Segmented Optical Distance Measurement Against Indirect Light

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Solution Overview

Problem

Optical detection devices face accuracy issues due to the reception of indirect light, which can degrade the precision of object detection and distance measurement, particularly when light is not applied to or reflected from the intended detection object through the assumed optical path.

Innovation Solution

The optical detection device employs a light emitter capable of full and partial irradiation, with divided light-emitting and light-receiving sections, and a processor that identifies and reduces indirect light by comparing light reception amounts during full and partial irradiation, adjusting irradiation patterns to minimize indirect light influence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the light emitter performs full irradiation to improve detection coverage, then the detection area is increased, but the light receiver receives more indirect light which reduces detection accuracy

Engineering Contradiction:
Improvedetection areaVSAvoiddetection accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The light emitter is divided into multiple light emission sections that can be independently controlled, and the light receiver is divided into multiple light reception sections. This segmentation allows selective irradiation of specific areas while monitoring for indirect light from other directions, thus maintaining detection coverage while improving accuracy by reducing indirect light interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different light emission sections are controlled with different irradiation patterns (full irradiation, partial irradiation, alternating irradiation) based on local conditions. The system applies local quality by adjusting which sections emit light and when, allowing optimal detection in each local area while minimizing overall indirect light reception.

Inventive Principle:
Principle #3Local quality

2Reliability

If the light receiver receives all reflected light to improve signal strength, then the detection sensitivity is increased, but the accuracy decreases due to inclusion of indirect light

Engineering Contradiction:
Improvedetection sensitivityVSAvoiddetection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system uses feedback by comparing light reception amounts between full irradiation and partial irradiation modes. When indirect light is detected through this comparison, the system adjusts the irradiation pattern to reduce indirect light while maintaining sufficient signal strength for accurate detection.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Instead of always performing full irradiation, the system uses partial irradiation where only certain light emission sections are activated. This partial action reduces the total amount of indirect light generated while maintaining enough reflected light signal for reliable detection in the irradiated areas.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If the system performs multiple irradiation patterns to reduce indirect light, then the detection accuracy is improved, but the processing time increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system employs periodic action by alternating irradiation between different light emission sections in a predetermined pattern. This allows the system to efficiently detect indirect light through comparison while maintaining continuous detection capability, reducing the time penalty compared to sequential full measurements.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system performs preliminary detection using partial irradiation patterns to identify the presence of indirect light before committing to full irradiation measurements. This preliminary action allows the system to avoid time-consuming re-measurements when indirect light conditions are detected.

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 enhances the accuracy of object detection and distance measurement by effectively distinguishing and reducing the impact of indirect light, improving precision and reducing processing time and load.

Implementation Method 1

a light emitter irradiates a measurement object with light, a light receiver receives reflected light reflected from the measurement object

Methodology Applied
Scientific EffectOptical reflection: Reflection

Data Source

PatentEP4224205B1Optical detection device, optical distance measurement device, optical detection method, and program
Publication Date: 2025.11.19 FUJIFILM BUSINESS INNOVATION CORP
  • EP4224205B1 patent drawingFigure 1
  • EP4224205B1 patent drawingFigure 2
  • EP4224205B1 patent drawingFigure 3

AI summary

An optical detection device includes a light emitter that irradiates an area of interest; a light receiver that receives reflected light that has been emitted by the light emitter and reflected on a detection object, the light receiver including plural light-receiving elements divided into plural light reception sections; and a processor configured to perform at least one of full irradiation for irradiating the whole area of interest and full light reception for outputting all light reception results and at least one of partial irradiation for irradiating part of the area of interest and partial light reception for outputting part of the light reception results one part by one part and perform an object detection process for detecting the detection object in accordance with light received by the light receiver. The processor is configured to, based on a difference between an amount of received light received at each of the light reception sections at a time when the light emitter performs the full irradiation and an amount of received light received at each of the light reception sections at a time when the light emitter performs the partial irradiation, perform an indirect light detection process for detecting that at least one of the plural light reception sections receives indirect light when the light emitter performs the full irradiation.