Abstract: A method of computing a computer generated hologram (CGH) for use in displaying a holographic image of a replay object. The method of generating a first computer generated hologram corresponding to the desired replay object (step 1); subdividing the first computer generated hologram into a plurality of blocks, each representing a sub CGH (step 2); for each block or sub CGH, calculating the corresponding replay sub-image hereafter called target wavefront data set (step 3); and generating for each target wavefront data set a second constrained modulation computer generated hologram wherein that second CGH is modulated within constrained values (step 5); and combining the plurality of second constrained modulation computer generated holograms to provide a third complete constrained modulation computer generated hologram (step 6).

Abstract: A reconfigurable, three-dimensional display (1) wherein knowledge of the viewer's (4) eyes is used to enable the effective exit pupil(s) of the display system to be optimised. The system utilises this knowledge to identify contributing regions (5) within the display (1) that contribute light to the viewer (4). Priority is given to calculating and displaying the part of the display corresponding to the contributing region (5), thereby allowing the system computation requirements to be minimised. Further computation savings are achievable by recognising that only light travelling in a limited range of angles need to be considered.