Patent ID: 8259550
Filing Date: 2012-09-04
Classification: G11B

Abstract:
1. Method of applying image data as a visually detectable pattern with at least one embedded data element at an optical record carrier, comprising the step of physically mapping at least one channel symbol onto the record carrier, the channel symbol being selected from a set of mutually different channel symbols, the channel symbols each comprising an area of size s 1 with a relatively low value v 1 for an optical property and an area with size s 2 with a relatively high value v 2 for said optical property, the channel symbols being distributed over a plurality of subsets each having a plurality of channel symbols wherein the plurality of channel symbols within a subset have a distance that is substantially less than the distance between channel symbols of mutually different subsets, wherein the distance between two channel symbols is defined as the absolute difference between the ratios s 1 /(s 1 +s 2 ), wherein the step of selecting comprises a step of determining a subset on the basis of the image data to be mapped in the visually detectable pattern and selecting one symbol from that subset on the basis of the at least one data symbol to be mapped.