Abstract: Disclosed are method and apparatus for forming multiple images of an object comprising a plurality of depth segments. An optical system comprises an infinity optical subsystem and a multi-image optical subsystem. The infinity optical subsystem is configured to receive light from the object and form a first image focussed at infinity. A multi-image optical subsystem is configured to receive the first image and form multiple images via multiple focussing lenses. Each multiple image can correspond to a different depth segment. A portion of the light from the first image can also be filtered before entering a focussing lens. Multiple images under different filtering conditions, corresponding to different depth segments or to the same depth segment, can be formed.

Abstract: This invention provides a method for contactless fingerprint detection and verification comprising illuminating a fingerprint and directing a reflected light through an imaging system using liquid crystal panels and birefringent elements to polarize the light. A plurality of polarized images are captured and used to calculate the depth of structural features on the fingertip. A means to generate a two-dimensional rolled equivalent image of the fingerprint is also provided which may then be used for verification and authentication. The invention also provides an imaging system for carrying out the method.

Abstract: An optical gage (10) with a small field of view for three-dimensional surface profile measurement includes a projector (20) having a light source (22) and projection optics (28, 30, 42) that guide light along a projection light path. An optical grating device (34) is arranged in the projection light path and modifies the projection light distribution to project a structured light pattern (46). A phase shifting apparatus (47) shifts the structured light pattern to at least three positions with desired phase shift on said surface (80) to be measured. A viewer (50) includes viewing optics with a viewing light path that is non-parallel to the projection light path, a light sensing array (58) for sensing images of diffuse reflections of the structured light patterns from said surface, and a camera (57) for recording the images.

Abstract: Disclosed are method and apparatus for forming multiple images of an object comprising a plurality of depth segments. An optical system comprises an infinity optical subsystem and a multi-image optical subsystem. The infinity optical subsystem is configured to receive light from the object and form a first image focussed at infinity. A multi-image optical subsystem is configured to receive the first image and form multiple images via multiple focussing lenses. Each multiple image can correspond to a different depth segment. A portion of the light from the first image can also be filtered before entering a focussing lens. Multiple images under different filtering conditions, corresponding to different depth segments or to the same depth segment, can be formed.

Abstract: This invention provides a method for contactless fingerprint detection and verification comprising illuminating a fingerprint and directing a reflected light through an imaging system using liquid crystal panels and birefringent elements to polarize the light. A plurality of polarized images are captured and used to calculate the depth of structural features on the fingertip. A means to generate a two-dimensional rolled equivalent image of the fingerprint is also provided which may then be used for verification and authentication. The invention also provides an imaging system for carrying out the method.

Abstract: A profilometry apparatus is provided. The profilometry apparatus includes a fringe projection device configured to project a fringe pattern on an object and an optical unit configured to capture an image of a distorted fringe pattern modulated by the object. The profilometry apparatus also includes a signal processing unit configured to process the captured image from the optical unit to filter noise from the image and to obtain real-time estimation of parameters associated with manufacture or repair of the object.

Abstract: A method for generating a mask for use with a light measurement system that includes a light source for projecting light onto an object, and an imaging sensor for receiving light reflected from the object. The method includes determining a profile of the object to be inspected, and generating an electronic mask based on the determined object profile. The electronic mask has an electronic opening having a profile defined to substantially match the determined object profile as viewed from one of the light source and the imaging sensor.

Abstract: A profilometry apparatus is provided. The profilometry apparatus includes a fringe projection device configured to project a fringe pattern on an object and an optical unit configured to capture an image of a distorted fringe pattern modulated by the object. The profilometry apparatus also includes a signal processing unit configured to process the captured image from the optical unit to filter noise from the image and to obtain real-time estimation of parameters associated with manufacture or repair of the object.

Abstract: A method for inspecting an object using a structured light measurement system that includes a light source for projecting light onto a surface of the object and an imaging sensor for receiving light reflected from the object. The method includes determining a position of at least one of the light source and the imaging sensor with respect to the object based on at least one of a three-dimensional model of the object and a three-dimensional model of the structured light measurement system.

Abstract: An image processing method for structured light profiling includes sampling an image of a structured light pattern to obtain an intensity distribution, selecting a number of sets of sampled points from the intensity distribution. Each of the respective sets includes a number of sampled points. The image processing method further includes fitting each of the sets of sampled points to a respective distribution function and filtering the distribution functions to select a representative distribution function for the intensity distribution.

Abstract: A method for generating a mask for use with a light measurement system that includes a light source for projecting light onto an object, and an imaging sensor for receiving light reflected from the object. The method includes determining a profile of the object to be inspected, and generating an electronic mask based on the determined object profile. The electronic mask has an electronic opening having a profile defined to substantially match the determined object profile as viewed from one of the light source and the imaging sensor.

Abstract: A method for inspecting an object using a structured light measurement system that includes a light source for projecting light onto a surface of the object and an imaging sensor for receiving light reflected from the object. The method includes determining a position of at least one of the light source and the imaging sensor with respect to the object based on at least one of a three-dimensional model of the object and a three-dimensional model of the structured light measurement system.

Abstract: A method for inspecting an object using a structured light measurement system that includes a light source and an imaging sensor includes illuminating each of a plurality of different areas of the object with different wavelengths of light using the light source, filtering light reflected from the object into a first wavelength of the different wavelengths, and receiving the first wavelength of light reflected from the object with the imaging sensor.

Abstract: In accordance with one aspect of the present technique, a system for measuring a shape of an object is provided. The system comprises a projection system operable to project a fringe pattern having a reference mark onto the object. The system further comprises an image-processing system operable to capture an image of the fringe pattern modulated by the object. The image-processing system is further operable to identify the reference mark in the image of the fringe pattern to construct a shape of the object based on the reference mark.

Abstract: An image processing method for structured light profiling includes sampling an image of a structured light pattern to obtain an intensity distribution, selecting a number of sets of sampled points from the intensity distribution. Each of the respective sets includes a number of sampled points. The image processing method further includes fitting each of the sets of sampled points to a respective distribution function and filtering the distribution functions to select a representative distribution function for the intensity distribution.

Abstract: A three dimensional surface contouring and ranging system (10) based on a digital fringe projection (18) and phase shifting technique is disclosed. In the system, three phase-shifted fringe patterns and an absolute phase mark pattern are used to determine the absolute phase map of the object (12). The phase map is then converted to the absolute x, y, and z coordinates of the object surface by a transformation algorithm. A calibration procedure is used to determine accurate values of system parameters required by the transformation algorithm. The parameters are initially indirectly measured through experiments to determine their approximate values. A calibration plate is then measured by the system at various positions. An iteration algorithm is then used to estimate the system parameters.