Photoacoustic Apparatus Waveform Control for Reflected Wave Interference
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Solution Overview
Problem
Photoacoustic imaging techniques face a decrease in quantitativity of optical property information due to components corresponding to reflected waves, which are not propagated directly and have different time of flight, leading to inaccurate reconstruction of optical absorbers.
Innovation Solution
A photoacoustic apparatus that transmits a controlled transmission acoustic wave to a specific area, superimposes it with a light-generated photoacoustic wave to form an interference wave, reducing the amplitude of the interference wave and subsequently the amplitude of the reflected wave, allowing for the acquisition of optical property information with reduced influence from reflected components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If photoacoustic imaging is performed without transmitting acoustic waves, then the imaging process is simple, but reflected waves cause decrease in quantitativity of optical property information
Solution Approach 1:
The invention applies preliminary anti-action by transmitting an acoustic wave before light irradiation that has a waveform designed to cancel out the reflected wave. The control unit calculates a transmission waveform that produces destructive interference with the reflected wave, thereby reducing its amplitude before it can degrade the measurement precision of optical property information.
Solution Approach 2:
The invention converts the harmful reflected wave into a beneficial effect by using it as part of the interference pattern. The control unit designs the transmission waveform such that the reflected wave interferes destructively with the direct wave, transforming the harmful reflection into a mechanism that enhances measurement precision by suppressing unwanted signals.
2Measurement precision
If transmission acoustic wave is used to reduce reflected wave amplitude, then quantitativity of optical property information is enhanced, but the system requires precise control of transmission waveform
Solution Approach 1:
The invention implements feedback by using the detected photoacoustic signal to calculate and adjust the transmission waveform. The control unit analyzes the received signal characteristics and determines the optimal transmission waveform that will produce destructive interference with reflected waves, creating a closed-loop system that adapts to actual measurement conditions.
Solution Approach 2:
The invention introduces the control unit as an intermediary that mediates between the acoustic wave transmission and light irradiation processes. This intermediary calculates and coordinates the timing and waveform of acoustic transmissions to optimize interference effects, simplifying the overall control difficulty by centralizing the coordination function.
3Use of energy by moving object
If light is emitted continuously, then sufficient optical energy is provided for photoacoustic wave generation, but acoustic wave timing control becomes critical
Solution Approach 1:
The invention applies periodic action by using pulsed light irradiation synchronized with periodic acoustic wave transmissions. The control unit coordinates these periodic pulses to ensure that the acoustic wave reaches the target region at the optimal time relative to light emission, maintaining energy efficiency while managing timing constraints through regular, predictable cycles.
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 apparatus effectively reduces the amplitude of reflected waves, thereby enhancing the quantitativity of optical property information, such as initial sound pressure and absorption coefficient distributions, by controlling the transmission waveform to match the antiphase of the photoacoustic wave generated on the subject's surface.
Implementation Method 1
pulsed light generated in a light source is emitted to a subject and an acoustic wave (typically, ultrasonic wave) generated in a subject tissue which absorbs energy of the pulsed light
Implementation Method 2
the control unit controls the transmission waveform in such a manner that amplitude of a photoacoustic wave generated in the specific area is reduced by the transmission acoustic wave transmitted from the acoustic wave transmission unit
Implementation Method 3
an acoustic wave reception unit configured to receive the acoustic wave and to output a time-series received signal
Data Source
AI summary
A photoacoustic apparatus disclosed in the present specification includes: an acoustic wave transmission unit configured to transmit a transmission acoustic wave to a specific area; a control unit configured to control a transmission waveform of the transmission acoustic wave transmitted from the acoustic wave transmission unit; a light source configured to generate light emitted to an area including the specific area when the acoustic wave reaches the specific area; an acoustic wave reception unit configured to receive the acoustic wave and to output a time-series received signal; and a signal processing unit configured to acquire optical property information based on the time-series received signal, wherein the control unit controls the transmission waveform in such a manner that amplitude of a photoacoustic wave generated in the specific area is reduced by the transmission acoustic wave transmitted from the acoustic wave transmission unit.