Imaging Lens Focus Breathing Correction via Image Processing

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Solution Overview

Problem

Existing imaging apparatuses struggle to effectively correct focus breathing through image processing, leading to inadequate configuration and image quality issues due to fluctuations in the angle of view during focusing operations.

Innovation Solution

The proposed solution involves an imaging apparatus with a zoom lens configuration that includes a fixed first lens group, movable lens groups, and a final fixed lens group, where the angle of view is corrected through magnification and reduction processing of source image data in conjunction with focusing, maintaining a constant angle of view by setting a reference angle of view for each focal length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If focus breathing is corrected through simple image processing (magnification and reduction processing), then the angle of view fluctuation is corrected, but the apparatus configuration becomes inadequate and image quality deteriorates

Engineering Contradiction:

Improveangle of view correction accuracyVSAvoidapparatus configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical lens configuration changes with image processing (magnification and reduction processing) to correct focus breathing. The angle-of-view correction unit processes image data to maintain constant angle of view during focusing operations, substituting optical mechanical adjustments with digital signal processing while maintaining compact apparatus configuration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the processing parameters (magnification and reduction ratios) dynamically based on focusing position to correct angle of view fluctuations. The system adjusts processing parameters in real-time during focusing operations to maintain constant angle of view, resolving the contradiction between correction accuracy and configuration complexity.

Inventive Principle:

Principle #35Parameter changes

2Length of moving object

If the first lens group is fixed during variable magnification with separate focusing lens groups, then the total length remains unchanged and configuration is simplified, but focus breathing occurs causing angle of view fluctuation

Engineering Contradiction:

Improvezoom lens total lengthVSAvoidangle of view stability

Core Design Contradiction:

Length of moving objectVSMeasurement precision

Solution Approach 1:

The patent segments the first lens group into a first-a lens group (fixed during focusing) and a first-b lens group (moves during focusing), separating the variable magnification function from the focusing function. This segmentation allows the total length to remain unchanged during variable magnification while enabling independent focusing control, though it introduces focus breathing that is subsequently corrected through image processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent substitutes mechanical angle of view stabilization with image processing. Instead of using complex mechanical mechanisms to prevent angle of view fluctuation during focusing, the system uses the angle-of-view correction unit to process image data and maintain constant angle of view, allowing the simplified lens configuration to be used while achieving angle of view stability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If electronic zoom or digital zoom is used to correct focus breathing, then angle of view fluctuation is corrected, but the apparatus cannot be appropriately configured and image quality is compromised

Engineering Contradiction:

Improveangle of view consistencyVSAvoidimage quality

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent implements feedback control where the angle-of-view correction unit continuously monitors and adjusts image data based on the focusing position. The system uses feedback from the focusing operation to dynamically apply magnification and reduction processing, ensuring angle of view consistency while maintaining image quality through controlled feedback-based adjustment rather than simple electronic zoom.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10880473B2Imaging apparatus with focus breathing correction

Publication Date: 2020.12.29 FUJIFILM CORP

AI summary

Provided are an imaging apparatus, a signal processing method for an imaging apparatus, and a non-transitory computer readable recording medium storing a signal processing program for an imaging apparatus capable of capturing a high quality image with a compact configuration. An imaging lens 10A is composed of, in order from an object side, a first lens group G1 that is fixed during variable magnification, a second lens group G2 and a third lens group G3 that move during variable magnification, and a fourth lens group G4 that is fixed during variable magnification. The first lens group G1 is composed, in order from the object side, a first-a lens group G1a that is fixed during focusing, a first-b lens group G1b that moves during focusing, and a first lens group rear group G1c that is fixed during focusing. Fluctuation of an angle of view with focusing is corrected through image processing.