Hologram Encoding Correction Function for Pixelated Modulators
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Solution Overview
Problem
Existing methods for encoding computer-generated holograms in pixelated light modulators fail to account for the real shape and transparency of pixels, leading to biased reconstructions and imprecision due to the conflict between point-wise computation and finite pixel extent, resulting in defects like undesired intensity changes and noise in the observer window.
Innovation Solution
A method that involves multiplying each sub-hologram with a correction function specific to the pixel shape and transparency, integrated into the computer generation of sub-holograms, which is either pre-computed for specific light modulators or object point distances, to correct for the pixel effects before forming the total hologram, thereby reducing computational load and improving reconstruction accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If point-wise computation of hologram is used, then computational simplicity is maintained, but reconstruction accuracy deteriorates due to pixel finite extent effects
Solution Approach 1:
The patent applies preliminary action by pre-computing correction functions that account for pixel finite extent effects before the actual hologram encoding process. These correction functions are calculated once and then applied to each sub-hologram during encoding, eliminating the need for complex real-time corrections while maintaining high reconstruction accuracy. This resolves the contradiction by preparing correction data in advance, keeping the main computation simple yet accurate.
2Measurement precision
If correction for pixel shape and transparency is applied, then reconstruction accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent reduces computational complexity by pre-computing correction functions that encapsulate pixel shape and transparency effects. These correction functions are calculated once based on the specific light modulator characteristics and then reused for all holograms, transforming a potentially complex per-hologram correction process into a simple multiplication operation during encoding.
Solution Approach 2:
The patent changes the parameter representation by transforming the physical pixel characteristics (shape, transparency) into mathematical correction functions. This parameter transformation allows the complex physical effects to be handled through pre-computed mathematical models rather than repeated complex calculations, maintaining accuracy while reducing computational burden.
3Loss of time
If pre-computed correction functions are used, then computing time is reduced, but adaptability to different light modulators decreases
Solution Approach 1:
The patent maintains adaptability by making the correction functions parameter-dependent on light modulator characteristics. Each light modulator type generates its specific correction functions based on its unique pixel shape, transparency, and pitch parameters. This allows the system to quickly adapt to different modulators by simply changing the pre-computed correction functions rather than recalculating everything, balancing speed and adaptability.
Data Source
AI summary
A method for encoding computer-generated holograms in pixelated light modulators, the encoding area of which comprises a pixel matrix whose pixels are provided with a pixel form and a pixel transparency, wherein the encoding area contains a hologram made up of sub-holograms, to each of which is assigned an object point of the object to be reconstructed by the hologram. The corruption of the reconstruction of the hologram caused by the real pixel form and the pixel transparency is largely eliminated and the computing time for correction of the hologram is reduced. Each individual computer-generated sub-hologram is multiplied by a correction function, and only thereafter the corrected sub-holograms are added up to form a total hologram, the correction function being based on the reciprocal of the transform of the pixel function (e.g. 1/sinc) associated with the virtual observer window.