University of Rochester

Aptina Imaging Corporation

Micron Technology Incorporated

Wanli Chi

Nicholas A George

A novel phase-coded aperture, associated imaging system, and design method is disclosed. The optical imaging system includes a coded-aperture followed optically by a detector array and includes an image processor. A diffraction pattern in the form of a band-limited uniformly redundant array is formed on the detector array when focusable radiation from a point source in object space is modulation by the transmission function of the coded-aperture. Since diffraction effects cannot be ignored in the optical regime, an iterative phase retrieval method is used to calculate the phase-coded aperture transmission function. Correlation type processing can be applied for the image recovery.

Optical element, device, method, and applications

An extended depth of field is achieved by a computational imaging system that combines a multifocal imaging subsystem for producing a purposefully blurred intermediate image with a digital processing subsystem for producing a recovered image having an extended depth of field. The multifocal imaging system preferably exhibits spherical aberration as the dominant feature of the purposeful blur. A central obscuration of the multifocal imaging subsystem renders point-spread functions of object points more uniform over a range of object distances. An iterative digital deconvolution algorithm for converting the intermediate image into the recovered image contains a metric parameter that speeds convergence, avoids stagnations, and enhances image quality.

Extended depth of field using a multi-focal length lens with a controlled range of spherical aberration and a centrally obscured aperture

Apparatus and method for extended depth of field imaging

A system for imaging with a circularly symmetric multifocal aspheric lens is provided for obtaining an extended depth of field. The system includes a camera for capturing an image of at least one object through a circularly symmetric multifocal aspheric lens to provide a blurred image, and a computer system for processing the captured blurred image to provide a recovered image of the object having an extended depth of field. The recovered image may be outputted to a display or other peripheral device. Processing of the blurred image utilizes one of inverse filtering, convolution matrix (e.g., edge sharpening matrix), or maximum entropy. The computer system performing image processing may be in the camera or represent a computer system external to the camera which receives the blurred image. The extended depth of field is characterized by the object being in focus over a range of distances in the recovered image.

Imaging using a multifocal aspheric lens to obtain extended depth of field

An extended depth of field is achieved by a computational imaging system that combines a multifocal imaging subsystem for producing a purposefully blurred intermediate image with a digital processing subsystem for producing a recovered image having an extended depth of field. The multifocal imaging system exhibits spherical aberration as the dominant feature of the purposeful blur. In an aspect, a central obscuration of the multifocal imaging subsystem renders point-spread functions of object points more uniform over a range of object distances, however, the system may not include a centrally obscured aperture to achieve intended results. An iterative digital deconvolution algorithm for converting the intermediate image into the recovered image based on maximum entropy involves a metric parameter that speeds convergence, avoids stagnations, and enhances image quality.

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Rochester, NY, United States of America

Wanli Chi