Lensless Imaging Device with Concentric Grating Modulator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing imaging devices without lenses, such as those using diffraction gratings, face complexity in computation and lack high functionality features like focus adjustment and autofocus.
Innovation Solution
The implementation of a modulator with concentric grating patterns on a grating substrate, where the pitch narrows inversely with radius, allows for simple computation and high functionality by generating moiré fringes and spatial frequency spectra, enabling refocusing, autofocus, and ranging through image processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a special diffraction grating substrate with spiral grating pattern is used to obtain object images without a lens, then the imaging device can be made thinner, but the computation complexity increases due to solving the inverse problem
Solution Approach 1:
Instead of using a spiral grating pattern that requires complex inverse problem solving, the patent inverts the approach by using a simple linear grating pattern on the diffraction grating substrate. This inversion of the grating pattern design fundamentally changes the computation from solving complex inverse problems to performing straightforward Fourier transforms, thereby reducing computation complexity while maintaining the lensless thinning benefit
Solution Approach 2:
The patent changes the key parameter of the grating pattern from a complex spiral shape to a simple linear shape with specific pitch characteristics. This parameter change in the grating structure simplifies the mathematical relationship between the captured pattern and the object image, enabling efficient computation through standard Fourier transform methods rather than complex iterative inverse problem solving
2Length of moving object
If a simple diffraction grating method is used to thin the device, then the device becomes thinner, but high functionality features like focus adjustment and autofocus are not achieved
Solution Approach 1:
The patent implements multi-functionality by enabling the lensless imaging device to perform not only basic image capture but also focus adjustment (refocusing at different depths), autofocus (automatic focus optimization), and ranging (depth information acquisition). The modulator with controllable grating patterns provides universal functionality, allowing a single device to replace multiple specialized imaging functions while maintaining thinness
Solution Approach 2:
The patent introduces dynamic control through a modulator that can adjust the grating pattern in real-time. This dynamic capability allows the device to switch between different grating configurations to achieve various functions such as focus adjustment and ranging, transforming a static simple grating system into a dynamic multi-functional imaging system that adapts to different operational requirements
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 configuration simplifies image processing, allowing for high functionality features like focus adjustment and ranging with a single photographing session, reducing computational complexity and enhancing imaging device capabilities.
Implementation Method 1
a special diffraction grating substrate is attached to an image sensor, and an incident angle of incident light is obtained by an inverse problem from a projection pattern generated by light transmitted through the diffraction grating substrate on the image sensor
Implementation Method 2
The implementation of a modulator with concentric grating patterns on a grating substrate, where the pitch narrows inversely with radius, allows for simple computation and high functionality by generating moiré fringes and spatial frequency spectra
Data Source
AI summary
To obtain an imaging device capable of achieving high functionality of the imaging device by facilitating detection of an incident angle of light transmitted through a grating substrate. There is provided an imaging device which includes an image sensor that converts an optical image captured by a plurality of pixels arranged in an array on an imaging surface into an image signal and outputs the image signal, a modulator that is provided on a light receiving surface of the image sensor and modulates light intensity, an image storing unit that temporarily stores the image signal output from the image sensor, and a signal processing unit that performs image processing of the image signal output from the image storing unit, and in which the modulator has a first grating pattern composed of a plurality of concentric circles, and the signal processing unit modulates the image signal output from the image storing unit with a virtual second grating pattern composed of a plurality of concentric circles so as to generate a moiré fringe image and changes a size of the concentric circle of the second grating pattern according to a focus position.