Camera-Based Photoacoustic Remote Sensing for Non-Contact Imaging
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Solution Overview
Problem
Existing photoacoustic imaging systems require physical contact or ultrasound coupling agents for detection, limiting their application in clinical and endoscopic procedures, and lack non-contact, high-resolution imaging capabilities in reflection mode with optical absorption contrast.
Innovation Solution
The Camera-Based Photoacoustic Remote Sensing (C-PARS) system uses a non-interferometric method to detect absorption-induced changes in reflected light with a camera, enabling non-contact, wide-field, real-time imaging of optical absorption without the need for ultrasound transducers or coupling agents, utilizing a pulsed-excitation-induced change in optical scattering and reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional photoacoustic imaging systems use piezoelectric transducers with ultrasound coupling medium, then detection sensitivity is improved, but ease of operation deteriorates due to requirement of physical contact and coupling agents
Solution Approach 1:
The patent replaces the mechanical piezoelectric transducer system with an all-optical detection system using a camera to detect photoacoustic signals. This substitution eliminates the need for mechanical contact and ultrasound coupling agents while maintaining detection capability through optical measurement of acoustic-induced refractive index changes.
Solution Approach 2:
The patent introduces an optical intermediary (camera-based optical detection system) to detect photoacoustic signals without direct mechanical contact. The optical field acts as a mediator between the acoustic waves generated in tissue and the detection system, enabling non-contact measurement while preserving signal detection sensitivity.
2Manufacturing precision
If optical-resolution photoacoustic microscopy (OR-PAM) is used, then manufacturing precision is improved with micron-scale resolution, but penetration depth deteriorates to limited 1 mm in tissue
Solution Approach 1:
The patent segments the detection approach by using a camera-based optical detection system that can capture photoacoustic signals from deeper tissue layers while maintaining optical resolution. This segmentation allows the system to overcome the 1 mm penetration limit of traditional OR-PAM by distributing detection across multiple optical channels and using optical sectioning techniques.
Solution Approach 2:
The patent changes the detection parameter from direct optical focusing (limited penetration) to optical detection of acoustic waves (deeper penetration). By detecting the acoustic-induced refractive index changes optically rather than mechanically, the system achieves both micron-scale resolution and deeper tissue penetration beyond 1 mm.
3Measurement precision
If interferometric methods are used to detect surface oscillations, then measurement precision is improved, but device complexity deteriorates due to phase-sensitive detection requirements
Solution Approach 1:
The patent replaces complex phase-sensitive interferometric detection with simpler intensity-based optical detection. By measuring intensity changes rather than phase changes, the system achieves comparable measurement precision without requiring complex interferometric setups, phase modulation, or sophisticated signal processing.
Solution Approach 2:
The patent uses a standard camera sensor instead of expensive interferometric detection systems. The camera-based approach uses readily available, cost-effective components to achieve high measurement precision, replacing costly and complex phase-sensitive detection hardware with simpler, more accessible technology.
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
C-PARS provides finer optical resolution, faster imaging speeds, and wider field-of-view imaging compared to traditional methods, achieving non-contact, real-time imaging of optical absorption with improved signal-to-noise ratio and eliminating the need for phase-sensitive detection.
Implementation Method 1
Photoacoustic imaging is an emerging hybrid imaging technology providing optical contrast with high spatial resolution. Nanosecond or picosecond laser pulses fired into tissue launch thermo-elastic-induced acoustic waves
Implementation Method 2
detecting photoacoustic signals by observing changes in an interrogation beam reflected from the sample
Implementation Method 3
detect absorption-induced changes in reflected light with a camera
Data Source
AI summary
A camera-based photoacoustic remote sensing system (C-PARS) for imaging a subsurface and deep structures in a sample, has an excitation beam configured to generate ultrasonic signals in the sample at an excitation location; an interrogation beam incident on the sample at the excitation location, a portion of the interrogation beam returning from the sample that is indicative of the generated ultrasonic signals; a camera to map the returning portion of the interrogation beam over the entire field of view.