Far Field Hologram Superposition for Spurious Noise Reduction
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Solution Overview
Problem
Far field holograms often suffer from isolated pixel errors that result in noticeable deviations from the intended image effect due to limitations in design and fabrication, particularly in low space bandwidth product (SBP) applications where spurious errors can cause confusion for the observer.
Innovation Solution
The implementation of a method that generates a far field transmission hologram using multiple unit holograms with differing noise characteristics, which are superposed to reduce spurious pixel errors while maintaining good overall noise performance, involves altering the optical properties of a substrate to form shift-invariant unit holograms with low spurious noise terms, selecting candidate holograms based on error measurements, and arranging them into a cluster to form a larger digital hologram.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single unit hologram is used, then the design and fabrication process is simple, but spurious pixel errors create noticeable deviations from the intended image effect
Solution Approach 1:
The hologram is divided into multiple unit holograms (first, second, third, and fourth unit holograms) that are arranged in a specific pattern. Each unit hologram contributes to the overall image while distributing the spurious error characteristics across multiple components, reducing the visibility of individual pixel errors in the composite image.
2Manufacturing precision
If multiple unit holograms with differing noise characteristics are superposed, then spurious pixel errors are reduced, but the device complexity increases
Solution Approach 1:
The unit holograms are positioned asymmetrically relative to the optical axis, with specific units located in different quadrants. This asymmetric arrangement ensures that spurious error patterns from each unit do not align constructively, thereby reducing the overall visibility of pixel errors in the composite holographic image.
Solution Approach 2:
The relative positions of the unit holograms are predetermined during the design phase to optimize noise cancellation. The holograms are arranged in advance with specific spacing and orientation relationships that are calculated to minimize spurious error visibility before the actual viewing process occurs.
3Manufacturing precision
If tight tolerance on relative positions is required, then image accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
By segmenting the hologram into multiple units with different noise characteristics, the system becomes less sensitive to positioning errors. The distributed architecture means that small misalignments do not cause catastrophic image degradation, as each unit contributes independently to the overall image formation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach minimizes spurious errors in the holographic light patterns, ensuring that the actual response corresponds to the intended perception of a tailored low SBP image, while maintaining acceptable overall noise performance and shift-invariance, allowing for faithful overlay of graphic images on natural scenes without requiring tight tolerance on the relative positions of the hologram and observer's eye.
Implementation Method 1
A hologram is a pattern recorded or applied to a substrate that provides a predetermined light diffraction effect
Data Source
AI summary
Systems, methods, and devices are provided relating to far field hologram viewing devices. A method of designing and manufacturing a far field hologram is provided. Holographic light patterns with minimal spurious pixel errors in the hologram response may be produced without requiring a tight tolerance on the relative positions of the hologram and an observer's eye. Far field viewing devices, and methods for making the same, that employ multiple unit holograms each having differing noise characteristics that superpose in a way to reduce the effects of spurious pixel errors while maintaining good overall noise performance.