Camera Unit Focus Calibration via Iterative Region Analysis

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Solution Overview

Problem

Digital cameras often struggle with achieving optimal focus, leading to blurred images due to inadequate focusing, which makes the imaging system unusable.

Innovation Solution

A method for calibrating camera optics using a calibration image with high contrast details, analyzing different regions to compute focus convergence parameters, and adjusting optical properties to improve focus quality by rotating the camera unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If focusing adjustment is performed using conventional methods, then the imaging system can capture images, but the focus quality is insufficient leading to blurred images

Engineering Contradiction:
Improvefocus qualityVSAvoidimaging system usability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements an automated feedback mechanism where the system captures calibration images, computes focus convergence parameters by analyzing edge detector operators across multiple regions, compares these parameters to determine if focus quality improved, and iteratively adjusts optical properties until optimal focus is achieved. This closed-loop feedback process eliminates manual intervention and ensures reliable focus calibration.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces manual mechanical focusing adjustment with an automated computational system. Instead of relying on mechanical focus adjustment mechanisms operated manually, the system uses image processing algorithms that compute focus convergence parameters from calibration images and automatically control the focus adjustment mechanism to achieve optimal sharpness.

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

2Measurement precision

If manual focusing adjustment is performed, then the process is simple, but the focus convergence is not optimal resulting in blurred images

Engineering Contradiction:
Improvefocus convergenceVSAvoidcalibration process complexity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system performs self-calibration by automatically capturing calibration images, computing focus convergence parameters through edge detector analysis, determining whether focus quality improved, and adjusting optical properties without requiring manual intervention. The calibration process is autonomous, with the system serving itself to achieve optimal focus convergence.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent systematically varies optical parameters during calibration, specifically adjusting the optical properties of camera optics to change the location of focus. By computing focus convergence parameters at different optical parameter settings and comparing them to identify improvement, the system optimizes focus convergence through controlled parameter changes.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If focus calibration is performed without automated analysis, then the process is simpler, but the imaging system produces blurred and messed up scenes

Engineering Contradiction:
Improveimaging system usabilityVSAvoidcalibration apparatus complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates multiple functions into a single calibration system: image capture, automated focus convergence parameter computation through edge detector analysis, comparison logic to determine improvement, and optical property adjustment. This multi-functional integrated approach ensures reliable focus calibration while managing system complexity through unified design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3542218B1Method and apparatus for calibration of a camera unit
Publication Date: 2021.03.17 NOKIA TECHNOLOGIES OY
  • EP3542218B1 patent drawingFigure 1a~1b
  • EP3542218B1 patent drawingFigure 2a~3
  • EP3542218B1 patent drawingFigure 4~6

AI summary

There are disclosed various methods and apparatuses for focus calibration of a camera unit (102). In some embodiments of the method, a first image captured by a camera unit (102) is obtained, a first set of two or more reference regions (502, 504) is selected from the first image, a first focus convergence parameter is computed based on the first set of two or more reference regions (502, 504) and optical properties of optics (207) of the camera unit (102) are adjusted and the camera unit (102) is rotated as a whole to change location of a focus of the optics (207). The method also comprises obtaining a second image captured by the camera unit (102), selecting a second set of two or more reference regions (502, 504) from the second image which may be different from the first set of two or more reference regions (502, 504) of the first image, and computing a second focus convergence parameter based on the second set of two or more reference regions (502, 504) of the second image. The first and second focus convergence parameters are compared to determine if focus quality was improved. In some embodiments the apparatus comprises means for implementing the method.