1. A method of detecting and tracking multiple targets within a surveillance zone with multiple cameras, comprising the steps of: (a) analyzing a detection result of a plurality of camera views using a target detection algorithm to generate a plurality of analysis data; (b) integrating the analysis data with a Baysian framework to create a target detection probability (TDP) distribution; and (c) simultaneously and automatically detecting and tracking a plurality of moving targets in the camera views within the surveillance zone, wherein the surveillance zone is determined by overlapping fields of view of all of the multiple cameras, and wherein the TDP distribution in the step (b) equals to a sum of a probability, G 1 (X), making a newly appearing target to be detected easily and a probability, G 2 (X), providing temporal information in the time domain between successive frames, and X is a location on a ground plane.