Abstract: A method and apparatus for color image processing using gamut mapping reduces halo artifacts by correcting terms in a gamut mapping algorithm. The color image may be represented by f, the in gamut image by g, the target gamut by C, and the gamut constraint by c. The method for reducing halo artifacts includes two correction steps. First a color distance term L2 in the gamut mapping algorithm is corrected. Second, a distance measure of an image gradient in the gamut mapping algorithm is corrected. The first correcting step comprises computing a function u=projectc(ƒ). The second correcting step comprises computing a scaled down function for f. Next, a function g(x,y) is determined that minimizes a functional comprising the color distance term and the image gradient term. The solution may be determined by iteration using a gradient descent operation by first initializing g0=projectc(ƒ), and then performing one or more iteration steps to compute g(x,y).

Abstract: A variational model for spatially dependent gamut mapping is described that includes inputting a gamut constraint, choosing a one dimensional gamut projection scheme, including selecting a transform color coordinate system, computing transform equations, and verifying gamut conditions. The model also includes inputting an original image to be rendered, where the original image is in a given color coordinate system, transforming the gamut constraint, the image, and the transform equations to the transform color coordinate system, whereby a three dimensional function is transformed into a one dimensional quadratic functional, finding a minimum solution to the functional, and transforming a projected image in the transform color coordinate system into a color coordinate system of a rendering device.

Abstract: A method and system for correcting geometric deformations in an aligned image. A shape deformation correction unit is provided for receiving the aligned image and based thereon for generating a shape-corrected image. A space deformation correction unit is coupled to the shape deformation correction unit and receives the shape-corrected image. The space deformation correction unit uses the shape-corrected image to generate edges and interfaces, and further generates a corrected image based on the interfaces and the shape-corrected image.

Abstract: The present invention relates to novel polymeric compositions that exhibit Reverse Thermal Gelation (RTG) properties for use as Support Materials (SM) in the manufacture of three-dimensional objects. These polymers are Temperature Sensitive Polymers that respond with a significant change of properties to a small change in temperature. Temperature Sensitive Polymers exhibit cloud point (CP) or lower critical solution temperature (LCST) in aqueous solutions. Water-soluble Temperature Sensitive Polymers are chosen to give low viscosity liquid at low temperature when dissolved in water and by that to permit easy dispensing at low temperature. Raising the temperature above their gelation temperature (Tgel) will result in solidification of the composition. At its gel position the material has favorable characteristics as a support and building material. The gel layers have the appropriate toughness and dimensional stability to support the model layers during the building process.

Abstract: Systems and methods for automatically generating and decoding a graphical bar code (i.e., an image that contains inconspicuous graphical modulations that encode embedded information) are described. In one aspect, an invertible graphical operation is applied between regions of a base image and information-encoding graphical templates that are selected from a predefined template set to produce a graphical bar code with regions from which graphical templates are recoverable by applying an inverse graphical operation between graphical bar code regions and corresponding base image regions. In another aspect, an invertible graphical operation is applied between regions of a graphical bar code and corresponding regions of a base image to produce a set of measurement blocks, and information-encoding graphical templates corresponding to the set of measurement blocks with the highest estimated probability is selected from a predefined template set.

Abstract: Systems and methods for automatically extracting a graphical bar code (i.e., an image that contains inconspicuous graphical modulations that encode embedded information) are described. In accordance with this automatic extraction scheme, a graphical bar code may be isolated from a composite image in a way that preserves the information-containing graphical modulations encoding the embedded information and avoids corrupting artifacts, such as markings contained in the composite image. The resulting extracted graphical bar code readily may be processed into a format that is tailored to the requirements of a decoding system that may be particularly sensitive to noise, such as extraneous markings and image corruption. In addition, this automatic extraction scheme robustly handles missed and incorrect detections.

Abstract: Fiducial mark patterns for graphical bar codes (i.e., images that contain inconspicuous graphical modulations that encode embedded information) that are characterized by high detection robustness and good local deformation tracking are described. In one bar coding method, a base image is modulated with a graphical encoding of a message to produce a graphical bar code, and a fiducial mark pattern comprising a plurality of dots arranged to track one or more reference locations and local deformation across the graphical bar code is generated. In another bar coding method, fiducial mark candidates are identified in a fiducial mark pattern, a fiducial mark path is computed based upon one or more of the identified fiducial mark candidates, and one or more reference locations are identified based upon the computed fiducial mark path.

Abstract: A digital image is hardcopy watermarked by modifying transform coefficients in a transform domain representation of the digital image, the transforms coefficients being modified according to bit values of an n-bit message. A message in a hardcopy watermarked image is identified by statistically decoding a transform domain representation of the watermarked image.

Abstract: Payment indicia generating schemes are described that enable users to customize the appearance of the payment indicium and to accommodate a wide variety of validation processing environments, while providing a substantial defense against fraudulent photocopy attack. In some embodiments, a corroborative digital token is generated from payment information, and a base image is modulated with a graphical encoding of the corroborative digital token to produce a payment indicium. In some embodiments, a payment indicium containing embedded payment information is rendered on a printing surface with a printing characteristic that degrades with photographic reproductions such that the embedded payment information is extractable from an original rendering of the payment indicium but is un-extractable from a photographic reproduction of an original rendering of the payment indicium.