An encoding apparatus partitions a digital image into multiple regions for subsequent encoding. A first encryption code is associated with a first region, a second encryption code is associated with a second region and the first code, and a third code is associated with the first code, the second code and a third region. An authentication apparatus authenticates the digital image in an inverse process.

Various features described herein may allow an authorized user to provide a guest with access to a secured location through use of an encoded image containing steganographically encoded access information. The encoded access information may be recognizable by a security system, and the security system may grant access to the secured location when the encoded image is presented to the security system. The authorized user may request the generation of the encoded image on an authorized computing device, and the encoded image may be provided to the guest on a guest computing device. When a monitoring device associated with the security system captures the encoded access information, the security system may, for example, open a door at the secured location.

In one aspect, assembly of multi-part food packaging is checked by reference to payloads of steganographically-encoded digital watermarks printed across the packaging components. Marking all surfaces of the packaging components allows arbitrary orientation of feed stock in assembly equipment, and wide latitude in placement of inspection cameras along the packaging line. In another aspect, a scanner at a retail checkout station is alert to any gap detected in steganographic encoding on retail product packaging and, if found, alerts an operator to possible presence of an adhesive label with a misleading barcode. A great variety of others features and arrangements are also detailed.

An encoding apparatus partitions a digital image into multiple regions for subsequent encoding. A first encryption code is associated with a first region, a second encryption code is associated with a second region and the first code, and a third code is associated with the first code, the second code and a third region. An authentication apparatus authenticates the digital image in an inverse process.

Various features described herein may allow an authorized user to provide a guest with access to a secured location through use of an encoded image containing steganographically encoded access information. The encoded access information may be recognizable by a security system, and the security system may grant access to the secured location when the encoded image is presented to the security system. The authorized user may request the generation of the encoded image on an authorized computing device, and the encoded image may be provided to the guest on a guest computing device. When a monitoring device associated with the security system captures the encoded access information, the security system may, for example, open a door at the secured location.

A method for measuring performance of virtual desktop services offered by a server including a processor is described. A first encoded watermark is embedded into user interface display generated by a virtual desktop when initiating an operation. The first encoded watermark includes pixels identifying the operation and indicating its initiation. A second encoded watermark is embedded into the user interface upon completion of the operation indicating completion of the operation. An action performance time is then computed and stored in a memory. Multiple performance times may be compiled from multiple operations of multiple virtual desktops to assess the performance of the system as a whole.

Methods, devices and computer program products allow embedding and detection of watermarks into and from a multimedia content. One watermark embedding method includes selecting a content segment that lacks inherent features for embedding of watermarks without producing perceptible artifacts, and obtaining a first dither pattern corresponding to a first watermark symbol of a watermark symbol alphabet, where each symbol is associated with a particular dither pattern. Further, each particular dither pattern, upon combination with the multimedia content segment that lacks inherent features, produces a composite content segment without perceptible artifacts. By combining the first dither pattern with the multimedia content segment that lacks inherent features, a first composite content segment with the first embedded watermark symbol is produced. The detection of watermarks messages can be carried out quickly by examining a small portions of the multimedia because even the featureless content segments include embedded watermarks.

Methods, devices and computer program products allow improved synchronization among multiple contents. One disclosed method includes receiving a first and a second content and performing watermark extraction to recover a first timecode as part of a watermark embedded into a segment of that content. The first timecode conforms to a first type of timing system. Next, a timing system associated with the second content is determined, and a mapping is obtained that allows timecode conversion between the first and the second timing systems. Using the mapping to synchronize the presentation of the second content with that of the first content. Thus synchronization of multiple contents is properly maintained even when processing operations such as format conversion and transcoding cause metadata streams that carry timing information to be removed.

Certain aspects of the present technology involve automated capture of several image frames (e.g., simultaneously in a single exposure, or in a burst of exposures), and application of a data-extraction process (e.g., watermark decoding) to each such image. Other aspects of the technology involve capturing a single scene at two different resolutions, and submitting imagery at both resolutions for watermark decoding. Still other aspects of the technology involve increasing the signal-to-noise ratio of a watermark signal by subtracting one image from another. Yet other aspects of the technology involve receiving focus distance data from a camera, and employing such data in extracting information from camera imagery. Smartphone camera APIs can be employed to simplify implementation of such methods. A great number of features and arrangements are also detailed. Embodiments of such technology can simplify image processing required for data extraction, with attendant reductions in required program memory and battery power consumption. Moreover, they can enlarge a system's operational envelopeenabling information to be extracted from imagery under conditions that lead to failure in prior art arrangements.

The present disclosure provides a watermark image processing method and apparatus, a device and a computer readable storage medium. In the embodiments of the present disclosure, it is feasible to obtain at least one similar image approximate to the watermark image according to the watermark image including the watermark, and obtain a replaceable image of each similar image of said at least one similar image in the watermark area, according to a watermark area where the watermark is located in the watermark image so that it is possible to obtain a carrier image not including the watermark, according to the watermark image and the replaceable image of said each similar image in the watermark area. Since the replaceable image of the similar image in the watermark area is employed to obtain the carrier image not including the watermark, the valid content in the watermark image covered by the watermark is restored and thereby the reliability of the image is improved.