Patent ID: 7542584

Claim:
An image processing method comprising: dividing digital content into run-lengths each including one or more consecutive pixels having an identical color using a processor; dividing the digital content into blocks using the processor; realizing a unique topology preserving function for each of the blocks, wherein the unique topology preserving function prohibits a run-length from being divided, prohibits the formation of a nested run-length, and prohibits the deletion of a run-length; and embedding digital watermark information in adjacent run-lengths of the digital content by changing the run-lengths, while saving topology according to a first topology preservation law and a fourth topology preservation law using the processor, said adjacent run-lengths being stacked on one another, said digital watermark information being expressed by one of an odd-numbered value and an even-numbered value of each of the run-lengths, wherein each of the odd-numbered value and the even-numbered value is assigned to a length of a run-length, wherein the first topology preservation law is a law that does not allow division of the run-lengths by inserting, into the run-lengths, one or more pixels having a color different from colors of the run-lengths and that does not delete the run-lengths, wherein the fourth topology preservation law is a law that does not allow division of the run-lengths by newly inserting one or more pixels having a different color in at least one of a horizontal direction and a vertical direction and that does not delete the run-lengths.