Patent ID: 8130374

Claim:
A method for calibrating a spatial light modulator comprising an array of individually addressable channels, the method comprising: selecting a plurality of channel sets from the array of channels, each channel set comprising a plurality of channels; operating each of the channel sets to provide corresponding first output radiation; determining a plurality of intensity values, each of the intensity values corresponding to the first output radiation provided by a different one of the channel sets; selecting a first intensity value from the plurality of intensity values, wherein the first intensity value corresponds to a first channel set in the plurality of channel sets; determining a difference between the first intensity value and a first target intensity value; performing a channel set adjustment, the channel set adjustment comprising adjusting a control level of each channel in the first channel set to reduce the determined difference between the first intensity value and the first target intensity value; selecting a plurality of channel subsets from the first channel set; providing a correction factor for each channel subset; and performing a channel subset adjustment, the channel subset adjustment comprising adjusting a control level of at least one channel in each of at least one of the channel subsets in accordance with a corresponding one of the correction factors.