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.