Imaging Through Scattering Media Using Diffractive Optical Element
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Imaging through scattering media, such as blood, results in reduced signal-to-noise ratio (SNR) and impaired imaging resolution due to blinding emissions from non-object planes, which existing technologies fail to effectively enhance using known super-resolution techniques.
Innovation Solution
A system utilizing a spatial and temporal coherent light source to project an array of spots on the object, combined with a diffractive optical element (DOE) that transmits ballistic photons while blocking scattered photons, and an optical arrangement for focusing light onto an imaging sensor, facilitating improved SNR and resolution through selective photon transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If imaging is carried out in a scattering medium, then the system can obtain images of objects behind the scattering medium, but the signal-to-noise ratio is greatly reduced and imaging resolution deteriorates due to blinding emissions from non-object planes
Solution Approach 1:
The invention segments photons into two categories: ballistic photons (which carry useful image information) and scattered photons (which contribute to noise). The diffractive optical element acts as a spatial filter that segments and transmits only ballistic photons while blocking scattered photons, thereby resolving the contradiction between obtaining images through scattering medium and maintaining signal-to-noise ratio
Solution Approach 2:
The diffractive optical element introduces local quality differentiation in the optical path by creating angle-dependent transmission characteristics. Ballistic photons traveling at specific angles are transmitted while scattered photons at different angles are blocked, enabling selective transmission that improves both imaging resolution and signal-to-noise ratio simultaneously
2Measurement precision
If known super-resolution techniques are applied, then imaging resolution may be enhanced, but the low signal-to-noise ratio prevents effective enhancement
Solution Approach 1:
The invention applies preliminary action by filtering scattered photons before they reach the imaging sensor. The diffractive optical element performs preliminary separation of ballistic and scattered photons, ensuring that only high-quality ballistic photons are transmitted to the sensor. This preliminary filtering creates the necessary signal-to-noise ratio condition that enables subsequent super-resolution techniques to be effective
3Object-affected harmful factors
If a conventional optical system is used, then the system structure is simple, but it cannot selectively transmit ballistic photons and block scattered photons
Solution Approach 1:
The diffractive optical element serves as an intermediary component between the scattering medium and the imaging sensor. It mediates the interaction by providing angle-selective transmission that allows ballistic photons to pass while blocking scattered photons. This intermediary approach achieves high signal-to-noise ratio without requiring complex optical arrangements, as the DOE is a relatively simple passive optical element
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 system significantly enhances imaging resolution and SNR by selectively focusing only ballistic photons, effectively reducing noise and improving image clarity in scattering media, as demonstrated by improved gray scale values and SNR ratios compared to images without the diffractive optical element.
Implementation Method 1
a diffractive optical element (DOE) configured to transmit ballistic photons of the captured light arriving from the object while blocking scattered photons
Implementation Method 2
a second optical setup to capture light transmitted by the DOE and focus that light onto an imaging plane of the imaging sensor
Implementation Method 3
a spatial and temporal coherent light source for generating an illumination beam to illuminate an object to be imaged through a scattering medium, so as to project an array of spots on the object
Data Source
AI summary
A system for imaging through a scattering medium may include a spatial and temporal coherent light source for generating an illumination beam to illuminate an object to be imaged through a scattering medium, so as to project an array of spots on the object; an imaging sensor for capturing an image of the object; a first optical setup to capture light transmitted through or reflected off the object and focus the captured light onto a diffractive optical element (DOE) configured to transmit ballistic photons of the captured light arriving from the object while blocking scattered photons; and a second optical setup for capturing light transmitted by the DOE and focus that light onto an imaging plane of the imaging sensor.