Patent ID: 7528848

Claim:
A method for decoding an embedded interaction code (EIC) pattern on a liquid crystal display (LCD), the method comprising steps of: receiving a captured image; processing the captured image to output an extracted bit stream; and decoding position data from the extracted bit stream; determining a position of the captured image with respect to a screen of the LCD based upon the decoded position data; wherein the step of processing includes steps of, preprocessing the captured image to determine pixels corresponding to LCD pixel grids associated with the EIC pattern; defining the LCD pixel grids based upon the pixels; recognizing the EIC pattern from the LCD pixel grids; extracting a bit stream of EIC bits based upon the recognized EIC pattern to obtain the extracted bit stream; wherein the step of preprocessing includes steps of, separating pixels that lie on edges and vertexes of the LCD pixel grids as a first mask; binary eroding the first mask to obtain a second mask, the second mask including fewer pixels than the first mask; separating connected regions of the second mask in accordance with a first threshold to obtain a third mask and a fourth mask; binary eroding the fourth mask to obtain a fifth mask; defining a second threshold corresponding to a region of the fifth mask; defining a sixth mask as pixels that belong to the regions of the fifth mask; and merging the third and the sixth masks to define the LCD pixel grids.