Adapted Slice Image Generation from Focal Stack

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Solution Overview

Problem

In light field camera technology, when an object is positioned on a focal plane, refocusing a slice image across the object results in both ends being blurred due to uneven distances from the intersection plane, leading to unsatisfactory image focus.

Innovation Solution

A method and apparatus that select a slice image from a focal stack and an all-in-focus image derived from the stack, allowing users to combine specific objects in the all-in-focus image onto the selected slice image to generate an adapted slice image, ensuring the selected objects appear in-focus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If refocusing is performed on a slice image across an object positioned on a focal plane, then the refocusing capability is achieved, but both ends of the object become blurred due to uneven distances from the intersection plane

Engineering Contradiction:

Improverefocusing capabilityVSAvoidimage focus quality

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The image processing is segmented into multiple components: identifying objects on the focal plane, extracting in-focus regions from the all-in-focus image, and selectively combining these regions with the slice image. This segmentation allows different parts of the image to be processed differently, maintaining focus quality while preserving refocusing capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by selectively applying focus enhancement only to specific objects or regions that are identified as being on the focal plane, rather than uniformly processing the entire slice image. This ensures that objects of interest maintain sharp focus while other regions retain the refocused appearance.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If an all-in-focus image is generated from the focal stack, then objects at different depths can be focused, but the device complexity increases due to additional processing requirements

Engineering Contradiction:

Improvedepth focus rangeVSAvoidimage processing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The all-in-focus image is generated in advance as a preprocessing step, storing focus information for all objects at different depths. This preliminary action allows subsequent operations to simply extract and combine relevant regions without performing complex depth analysis during the actual refocusing operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The all-in-focus image serves as an intermediary data structure that bridges the focal stack and the final refocused images. It acts as a lookup table or reference image that provides pre-computed in-focus regions, simplifying the complexity of generating focus information on-demand.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10270957B2Method and apparatus for generating an adapted slice image from a focal stack

Publication Date: 2019.04.23 INTERDIGITAL CE PATENT HOLDINGS SAS

AI summary

A method for generating an adapted slice image from a focal stack of refocused images using an all-in-focus image derived from the focal stack comprises: selecting a slice image in the focal stack; selecting at least one object in the all-in-focus image to be focused in the adapted slice image; and generating the adapted slice image by combining the selected at least one object in the all-in-focus image onto the selected slice image.