Computational Scheimpflug Focusing via Plenoptic Light Field Capture

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Solution Overview

Problem

Conventional digital cameras lose the ability to focus on tilted planes due to the fixed parallel orientation of their image and lens planes, limiting photographic flexibility and depth of field control.

Innovation Solution

The implementation of a plenoptic camera system with a microlens array that captures 4D light field data, allowing for post-capture computational focusing on any image plane, including tilted planes, using Scheimpflug principles to enable tilt-shift functionality without mechanical adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional cameras use fixed parallel orientation of image and lens planes, then device complexity is reduced, but adaptability for focusing on tilted planes is lost

Engineering Contradiction:
Improvefocusing capability on tilted planesVSAvoidhardware manipulation requirements
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical system of tilting lens planes and image detectors with a computational approach. Light field data captured by the plenoptic camera is processed using algorithms that simulate Scheimpflug tilt geometry, enabling virtual focusing on tilted planes without any physical hardware manipulation. This substitution of mechanical adjustment with computational processing resolves the contradiction by maintaining fixed hardware while achieving adaptability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent applies preliminary action by capturing complete light field data during the initial image capture. This light field data contains information about light rays from all directions and depths, which is then used in post-processing to focus on any desired plane including tilted planes. By capturing all necessary information upfront, the system eliminates the need for subsequent hardware manipulation to achieve different focus planes.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If multiple images are captured with hardware manipulation for each focus position, then focusing precision on specific areas is improved, but productivity is reduced

Engineering Contradiction:
Improvefocus positioning accuracyVSAvoidimage capture efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent captures all necessary light field information in a single exposure, performing the preliminary action of data collection. The captured light field data contains sufficient information to generate focused images at multiple depths and tilted planes through computational processing. This eliminates the need to capture multiple images with hardware adjustments, thereby improving productivity while maintaining focus precision through algorithmic processing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent transitions from capturing 2D images at fixed focus planes to capturing 4D light field data that encodes information about light rays in both spatial and angular dimensions. This additional dimensional information enables post-capture focusing at any depth and orientation without requiring multiple physical captures, thus improving both productivity and focus precision simultaneously.

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

3Adaptability or versatility

If light field data is captured using plenoptic camera, then adaptability for post-capture focusing is improved, but device complexity increases

Engineering Contradiction:
Improvepost-capture refocusing capabilityVSAvoidoptical system structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs segmentation by placing an array of microlenses over the image sensor, dividing the optical system into multiple functional units. Each microlens captures light rays from a specific angular range, and the combined data from all microlenses forms the complete light field. This segmentation enables the complex light field capture capability while structuring the device in a manageable, modular way that balances adaptability with structural organization.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables flexible focusing on tilted planes, improving image capture capabilities by allowing refocusing and 3D view rendering, enhancing features like HDR and multi-spectral imaging without the need for hardware manipulation.

Implementation Method 1

a plenoptic camera system with a microlens array that captures 4D light field data

Methodology Applied
Scientific EffectLight field capture:

Implementation Method 2

The microlens array focuses light onto the image sensor, creating multiple micro-images that encode spatial and angular information about the light field

Methodology Applied
Scientific EffectLens focusing: Lens

Data Source

PatentEP3395059B1Method and apparatus for computational scheimpflug camera
Publication Date: 2019.12.25 QUALCOMM INC
  • EP3395059B1 patent drawingFigure 1
  • EP3395059B1 patent drawingFigure 2A~2B
  • EP3395059B1 patent drawingFigure 3

AI summary

Method and devices are disclosed for focusing on tilted image planes. For example, one imaging device includes an objective lens configured to focus a scene at an image plane, the scene having an object plane tilted relative to the objective lens plane and a sensor receive light from the objective lens, the sensor having a plurality of light sensing elements configured to generate image data based on the light received at the sensor. The imaging device also includes a processor and memory component configured to receive the image data, the image data indicative of a first image; receive a tilt parameter indicative of an orientation of a selected non-parallel image plane, and convert the image data to relative image data based on the tilt parameter, the relative image data indicative of a second image focused along the non-parallel image plane.