System and method for estimating target size

A method for estimating target size using scale space of pixel standard deviations (100) characterized by the steps of;

• receiving a pixel image including at least one target object and at least a coordinate of a pixel on a target (101),
• calculating pixel standard deviations for pixels lying within a rectangular window centred around the received pixel on the target, successively enlarging the window in at least one direction by its step-size, starting from an initial window size and obtaining at least one window size versus standard deviation graph, up to the desired window size (102),
• is the graph monotonically decreasing? (103),
• recording the window size at the point where the standard deviation first starts to decrease with increasing window size (104),
• is a previously recorded window size existent? (105),
• estimating the window size that encapsulates the whole target with minimum possible number of background pixels as the window size last recorded (106),
• is maximum iteration limit exceeded? (107),
• increasing the step-size and the initial window size, which is used to generate standard deviation graph by predetermined amounts (108),
• estimating the window size as the predetermined minimum window size (109).