Patent ID: 8279179

Claim:
A data input system comprising: an encoded pad having position encoding; and a data input device adapted to image a portion of said encoded pad to determine position and orientation of said data input device relative to said encoded pad; wherein the encoded pad further comprises: a linear variation of a first reflectance along a first axis of the encoded pad, the linear variation of the first reflectance material being formed in accordance to positional information in the first axis of the encoded pad; and a linear variation of a second reflectance along a second axis of the encoded pad, the linear variation of the second reflectance material being formed in accordance to positional information in the second axis of the encoded pad wherein each of the first and second reflectances is a wavelength dependent reflectance; a third reflectance uniformly distributed on the encoding pad, wherein position of the input device is computed through the ratio of the first reflectance to the third reflectance, and the ratio of the second reflectance to the third reflectance.