In-Vehicle Camera Lens Alignment via Vignetting Analysis

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Solution Overview

Problem

In-vehicle camera devices face challenges in accurately determining positional displacement between the lens and imaging element due to temperature/humidity changes and aging, which affects the accuracy of distance calculation and optical distortion correction in driving support systems.

Innovation Solution

The imaging device employs an image processing unit to calculate the optical axis position based on the shapes of vignetting areas, allowing for accurate determination of positional displacement between the lens and imaging element, and corrects optical distortion using an affine table created from a lattice chart.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the lens and imaging element are adjusted manually to achieve initial alignment, then the initial imaging quality is improved, but the positional displacement caused by temperature/humidity changes and aging cannot be completely eliminated

Engineering Contradiction:
Improveinitial alignment precisionVSAvoidstability under environmental changes
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the imaging device automatically detects positional displacement between the lens and imaging element by analyzing vignetting area shapes in captured images. The system calculates displacement quantities based on changes in vignetting area characteristics and automatically generates correction instructions to realign the optical axis, thereby maintaining imaging quality despite environmental changes and aging.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The imaging device performs self-diagnosis and self-correction by using its own imaging function to detect alignment errors. The system automatically analyzes the vignetting patterns in captured images, calculates the degree of misalignment, and executes correction without requiring external intervention or specialized testing equipment.

Inventive Principle:
Principle #25Self-service

2Reliability

If complex adjustment mechanisms are added to compensate for positional displacement, then the stability under environmental changes is improved, but the device complexity increases

Engineering Contradiction:
Improvestability under environmental changesVSAvoidadjustment mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical adjustment mechanisms with an information-processing approach. Instead of using mechanical sensors and actuators to detect and correct alignment errors, the system uses image processing algorithms to analyze vignetting patterns and calculate displacement quantities, then controls the imaging element position based on these calculations, thereby simplifying the overall device structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces vignetting area analysis as an intermediary method to detect positional displacement. Rather than directly measuring the physical distance or position between the lens and imaging element, the system uses the optical phenomenon of vignetting as an intermediate indicator that reflects alignment status, enabling indirect but accurate detection of misalignment.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If frequent manual re-adjustment is performed to maintain alignment accuracy, then the measurement precision of distance calculation is improved, but the loss of time and operational efficiency deteriorates

Engineering Contradiction:
Improvedistance calculation accuracyVSAvoidtime for manual re-adjustment
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent enables continuous monitoring and correction of alignment status by automatically analyzing vignetting patterns in successive images. The system continuously detects positional displacement and performs real-time correction, ensuring that alignment accuracy is maintained without interruption or manual intervention, thereby eliminating time loss associated with periodic manual re-adjustment.

Inventive Principle:
Principle #20Continuity of useful 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 enables precise determination of positional displacement and correction of optical distortion, enhancing the accuracy of distance calculation and object recognition in varying environments, while reducing manufacturing costs.

Implementation Method 1

an imaging element 2 disposed on the other side of the lens 1 opposite to the imaging object

Methodology Applied
Scientific EffectOptical imaging: Lens

Implementation Method 2

calculate the optical axis position based on the shapes of vignetting areas, allowing for accurate determination of positional displacement

Methodology Applied
Scientific EffectVignetting:

Data Source

PatentEP3564747B1Imaging device and imaging method
Publication Date: 2021.10.27 ASTEMO LTD
  • EP3564747B1 patent drawingFigure 1~2
  • EP3564747B1 patent drawingFigure 3~4
  • EP3564747B1 patent drawingFigure 5~6

AI summary

The present invention provides an imaging device and an imaging method, wherein it is possible to accurately determine positional displacement quantity between a lens and an imaging element. The present invention is provided with: a lens 1 that is disposed to face an imaging object; and an imaging element that is disposed on the other side of the lens 1 opposite to the imaging object so as to have vignetting areas 4a-4d located outside an image circle 3 which is a range where incident light coming in through the lens 1 forms an image. Displacement quantity between the lens 1 and the imaging element 2 with respect to the initial positions thereof is calculated by calculating the position of an optical axis 1a of the lens 1 on the imaging element 2, on the basis of the shapes of vignetting areas 4e-4g with respective to the initial relative position between the lens 1 and the imaging element 2 and the shapes thereof with respect to a displaced position which results from displacement in the relative position between the lens 1 and the imaging element 2.