Patent ID: 8212794

Claim:
A user input device comprising: an optical element comprising a finger interface surface; a light source in optical communication with the finger interface surface and configured to provide light from the light source to the finger interface surface; a sensor array configured to detect light reflected from the finger interface surface in response to contact between a finger and the finger interface surface; a navigation engine coupled to the sensor array, the navigation engine configured to generate lateral movement information, which is indicative of lateral movement of the finger relative to the sensor array, in response to the detected light, wherein the lateral movement information comprises first and second orthogonal components; and a quantization engine coupled to the navigation engine, the quantization engine configured to compare the first orthogonal component to the second orthogonal component and to generate first and second quantized orthogonal components in response to the comparison; wherein the quantization engine is configured to compare the lateral movement information to a window and to generate movement information indicative of one-dimensional movement if the lateral movement information falls outside the window and to generate movement information that is indicative of no movement if the lateral movement information falls inside the window; wherein the window is defined by a linear function, wherein the linear function is defined as |DY|=M*|DX|+C, where |DY| is absolute y direction movement, |DX| is absolute x direction movement M is a gradient, and C is the y intercept, and wherein if |DY| is greater than or equal to M*|DX|+C then the x direction movement is reduced, if |DY| is less than M −1 *|DX|−C then the y direction movement is reduced, and if |DY| is less than or equal to M*|DX|+C and greater than M −1 *|DX|−C then both the x and y direction movement is reduced.