1. An object analyzation method of an optical touch system, comprising: capturing a first image across a touch surface of a panel with an image sensing apparatus, wherein the first image has an object image formed therein corresponding to the position of a pointer on the touch surface; defining an image window corresponding to the object image in the first image; and determining whether the pointer is touching the touch surface or hovering over the touch surface according to the brightness difference among a plurality of pixels in the image window.