In an example a method includes deriving a print agent coverage vector specifying an area coverage for each of a plurality of elements, wherein each element is associated with a print agent, a print agent combination or an absence of print agent. Deriving the print agent coverage vector comprises, for a first element of the print agent coverage vector, applying a first weighting function which varies based on an intended area color value.

In an example a method includes deriving a print agent coverage vector specifying an area coverage for each of a plurality of elements, wherein each element is associated with a print agent, a print agent combination or an absence of print agent. Deriving the print agent coverage vector comprises, for a first element of the print agent coverage vector, applying a first weighting function which varies based on an intended area color value.

Techniques to improve detection and security of images, including formation and detection of matrix-based images. Some techniques include logic to process image data, generate one or more colorspaces associated with that data, and perform colorspace conversions based on the generated colorspace. The logic may be further configured to generate an image based on the colorspace conversions, including but not limited to a matrix bar code. The logic may be further configured to apply one or both of an ultraviolet layer and an infrared layer to the image, e.g. matrix barcode, generated from the colorspace conversion(s). Other embodiments are described and claimed.

Techniques to improve detection and security of images, including formation and detection of matrix-based images. Some techniques include detecting a matrix-based image that is optimized for detection in a particular environment. The matrix-based image may be a matrix bar code. The matrix bar code may include a plurality of non-black and non-white colors, where each one of the plurality of non-black and non-white colors are at least one of an absent color in relation to the environment and a least prevalent color associated with the environment.

A method of palette management for palette coding in a video coding system receives input data associated with a current block in a high-level picture structure and initializes a palette predictor in the high-level picture structure before a corresponding palette of a first palette-coded block in the high-level picture structure is coded. If a palette mode is selected for the current block, the method applies the palette coding to the current block using a current palette and updates the palette predictor based on the current palette to generate an updated palette predictor for a next block coded in the palette mode.

Techniques to improve detection and security of images, including formation and detection of matrix-based images. Some techniques include detecting a matrix-based image that is optimized for detection in a particular environment. The matrix-based image may be a matrix bar code. The matrix bar code may include a plurality of non-black and non-white colors, where each one of the plurality of non-black and non-white colors are at least one of an absent color in relation to the environment and a least prevalent color associated with the environment.

Innovations in encoding or decoding when switching color spaces are presented. For example, some of the innovations relate to signaling of control information for adaptive color space transformation (ACT). Other innovations relate to ACT operations. These innovations can improve coding efficiency when switching between color spaces during encoding and decoding.

A computer-readable recording medium storing a program that causes a computer to execute a process, the process includes specifying occurrence frequencies of respective gradation values with regard to pixels included in image data and represented by gradation values of a predetermined bit count; extracting a predetermined number of gradation values from a gradation value having a high occurrence frequency in a descending order; generating correspondence information for performing bit conversion of the extracted gradation values into coded values of a bit count in accordance with the predetermined number; and encoding the image data by performing bit conversion of first pixels having any one of the predetermined number of gradation values among the pixels based on the correspondence information, and performing bit conversion of second pixels having any one of gradation values other than the predetermined number of gradation values among the pixels.

The disclosure describes a high dynamic range video coding pipeline that may reduce color artifacts and improve compression efficiency. The disclosed pipeline separates the luminance component from the chrominance components of an input signal (e.g., an RGB source video) and applies a scaling of the chrominance components before encoding, thereby reducing perceivable color artifacts while maintaining luminance quality.

A method of palette management for palette coding in a video coding system receives input data associated with a current block in a high-level picture structure and initializes a palette predictor in the high-level picture structure before a corresponding palette of a first palette-coded block in the high-level picture structure is coded. If a palette mode is selected for the current block, the method applies the palette coding to the current block using a current palette and updates the palette predictor based on the current palette to generate an updated palette predictor for a next block coded in the palette mode.