Watermark data is converted to watermark coefficients, which may be embedded in an image by converting the image to a frequency domain, embedding the watermark in image coefficients corresponding to medium-frequency components, and converting the modified coefficients to the spatial domain. The watermark data is extracted from the modified image by converting the modified image to a frequency domain, extracting the watermark coefficients from the image coefficients, and determining the watermark data from the watermark coefficients. The watermark data may be truncated image data bits such as truncated least significant data bits. After extraction from the watermark, the truncated image data bits may be combined with data bits representing the original image to increase the bit depth of the image. Watermark data may include audio data portions corresponding to a video frame, reference frames temporally proximate to a video frame, high-frequency content, sensor calibration information, or other image data.

The present disclosure relates generally to data hiding for retail product packaging and other printed objects. One embodiment embeds an information signal in a spot color for product packaging. The spot color is screened, and overprinted with process color tint. The tint is modulated prior to overprinting with optimized signal tweaks. The optimization can include consideration of a detector spectral dependency (e.g., red and/or green illumination). Many other embodiments and combinations are described in the subject patent document.

A memory stores video information obtained by photographing an object that reflects light in which embedded information is superimposed onto a plurality of components in a color space. A processor emphasizes a signal obtained from an image included in the video information on the basis of a result of emphasizing a first color component more than a second color component according to a spectral reflection characteristic in a range including the object, and detects the embedded information from the emphasized signal, the first color component and the second color component being from among a plurality of color components that correspond to a plurality of wavelengths, the first color component having a reflectance higher than a reflectance of the second color component. A display device outputs information on the basis of the embedded information detected by the processor.

The present disclosure relates generally to encoding signals for spot colors. In one implementation a substitute spot color+CMY tint is selected to replace an original spot color. The CMY tint can be transformed to carry an encoded signal. Of course, other features, combinations and technology are described herein.

A method, non-transitory computer readable medium and apparatus for generating a multi-layer correlation mark via a monochrome printer are disclosed. For example, the method includes setting a first scalar value of a channel of the monochrome printer, setting a second scalar value of the channel of the monochrome printer, generating a first layer of the multi-layer correlation mark at the first scalar value of the channel, generating a second layer of the multi-layer correlation mark at the second scalar value of the channel and printing the multi-layer correlation mark comprising the first layer at the first scalar value of the channel and the second layer at the second scalar value of the channel.

Sparse signal modulation schemes encode a data channel on a substrate in a manner that is robust, flexible to achieve perceptual quality constraints, and provides improved data capacity. The substrate is printed by any of a variety of means to apply the image, with sparse signal, to an object. After image capture of the object, a decoder processes the captured image to detect and extract data modulated into the sparse signal. The sparse signal may incorporate implicit or explicit synchronization components, which are either formed from the data signal or are complementary to it.

Examples disclosed herein relate to selection of machine-readable link type. Examples include acquisition of an electronic document, selection of a machine-readable link type for evaluation, and a decision of whether at least one characteristic of the document satisfies at least one evaluation metric for use of the selected type of machine-readable link.

The present disclosure relates generally to digital watermarking for spot colors. In one implementation a substitute spot color+CMY tint is selected to replace an original spot color. The CMY tint can be transformed to carry a digital watermark signal. Of course, other features, combinations and technology are described herein.

A device comprising: an input for receiving images captured by a camera, of an environment illuminated by light from a light source; an image processing module; and a verification module. The image processing module is configured to process one or more of the images to decode a timestamp modulated into the light, and to output an indication of the decoded timestamp. The verification module is arranged to receive the indication of the decoded timestamp output by the image processing module, and based thereon to perform an at least partially automated verification of a time at which the one or more images were captured.

The present invention provides a printer responsive to commands from printer driver software. The printer driver software is characterized by being responsive to two types of input data. One of the types includes text data, and the other of the types includes watermark data. The two types of data are separately applied to printer driver software, rather than integrated together prior to application to the printer driver software.