Method and apparatus for coding information by inserting codes in strongly featured image regions
AssigneeCentral Research Laboratories Limited
InventorMartin Peter Todd
Life of this patent
Estimating the term…
Abstract
A method of encoding invisible identification code into an image, which is highly resistant to degradation across communications links, and which does not require the presence of the original image for decoding, comprises analyzing the image and determining strongly featured regions such as edges, and inserting code into such regions by altering the structure of the image in a predictable manner, as for example a concave elliptical insert centered on and aligned with an edge, which alteration is not visible to the eye. When decoding, area of concavity are determined, and a correlation is performed with a predicted insert function to assess whether code has been inserted. A hardware embodiment is described.
Claims32
A method of inserting coded information into an image, comprising analyzing the image, identifying at least one strongly featured region, and inserting into the or each such region a predetermined geometric insert function extending spatially within such region, in order to represent coded information, wherein said method includes determining the maximum strength said insert function may have without producing a visible artefact, and determining the intensity of the insert function in accordance with said maximum strength.
A method of inserting coded information into an image, comprising analyzing the image, identifying at least one strongly featured region, and inserting into the or each such region a predetermined geometric insert function extending spatially within such region, in order to represent coded information, wherein said method includes determining whether the strongly featured region is sufficient well defined to permit insertion of coded information.
A method of inserting coded information into an image, comprising analyzing the image, identifying at least one strongly featured region, and inserting into the or each such region a predetermined geometric insert function extending spatially within such region, in order to represent coded information, further comprising dividing the image up into blocks formed in N rows and M columns, and carrying out the aforesaid analysing and inserting steps in each block.
A method of decoding information contained in an image, the method comprising analysinq the image, identifying a strongly featured region, determining for the region a predetermined geometric insert function extending spatially within the region and representing coded information, and performing a correlation operation with such predetermined insert function and the image to determine the value of coded information inserted into the strongly featured region, wherein the method further comprises dividing the image up into blocks formed in N rows and M columns, and carrying out the aforesaid decoding steps in each block.
A method of inserting coded information into an image, comprising analyzing the image, identifying at least one strongly featured region, and inserting into the or each such region a predetermined geometric insert function extending spatially within such region, in order to represent coded information, wherein the at least one strongly featured region comprises edge regions between areas of different luminance and/or chrominance.
A method of inserting coded information into an image, comprising analyzing the image, identifying at least one strongly featured region, and inserting into the or each such region a predetermined geometric insert function extending spatially within such region, in order to represent coded information, wherein the at least one strongly featured region comprises textured regions having randomly distributed therein local areas of different luminance and/or chrominance values.
Apparatus for inserting coded information into an image, comprising means for analyzing the image and identifying strongly featured regions, and means for inserting into at least one such region a predetermined geometric insert function extending spatially within such region and representing coded information, and further including means for determining the maximum strength the insert function may have without producing a visible artefact, and means for determining the intensity of the insert function in accordance with said maximum strength.
Apparatus for inserting coded information into an image, comprising means for analyzing the image and identifying strongly featured regions, and means for inserting into at least one such region a predetermined geometric insert function extending spatially within such region and representing coded information, and further including means for dividing the image up into blocks formed in N rows and M columns, and carrying out the aforesaid analysing and inserting steps in each block.
Apparatus for decoding information contained in an image, comprising means for analyzing the image and identifying a strongly featured region, means for determining for the region an anticipated geometric insert function extending spatially within the region and representing coded information, and means for Performing a correlation operation with such anticipated insert function and the image to determine the value of coded information inserted into the strongly featured region, and further comprising means for dividing the image up into blocks formed in N rows and M columns, and means for carrying out the aforesaid decoding steps in each block.
A method of decoding information contained in an image, the method comprising analyzing the image, identifying a strongly featured region, determining for the region a predetermined geometric insert function extending spatially within the region and representing coded information, and performing a correlation operation with such predetermined insert function and the image to determine the value of coded information inserted into the strongly featured region, wherein the strongly featured region comprises edge regions between areas of different luminance and/or chrominance.
A method of decoding information contained in an image, the method comprising analyzing the image, identifying a strongly featured region, determining for the region a predetermined geometric insert function extending spatially within the region and representing coded information, and performing a correlation operation with such predetermined insert function and the image to determine the value of coded information inserted into the strongly featured region, wherein the strongly featured region comprises textured regions having randomly distributed therein local areas of different luminance and/or chrominance values.
Dependencies are inferred from the claim text.