We report experimental verification of an extended depth of focus (EDF) system with near-diffraction-limited performance capabilities. Dowski and Cathey [Appl. Opt. 34, 1859–1866 (1995)] described the theory of this system in detail. We can create an EDF system by modifying a standard incoherent optical system with a special cubic phase plate placed at the aperture stop. We briefly review the theory and present the first optical experimental verification of this EDF system. The phase plate codes the wave front, producing a modified optical transfer function. Once the image is transformed into digital form, a signal-processing step decodes the image and produces the final in-focus image. We have produced a number of images from various optical systems using the phase plate, thus demonstrating the success of this EDF system.
© 1997 Optical Society of America
Original Manuscript: March 26, 1997
Revised Manuscript: July 15, 1997
Published: December 10, 1997
Sara Bradburn, Wade Thomas Cathey, and Edward R. Dowski, "Realizations of focus invariance in optical–digital systems with wave-front coding," Appl. Opt. 36, 9157-9166 (1997)