3D Mapping Using Single-Sensor Speckle Pattern Analysis
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Solution Overview
Problem
Current 3D imaging technologies using speckle patterns require multiple cameras and complex processing to achieve accurate depth mapping, which can be cumbersome and inefficient, especially for real-time applications.
Innovation Solution
A system utilizing a single coherent light source and a stationary image sensor to project and capture primary speckle patterns, allowing for accurate 3D mapping by computing correlation coefficients between successive images, with novel illumination and image processing schemes to enhance accuracy and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple cameras and complex processing are used, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple camera systems into a single camera by projecting multiple speckle patterns simultaneously using a spatial light modulator. This combines the functionality of multiple cameras into one device, reducing system complexity while maintaining the capability to capture multiple depth layers through computational processing of the combined speckle patterns.
Solution Approach 2:
The single camera system is designed to perform multiple functions: capturing specular reflections, diffuse reflections, and transmissive properties simultaneously through different speckle patterns. This multi-functional approach replaces what would traditionally require multiple specialized cameras, reducing device complexity while preserving measurement precision across different object properties.
2Measurement precision
If multiple cameras and complex processing are used, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The system pre-calibrates and stores reference speckle patterns for different material properties (specular, diffuse, transmissive) before actual measurement. During real-time operation, the captured speckle pattern is quickly compared against these pre-prepared references using efficient correlation algorithms, significantly reducing processing time while maintaining accurate depth mapping across different material types.
Solution Approach 2:
The spatial light modulator rapidly switches between different speckle patterns in a periodic sequence, projecting multiple patterns in quick succession. This periodic modulation allows the single camera to capture multiple depth layers within a single frame rate, achieving real-time processing speed comparable to multiple simultaneous cameras while maintaining measurement precision through temporal multiplexing.
3Device complexity
If a single image sensor is used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The system changes the parameters of the projected light by using a spatial light modulator to generate multiple distinct speckle patterns with different spatial frequencies and orientations. By varying these optical parameters and capturing the resulting speckle patterns from a single sensor, the system extracts multiple depth layers through computational analysis, achieving 3D mapping accuracy comparable to multiple cameras while maintaining device simplicity.
Solution Approach 2:
The patent transitions from spatial multiplexing (multiple cameras capturing simultaneous views) to temporal multiplexing (single camera capturing sequential speckle patterns). By adding the time dimension to the measurement process and using computational algorithms to analyze the temporal variations in speckle patterns, the single sensor achieves multi-depth-layer precision that would traditionally require multiple spatial sensors.
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
Enables rapid and accurate 3D mapping of objects in real-time using a single image sensor and light source, improving depth of field and computational efficiency, suitable for applications like gesture recognition and 3D object profiling.
Implementation Method 1
When a coherent beam of light passes through a diffuser and is projected onto a surface, a primary speckle pattern can be observed on the surface. The primary speckle is caused by interference among different components of the diffused beam.
Implementation Method 2
The term 'primary speckle' is used in this sense in the present patent application and in the claims, in distinction to secondary speckle, which is caused by diffuse reflection of coherent light from the rough surface of an object
Data Source
AI summary
Apparatus (20) for 3D mapping of an object (28) includes an illumination assembly (30), including a coherent light source (32) and a diffuser (33), which are arranged to project a primary speckle pattern on the object. A single image capture assembly (38) is arranged to capture images of the primary speckle pattern on the object from a single, fixed location and angle relative to the illumination assembly. A processor (24) is coupled to process the images of the primary speckle pattern captured at the single, fixed angle so as to derive a 3D map of the object.