Image Pickup Control Apparatus Tilt Axis Focusing

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Solution Overview

Problem

Existing image pickup apparatuses face challenges in achieving highly accurate focusing due to mechanical errors, which can result in incorrect tilt angles and focus positions, especially when determining the in-focus level of objects based on area settings.

Innovation Solution

A control apparatus that switches focusing control methods based on the position of the evaluation value calculating area relative to the tilt axis, using a combination of tilt and focus control units to adjust the image sensor and optical system, ensuring accurate focusing by determining the optimal tilt and focus positions through evaluation value calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If control is performed based on calculated control target position, then focus control can be automated, but mechanical errors cause incorrect tilt angles and focus positions

Engineering Contradiction:
Improveautomated focus controlVSAvoidtilt angle and focus position accuracy
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent implements feedback by using the in-focus level detected from the evaluation value acquiring area to adjust and determine the tilt angle. Instead of relying solely on pre-calculated positions, the system continuously monitors the actual in-focus level and uses this feedback to correct and refine the tilt angle, thereby compensating for mechanical errors and achieving higher precision in both automated control and measurement accuracy.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If tilt angle and focus position are controlled while determining in-focus level, then focusing accuracy can be improved, but incorrect area settings cause wrong tilt angle and focus position determination

Engineering Contradiction:
Improvefocusing accuracyVSAvoidcontrol correctness
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies local quality by designating a specific evaluation value acquiring area that is positioned away from the tilt axis. This local area selection ensures that the in-focus level detection is performed in a region where tilt angle changes produce measurable variations in evaluation values, thereby improving the reliability of control correctness while maintaining high focusing accuracy.

Inventive Principle:
Principle #3Local quality

3Area of stationary object

If evaluation value acquiring area is set near tilt axis, then area coverage is maximized, but in-focus level determination becomes inaccurate

Engineering Contradiction:
Improveevaluation value acquiring area coverageVSAvoidin-focus level determination accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary approach by selecting an evaluation value acquiring area that is positioned at an optimal distance from the tilt axis - not too close to lose measurement precision, and not too far to reduce area coverage. This intermediary positioning allows the system to maintain both adequate area coverage and accurate in-focus level determination, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4084465B1Control apparatus, image pickup apparatus, control method, and program
Publication Date: 2025.01.08 CANON KK
  • EP4084465B1 patent drawingFigure 1
  • EP4084465B1 patent drawingFigure 2
  • EP4084465B1 patent drawingFigure 3A~3C

AI summary

A control apparatus includes a tilt driving unit (118) configured to perform tilt driving, a focus driving unit (119), a control unit (115, 116) configured to control the focus driving unit and the tilt driving unit for focusing on at least a first area and a second area in a plurality of areas in an image, and a first determination unit (113) configured to determine a control method of the control unit based on whether or not a difference between a position of at least one of the first area and the second area and a position corresponding to a tilt axis (301) in the image is smaller than a predetermined threshold.