Focus Abnormality Detection Using Vignetting Region Changes

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Solution Overview

Problem

Conventional systems fail to accurately detect focus abnormality in imaging devices used in movable bodies due to the need for generating stereo image data, which imaging devices with a single viewpoint cannot handle.

Innovation Solution

An abnormality detection device that utilizes an image sensor with a lens having an effective image circle smaller than the imaging surface to detect focus abnormality by analyzing changes in the vignetting region of captured images, combined with sharpness analysis to confirm the presence of focus issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If parallax image data is generated from stereo image data to determine imaging device abnormality, then focus abnormality detection is enabled, but imaging devices with single viewpoint cannot perform abnormality detection

Engineering Contradiction:

Improveabnormality detection capabilityVSAvoidcompatibility with single viewpoint imaging devices

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the detection parameter from parallax image data (requiring stereo cameras) to vignetting region characteristics (workable with single viewpoint). By analyzing the vignetting region size and its relationship with the effective image circle, the system achieves focus abnormality detection using only single viewpoint image data, thus resolving the contradiction between detection reliability and device adaptability

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If an effective image circle smaller than imaging surface is used to create vignetting region for detection, then focus abnormality can be detected through vignetting changes, but image utilization area is reduced

Engineering Contradiction:

Improvefocus abnormality detection accuracyVSAvoideffective imaging area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent extracts the vignetting region (caused by the effective image circle being smaller than the imaging surface) as a useful detection feature. Instead of viewing the reduced imaging area as a loss, the system utilizes the vignetting characteristics as a diagnostic tool for focus abnormality detection, thus converting the area reduction into a measurement advantage

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentEP3998769B1Abnormality detection device, abnormality detection method, program, and information processing system

Publication Date: 2026.03.04 SONY SEMICON SOLUTIONS CORP

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AI summary

The imaging unit 500 captures an image using a lens having an effective image circle smaller than the imaging surface of an image sensor. A vignetting amount calculation unit 2212 of a detection unit 221 individually calculates, for four corners, a region size of a vignetting region generated in the captured image acquired by the imaging unit 500, for example. A determination unit 2214 detects a change in the region size calculated at the time of focus abnormality detection processing with respect to the region size calculated at the reference time, and determines that a focus abnormality is detected when the change in the region size exceeds a threshold at any of the four corners. This enables accurate detection of focus abnormality.