Device and method of improving the perceptual luminance nonlinearity-based image data exchange across different display capabilities

摘要

A handheld imaging device has a data receiver that is configured to receive reference encoded image data. The data includes reference code values, which are encoded by an external coding system. The reference code values represent reference gray levels, which are being selected using a reference grayscale display function that is based on perceptual non-linearity of human vision adapted at different light levels to spatial frequencies. The imaging device also has a data converter that is configured to access a code mapping between the reference code values and device-specific code values of the imaging device. The device-specific code values are configured to produce gray levels that are specific to the imaging device. Based on the code mapping the data converter is configured to transcode the reference encoded image data into device-specific image data, which is encoded with the device-specific code values.

主权项

1. A method performed on an imaging device for transcoding reference encoded image data into device-specific image data, the method comprising the steps of:
determining a digital code mapping between a set of reference digital code values and a set of device-specific digital code values, wherein the set of reference digital code values is mapped in a reference mapping to a set of reference gray levels, and wherein the set of device-specific digital code values is mapped in a device-specific mapping to a set of device-specific gray levels; receiving reference encoded image data encoded with the set of reference digital code values, wherein luminance values in the reference encoded image data are based on the set of reference digital code values, wherein a luminance difference between two reference gray levels represented by two adjacent reference digital code values in the set of reference digital code values is inversely proportional to a peak contrast sensitivity of human vision adapted at a particular light level; and transcoding, based on the digital code mapping, the reference encoded image data encoded with the set of reference digital code values into device-specific image data encoded with the set of device-specific digital control codes, wherein luminance values in the device-specific image data are based on the set of device-specific digital code values; wherein at least one of the reference mapping and the device-specific mapping is determined based at least in part on a functional model represented with the functionL=[D1/m-c1c2-c3⁢D1/m]1/nwherein D represents a digital code value to be mapped, and L represents a gray level corresponding to the digital code value.