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