Image data control unit for SLM-based photofinishing system

A method of using an SLM-based photofinishing system to expose an exposure region on a photographic medium with images based on source pixel data, each line of the printed image being exposed with multiple exposure phases of the SLM, comprising the steps of:

• storing a number of rows of source pixel data, each value of the source pixel data representing a greyscale level;
• accessing a look-up memory that stores a table of SLM settings, indexed by greyscale levels and exposure phases;
• generating an exposure phase signal for each exposure phase, each signal providing access to the look-up memory to obtain a setting value corresponding to a greyscale value and an exposure phase;
• generating control signals for operating the SLM;
• storing settings for a number of rows of the SLM;
• loading the SLM with settings;
• and
• exposing the exposure region of the image.

An exposure unit for an SLM-based photofinishing system that produces images based on source pixel data, each line of the image being exposed with multiple rows of the SLM, one new line being exposed during each exposure phase, comprising:

• a row buffer that stores a number of rows of source pixel data, each value of the source pixel data representing a greyscale level;
• a look-up memory that stores a table of SLM settings, indexed by greyscale levels and exposure phases;
• a controller that generates an exposure phase signal for each exposure phase, each exposure phase signal providing access to the look-up memory to obtain an SLM setting value corresponding to a greyscale value and an exposure phase, and further generates control signals for operating the SLM;
• a settings buffer that receives settings from the look-up memory and stores them for delivery to the SLM;
• and
• at least one spatial light modulator that generates an exposure image during each exposure phase in accordance with settings stored in the settings buffer.