Codeword Boundary Detection for Structured Light Depth Maps

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Solution Overview

Problem

Generating depth maps using structured light systems is computationally expensive, hindering the commercialization of these systems due to the high computation time required.

Innovation Solution

The system employs a structured light active sensing method that projects and receives spatial codes (codewords) to generate depth maps, utilizing a transmitter and receiver configuration with a code mask to identify codeword boundaries and calculate disparities, thereby reducing processing complexity through efficient codeword boundary detection and disparity mapping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional structured light depth map generation methods are used, then depth map accuracy is maintained, but computation time becomes excessively long

Engineering Contradiction:
Improvedepth map accuracyVSAvoidcomputation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the depth map generation process into distinct phases: codeword boundary detection, codeword identification, and disparity calculation. By dividing the received image into potential codeword regions first and then processing each segment independently, the system reduces overall computation time while maintaining depth map accuracy through systematic processing of each segmented region.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary codeword boundary detection and candidate codeword identification before final disparity calculation. By pre-identifying potential codeword locations and boundaries in the received image, the system prepares data structures and reduces the search space for subsequent depth calculation, significantly reducing computation time while preserving measurement precision.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If comprehensive image processing is performed to ensure accurate depth extraction, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improvedepth extraction accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the complex image processing task into segmented steps: boundary detection, codeword candidate identification, and disparity computation. Each segment handles a specific aspect of the problem with dedicated algorithms, reducing overall processing complexity while maintaining accuracy through systematic multi-stage processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces intermediate data structures and processing stages, such as codeword candidate regions and boundary detection maps, that serve as mediators between the raw received image and the final depth map. These intermediaries organize complex processing into manageable steps, reducing device complexity while preserving measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3494545B1Methods and apparatus for codeword boundary detection for generating depth maps
Publication Date: 2023.10.04 QUALCOMM INC
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AI summary

A structured light active sensing systems may be configured to transmit and received codewords to generate a depth map by analyzing disparities between the locations of the transmitted and received codewords. To determine the locations of received codewords, an image of the projected codewords is identified, from which one or more codeword boundaries are detected. The codeword boundaries may be detected based upon a particular codeword bit of each codeword. Each detected codeword boundary may be constrained from overlapping with other detected codeword boundaries, such that no pixel of the received image is associated with more than one codeword boundary.