Lensless Imaging Device Using Precomputed Lookup Table

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Solution Overview

Problem

Existing digital cameras, such as those on smartphones, face challenges in reducing thickness while maintaining effective image capture and processing efficiency, particularly due to high operation quantities associated with development processing.

Innovation Solution

A lensless imaging device using a modulator with a concentric pattern and an image sensor, where the modulator modulates light intensity and the image sensor converts it into image data, with an image processing unit restoring images through cross-correlation operations with pattern data, reducing the operation quantity and processing time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If a grating pattern is formed at the upper surface of a substrate attached onto an image sensor for lensless imaging, then the camera thickness can be reduced, but the operation quantity for solving the inverse problem increases significantly

Engineering Contradiction:
Improvecamera thicknessVSAvoidoperation quantity for development processing
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing the relationship between projection patterns and object images in a lookup table before actual imaging. When an image needs to be developed, the system simply queries the pre-computed lookup table rather than solving the inverse problem in real-time, thereby reducing the operation quantity during development processing while maintaining lensless thin-camera design

Inventive Principle:
Principle #10Preliminary action

2Length of moving object

If complex inverse problem solving is used for image development in lensless imaging, then image capture is achieved without lenses, but processing time and computational resources increase

Engineering Contradiction:
Improvecamera thicknessVSAvoidprocessing time for image development
Core Design Contradiction:
Length of moving objectVSLoss of time

Solution Approach 1:

The patent performs the computationally intensive inverse problem solving in advance and stores the results in a lookup table. During actual image development, the system retrieves pre-computed solutions rather than solving the inverse problem from scratch, significantly reducing processing time while enabling lensless imaging with reduced camera thickness

Inventive Principle:
Principle #10Preliminary action

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

The solution enables a reduction in the operation quantity for image development, allowing for thinner and more efficient digital cameras with reduced power consumption and cost, capable of displaying images quickly without the need for high-performance CPUs.

Implementation Method 1

a modulator 11 having a concentric pattern

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

an image sensor 12 which converts the light into image data

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP3306911B1Imaging device and imaging method
Publication Date: 2022.09.14 HITACHI LTD
  • EP3306911B1 patent drawingFigure 1
  • EP3306911B1 patent drawingFigure 2
  • EP3306911B1 patent drawingFigure 3

AI summary

An imaging device 10 includes: a modulator 11 with a first pattern, which is configured to modulate light intensity; an image sensor 12 configured to convert light passing through the modulator 11 to image data, and output the image data; and an image processing unit 13 configured to restore an image on the basis of cross-correlation operation with the image data and pattern data that represents a second pattern.