Optical Touch Tomography

A method of resolving a multi-touch event occurring at a plurality of touch regions on a touch sensitive surface, the method comprising a computer processor executing the steps of:

• receiving a plurality of beam measurement values bn resulting from the multi-touch event, wherein different beam measurement values bn result from different optical beams transmitted across the touch sensitive surface and the multi-touch event disturbs optical beams in a vicinity of the touch region;
• determining binding value estimates p′i from the beam measurement values bn, the binding value estimates p′i estimating optical beam disturbance at corresponding locations Li of the touch-sensitive surface, wherein determining the binding value estimates p′i is based on modeling a transfer function from binding values pi to the beam measurement values bn as a linear transfer function;
• and
• determining the touch regions for the multi-touch event from the binding value estimates p′i.