Camera Autofocus View Angle Stability via Image Cropping

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Solution Overview

Problem

The screen wobbling phenomenon occurs when the view angle of an image changes repeatedly during autofocus in electronic devices with camera modules, leading to an unstable display experience.

Innovation Solution

The electronic device employs a method to control the autofocus function by selecting and displaying a part of the image, ensuring the view angle remains consistent by cropping the image based on predetermined movement distances and using depth from defocus calculations to determine focus locations, thereby maintaining a stable image display.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the lens location is moved automatically along the optic axis for autofocus, then the focus location is adjusted, but the view angle of the displayed image varies causing screen wobbling

Engineering Contradiction:
Improvefocus location accuracyVSAvoidview angle stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent extracts and displays only a specific portion of the captured image that corresponds to the original view angle, separating the autofocus function from the view angle stability requirement. By cropping the image to match the initial view angle, the system maintains stable display composition while still moving the lens for focus adjustment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the parameter being displayed from the full captured image to a cropped portion of the image. By adjusting which portion of the image is displayed rather than changing the lens position parameters, the system maintains constant view angle while achieving autofocus through lens movement.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the view angle changes during autofocus adjustments, then different focus locations are achieved, but the displayed image becomes unstable

Engineering Contradiction:
Improvefocus adjustment capabilityVSAvoiddisplay stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system extracts a specific region from the captured image that maintains the original view angle boundaries. This extracted portion is then displayed instead of the full image, ensuring display stability while the lens continues to move for focus adjustment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of maintaining constant view angle by preventing lens movement, the patent inverts the approach by allowing lens movement but compensating through image cropping. The display stability is achieved not by constraining the optical system but by constraining the displayed image boundaries.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3718296B1Electronic device and method for controlling autofocus of camera
Publication Date: 2023.11.01 SAMSUNG ELECTRONICS CO LTD
  • EP3718296B1 patent drawingFigure 1
  • EP3718296B1 patent drawingFigure 2~3
  • EP3718296B1 patent drawingFigure 4

AI summary

An electronic device includes a display; a camera module configured to move an image sensor, wherein the camera module includes a lens unit comprising at least one lens disposed on the image sensor and a lens driving unit configured to move the at least one lens; and a processor configured to display a first image comprising an external object obtained with a first view angle by using the camera module through the display, move a location of the at least one lens by using the lens driving unit so that a view angle of the external object changes from the first view angle to a second view angle, obtain a second image comprising the external object with the second view angle by using the camera module, select a part of the second image so that a view angle of the second image becomes practically identical to the first view angle, and display a part of the selected second image by using the display.