Array Camera Pixel Aperture Control for Super-Resolution
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Solution Overview
Problem
Conventional digital cameras face challenges in increasing pixel density due to form factor constraints, particularly in mobile devices, leading to limitations in dynamic range, signal-to-noise ratio, and low light sensitivity, and struggle with aliasing issues that affect image quality and super-resolution processing.
Innovation Solution
The introduction of array cameras with multiple focal planes and controlled pixel apertures, microlenses, and adjusted pixel pitches to intentionally introduce aliasing, which is then exploited through super-resolution processing to enhance image resolution and quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels in an image sensor is increased to improve resolution, then image quality is improved, but the form factor of the lens system increases which is not acceptable in mobile devices
Solution Approach 1:
The patent divides a single high-resolution sensor into multiple lower-resolution sensor arrays (e.g., 2x2, 3x3, or 4x4 arrays). Each sensor array captures images from a slightly different spatial position, and the combined data from all arrays reconstructs a high-resolution image, achieving the resolution of a single large sensor while using multiple smaller sensors that fit within mobile device form factors.
Solution Approach 2:
The patent transitions from a single-plane sensor architecture to a multi-plane or multi-layer sensor array architecture. By arranging multiple sensor arrays in different spatial positions (different dimensions), the system captures additional spatial information that enables high-resolution reconstruction without requiring a single large sensor, thus solving the form factor constraint.
2Object-generated harmful factors
If conventional anti-aliasing filters are used to reduce aliasing, then image artifacts are reduced, but high-frequency information is lost which degrades super-resolution processing quality
Solution Approach 1:
The patent intentionally allows aliasing to occur during image capture by each sensor array, then uses sophisticated super-resolution algorithms to process the aliased images from multiple arrays. The combination of multiple aliased images with different spatial sampling patterns enables the recovery of high-frequency information that would be lost with conventional anti-aliasing filters, converting the harmful aliasing effect into a beneficial source of high-frequency data.
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
This approach allows for increased resolution and improved image quality by leveraging aliasing information, facilitating higher frequency content recovery and parallax correction, while maintaining sensitivity and reducing blur, thus overcoming the limitations of traditional camera designs.
Implementation Method 1
a pixel stack including a microlens and an active area, where light incident on the surface of the microlens is focused onto the active area by the microlens
Data Source
AI summary
Imager arrays, array camera modules, and array cameras in accordance with embodiments of the invention utilize pixel apertures to control the amount of aliasing present in captured images of a scene. One embodiment includes a plurality of focal planes, control circuitry configured to control the capture of image information by the pixels within the focal planes, and sampling circuitry configured to convert pixel outputs into digital pixel data. In addition, the pixels in the plurality of focal planes include a pixel stack including a microlens and an active area, where light incident on the surface of the microlens is focused onto the active area by the microlens and the active area samples the incident light to capture image information, and the pixel stack defines a pixel area and includes a pixel aperture, where the size of the pixel apertures is smaller than the pixel area.