Abstract: A data-bearing medium is disclosed. The data-bearing medium includes a section of cells having a set of opposite-shifted clusters. The cells include a combination of opposite shifts of the set of opposite-shifted clusters, which represent a single value.

Abstract: A method is disclosed. The method comprises defining a region of interest on a three-dimensional model of an object. The method may comprise capturing an image of an object manufactured according to the three-dimensional model. The method may comprise determining, using a processor, a position and orientation of the three-dimensional model with respect to the object in the captured image. The method may comprise locating the region of interest on the manufactured object. A portion of the manufactured object within the region of interest may comprise an identifiable feature. An apparatus and a machine-readable medium are also disclosed.

Abstract: Digital signature authentication systems and methods are disclosed. An example method of authenticating a digital signature extracted from a high resolution image includes comparing an extracted signature from an image to a reference signature. The example method also includes authenticating the extracted signature against the reference signature according to one of a plurality of different authentication protocols.

Abstract: Examples disclosed herein relate to determining image capture position information based on a quasi-periodic pattern. For example, a processor may determine whether a target area is within a captured image based on the detection of a quasi-periodic pattern in a first detection area and in a second detection area of the captured image.

Abstract: An example system in accordance with an aspect of the present disclosure includes a halftone engine and a gray value engine. The halftone engine is to apply halftoning to an image recursively across a plurality of levels of image scales and spatial resolutions, to generate a pattern that is at least quasi-periodic across the plurality of levels. The gray value engine is to substitute gray values recursively for at least a portion of the halftoning.

Abstract: A computing system includes a projector, a camera, a calibration target, and a processor. The calibration target has known dimensions and four corners in a fixed position relative to both the projector and the camera. The processor causes the projector to project a calibration image having four corners and a repetitive pattern. The processor further causes the camera to capture a captured image of the calibration image and determine a rotation and translation that brings the four corners of the captured image into correspondence with the four corners of the calibration target and identify internal corner points of the repetitive pattern. The processor further selects an intrinsic parameter value and calibrates a 3D coordinate system of at least one of the camera and the projector to the calibration target using the selected intrinsic parameter value, the rotation and translation, and the internal corner points.

Abstract: An example system in accordance with an aspect of the present disclosure includes a halftone engine and a gray value engine. The halftone engine is to apply halftoning to an image recursively across a plurality of levels of image scales and spatial resolutions, to generate a pattern that is at least quasi-periodic across the plurality of levels. The gray value engine is to substitute gray values recursively for at least a portion of the halftoning.

Abstract: Examples disclosed herein relate to determining the presence of quasi-periodic two-dimensional object. In one implementation, a processor determines peak points of a DFT of an image where the peak points are points with a value above a threshold relative to surrounding points. The processor may then output information indicating the existence of a quasi-periodic two-dimensional object within the image based on the peak points.

Abstract: Examples disclosed herein relate to determining peak distances between an origin, point in the frequency domain and peak points of a discrete Fourier transform magnitude of an image of a periodic or quasi-periodic target. In some implementations, a range distance between the target and the imaging lens is determined based on the peak distances.

Abstract: An example system includes a feature extraction engine. The feature extraction engine is to determine a plurality of scale-dependent features for a portion of a target. The system also includes a signature-generation engine to select a subset of the plurality of scale-dependent features based on a strength of each feature. The signature-generation engine also is to store a numeric representation of the portion of the target and the subset of the plurality of scale-dependent features.

Abstract: A data-bearing image (391) is created from a carrier image (371). The carrier image (371) is scaled to produce a scaled image. A clustered-dot halftone screen is applied to the scaled image to produce a halftone image. A resulting number of cells in the halftone image conforms to a cell count (372) that includes a horizontal cell value and a vertical cell value. Payload data is encoded into the halftone image to produce a data-bearing halftone image, including shifting pixel clusters within cells of the halftone image that include pixel clusters.

Abstract: An example method of rapid image registration includes recovering an affine transform of a quasi-periodic object based on peak locations of Discrete Fourier Transform (DFT) in a captured image. The example method also includes filtering a region of the captured image to match a filtered version of a reference image including the quasi periodic object. The example method also includes recovering translation parameters to reduce image differences between the reference image and the captured image for a subset of the image locations of the filtered image and outputting an approximate transform including translation.

Abstract: An example method of recovering a planar projection in a captured image. The example method includes selecting displaced points in the captured image. The example method also includes recovering an affine transform of a quasi-periodic object for each of the displaced points based on peak locations of Discrete Fourier Transform (DFT) of the captured image. The example method also includes combining each of the affine transforms for the displaced points to recover the planar projection and correct for perspective distortion in the captured image.

Abstract: Examples disclosed herein relate to classifying paper based on three-dimensional characteristics of the paper. For example, a representation of the three-dimensional characteristics of the paper may be created, and statistical summary information related to the three-dimensional characteristics of the paper may be determined based on the representation. The paper may be classified based on the statistical summary information.

Abstract: An example system in accordance with an aspect of the present disclosure includes a halftone engine and a gray value engine. The halftone engine is to apply halftoning to an image recursively across a plurality of levels of image scales and spatial resolutions, to generate a pattern that is at least quasi-periodic across the plurality of levels. The gray value engine is to substitute gray values recursively for at least a portion of the halftoning.

Abstract: Examples disclosed herein relate to determining image capture position information based on a quasi-periodic pattern. For example, a processor may determine whether a target area is within a captured image based on the detection of a quasi-periodic pattern in a first detection area and in a second detection area of the captured image.

Abstract: Digital signature authentication systems and methods are disclosed. An example method of authenticating a digital signature extracted from a high resolution image includes comparing an extracted signature from an image to a reference signature. The example method also includes authenticating the extracted signature against the reference signature according to one of a plurality of different authentication protocols.

Abstract: Examples disclosed herein relate to calibrating a device based on intrinsic parameter value selection and a projected calibration target. A process may calibrate a camera and/or device by creating 3D calibration information for a device, such as a camera or projector, based on a set of intrinsic calibration intrinsic parameter value options, a calibration target of known dimensions, and a virtual calibration target created based on an image captured by the camera of a projection by the projector onto the calibration target.

Abstract: A forensic verification system extracts a print signature via a print signature extractor from an interior of a halftone contained in an image. The system utilizes a comparator to compare the print signature to a reference signature stored in a registry to determine differences between the print signature and the reference signature. The system utilizes a forensic analyzer to perform a forensic analysis on the signatures based on the comparison to authenticate the image.

Abstract: An example method of recovering a planar projection in a captured image. The example method includes selecting displaced points in the captured image. The example method also includes recovering an affine transform of a quasi-periodic object for each of the displaced points based on peak locations of Discrete Fourier Transform (DFT) of the captured image. The example method also includes combining each of the affine transforms for the displaced points to recover the planar projection and correct for perspective distortion in the captured image.