Title

An entropy based adaptive image encoding technique

Keywords

Entropy (Information theory), Image compression, Image processing -- Digital techniques

Abstract

Many image encoders exist that reduce the amount of information that needs to be transmitted or stored on disk. Reduction of information reduces the transmission rate but compromises i~age quality. The encoders that have the best compression ratios often lose image quality by distorting the high frequency portions of the image. Other encoders have slow algorithms that will not work in real time. Encoders that use quantizers often exhibit a gray scale contouring effect due to insufficient quantizer levels. This paper presents a fast encoding algorithm that reduces the number of quantizer levels without introducing an error large enough to cause gray scale contouring. The new algorithm uses entropy to determine the most advantageous difference mapping technique and the number of bits per pixel used to encode the image. The double Difference values are reduced in magnitude such that an eight level power series quantizer can be used without introducing an error large enough to cause gray scale contouring. The one dimensional application of the algorithm results in 3.0 bits per pixel with a RMS error of 4.2 gray scale values. Applied two dimensionally, the algorithm reduces the image to 1.5 bits per pixel with a RMS error of 6.7 gray scale values.

Notes

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Graduation Date

1990

Semester

Fall

Advisor

Alsaka, Yacoub A.

Degree

Master of Science (M.S.)

College

College of Engineering

Department

Electrical Engineering

Format

PDF

Pages

139 p.

Language

English

Length of Campus-only Access

None

Access Status

Masters Thesis (Open Access)

Identifier

DP0027334

Subjects

Dissertations, Academic -- Engineering; Engineering -- Dissertations, Academic

Accessibility Status

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