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Realizations of focus invariance in optical-digital systems with wave-front coding.

S Bradburn, W T Cathey, E R Dowski

|February 12, 2008

Summary

This study experimentally verifies an extended depth of focus (EDF) optical system. The system uses a cubic phase plate and digital processing to achieve in-focus images with near-diffraction-limited performance.

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Area of Science:

Optical Engineering
Image Processing
Diffractive Optics

Background:

Extended Depth of Focus (EDF) systems aim to increase the range of distances in focus within an optical system.
Previous theoretical work by Dowski and Cathey described EDF systems using cubic phase plates.

Purpose of the Study:

To provide the first experimental verification of an extended depth of focus (EDF) system.
To demonstrate near-diffraction-limited performance of the proposed EDF system.

Main Methods:

Modification of a standard incoherent optical system using a cubic phase plate at the aperture stop.
Digital signal processing to decode the wavefront-coded image and reconstruct a sharp, in-focus image.

Main Results:

Successful experimental demonstration of the EDF system's capability.
Production of multiple in-focus images from various optical setups using the phase plate.
Achieved near-diffraction-limited performance.

Conclusions:

The experimental verification confirms the viability of the cubic phase plate-based EDF system.
The integration of optical modification and digital processing effectively enhances image focus.
This EDF system shows significant promise for applications requiring extended imaging ranges.