3D Depth Mapping Using ToF and Pattern Distortion
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Solution Overview
Problem
Conventional 3D imaging techniques struggle to produce high-quality depth maps in wide depth ranges, especially under low-texture and low-illumination conditions, due to limitations in stereoscopic passive and active projective schemes.
Innovation Solution
A method and device using a beam projector and detector to project and detect beams, identifying time-of-flight (ToF) and pattern distortion to generate a depth map, combining ToF and structured light (SL) schemes for improved depth estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If stereoscopic passive scheme is used to generate depth map, then device complexity is reduced, but measurement precision deteriorates under low-texture and low-illumination conditions
Solution Approach 1:
The patent combines stereoscopic passive scheme and active projective scheme into a hybrid system. The beam projector projects patterns onto the object while the beam detector captures reflected beams, merging the simplicity of passive stereo with the active illumination capability to maintain measurement precision under low-texture and low-illumination conditions.
Solution Approach 2:
The patent introduces a beam pattern as an intermediary element. By projecting a known pattern of beams and detecting its distortion upon reflection, the system creates an intermediate representation that enables accurate depth measurement even in challenging lighting and texture conditions, resolving the limitation of passive stereo alone.
2Measurement precision
If active projective scheme with ToF is used to generate depth map, then measurement precision is improved, but depth errors become significant within short range
Solution Approach 1:
The patent applies different measurement approaches to different depth ranges. For short-range objects, the system utilizes pattern distortion analysis which provides high accuracy. For longer ranges, ToF measurement is employed. This local differentiation of measurement quality resolves the contradiction between overall precision improvement and short-range reliability.
Solution Approach 2:
The system dynamically switches between pattern distortion-based measurement and ToF-based measurement depending on the detected object distance. This dynamic adaptation allows the system to maintain high reliability across varying depth ranges while benefiting from the precision advantages of active projective schemes.
3Measurement precision
If pattern distortion scheme with triangulation is used to generate depth map, then measurement precision is improved within short range, but errors become serious as range expands
Solution Approach 1:
The system dynamically adapts the measurement method based on object distance. For nearby objects where pattern distortion provides high precision, the system uses triangulation. For distant objects where triangulation errors amplify, the system switches to ToF measurement, thus maintaining reliability across the entire depth range while preserving short-range precision.
Solution Approach 2:
By merging pattern distortion scheme and ToF scheme into a unified system that automatically selects the appropriate method based on range, the patent achieves both short-range precision and long-range reliability, overcoming the limitations of either scheme alone.
4Measurement precision
If higher calculation complexity is used to create dense depth map, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the depth map generation process into two independent pathways: one for pattern distortion analysis and another for ToF measurement. Each pathway processes specific portions of the scene independently, reducing the overall computational burden while maintaining high precision through the combination of results from both pathways.
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 allows for the generation of high-quality depth maps in a wide depth range with reduced computational load, enhancing 3D imaging capabilities.
Implementation Method 1
identifying time-of-flight (ToF) of each of the plurality of projected beams based on the plurality of detected beams
Implementation Method 2
identifying a distortion of the pattern, which is caused by the object, based on the plurality of detected beams
Data Source
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AI summary
A method and device are provided for obtaining a 3D image. The method includes sequentially projecting a plurality of beams to an object, each of the plurality of projected beams corresponding to a respective one of a plurality of sectors included in a pattern; detecting a plurality of beams reflected off of the object corresponding to the plurality of projected beams; identifying time-of-flight (ToF) of each of the plurality of projected beams based on the plurality of detected beams; identifying a distortion of the pattern, which is caused by the object, based on the plurality of detected beams; and generating a depth map for the object based on the distortion of the pattern and the ToF of each of the plurality of projected beams, wherein the plurality of detected beams are commonly used to identify the ToF and the distortion of the pattern.