Optical Device Speckle Noise Reduction via Angular Diversity
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Solution Overview
Problem
Conventional three-dimensional measurement systems using coherent light sources, such as laser diodes, suffer from speckle noise due to the interference of scattered light, which degrades measurement accuracy and image quality.
Innovation Solution
An optical device employing a plurality of light emitting elements arranged at a predetermined distance, with an optical system converting their light into line light beams and a light deflection element that aligns the longitudinal direction of each line light beam with the rotating axis of the deflection element, achieving angular diversity to reduce speckle noise by overlapping different speckle patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coherent light from laser diode is used as light source, then measurement capability is enabled, but speckle noise is generated which degrades measurement accuracy
Solution Approach 1:
The patent divides a single coherent light source into multiple independent light emitting elements (first, second, and third light emitting elements) arranged at specific intervals. Each element generates its own speckle pattern, and the superposition of these multiple patterns reduces the overall speckle noise while maintaining measurement capability.
Solution Approach 2:
The patent combines light beams from multiple light emitting elements through an optical system that superimposes them. The multiple speckle patterns from different light sources are merged in the projection area, creating an averaged speckle pattern that reduces noise and improves measurement accuracy.
2Measurement precision
If multiple light emitting elements are used to reduce speckle noise, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent employs a single light deflection element that serves multiple functions: it deflects light beams from all light emitting elements simultaneously and rotates to control the projection area. This multi-functional approach reduces the need for separate deflection mechanisms for each light source, thereby managing device complexity.
Solution Approach 2:
The patent introduces temporal dimension through rotation of the light deflection element, allowing a single element to cover multiple projection areas sequentially. This dimensional approach enables one light emitting element to effectively serve multiple spatial zones, reducing the total number of elements needed.
Data Source
AI summary
An optical device according to an embodiment of the present disclosure includes a light source in which a plurality of light emitting elements are arranged at a predetermined distance, an optical system configured to convert light beams from the plurality of light emitting elements into line light beams, and a light deflection element configured to deflect each of the line light beams. Each of the line light beams is caused to be incident on the light deflection element such that a longitudinal direction of each of the light beams is aligned with a direction of a rotating axis of the light deflection element.