Digital display

A head-mountable or helmet-mountable digital display system, comprising:

• a digital display device for displaying an image;
• and
• a display controller arranged to control the digital display device to display pixels in an image each at a required level of brightness, wherein the display controller comprises:
• an input for receiving image data defining, for each of one or more pixels in an image to be displayed or updated, a brightness level selected from a predetermined plurality of brightness levels;
• a processor arranged to receive image data from the input and to transform a brightness level indicated for a pixel in the received image data into a representation defining a predetermined sequence of pulses of relative durations defined by weightings selected from a predetermined set of a plurality of binary pulse weightings and a plurality of non-binary pulse weightings, wherein the plurality of non-binary pulse weightings are greater than the plurality of binary pulse weightings, wherein a highest-value weighting in the set of non-binary pulse weightings represents the a pulse of duration less than one half of a total duration of pixel illumination required within an image refresh period to achieve illumination of the pixel at a greatest of said plurality of brightness levels and to generate a sequence of outputs for storage in an image buffer associated with the digital display device, each output comprising, for a pulse of a duration defined according to a weighting in the set of pulse weightings, indications of those pixels to be illuminated with the pulse of said defined duration, wherein ones of the plurality of binary pulse weightings are alternately intermixed with ones of the plurality of non-binary pulse weightings;
• and
• means for controlling the digital display device to illuminate those pixels indicated by the contents of the image buffer.