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.

A marking color of a marking material (e.g., ink, toner, etc.) within a printer has a marking spectral reflectance property. Print media that has a media color approximately matching the marking color, but a different media spectral reflectance property, is identified (to form a geometric metameric pair). Differently colored calibration patches of the marking material are printed on a test sheet of the print media. A calibration patch, in which the printed color of the marking material most closely visually matches the media color, is used to identify a revised marking color. A watermark is printed on the print media using the revised marking color. The difference between the marking spectral reflectance property and the media spectral reflectance property causes the watermark to be visibly observable on the print media from one angle but prevents the watermark from being visibly observable from a different angle.

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.

Content is identified using watermarking and/or other content recognition combined with contextual metadata, which facilitates identification and correlation with other content and metadata when it is posted to a network.

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.

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.

A marking color of a marking material (e.g., ink, toner, etc.) within a printer has a marking spectral reflectance property. Print media that has a media color approximately matching the marking color, but a different media spectral reflectance property, is identified (to form a geometric metameric pair). Differently colored calibration patches of the marking material are printed on a test sheet of the print media. A calibration patch, in which the printed color of the marking material most closely visually matches the media color, is used to identify a revised marking color. A watermark is printed on the print media using the revised marking color. The difference between the marking spectral reflectance property and the media spectral reflectance property causes the watermark to be visibly observable on the print media from one angle but prevents the watermark from being visibly observable from a different angle.

A method for low latency audio watermark embedding buffers samples of an audio stream in a buffer, including previous blocks of audio samples in the audio stream. It computes a perceptual mask from the audio samples in the buffer, generates a watermark signal; and applies the perceptual mask to the watermark signal for the first block to produce a mask-applied watermark signal. It inserts the mask-applied watermark signal into the audio samples of the first block without waiting for a subsequent audio block of samples in the audio stream and outputs watermarked audio of the first block.