the present invention relates to various digital watermarking methods , apparatus and systems . one claim recites a method of determining a size or denomination of a momentary object . the method includes : utilizing a configured , multi - purpose electronic processor , decoding a digital watermark embedded in a monetary object , the watermark including data corresponding to a denomination of the monetary object ; based on the data , determining feedback to indicate the denomination of the monetary object ; and providing the feedback . handheld computing devices can be advantageously employed with this combination . of course , other combinations are provided and claimed .