Portable optical touch system

A portable optical touch system, comprising:

• a first image sensing module comprises a first housing and a first image sensor disposed in the first housing;
• a second image sensing module comprises a second housing and a second image sensor disposed in the second housing, wherein a field of view of the first image sensing module and a field of view of the second image sensing module are partially overlapped and the partially overlapped field of views is for defining a touch region;
• a length-adjustable connecting device connecting the first image sensing module and the second image sensing module, wherein the length-adjustable connecting device adjust a distance between the first image sensing module and the second image sensing module;
• a communication interface;
• and
• a processing circuit, coupled to the first and the second image sensing module, for calculating a position of an object in the touch region according to images of the object acquired by the first image sensing module and the second image sensing module, and for outputting information of the position through the communication interface;
• wherein the first housing comprise a first body and a second body, the second body is configured to connect to the length-adjustable connecting device, and the second body rotates relative to the first body to form a first predetermined included angle between an image sensing surface of the first image sensor and a bottom surface of the first housing, and a second predetermined included angle between an image sensing surface of the second image sensor and a bottom surface of the second housing.