Document Type

Thesis

Date of Award

5-31-1983

Degree Name

Master of Science in Electrical Engineering - (M.S.)

Department

Electrical Engineering

First Advisor

Andrew Ulrich Meyer

Second Advisor

Arthur B. Ritter

Abstract

A system was constructed which allows direct observation of the coronary microcirculation of the beating rat heart. An EKG triggered strobe is used on the microscope light source to "stop" the action of the beating heart so the surface microvessels can be observed di rectly under the microscope. Experimental results are recorded on videotape and played back for frame-by-frame analysis of the data using digital Image processing techniques such as digital filtering, image extraction, image enhancement and edge detection.

The application of image enhancement techniques (high order and low order enhancement methods ) as well as edge detection using a Kirsch operator fails for pictures in which graycolour differences between adjacent pixels are less than thirty ( on a scale from 0 to 255 ). In that case, either not se will be enhanced by the Laplacian and produce a "salt and pepper" picture (alternating light and dark spots) or the narrow greycolour ranges will cause the edges of any objects present to be smoothed out by the high order enhancement methods. For pictures with narrow graycolour histograms better contrast is achieved by first expanding the narrow range into 10 subranges and transforming the subranges into the full 0 to 255 graycolour range using thresholding. Objects and their boundaries can then be enhanced and detected using the enhancement methods coupled with edge detection. For picture images with graycolour differences between adjacent pixels are greater than thirty, the enhancement methods and edge detection algorithms are powerful techniques for removing noise, increasing contrast and detecting object boundaries within the video image.

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