I. Introduction
Automatic detection of man-made objects in natural scenery from infrared images is an important and potential area in pattern based image analysis. The main difficulties are: 1) there is sometimes no significant difference between man-made object and its surroundings in thermal contrast; 2) infrared images usually have a high noise level and a low signal to noise ratio ; and 3) for small man-made objects, there is no geometric, spatial distribution, and statistical information to make use of [1]. Since fractal geometry was introduced by Mandelbrot to describe highly complex objects and natural scenery [2], it has been applied to detect man-made objects from complex natural scenery [3]–[6].