Multiple Exposure Structured Light Speckle Pattern Noise Reduction
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Solution Overview
Problem
Time-of-flight depth cameras using structured light patterns face noise issues due to light intensity variations, limiting their ability to generate high-resolution depth maps, especially when using infrared images or standard imaging technologies.
Innovation Solution
Generating multiple complementary speckle patterns that are projected into the image environment in sequence, allowing for the summation of images to reduce noise and enhance resolution by filling in areas not illuminated by other patterns, thereby creating a substantially uniform illumination pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If structured light patterns are used for depth mapping, then depth information can be obtained, but noise and intensity variations limit resolution
Solution Approach 1:
The illumination pattern is segmented into multiple complementary speckle patterns that are projected sequentially. Each pattern covers different spatial regions with varying intensity distributions, and their combination fills in gaps and reduces noise, thereby improving depth map resolution while mitigating structure noise effects
Solution Approach 2:
Multiple images captured under different speckle patterns are merged through summation or averaging. This combining process integrates information from all patterns, filling in under-illuminated areas and reducing random noise, resulting in a high-resolution depth map with minimized structure noise
2Measurement precision
If multiple speckle patterns are projected in sequence, then noise is reduced and resolution enhanced, but illumination uniformity becomes challenging
Solution Approach 1:
Each speckle pattern is designed with specific local intensity characteristics that complement other patterns. Individual patterns may have non-uniform illumination in certain regions, but their complementary nature ensures that areas dark in one pattern are bright in another, achieving overall uniformity when combined
Solution Approach 2:
Multiple speckle patterns are projected in a periodic sequence, with each pattern providing complementary illumination information. The cyclic projection and capture of these patterns allows temporal averaging that reduces noise while the complementary design ensures spatial uniformity across the entire illumination sequence
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 enables the generation of clean, high-resolution depth maps with reduced structure noise by averaging complementary speckle patterns, improving the overall image resolution and eliminating noise caused by structured light patterns.
Implementation Method 1
the at least one transparent patterned element configured, for each received instance of coherent light, to cause interference of waves of the received instance of coherent light to generate a corresponding instance of illumination light that contains a respective speckle pattern
Data Source
AI summary
Methods, systems, apparatuses, and computer program products are provided for illuminating a scene with light containing speckle patterns. A plurality of instances of coherent light are generated in sequence. From each instance of coherent light of the plurality of instances of coherent light, a corresponding instance of illumination light is generated that contains a respective speckle pattern, thereby generating a plurality of instances of illumination light containing a plurality of respective speckle patterns. The plurality of speckle patterns are configured such that a summation of the plurality of speckle patterns forms a substantially uniform illumination pattern. The plurality of instances of illumination light are projected into an illumination environment in sequence.