Extended Focal Plane Generation for Large Viewpoint Changes

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Solution Overview

Problem

Current multi-focal-plane (MFP) displays struggle to fully preserve information, especially behind occluding objects, due to limitations in capturing and processing light field data for large viewpoint changes.

Innovation Solution

The method involves capturing a set of texture images with varying focal lengths using a large aperture, generating corresponding depth maps, and applying focal weight maps to form extended focal plane images that include information behind occluding objects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a small number of focal planes (4-6 planes) are used with depth blending, then the display is technically feasible and easier to implement, but information behind occluding objects is lost and disocclusions occur during viewpoint changes

Engineering Contradiction:
Improveimplementation feasibilityVSAvoidinformation behind occluding objects
Core Design Contradiction:
Ease of manufactureVSLoss of information

Solution Approach 1:

The patent performs preliminary action by capturing multiple focus stack images at different focal distances before display. These images are processed to create extended focal planes that contain information from multiple depths, including areas behind occluding objects. This pre-captured data is then used during viewpoint changes to fill in disoccluded regions without requiring real-time computation or additional hardware complexity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary processing step that combines multiple focus stack images to create extended focal plane representations. This intermediary data structure serves as a mediator between the limited focal planes and the full light field information, allowing viewpoint synthesis to access information behind occlusions without requiring a complete light field capture system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If a large number of focal planes (14 or more) are used without depth blending, then information behind occluding objects is preserved, but the device complexity and processing requirements increase significantly

Engineering Contradiction:
Improveinformation behind occluding objectsVSAvoidnumber of focal planes
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent merges multiple focus stack images captured at different focal distances into extended focal plane representations. By combining these images through image processing algorithms, the system consolidates information from what would traditionally require many discrete focal planes into a compressed set of extended planes, reducing the effective number of planes needed while preserving information behind occlusions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the parameter representation from discrete focal plane indices to continuous focus stack parameters. Instead of treating each focal plane as a separate entity, the system uses focus stack imagery with varying focal lengths as a continuous parameter space, allowing efficient interpolation and synthesis of intermediate views without requiring a large discrete number of focal planes.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If focal planes are shifted for large viewpoint changes, then virtual reality and augmented reality applications are enhanced, but disocclusions and holes appear in the synthesized views

Engineering Contradiction:
Improveviewpoint change capabilityVSAvoiddisocclusions and holes
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent performs preliminary action by pre-capturing focus stack images that contain information from multiple depths and angles. When viewpoint changes occur, the system can synthesize new views by combining information from these pre-captured images, filling in disoccluded regions that would otherwise be missing. This preliminary data collection enables robust viewpoint transformation without information loss.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent adds a depth dimension to the traditional 2D image synthesis by utilizing focus stack information from multiple focal distances. This extra dimensional information allows the system to fill in disoccluded regions during viewpoint changes by projecting information from different depth planes into the synthesized view, effectively adding a third dimension (depth) to the viewpoint synthesis process.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4270944B1Method and system for forming extended focal planes for large viewpoint changes
Publication Date: 2025.04.09 INTERDIGITAL VC HOLDINGS INC
  • EP4270944B1 patent drawingFigure 1A
  • EP4270944B1 patent drawingFigure 1B
  • EP4270944B1 patent drawingFigure 2

AI summary

Methods and systems are described for capturing and displaying content for multiple focal plane (MFP) displays. In one example, a plurality of texture images of a scene are captured using a large-aperture camera, each texture image having a different focal distance. For each texture image, a focal plane image is generated. To generate the focal plane image, in some embodiments, each pixel in each texture image is multiplied by a respective weight value. The weight value may be based on a measured depth of the respective pixel (e.g. as determined using a captured depth map) and/or on a level of focus (or defocus) of the respective pixel as determined through filtering. The focal plane images may be displayed on a multifocal-plane display and may be used to generate a virtual viewpoint.