Tilted Structured Light Transmitter Near Field Depth Mapping

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Structured light systems face challenges in achieving a close near field of view without limiting the selection of optical components, as the design requires a careful balance of aperture size, focal length, and speckle noise tolerance, making it complex to generate depth maps for objects close to the device.

Innovation Solution

The system tilts the optical transmitter relative to the receiver, causing the projection and capture fields to intersect closer to the device, allowing for a wider variety of optical components and increasing the near field of view without the need for specialized components, while compensating for the tilt in depth map calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the transmitter and receiver are positioned with parallel optical axes, then the system can maintain a simple design, but the near field of view becomes too far away to be useful

Engineering Contradiction:
Improvenear field of view distanceVSAvoidoptical component design complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by tilting the transmitter optical axis relative to the receiver optical axis at a specific angle (e.g., 15-30 degrees), breaking the parallel symmetry of conventional systems. This asymmetric configuration allows the projection field and capture field to intersect closer to the device, achieving a closer near field of view while maintaining manageable system complexity through calculated geometric relationships

Inventive Principle:
Principle #4Asymmetry

2Length of moving object

If the transmitter is tilted relative to the receiver to achieve closer near field of view, then the near field of view distance improves, but the optical component selection becomes more limited

Engineering Contradiction:
Improvenear field of view distanceVSAvoidoptical component selection range
Core Design Contradiction:
Length of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent changes the geometric parameter of the optical axis angle from the conventional 0 degrees (parallel) to a tilted angle (15-30 degrees). This parameter change fundamentally alters the field intersection geometry, enabling closer near field of view while actually expanding optical component selection to include standard off-the-shelf components that would not work in parallel configurations

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the optical components are selected with standard specifications, then the ease of manufacture improves, but the depth map accuracy for close objects deteriorates

Engineering Contradiction:
Improveoptical component availabilityVSAvoiddepth map accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing correction factors and geometric relationships in lookup tables before operation. The system pre-characterizes the tilted optical geometry and prepares compensation algorithms that automatically correct depth calculations, allowing standard optical components to achieve accurate depth measurements for close objects without requiring custom precision components

Inventive Principle:
Principle #10Preliminary action

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 a closer near field of view while maintaining system accuracy and allowing for the use of various optical components, with a potential 5% gain in useful depth map size and reduced component specificity.

Implementation Method 1

receiving, with an optical receiver, a reflection of the structured light

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3400414B1Depth map generation in structured light system
Publication Date: 2023.03.29 QUALCOMM INC
  • EP3400414B1 patent drawingFigure 1A
  • EP3400414B1 patent drawingFigure 1B
  • EP3400414B1 patent drawingFigure 2

AI summary

Techniques are disclosed for depth map generation in a structured light system where an optical transmitter is tilted relative to an optical receiver. The optical transmitter has a transmitter optical axis around which structured light spreads, and the optical receiver has a receiver optical axis around which a reflection of the structured light can be captured. The transmitter optical axis and the receiver optical axis intersect one another. A processing circuit compensates for the angle in the tilt in the reflected pattern to generate the depth map.