Lensless Imaging Sensor with Angle-Directive Pixels for Image Restoration
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Solution Overview
Problem
Imaging apparatuses without imaging lenses struggle to generate accurate image signals due to aberrations and limitations in downsizing, while those with pinholes face challenges in high-speed imaging due to reduced light intensity, requiring longer exposure times or increased gain.
Innovation Solution
An information processing apparatus that includes an image conversion section using pixel outputs from an imaging device with multiple pixel output units, where the outputs differ in incident angle directivity, allowing for the generation of a restored image by solving simultaneous equations and accounting for defective pixel outputs through detection and coefficient adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an imaging lens is used to concentrate light and form an image, then image quality and light intensity are improved, but device complexity and size increase due to the essential building block requirement
Solution Approach 1:
The patent extracts and removes the imaging lens from the traditional imaging system, replacing it with a lensless imaging device that uses a sensor array with microlens arrays and optical filters. This extraction eliminates the complex lens assembly while maintaining imaging functionality through computational methods and structured light modulation at the sensor level.
Solution Approach 2:
The patent transitions from conventional 2D image capture to a multi-dimensional approach by incorporating depth information through time-of-flight measurements and spectral information through multiple optical filters. This dimensional expansion allows lensless imaging to achieve functionality previously requiring complex lens systems.
2Device complexity
If a pinhole is used instead of an imaging lens, then device complexity is reduced, but light intensity decreases requiring longer exposure times or increased gain
Solution Approach 1:
The patent segments the sensor surface into multiple pixel output units, each equipped with its own microlens array and optical filter combination. This segmentation allows each pixel to capture light from specific angular directions and wavelength ranges, effectively multiplying the light collection capability compared to a single pinhole while maintaining device simplicity.
Solution Approach 2:
The imaging device performs multiple functions simultaneously: it captures spatial information, angular information through incident angle directivity, spectral information through optical filters, and depth information through time-of-flight measurements. This multi-functionality replaces the need for separate optical components while maintaining high light efficiency.
3Measurement precision
If pixel outputs from multiple units with different incident angle directivity are used, then image restoration accuracy is improved, but processing complexity increases due to solving simultaneous equations
Solution Approach 1:
The patent pre-calculates and stores coefficient sets that represent the relationship between pixel outputs and object light intensities for various incident angles and filter combinations. During actual imaging, the system only needs to perform matrix operations using these pre-computed coefficients, significantly reducing processing complexity while maintaining high restoration accuracy.
Solution Approach 2:
The patent creates multiple virtual images through computational processing, where each pixel output unit effectively captures a different virtual view of the scene. By combining these virtual images through the coefficient sets, the system reconstructs the true object light intensity distribution with high precision.
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 highly accurate restoration of captured images without relying on imaging lenses or pinholes, improving image quality and enabling downsizing of imaging apparatuses for applications requiring compact designs.
Implementation Method 1
an imaging device that includes a plurality of pixel output units which receive subject light that enters without going through an imaging lens and a pinhole
Data Source
AI summary
An imaging section includes a plurality of pixel output units that receive subject light that enters without going through an imaging lens and a pinhole. Output pixels of at least two of the plurality of pixel output units differ in incident angle directivity as a result of modulation of the incident angle directivity based on the incident angle of the subject light. A defective pixel detection section detects a defective pixel of the imaging section on the basis of pixel outputs of the imaging section. The defective pixel detection section discriminates a defective pixel that has produced a pixel output whose signal level is larger than or smaller than a threshold range. The image conversion section performs restoration computations by using pixel outputs generated for the respective pixels other than that of the defective pixel and a coefficient set stored in the coefficient storage section, thus generating a restored image.