US Patent 9053381 Interaction system and motion detection method

A motion detection method applied in an interaction system is provided. The method has the following steps of: retrieving a plurality of images; recognizing a target object from the retrieved images; calculating a first integral value of a position offset value of the target object along a first direction from the retrieved images; determining whether the calculated first integral value is larger than a first predetermined threshold value; and determining the target object as moving when the calculated first integral value is larger than the first predetermined threshold value.