A system and method for sensing phase errors in a multiple receiver array use three non-collinear transmitters transmitting first, second, and third signals to a target and receiving corresponding signals reflected from the target using the multiple receiver array. In one embodiment, each transmitter transmits a characteristic signal which can be distinguished from each other by the receivers. In one embodiment, each transmitter transmits a slightly different monotone frequency that is preferably outside any imaging bandwidth. The sheared products computed from heterodyne measurements at the receivers in the array based on the reflected signals from the three transmitters are used to determine and correct for the combined transmitter/receiver phase errors at each of the receivers in the array.
Structured Illumination For Imaging Of Stationary And Non-Stationary, Fluorescent And Non-Fluorescent, Objects
Sapna Shroff - Rochester NY, US David R. Williams - Rochester NY, US James Fienup - Rochester NY, US
Assignee:
University of Rochester - Rochester NY
International Classification:
H04N 5/222
US Classification:
348370
Abstract:
An object to be imaged is illuminated with a structured (e. g. , sinusoidal) illumination at a plurality of phase shifts to allow lateral superresolution and axial sectioning in images. When an object is to be imaged in vitro or in another situation in which the phase shifts cannot be accurately determined a priori, the images are taken, and the phase shifts are estimated a posteriori from peaks in the Fourier transforms. The technique is extended to the imaging of fluorescent and non-fluorescent objects as well as stationary and non-stationary objects.
Optical System Design Techniques Using Holographic Optical Element
Environmental Research Institute of Michigan - Ann Arbor MI
International Classification:
G03H 108
US Classification:
350320
Abstract:
The merit function of an optical system employing a holographic optical element (HOE) is optimized by determining the ideal phase transfer functions of the hologram over a set of field angles and then arriving at the phase transfer function of the hologram by averaging over the ideal phase transfer functions.
Method And Article Having Predetermined Net Reflectance Characteristics
Environmental Research Institute of Michigan - Ann Arbor MI
International Classification:
G02B 532
US Classification:
350 37
Abstract:
An optically transmissive article having predetermined net reflectance characteristics and a method of forming such an article is disclosed. The article includes a holographic layer with fringe patterns generally paralleling a major surface of the article. The fringe patterns have been formed in such a way that the amplitude and phase of the light diffracted therefrom is in a predetermined relationship with the amplitude and phase of the reflected light. The relationship between the respective amplitudes and phases of the diffracted and reflected light determines the net reflectance characteristics of the article. In a preferred embodiment, the hologram is formed such that the diffracted light has the same amplitude but is 180. degree. out of phase with the reflected light so as to provide an antireflective coating for the article. In the method of making the article, the phase of one of the beams utilized in the formation of the hologram is adjusted until the desired net reflectance characteristics are detected.