The marriage of optics and electronics has recently produced another breakthrough that would have been hard to believe just a few years ago--a lens with enormously enhanced depth of field. 

Anyone who has used a camera or an optical microscope is familiar with the concept of depth of field:  When you focus your camera on a object in the foreground, objects in the background are out of focus. When you focus on the background, objects in the foreground become blurry. You can extend the depth of field by reducing the aperture (lens opening), but this means that less light reaches the film and you either need a longer exposure time or a more sensitive film.

A team of researchers from the University of Colorado at Boulder has developed a system, called "wavefront coding," that can take an image and process it electronically (using ideas borrowed from radar technology), thereby increasing its depth of field by a factor of ten.  (Some wonderful examples can be found on the University's web site.) The team recently formed a company--CDM Optics, Inc.--to commercialize the technology. They have concluded a licensing agreement with Carl Zeiss, the German microscope manufacturer, who will produce extended depth of field microscopes using wavefront coding.  Other potential applications include robots, medical equipment, extremely small cameras for consumer products (including mobile phones) that could focus without moving parts, and much more. 

Links:
= highly recommended

CDM Optics, Inc. web site.  Includes a tutorial on how wavefront coding works, examples of applications, images produced with and without wavefront coding, and information on the company that is pioneering this technology.

"A Whole New Way of Seeing Things," by Erick Schonfeld (Futureboy), Business2.0 (January 11, 2002). "Engineers at a tiny tech firm in Colorado have developed a lens that could revolutionize the science of optics."

"Technology Corner:  Wavefront Coding," an early article on the subject (February 1995) from Vexcel Corporation, a Boulder, CO, firm specializing in remote sensing technologies.

"Image Processing Key to Camera Design," by Ed Dowski, Vice President, CDM Optics Inc., EE Times (November 15, 1999).  An article by a member of the team that developed wavefront coding describes its application to disposable cameras for the consumer market.

"Marrying Optics and Electronics," by Edward Dowski, Jr., and Greg Johnson, CDM Optics, Inc., OE Magazine, January 2001.  Describes how wavefront coding systems work in fairly technical terms.

"Extended Depth of Field Through Wavefront Coding," an early (1995) paper by Edward R. Dowski, Jr. and W. Thomas Cathey, then at the University of Colorado's Imaging Systems Laboratory (Boulder).

"Depth of Field/Depth of Focus vs. F/# Trade-Off," from the Imaging Systems Laboratory at the University of Colorado-Boulder.  Images showing the effects of wavefront coding. Other interesting images can be found on this page.

Center for Adaptive Optics, a science and technology center funded by the US National Science Foundation and located in Santa Cruz, California.  Adaptive optics compensates for the blurring effects caused by changing distortion in optical systems (e.g., the motion of the atmosphere that makes stars twinkle and drives ground-based astronomers crazy) providing much clearer images than otherwise possible.  See the picture gallery for some examples.

SPIE--the International Society for Optical Engineering.  The professional organization for researchers in optics, photonics, and imaging.