Structured Light Proximity Sensing for Close-Range Depth Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing mobile devices require separate depth mapping and proximity sensing modules, increasing size and cost while reducing image display area, as existing depth mapping systems are ineffective in close proximity ranges.
Innovation Solution
A single module combines depth mapping and proximity sensing by projecting a pattern of spots, using a diffractive optical element (DOE) to extend the useful range of depth mapping to shorter distances through novel image processing algorithms, eliminating the need for a separate proximity sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate depth mapping and proximity sensing modules are used, then sensing accuracy is improved, but device size and cost increase
Solution Approach 1:
The patent combines depth mapping and proximity sensing functions into a single module. The structured light projector and image sensor used for depth mapping are also utilized for proximity sensing by detecting the pattern of spots at close ranges, eliminating the need for a separate proximity sensor and reducing device size.
Solution Approach 2:
The depth mapping module is designed to perform multiple functions: it can measure depth at various distances and detect proximity objects. The same hardware components (projector, image sensor, processor) handle both depth mapping and proximity sensing tasks, making the system multi-functional and reducing overall device complexity.
2Measurement precision
If separate depth mapping and proximity sensing modules are used, then sensing accuracy is improved, but image display area is reduced
Solution Approach 1:
By merging proximity sensing into the depth mapping module, the patent eliminates the need for separate sensor modules that would occupy additional space on the device. This integration preserves image display area while maintaining sensing accuracy through the shared structured light system.
3Adaptability or versatility
If depth mapping is extended to shorter distances, then proximity sensing capability is improved, but measurement precision may deteriorate
Solution Approach 1:
The patent applies different processing methods for different distance ranges. For close proximity objects, the system detects the pattern of spots and their positions to determine distance, while for farther objects it uses traditional depth mapping techniques. This localized approach ensures measurement precision is maintained across different ranges.
Solution Approach 2:
The system changes the operational parameters of the structured light pattern based on distance. By adjusting the pattern characteristics and detection algorithms according to the target distance, the system maintains measurement precision while extending capability to short distances for proximity sensing.
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
The solution effectively integrates depth and proximity sensing functions in a single module, extending the range of depth mapping to close proximity without additional hardware cost, thus reducing device size and cost while maintaining sensing accuracy.
Implementation Method 1
Some structured-light depth mapping systems use diffractive optical elements (DOEs) in creating and projecting a pattern of spots. The first DOE is configured to apply to the input beam a pattern with a specified divergence angle, while the second DOE is configured to split the input beam into a matrix of output beams with a specified fan-out angle.
Data Source
AI summary
Sensing apparatus includes a projector, which projects toward a target a pattern of spots extending over a predefined angular range about a projection axis. An imaging assembly includes an image sensor and objective optics, which form on the image sensor an image of the target along an imaging axis, which is offset transversely relative to the projection axis. A processor is configured to process signals output by the image sensor so as generate, while the target is within a first span of distances from the apparatus, a depth map of the target responsively to shifts of the spots in the image, and to estimate, while the target is within a second span of distances, nearer to the apparatus than the first span, a distance to the target from the apparatus by detecting in the image a part of the pattern located at an edge of the angular range.