Biological Vision

About the Book

After applying the principles of visual science to military reconnaissance and intelligence for many years, the author has prepared a tutorial integrating the many fundamental mechanisms underlying the visual capability found in the animal kingdom. He shows that multicolor vision has been found in the animal kingdom from the beginning (for at least 500 million years) and that vision is generally tetrachromatic. He shows that human vision follows this general plan, although its spectral performance is partially blocked by the absorption inherent in the lens of the eye. As a result, the human can be considered a blocked tetrachromat; in the vernacular but unscientifi cally, a trichromat. He provides an extensive series of circuit diagrams, from those defi ning the electrical performance of individual neurons, synapses and Nodes of Ranvier to complete diagrams integrating all of the major visual circuits of the eyes and the brain. The fundamental mechanisms and physiology associated with the photoreceptor cell of the eye are developed in detail, including the precise chemical composition of the four chromophores of vision. The concept of an ion-pump is defi ned in terms of the underlying electrostenolytic process for the fi rst time. It is shown that glutamic acid (glutamate) is the primary energy source powering the neural systems of all animals. The key elements of the midbrain involved in reading are described for the fi rst time. The book closes with a variety of fi gures describing the spatial and chromatic performance of the human visual system. Additional fi gures, an extensive glossary, an expanded tabulation of the parameters of the human eye, and more than 1000 references are available at the associated website, www.4colorvision.com.

About the Author

James Fulton began his professional career in the late 1950's as an officer in the military-- supporting the Office of Special Projects under the Secretary of the Air Force. A very early task was to evaluate and compare the ultimate performance of television, photographic and human visual techniques as applied to high performance reconnaissance systems. This study clearly showed the superior performance of the eye in terms of ultimate sensitivity (quantum efficiency) but its limited signal amplification performance compared to the other systems. A quick series of projects implemented the same adaptation technique used in vision to the television cameras used in guided weapons such as the maverick. The use of this same technique led to the remarkable color-constancy achieved by the early vidicon-based color television cameras. This level of color constancy is again being sought in the non-vidicon commercial industry today.

To optimize a wide range of intelligence gathering equipment, understanding the photochemistry used in the visual process was important. This was successfully determined to be analogous to the photochemistry of color photographic film during the mid 1960's. The precise molecular structure of each chromophore was presented along with its unique liquid crystalline requirements.

Another critical task was the determination of the bandwidth and time delay found in the human visual system needed to optimize hand-eye coordination in the control of air-launched guided missiles.

The above studies led to a variety of military system implementations based on analogs of the biological visual system. A particularly interesting application was the emulation of the eye of a frog in a space-borne missile tracking system. Like the frog's eye, and the human eye in the absence of tremor, the sensor was blind to the scene presented to it except for targets that moved. This greatly simplified the data processing demanded of early (1970's) transistor-based computers.

Subsequently, the author patented one of the earliest examples of the two-dimensional retina used in current video cameras. This device incorporated many signal processing circuits found initially in the animal retina.

Recently, the author also patented the Activa, the man-made equivalent of the electrolytically-based amplifier found within each neuron of any neural system. This liquid-crystalline state semiconductor device is a direct analog of the man-made solid state semiconductor device known as a transistor.

The author held major engineering management positions within Grumman Aerospace Corporation and Hughes Aircraft Company. He was a Vice President of Hughes Optical Products, Inc. He retired from industry after leading the largest design and manufacturing operation in the world devoted to man-made retinas for the military. He is currently Director of Research for Vision Concepts of Corona Del Mar, California.

After applying the principles of visual science to military reconnaissance and intelligence for more than thirty years, the time came to reverse this process and describe the operation of the biological visual system for the unclassified community. This effort resulted in a very large and comprehensive work (2400 pages including more than 1000 figures), "Processes in Biological Vision," available at www.4colorvision.com. That work explores all aspects of vision in detail.

The size of the above work suggested that a more manageable introductory work was needed. The current work, "Biological Vision: A 21st Century Tutorial," is the outgrowth of that need.