Determination of size / scale and orientation of a pointer on a touch system based on a camera.

A touch system (50) comprising: at least two optical devices (630-633) associated with a touch surface (60); said optical devices (630-633), at least two, are aimed at acquiring images of said touch surface (60) of different locations and with overlapping fields of view; characterized in that said touch system (50) further comprises a processing circuitry (84,54) for processing image data acquired by said optical recording devices, at least two, (630-633), to detect edges of a pointer in said images and to triangulate the detected edges to determine a bounding area defining a pointer perimeter.