A color chart includes a first portion and a second portion. The first portion includes no patch. The second portion includes a plurality of patches having different densities or luminances. The plurality of patches includes a reference patch indicating a color having a reference density or luminance. The reference patch is adjacent to the first portion. The plurality of patches is located in order of increasing density from the density of the color indicated by the reference patch, decreasing density from the density of the color indicated by the reference patch, increasing luminance from the luminance of the color indicated by the reference patch, or decreasing luminance from the luminance of the color indicated by the reference patch.

Certain examples described herein relate to a color processing apparatus and a method of generating configuration data for a color rendering device. The color rendering device operates based on color state instructions indicating output color states for portions of a rendered output. Render data may be generated by applying a halftone matrix and color data may indicate probability values for the output color states for input image areas corresponding to the portions of the rendered output. In described examples, configuration data defines an order of output color states for application of the halftone matrix. In the order, the output color states are grouped within the data based on color properties of a rendered output and an order within the clusters is based on colorant composition.

In a method for dithering image data, a processor receives an input image in a first color space and a first bit depth larger than 8 bits. The processor converts the input image into a first image in a perceptually uniform color space, such as the BT. 2100 ICtCp color space, with pixel values scaled to be within a target bit depth, it quantizes the first image to generate a quantized image, it generates an error image between the first image and the quantized image, and using a random threshold, it generates a dithered image based on the random threshold, the error image, and the quantized image, allowing to reduce the bit-depth representation for visually consistent reproduction by two bits.

An image reproduction system and methods for providing colorant data to an end device. A method includes extracting general HSV value data for each pixel of an image from image data. For each pixel, the general HSV value data is transformed to generate universal perceived brightness, Bp, and universal perceived-chroma, Cp, value data. End-device colorant data associated with the general HSV value data is retrieved for each pixel and scaled using the Bp and Cp value data to obtain scaled end-device colorant data. The scaled end-device colorant data is transmitted to the end device.

An image reproduction system and methods for providing colorant data to an end device are disclosed. A method includes extracting general HSV value data for each pixel of an image from image data. For each pixel, the general HSV value data is transformed to generate universal perceived brightness, Bp, and universal perceived-chroma, Cp, value data. End-device colorant data associated with the general HSV value data is retrieved for each pixel and scaled using the Bp and Cp value data to obtain scaled end-device colorant data. The scaled end-device colorant data is transmitted to the end device.

An image reproduction system and methods for providing colorant data to an end device are disclosed. A method includes extracting general HSV value data for each pixel of an image from image data. For each pixel, the general HSV value data is transformed to generate universal perceived brightness, Bp, and universal perceived-chroma, Cp, value data. End-device colorant data associated with the general HSV value data is retrieved for each pixel and scaled using the Bp and Cp value data to obtain scaled end-device colorant data. The scaled end-device colorant data is transmitted to the end device.

The color coding approach adopted by the Anchor Point Cloud Compression (PCC) leads to a significant color distortion, even at very low compression ratios. This color distortion is also referred to as color leaking. Two approaches are able to mitigate the color leaking. Both approaches reduce the color leaking significantly, while one of them (e.g., 1D subsampling) is more robust and preferred in most cases. A more general approach is an adaptive selection between these two approaches.

In an image data conversion device, color image data is represented in gray scale, a histogram of brightness values is created for the gray-scaled image data, it is determined based on the created histogram which image pattern of a plurality of image patterns the gray-scaled image data is classified into, a range subjected to gamma correction and a range fixed to at least one of a minimum value and a maximum value of gray scale are set for each image pattern, and image data conversion including the gamma correction is performed on the gray-scaled image data.

An image processing method includes acquiring an image in a chrominance-luminance separation color mode; performing scene recognition of the image to determine a scene of the image; traversing luminance components of respective pixel points in the image, and generating a luminance distribution of the image according to a traversing result of the luminance components; generating a luminance mapping relation based on a standard luminance distribution corresponding to the scene of the image and the luminance distribution of the image; and adjusting the luminance components of the respective pixel points in the image according to the luminance mapping relation to generate a first processed image.

In an image data conversion device, color image data is represented in gray scale, a histogram of brightness values is created for the gray-scaled image data, it is determined based on the created histogram which image pattern of a plurality of image patterns the gray-scaled image data is classified into, a range subjected to gamma correction and a range fixed to at least one of a minimum value and a maximum value of gray scale are set for each image pattern, and image data conversion including the gamma correction is performed on the gray-scaled image data.