A holographic display apparatus capable of providing an expanded viewing window and a display method are provided. The holographic display apparatus includes an image processor configured to provide computer generated hologram (CGH) data to a spatial light modulator, wherein the image processor is further configured to generate a hologram data array comprising information of the holographic image to be reproduced at the first resolution or a resolution less than the first resolution, perform an off-axis phase computation on the hologram data array at the second resolution, and then, generate the CHG data at the first resolution.

An all-optical hologram reconstruction system and method is disclosed that can instantly retrieve the image of an unknown object from its in-line hologram and eliminate twin-image artifacts without using a digital processor or a computer. Multiple transmissive diffractive layers are trained using deep learning so that the diffracted light from an arbitrary input hologram is processed all-optically to reconstruct the image of an unknown object at the speed of light propagation and without the need for any external power. This passive diffractive optical network, which successfully generalizes to reconstruct in-line holograms of unknown, new objects and exhibits improved diffraction efficiency as well as extended depth-of-field at the hologram recording distance. The system and method can find numerous applications in coherent imaging and holographic display-related applications owing to its major advantages in terms of image reconstruction speed and computer-free operation.

A method and apparatus for generating a hologram with a wide viewing angle is disclosed. The method includes generating a elemental complex hologram by applying oblique projection to three-dimensional (3D) information of an object based on a viewing direction, and generating a final hologram by superposing a plurality of elemental complex holograms generated based on different viewing directions.

A holographic display and a method, performed by the holographic display, of forming a holographic image are disclosed. The holographic display includes an electrically addressable spatial light modulator (EASLM); a diffractive optical element (DOE) mask array arranged on the EASLM; and a controller configured to operate the holographic display to form a hologram image, wherein the controller is further configured to address the EASLM to backlight the DOE mask array required to form a set of hologram image voxels by turning on a corresponding EASLM pixel.

A logic circuit that can output a stream of sequential values, representing pixel position values, for a pixelated display device such as a spatial light modulator. The logic circuit may comprise an advanced integrated circuit such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). The stream of sequential values that is output by the logic circuit can be used by another logic circuit to calculate corresponding values of a software function, for populating those pixels of the pixelated display device. The software function can be, for example, a lens function or a grating function, which might be combined with a hologram, such as a computer-generated hologram (CGH), for display on the pixelated display device.

A phase modulation structure includes a recording surface including phase angle recording regions in a plurality of calculated element regions corresponding to reconstruction points of an image on a one-to-one basis, each phase angle recording region being formed of a plurality of unit blocks in each of which a phase angle is recorded, the phase angle being calculated based on a phase that is a sum of a plurality of phases of light from the corresponding reconstruction points; and a representative area that is one of divisions of the calculated element region, the representative area being obtained by radially dividing the calculated element region centered on a point on the calculated element region, the point being obtained by extending a normal line from the corresponding reconstruction point to the calculated element region on the recording surface.

A head-up display is described. A spatial light modulator is arranged to display a diffractive pattern of first picture content and/or second picture content. A screen assembly has first and second diffusers arranged in a stepped configuration so that the first diffuser is spatially offset from the second diffuser by a perpendicular distance. A light source is arranged to illuminate the diffractive pattern such that the first picture content is formed on the first diffuser and/or the second picture content is formed on the second diffuser. An optical system comprising at least one optical element having optical power is arranged so that the first and second diffusers have different object distances to the optical system.

A holographic projector comprises an image processing engine, a hologram engine, a display engine and a light source. The image processing engine is arranged to receive a source image for projection and generate a plurality of secondary images from the source image. The source image comprises pixels. Each secondary image comprises fewer pixels than the source image. A first secondary image has more pixels that a second secondary image. The hologram engine is arranged to determine, such as calculate, a hologram corresponding to each secondary image to form a plurality of holograms. Thus, a first hologram corresponding to the first secondary image has more pixels than a second hologram corresponding to the second secondary image. The display engine is arranged to display each hologram in turn on the display device. The light source is arranged to Illuminate each hologram during display to form a holographic reconstruction corresponding to each secondary image on a replay plane.

Image persistence of the spatial light modulator is suppressed. A projection device (1) includes: an illumination optical system (12) that emits light; an information processing unit (20) that generates a hologram pattern based on an input image; a spatial light modulator (14) that forms the hologram pattern generated by the information processing unit and transmits light emitted by the illumination optical system; and a projection optical system (16) that projects an output of the spatial light modulator onto a projection surface and projects an output image, and the information processing unit generates the new hologram pattern obtained by shifting the hologram pattern in a predetermined direction for every predetermined frame.

A holographic system comprises an image processor, a hologram calculator and a display driver. The image processor is arranged to determine first and second secondary images by sampling the pixel values of a primary image at a regular array of sampling positions. The hologram calculator is arranged to determine a hologram of each secondary image. The display driver is arranged to display each hologram in rapid succession on a display device, first and second times, so as to reconstruct each secondary image from the respective hologram such that respective first and second arrays of image pixels corresponding to the primary image are perceivable. Image pixels of the reconstruction of the second secondary image are interposed between image pixels of the reconstruction of the first secondary image in the first direction.