In some arrangements, product packaging is digitally watermarked over most of its extent to facilitate high-throughput item identification at retail checkouts. Imagery captured by conventional or plenoptic cameras can be processed (e.g., by GPUs) to derive several different perspective-transformed views—further minimizing the need to manually reposition items for identification. Crinkles and other deformations in product packaging can be optically sensed, allowing such surfaces to be virtually flattened to aid identification. Piles of items can be 3D-modelled and virtually segmented into geometric primitives to aid identification, and to discover locations of obscured items. Other data (e.g., including data from sensors in aisles, shelves and carts, and gaze tracking for clues about visual saliency) can be used in assessing identification hypotheses about an item. Logos may be identified and used—or ignored—in product identification. A great variety of other features and arrangements are also detailed.

Differential modulation schemes encode a data channel within host signal or noisy environment in a manner that is robust, flexible to achieve perceptual quality constraints, and provides improved data capacity. Differential arrangements enable a decoder to suppress host signal or other background signal interference when detecting, synchronizing and extracting an encoded data channel. They also enable the incorporation of implicit or explicit synchronization components, which are either formed from the data signal or are complementary to it.

This disclosure relates to advanced signal processing technology including steganographic embedding and digital watermarking. One combination disclosed in the description includes an image processing method. The method includes: obtaining an image comprising a plurality of color channels; for each color channel of the plurality of color channels, creating a grayscale version of the color channel and creating an inverted greyscale version of the color channel; analyzing the grayscale inverted version and the grayscale non-inverted version to locate image areas including an encoded signal, said analyzing yielding a plurality of image areas; generating one or more detectability measures corresponding to the encoded signal for each of the plurality of image areas; for each color channel selecting only one (1) image area as a validation point based on one or more generated detectability measures for that color channel; and generating information associated with a spatial location of each of the validation points in the image. Of course, other features and combinations are described as well.

A method of tracking a source display panel from which an illegal copy of an image is captured by a camera is provided. The method includes generating a content image visible to human eyes using a visible light component integrated in an integrated light emitting source; generating a watermark image invisible to the human eyes in real time using an invisible light component integrated in the same integrated light emitting source; and simultaneously displaying the content image and the watermark image on the source display panel. Generating the watermark image includes generating an image of an identifier unique to the source display panel. The method further includes analyzing the image captured by the camera to extract the image of an identifier unique to the source display panel; and identifying the source display panel based on the identifier unique to the source display panel.

A method for transforming an input array of pixel data into an output array of data, to yield enhanced expression of a digital watermark signal in the output array. One such method includes, for each pixel in the input array, generating a first datum that indicates a value difference between said pixel and a neighboring pixel in a first direction, the first data thereby collectively comprising a first directional difference array. Similarly, for each such pixel in the input array, generating a second datum that indicates a value difference between said pixel and a neighboring pixel in a second direction, the second data thereby collectively comprising a second directional difference array. One or more transforms to a spatial frequency domain are then performed, using these first and second directional difference arrays as input data. First and second results from the one or more transformations are then combined to yield an output array. The just detailed process causes the digital watermark signal in the output array to exhibit a greater signal-to-noise ratio than in the digital watermark signal in the input array. A great number of other features and arrangements are also detailed.

Examples described herein include adding a digital watermark into acoustic data. For example, the digital watermark data can be embedded using a key such that the watermark data is spread across a spectrum of the acoustic data. Thus, the data for the digital watermark may have no or minimal visible impact in the images generated using the marked acoustic data. The digital watermark may provide improved security and privacy. Moreover, the digital watermark may be incorporated into the reconstruction process of images.

Variable data printing workflows are enhanced for use with content that includes 2D code patterns, such as digital watermark data. One arrangement includes applying a filter to a content stream within a PDF document to extract both first variable pattern data for a first watermark pattern and second variable pattern data for a second watermark pattern. A first composite watermark pattern is then defined based on the extracted first variable watermark pattern data in conjunction with static watermark pattern data, and a second composite watermark pattern is defined based on the extracted second variable watermark pattern data in conjunction with the static watermark pattern data. A variety of other features and arrangements are also detailed.

A steganographic digital watermark signal is decoded from host imagery without requiring a domain transformation for signal synchronization, thereby speeding and simplifying the decoding operation. In time-limited applications, such as in supermarket point-of-sale scanners that attempt watermark decode operations on dozens of video frames every second, the speed improvement allows a greater percentage of each image frame to be analyzed for watermark data. In battery-powered mobile devices, avoidance of repeated domain transformations extends battery life. A great variety of other features and arrangements, including machine learning aspects, are also detailed.

The first image data is converted into the second image data defined by a color space that depends on an output apparatus that outputs image data. Additional information is multiplexed on the converted second image data by using a multiplex parameter.

A method for detection of modification of an item of content, the method comprising: obtaining, for the item of content, a respective first value of each attribute in a set of one or more attributes of the item of content, the set of one or more attributes selected such that, for each of one or more predetermined types of modification, said type of modification affects the value of at least one attribute in the set of one or more attributes; performing a watermark decoding operation on the item of content; and in response to the watermark decoding operation producing payload data from the item of content: determining that the one or more predetermined types of modification have not been applied to the item of content if, for each attribute in the set of one or more attributes, the respective first value for that attribute matches a respective second value for that attribute determined using the payload; or determining that a modification has been applied to the item of content if, for at least one attribute in the set of one or more attributes, the respective first value for that attribute does not match a respective second value for that attribute determined using the payload.