Programmable lens assemblies and optical systems incorporating them
AssigneeQinetiq Limited
InventorBrian S Lowans
Life of this patent
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Abstract
An imaging system (10) has a fixed lens combination (22), a spatial light modulator (SLM) (20) and a linear detector array (12). A scene image is scanned across a simple array (12) in a direction perpendicular to the array (12) by the SLM (20). This is achieved by displaying a diffraction pattern on the SLM that changes to achieve the scanning. The diffraction pattern displayed typically has a linear element (40) and a quadratic element (42). By having a programmably changed combined chirp pattern (36) displayed on the SLM, and by being able to change it thousands of times a second, an army with fast read out can take the place of a 2-D imaging array.
Claims14
An optical assembly for observing a scene comprising an optical input to the assembly, said assembly comprising:
- a spatial light modulator (SLM),
- a controller controlling the display of the SLM, and
- a detector;
- wherein the controller modifies a pattern displayed on the SLM to sequentially scan radiation from said observed scene across the detector, said radiation scanned from a plurality of different angular regions or depth regions in 3-D space of the scene or a surface region through the 3-D space that the optical assembly is observing, wherein the pattern displayed on the SLM has a component comprised of a substantially linear diffraction grating pattern and a component comprised of a substantially chirp function.
A method of directing a scene image onto a detector comprising using a programmed SLM controlled by a controller to control the x-y part of the scene image that is directed onto the detector and/or the imaged plane of the scene in the z direction that is in focus, the direction between the scene and the detector being in the z direction, in which the display on the SLM is programmably controlled by a controller by application of a chirp and/or a linear grating to the SLM so as to scan the scene image over the detector over time, with the controller taking time-spaced records of what the detector detects.
Dependencies are inferred from the claim text.