • a viewer’s pupil can receive a plurality of spikes by positioning the spikes so that a viewer’s pupil receives more than one spike simultaneously, such as by using an optical system that forms a Fourier plane at or close to a viewer’s pupil and the spikes being positioned within the area of the viewer’s pupil.
  • the initialising complex array may comprise at least four weighted affine phase profiles, these then correspond to at least four spikes in the Fourier domain.
  • the number of weighted affine phase profiles (and hence the number of spikes in the Fourier domain) may be at least five, at least six, at least seven, at least eight or at least nine. Increasing the number of spikes increases the defocus benefits and may be particularly advantageous when combined with a substantially uniform distribution of the spikes.
  • the image array and the initialising complex array may have the same dimensions and the initialising may then comprise a pointwise multiplication of the image array by the initialising complex array.
  • the image array and the phase array have the same dimensions, they can be applied efficiently by pointwise multiplication.
  • techniques such as interpolation on the image array may be used to match their dimensions before the pointwise multiplication.
  • the method may be applied to a CGH display system comprising: an at least partially coherent illumination source; a spatial light modulator arranged to be illuminated by the at least partially coherent illumination source; an optical system for relaying an image formed by the spatial light modulator to a viewer; and a processor configured to control the spatial light modulator to display a computer generated hologram according to the method discussed above, with or without optional features also described.
  • the CGH display system may form part of a head-mounted display or a heads-up display in a vehicle.
  • Figure 1A shows a diagrammatic representation of the spatial filter of Figure 1 positioned substantially in a Fourier plane and the resulting spike locations in the filtered Fourier domain;
  • Figure 2 a diagrammatic representation of spike locations in a Fourier domain for use with the CGH display system of Figure 1;
  • Figure 3 shows a diagrammatic representation of an example amplitude pattern introduced by an initialising complex array corresponding to Figure 2;
  • Figure 4 shows a diagrammatic representation of sine waves and the magnitude of their sum corresponding to the amplitude pattern of Figure 3;
  • Figure 5 shows a diagrammatic representation of phase offset sine waves and the magnitude of their sum

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Holo Graphy (AREA)

Abstract

L'invention concerne un procédé permettant d'afficher un hologramme généré par ordinateur (CGH). Un réseau d'images destiné à être affiché sous forme de CGH est initialisé à l'aide d'un réseau complexe d'initialisation pour produire un réseau initialisé, le réseau complexe d'initialisation comprenant une somme d'une pluralité de profils de phase affines pondérés, chaque profil de phase affine pondéré comprenant un poids réel, un gradient de phase linéaire et un décalage de phase, et correspondant à un pic dans un domaine de Fourier. Un motif de modulation, H, destiné à être affiché par un modulateur spatial de lumière est déterminé à l'aide du réseau initialisé, la transformée de Fourier de H, F(H), comprenant de multiples pics. Le motif de modulation est affiché à l'aide d'un modulateur spatial de lumière et d'un système optique.
PCT/EP2025/050702 2024-01-12 2025-01-13 Procédé et système d'affichage Pending WO2025149675A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB2400478.0 2024-01-12
GB2400478.0A GB2638945A (en) 2024-01-12 2024-01-12 Method and display system

Publications (1)

Publication Number Publication Date
WO2025149675A1 true WO2025149675A1 (fr) 2025-07-17

Family

ID=89984048

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2025/050702 Pending WO2025149675A1 (fr) 2024-01-12 2025-01-13 Procédé et système d'affichage

Country Status (2)

Country Link
GB (1) GB2638945A (fr)
WO (1) WO2025149675A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180173082A1 (en) * 2015-06-23 2018-06-21 Nec Corporation Projection device, projection system, and interface apparatus
US20230026771A1 (en) * 2019-12-11 2023-01-26 Dolby Laboratories Licensing Corporation Projection system and method of driving a projection system
WO2023002175A1 (fr) 2021-07-21 2023-01-26 Vividq Limited Système d'affichage holographique et procédé de réduction des effets du bruit de quantification
WO2023180693A1 (fr) 2022-03-25 2023-09-28 Vividq Limited Affichages holographiques et procédés

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180173082A1 (en) * 2015-06-23 2018-06-21 Nec Corporation Projection device, projection system, and interface apparatus
US20230026771A1 (en) * 2019-12-11 2023-01-26 Dolby Laboratories Licensing Corporation Projection system and method of driving a projection system
WO2023002175A1 (fr) 2021-07-21 2023-01-26 Vividq Limited Système d'affichage holographique et procédé de réduction des effets du bruit de quantification
WO2023180693A1 (fr) 2022-03-25 2023-09-28 Vividq Limited Affichages holographiques et procédés

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
MADSEN ANDREAS ERIK GEJL ET AL: "Comparison of state-of-the-art Computer Generated Holography algorithms and a machine learning approach", OPTICS COMMUNICATIONS, ELSEVIER, AMSTERDAM, NL, vol. 505, 30 October 2021 (2021-10-30), XP086869052, ISSN: 0030-4018, [retrieved on 20211030], DOI: 10.1016/J.OPTCOM.2021.127590 *

Also Published As

Publication number Publication date
GB2638945A (en) 2025-09-10
GB202400478D0 (en) 2024-02-28

Similar Documents

Publication Publication Date Title
US20220357702A1 (en) Method of computing a hologram
EP3067754B1 (fr) Appareil et procédé d'affichage d'une image vidéo
KR101496799B1 (ko) 실시간 컬러 비디오 홀로그램 렌더링 및 생성 방법
JP5530927B2 (ja) ホログラフィック再構成装置
WO2009040570A1 (fr) Améliorations apportées ou associées à l'affichage d'une image holographique
WO2025149675A1 (fr) Procédé et système d'affichage

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 25701336

Country of ref document: EP

Kind code of ref document: A1