Patent ID: 8902195

Claim:
An input panel for an interactive input system comprising: an optical waveguide; a first radiation source that is turned on and off, when on said first radiation source directing radiation into said optical waveguide, said radiation undergoing total internal reflection within said optical waveguide; a diffusion layer adjacent to and disposed on one major outer side of the optical waveguide, totally internally reflected radiation within said optical waveguide being frustrated and escaping the optical waveguide in response to one or more pointer contacts on the diffusion layer; at least one second radiation source that is turned on and off, when on said at least one second radiation source directing radiation towards an opposite major outer side of the optical waveguide; and at least one imaging device having a field of view looking at the opposite major outer side of the optical waveguide and capturing image frames, wherein during image frame capture operation, image frames are captured at least when (i) the first radiation source is on and the at least one second radiation source is off (ii) the first radiation source is off and the at least one second radiation source is on and (iii) the first radiation source is off and the at least one second radiation source off.