Anti-counterfeiting and diffusive screens
AssigneeDurand Limited
InventorsNicholas John Phillips, Jonathan Michael Blackledge, William Nevil Heaton Johnson
Life of this patent
Estimating the term…
Abstract
Anti-counterfeiting marking for documents, which marking may be disguised as an incidental or artistic feature of overall marking on the documents is adapted to be read by a complementary reading device. In one embodiment the marking may be a one, two or three-dimensional statistically fractal marking and is representative of an array of digits in which the value of each digit is represented by the fractal dimensions over a corresponding region or set of regions of the document bearing the marking. Corresponding apparatus for reading the anti-corresponding marking is also provided.
Claims7
Anti-counterfeiting marking for documents, which marking is disguised as an incidental or artistic feature of overall marking on the documents, but is adapted to be read by a complementary reading device,
- said marking is a one, two or three-dimensional statistically fractal marking, and
- said marking is representative of an array of digits in which the value of each digit is represented by the fractal dimensions over a corresponding region, or set of regions of the area of a document bearing the marking.
Apparatus for reading an anti-counterfeiting marking comprising light sensing means for determining the relative density of each elemental area in a set of elemental areas occupying predetermined positions within, and with respect to, a notional window in the area of such marking and means for deriving from the densities so determined a numerical value statistically representative of said set, said apparatus including scanning means adapted to conduct a scan of said window over the area of said marking and to determine such a value for each of a plurality of reference positions of such window within such scan, and means to determine from said values a corresponding indicator or string, the apparatus further including means for displaying the last-noted number of text or for comparing it, for validation purposes with a predetermined string or indicator,
- said anti-counterfeiting marking being for documents, which marking is disguised as an incidental or artistic feature of an overall marking on the documents, but is adapted to be read by a complementary reading device, and
- said apparatus being adapted for use in reading items having a coded area which is statistically fractal, the apparatus being arranged to calculate said values as at least approximately the fractal dimension of the portion of the marking within said window.
Apparatus for reading an anti-counterfeiting marking in which the apparatus is adapted to effect a raster scan of the coded area of the item, with each line of the raster being treated as a respective linear scan,
- said anti-counterfeiting marking being for documents, which marking is disguised as an incidental or artistic feature of overall marking on the documents, but is adapted to be read by a complementary reading device, and
- said apparatus being adapted for use in reading items having a coded area which is statistically fractal, the apparatus being arranged to calculate said values as at least approximately the fractal dimension of the portion of the marking within said window.
Dependencies are inferred from the claim text.