Abstract: A method of generating a computer-generated hologram from a three-dimensional image comprising a plurality of two-dimensional image layers is provided. The method comprises generating hologram data for each layer of the image, and updating the hologram data of at least one layer of the image based on the hologram data of the other layers of the image.

Abstract: A holographic image display system comprising a processor receiving image data at an input and producing output hologram data based on the image data. The image data comprises three-dimensional image data that is separable into a plurality of two-dimensional image layers at different image planes. The processor is configured to: a) perform a space-frequency transform on each image layer to provide a transformed image layer, b) apply a focus factor to each transformed image layer, c) apply a pseudo-random phase factor to each transformed image layer, and d) sum the transformed image layers to form a holographic sub-frame, e) repeat steps (c) and (d) for a plurality of iterations, applying a different pseudo-random phase factor to the transformed image layers in each iteration to form a plurality of holographic sub-frames; and f) drive a spatial light modulator with the holographic sub-frames in rapid temporal succession to generate a holographic image.

Abstract: A method for adjusting the apparent brightness of a computer-generated hologram display is disclosed. The method comprises: receiving source data representative of a scene to be displayed as a hologram; determining hologram data to display a computer-generated hologram representing the scene; determining a scene energy based on the source data, the scene energy being quantised using a scale which is non-linear and which has a closer spacing between values in a mid-section of the scale than between values towards a minimum and a maximum of the scale; associating the scene energy with the hologram data; controlling a holographic display according to the hologram data and simultaneously controlling an output power of an illumination source of the holographic display according to the scene energy. A holographic display apparatus implementing the method is also disclosed.

Abstract: A holographic display comprises: an illumination source which is at least partially coherent; a plurality of display elements positioned to receive light from the illumination source and spaced apart from each other, each display element comprising a group of at least two sub-elements; and a modulation system associated with each display element and configured to modulate at least a phase of each of the plurality of sub-elements.

Abstract: An optical assembly is provided for use in holographic display of a replay image. The optical assembly may be of particular use is an augmented reality headset. The optical assembly includes a light-modulation element arranged to be illuminated off-axis by a light beam. The light-modulation element modulates the incident light to generate a replay image and generates a zero-order light beam. A focusing system is arranged after the light-modulation element. A light remover is positioned after the focussing system and is configured to remove the zero-order light beam from the light focussed by the focussing system. The focussing system is configured to focus zero-order light from the light-modulation element in a first plane different from a second plane which is the plane of focus of parallel light of the replay image. The light remover removes the zero-order light in the first plane.

Abstract: A holographic image display system comprising a processor receiving image data at an input and producing output hologram data based on the image data. The image data comprises three-dimensional image data that is separable into a plurality of two-dimensional image layers at different image planes. The processor is configured to: a) perform a space-frequency transform on each image layer to provide a transformed image layer, b) apply a focus factor to each transformed image layer, c) apply a pseudo-random phase factor to each transformed image layer, and d) sum the transformed image layers to form a holographic sub-frame, e) repeat steps (c) and (d) for a plurality of iterations, applying a different pseudo-random phase factor to the transformed image layers in each iteration to form a plurality of holographic sub-frames; and f) drive a spatial light modulator with the holographic sub-frames in rapid temporal succession to generate a holographic image.