Depth Resolution via Analog Blur Restoration in ToF Systems

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Solution Overview

Problem

The resolution of depth in three-dimensional measurement techniques using the time of flight method is limited by the sampling period, which restricts the measurement range and accuracy.

Innovation Solution

An information processing apparatus that employs analog degradation of reference light followed by restoration processing to enhance depth resolution, involving a degradation unit that blurs the light reception image based on a known degradation characteristic and a restoration unit that restores the light reception data using an inverse characteristic, allowing for more accurate depth estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the sampling period is lengthened to widen the distance measurement range, then the measurement range increases, but the depth resolution decreases

Engineering Contradiction:
Improvedistance measurement rangeVSAvoiddepth resolution
Core Design Contradiction:
Length of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies preliminary degradation to the light reception data before depth estimation. By intentionally blurring the light reception image based on a known degradation characteristic (such as point spread function) before sampling, the system prepares the data in advance to enable super-resolution reconstruction. This preliminary action allows the restoration unit to later recover depth information with resolution exceeding the sampling period limitation, thus resolving the contradiction between measurement range and depth resolution.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the sampling period is shortened to improve depth resolution, then the depth resolution improves, but the measurement range becomes limited

Engineering Contradiction:
Improvedepth resolutionVSAvoidmeasurement range
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent introduces an additional processing dimension by applying degradation and restoration operations in the spatial domain before depth calculation. Instead of directly sampling the light reception data, the system transforms the problem by convolving with a degradation kernel (point spread function) and then restoring using inverse filtering or iterative optimization. This dimensional transformation enables the system to achieve high depth resolution while maintaining wide measurement range, as the restoration process can recover fine depth details without being constrained by the original sampling period.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If analog degradation processing is applied to improve depth resolution, then depth resolution and measurement range improve, but processing complexity increases

Engineering Contradiction:
Improvedepth resolutionVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the parameters of the light reception data by applying controlled analog degradation (blurring) with specific degradation characteristics such as point spread function models. By adjusting degradation parameters (blur radius, kernel type) and restoration parameters (regularization strength, iteration count), the system optimizes the balance between depth resolution improvement and processing complexity. The degradation characteristic is designed to match the optical system's actual point spread function, enabling effective restoration while keeping computational load manageable through parameter optimization.

Inventive Principle:
Principle #35Parameter changes

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 improves the depth resolution beyond the limitations of the sampling period, reducing saturation issues and enhancing the accuracy of depth measurement across a wider range, while also improving spatial resolution.

Implementation Method 1

A three-dimensional measurement technique using a time of flight (ToF) method is known. In this method, reference light such as an infrared pulse is projected toward a subject, and the depth of the subject is detected on the basis of information on the time until the reflected light is received.

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentUS20240144502A1Information processing apparatus, information processing method, and program
Publication Date: 2024.05.02 SONY GROUP CORP
  • US20240144502A1 patent drawing
  • US20240144502A1 patent drawing
  • US20240144502A1 patent drawing

AI summary

An information processing apparatus (30) includes a degradation unit (31), a restoration unit (33), and a depth estimation unit (35). The degradation unit (31) blurs a light reception image of reference light (PL) received by a light reception unit (20) on the basis of a known degradation characteristic. The restoration unit (33) restores light reception data of the reference light (PL) using a restoration characteristic that is an inverse characteristic of the degradation characteristic. The depth estimation unit (35) estimates the depth of a subject on the basis of the restored light reception data.