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Visual Communication: An Information Theory Approach presents an
entirely new look at the assessment and optimization of visual
communication channels, such as are employed for telephotography
and television. The electro-optical design of image gathering and
display devices, and the digital processing for image coding and
restoration, have remained independent disciplines which follow
distinctly separate traditions; yet the performance of visual
communication channels cannot be optimized just by cascading
image-gathering devices, image-coding processors, and
image-restoration algorithms as the three obligatory, but
independent, elements of a modern system. Instead, to produce the
best possible picture at the lowest data rate', it is necessary to
jointly optimize image gathering, coding, and restoration. Although
the mathematical development in Visual Communication: An
Information Theory Approach is firmly rooted in familiar concepts
of communication theory, it leads to formulations that are
significantly different from those that are found in the
traditional literature on either rate distortion theory or digital
image processing. For example, the Wiener filter, which is perhaps
the most common image restoration algorithm in the traditional
digital image processing literature, fails to fully account for the
constraints of image gathering and display. As demonstrated in the
book, digitally restored images improve in sharpness and clarity
when these constraints are properly accounted for. Visual
Communication: An Information Theory Approach is unique in its
extension of modern communication theory to the end-to-end
assessment of visual communication. from scene to observer. As
such, itties together the traditional textbook literature on
electro-optical design and digital image processing. This book
serves as an invaluable reference for image processing and
electro-optical system design professionals and may be used as a
text for advanced courses on the subject.
not a coincidence, but is the result of a carefully planned time of
landing (sun elevation) and lander orientation (sun azimuth). * The
picture was started 25 seconds after touchdown and took 15 seconds
to acquire. The alternating bright and dark vertical striations at
the left side of the image and the fine particles deposited on the
footpad at the right side were caused by a turbulent cloud of dust
raised by the lander's retrorockets. t *F. O. Huck and S. D. Wall,
"Image quality prediction: An aid to the Viking Lander imaging
investigation on Mars. " Appl. Opt. 15, 1748-1766 (1976). tT. A.
Mutch, A. B. Binder, F. O. Huck, E. C. Levinthal, S. Liebes, Jr.,
E. C. Morris, W. R. Patterson, J. B. Pollack, C. Sagan and G. R.
Taylor, "The Surface of Mars: The view from the Viking 1 Lander. "
Science 193, 791-801 (1976). VISUAL COMMUNICATION An Information
Theory Approach Chapter 1 Introduction 1. 1 OBJECTIVE l The
fundamental problem of communication, as Shannon stated it, is that
of reproducing at one point either exactly or approximately a
message selected at another point. In the classical model of
communication (Fig. 1. 1), the infor mation source selects a
desired message from a set of possible messages which the
transmitter changes into the signal that is actually sent over the
commu nication channel to the receiver. The receiver changes this
signal back into a message, and hands this message to the
destination."
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