William D. McFarland

Computerized 3-dimensional analysis of mitochondrial structure

A computer program has been written to calculate surface area and volume of subcellular organelles. Sophisticated and extremely accurate point sampling routines and volume computational techniques have been developed. This program has been used to study mitochondrial 3-dimensional structure when stereological estimates have proven inadequate.

Computer processing of CT images: advances and prospects

Computerized tomography (CT) images are created by computer and as such are inherently amenable to computer image processing techniques. Advances have been made in the areas of alternative visualization (coronal views, etc.), image enhancement, feature extraction, and computer analysis of the extracted information. Further advances await imaginative application of these techniques and time; others will depend upon necessary advances in image processing methods.

Computer Analysis Of Radiographic Images

The significant steps in computer anal-ysis of radiographic images are 1) digitization of the x-ray image; 2) preprocessing of digital images; 3) extraction of significant features; and 4) automatic classification for normal, abnormal, and differential diagnosis. A typical digital image processing facility is described, including the needed interactive type digital displays. Techniques used for preprocessing radio-graphic images are detailed; typically, these are used to ensure a higher degree of success in the later stages of digital processing. Contour tracing and region enumeration algorithms are detailed for use in the com-puter analysis of radiographs. The important descriptive approach to the problem of feature extraction is provided along with illustrative examples. A case study of rheumatic and congenital heart disease is presented for the cardiac shape analysis of PA chest films.

Automated Chest X-Ray Analysis

A brief review of the development of computer analysis of chest X-rays at the University of Missouri - Columbia is given. Chest analysis by computer has developed from cardiac silhouette shape and size analysis to lung field analysis in the form of image texture algorithms. The overriding problem is the variability in the normal human anatomy, especially as it is presented in radiographs. A major effort has been made to produce and verify valid data bases of substantial size. The diagnostic effectiveness of digital image analysis algorithms has been the utmost concern. Success has been achieved on a small scale relative to the total area of automated chest X-ray analysis.

A Microprocessor Based Interactive Radiographic Image Display

A microprocessor controlled digital image display has been designed and constructed in the Bioengineering/Advanced Automation Program at the University of Missouri-Columbia. The unit has under gone clinical evaluation in the Department of Radiology, University of Missouri Medical Center. The application of a microprocessor in this instance replaced special purpose display hardware and afforded a high degree of flexibility. Modular design of the display system has allowed expansion and flexibility over the past two years as requirements are modified. The system has been expanded from an original fixed display device to a flexible general purpose microcomputer for diagnostic radiologic experiments.

A System For Graphical Image Analysis

A system to perform digital analysis of graphical images has been developed and utilized in the analysis of six channel strip chart recordings over the past three years. Silicon linear photo-diode arrays were employed as the image digitizer, simplifying preprocessing techniques in the scanner. The scanner consists of control and logic electronics, light source, lenses, paper transport mechanism and six 128 x 1 photo-diode integrated circuit arrays. The graphics scanner is interfaced to a minicomputer system which includes display, storage, and analysis capabilities. The scanners preprocessing includes threshold detection of edges and removal of reference grid lines from the digitized image. This system has been used to perform statistical analysis on wideband communications data as recorded on six channel strip chart recordings by the United States Air Force Communications Service at Richards-Gebaur Air Force Base. Several thousand meters of strip chart have been analyzed over the past three years, successfully demonstrating the utilization of solid state scanners and computerized analysis of graphical data.

An Interactive Digital Image Processing System

A mini-computer system has been implemented to perform interactive image processing. The computer system presents an in-tegrated modular approach to hardware development as well as software development. Digitally controlled scanners are interfaced with the system and are treated as extensions of core memory. This technique alleviates a mmajor constraint on the total amount of core memory that may be required for image processing. Scanning and processing may be accomplished simultaneously on a line-by-line basis. An image dissector scanner is the primary digitizer at this time. Several displays are interfaced to the mini-computer for on-line image output. Program, or algorithm, analysis is provided by image displays at various stages of the processing. A high contrast interactive Digital Disc Display serves as the primary image out-put at this time. Applications of the system include on-line analysis of chest radiographs for the detection of heart disease, feasible detection of increased or decreased vascularity in the lung fields, and automatic area measurements on cells from pathological slides.