Image and Sparse Depth Fusion for Scale-Accurate Depth Maps

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Solution Overview

Problem

Current depth mapping technologies using a single sensor type suffer from scale ambiguity, sparse depth information, limited depth range, and limited field of view, leading to incomplete and inaccurate depth estimation.

Innovation Solution

A hybrid approach utilizing both an image sensor and a sparse depth sensor, employing a fusion network and multi-stage depth prediction to generate a high-resolution dense depth map, which includes preprocessing to reduce noise and enhance resolution, and a light-weight encoder-decoder design to reduce computational burden.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If only an RGB camera sensor is used for depth mapping, then the system complexity is reduced, but scale ambiguity and inaccurate depth estimation occur

Engineering Contradiction:
Improvesensor system complexityVSAvoiddepth estimation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent combines data from an RGB camera sensor and a Time-of-Flight (ToF) sensor to generate depth maps. The RGB sensor provides wide-field depth information while the ToF sensor provides accurate sparse depth measurements, and their fusion resolves scale ambiguity to achieve both reduced complexity and improved accuracy.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If only a Time-of-Flight (ToF) sensor is used for depth mapping, then the measurement precision is improved, but the field of view and depth information completeness are limited

Engineering Contradiction:
Improvedepth measurement accuracyVSAvoidfield of view coverage
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent merges the sparse but accurate depth data from the ToF sensor with the dense but ambiguous depth data from the RGB sensor. This combination extends the effective field of view while maintaining measurement precision through data fusion and scale correction.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If a hybrid sensor system with fusion network is used, then the depth estimation accuracy is improved, but the computational burden increases

Engineering Contradiction:
Improvedepth map accuracyVSAvoidprocessing system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary actions by pre-processing the sparse depth frame from the ToF sensor before fusion, including noise reduction and coordinate transformation. This preparation reduces the complexity of the subsequent fusion operation and enables efficient processing on mobile devices.

Inventive Principle:
Principle #10Preliminary action

4Loss of information

If preprocessing and fusion operations are performed on sparse depth frames, then the depth information completeness is improved, but the processing time increases

Engineering Contradiction:
Improvedepth information completenessVSAvoidprocessing time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The patent applies partial preprocessing operations focused only on critical aspects of the sparse depth frame (noise reduction in depth values, coordinate alignment) rather than complete image processing. This selective approach recovers lost depth information while minimizing processing time for real-time applications.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS12488421B2Depth estimation based on data fusion of image sensor and depth sensor frames
Publication Date: 2025.12.02 BLACK SESAME TECH INC
  • US12488421B2 patent drawing
  • US12488421B2 patent drawing
  • US12488421B2 patent drawing

AI summary

A method of depth estimation, including, receiving an image frame, determining a relative depth map based on the image frame, receiving a sparse depth frame, preprocessing the sparse depth frame, determining a scale-adjusted relative depth map based on the relative depth map and the preprocessed sparse depth frame and fusing the relative depth map and the scale-adjusted relative depth map to produce an absolute depth map.