Large areas undistorted imaging apparatus for light speckles and method thereof

Abstract

The present invention relates to a large area undistorted imaging apparatus for light speckles and a method thereof. The large area undistorted imaging apparatus for light speckles comprises a light-emitting device, a light-limiting module, and a sensor. The light-limiting module is adapted in front of the sensor, and includes a plurality of light-limiting members. The light-limiting members are arranged in a one- or two-dimensional array. When the light-emitting device emits light to an object surface, one or more rays of scattered light are produced. By means of the light-limiting module, said one or more rays of scattered light are limited, and a plurality of rays of diffraction light is produced. The plurality of rays of diffraction light within a certain angular field of view produced by a light-limiting member interferes with each other and produces a plurality of undistorted light speckles, and forms an array of light-speckle images on the sensor. Finally, according to the array of light-speckle images, a large-area and undistorted light-speckle pattern is given. Because the light-speckle pattern is undistorted and records the three-dimensional characteristics of the object surface, the undistorted imaging apparatus can be applied to computer mice, finger guiders, smart cards, three-dimensional fingerprint identification apparatuses, a machine tool or precise manipulator positioning systems.