DIGITAL IMAGE-PROCESSING AND ISOCLINICS

Isoclinics contain very important information about the direction of principal stresses. Unfortunately, it is frequently found that the isoclinics are vague or vanish altogether in certain regions of a plate. The isoclinic lines representing stress direction and the isochromatic lines representing stress magnitude are superimposed on each other. It is extremely difficult to separate them and to get isoclinics. In 1985, Zhang and Su introduced the TX-1 digital-image-processing system and sought new ideas to track isoclinics. In 1986, Yao developed a new image-division method (IDV) which is easy to apply in the digital image processing techniques to track isoclinics. This paper introduces other new methods: an image-differentiation method (IDF) and an image-division and differentiation method (IDD), and discusses some image-processing techniques. Experiments with a disk in diametral compression and with a slice from a three-dimensional frozen model are used to demonstrate such methods. © 1990 Society for Experimental Mechanics, Inc.