The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 22, 1999
Filed:
Jun. 05, 1996
Zetetic Institute, Tucson, AZ (US);
Abstract
A method and apparatus for discriminating an in-focus image from an out-of-focus image which may be implemented in accordance with either or both an illumination procedure and a signal detection procedure includes collimating light rays emanating from a point in an object plane in an object to produce collimated rays. The collimated rays are focused onto a spot in an in-focus image plane. Light impinging on the spot is detected to measure the intensity thereof. The phase of a first portion of the collimated rays is shifted to produce a first quantity of phase-shifted rays, and the phase of a second portion of the collimated rays also is shifted to produce a second quantity of phase-shifted rays. The first and second quantities of phase-shifted rays are focused onto the spot. Light including the remaining non-phase-shifted rays and the first and second quantities of phase-shifted rays impinging on the spot is detected to measure the intensity thereof. The intensities measured for the remaining non-phase-shifted rays and the first and second quantities of phase-shifted rays are subtracted from the intensities measured for the rays focused on the spot in the in-focus image plane to cancel the effects of light from the out-of-focus image impinging on the spot to obtain an accurate representation of the object at the point in the object plane.