Abstract: An optical system (100) comprises a coherent light source (101) and optical elements for directing light from the source to a target (1001). The optical elements include at least one diffusing element (141, 161) arranged to reduce a coherence volume of light from the source and a variable optical property element (151). A control system (1021) controls the variable optical property element such that different speckle patterns are formed over time at the target (1001) with a temporal frequency greater than a temporal resolution of an illumination sensor or an eye (1011) of an observer so that speckle contrast ratio in the observed illumination is reduced. The variable optical property element (151) may be a deformable mirror with a vibrating thin plate or film.

Abstract: An optical system (100) comprises a coherent light source (101) and optical elements for directing light from the source to a target (1001). The optical elements include at least one diffusing element (141, 161) arranged to reduce a coherence volume of light from the source and a variable optical property element (151). A control system (1021) controls the variable optical property element such that different speckle patterns are formed over time at the target (1001) with a temporal frequency greater than a temporal resolution of an illumination sensor or an eye (1011) of an observer so that speckle contrast ratio in the observed illumination is reduced. The variable optical property element (151) may be a deformable mirror with a vibrating thin plate or film.

Abstract: A system and method for generating forensically marking image data from source material. A generated forensic mark will vary from copy to copy by using a selected forensic marking technique and forensic marking parameters that change from copy to copy of the source image data.

Abstract: A display device (1) has a photon source (20) that displays an image scene in which the user perceives points at differents distances, resulting in optical stimulation of the eye's accommodative response. This is achieved by an intermediate optical system (21) forming the photons into pencils and a variable power optical system (22) positioned for convergence of the pencils. A control system (8) controls the variable power optical system (22) to modulate photon wavefront curvature according to image pixel co-ordinate and intensity data and data representing required perceived pixel distance.

Abstract: A display device (1) has a photon source (20) that displays an image scene in which the user perceives points at differents distances, resulting in optical stimulation of the eye's accommodative response. This is achieved by an intermediate optical system (21) forming the photons into pencils and a variable power optical system (22) positioned for convergence of the pencils. A control system (8) controls the variable power optical system (22) to modulate photon wavefront curvature according to image pixel co-ordinate and intensity data and data representing required perceived pixel distance.

Abstract: A display device (1) has a photon source (20) that displays an image scene in which the user perceives points at differents distances, resulting in optical stimulation of the eye's accommodative response. This is achieved by an intermediate optical system (21) forming the photons into pencils and a variable power optical system (22) positioned for convergence of the pencils. A control system (8) controls the variable power optical system (22) to modulate photon wavefront curvature according to image pixel co-ordinate and intensity data and data representing required perceived pixel distance.

Abstract: A display device (1) has a photon source (20) that displays an image scene in which the user perceives points at differents distances, resulting in optical stimulation of the eye's accommodative response. This is achieved by an intermediate optical system (21) forming the photons into pencils and a variable power optical system (22) positioned for convergence of the pencils. A control system (8) controls the variable power optical system (22) to modulate photon wavefront curvature according to image pixel co-ordinate and intensity data and data representing required perceived pixel distance.