3D Laser Scanning Microscope Motion Artifact Correction
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Solution Overview
Problem
Existing 3D laser scanning microscopes face challenges in correcting motion artifacts during in vivo fluorescence measurements and are limited by the sampling rate due to large optical aperture sizes of acousto-optic deflectors.
Innovation Solution
The method involves using a 3D laser scanning microscope with acousto-optic deflectors to derive a one-to-one relationship between focal spot coordinates and speed, and chirp parameters, allowing for fast scanning drifts along arbitrary 3D lines. This is achieved by selecting guiding points, extending them to surface elements, and using non-linear chirp signals to continuously move the focus spot along scanning lines, thereby correcting motion artifacts and increasing measurement speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If 3D random-access AO microscopy is used to increase measurement speed and signal collection efficiency, then the product of measurement speed and square of signal-to-noise ratio increases by ratio of total image volume to volume covered by pre-selected scanning points, but fluorescence data are lost or contaminated with large amplitude movement artifacts during in vivo recordings
Solution Approach 1:
The system uses feedback by continuously monitoring the actual focal spot position through the relationship between chirp parameters and focal coordinates, and adjusting the chirp signals to compensate for tissue movement. This closed-loop approach corrects motion artifacts while maintaining high measurement speed
Solution Approach 2:
The invention changes the parameters of the acousto-optic deflectors by using time-varying chirp signals with changing frequency and amplitude. This allows dynamic adjustment of the focal spot position to track and compensate for tissue movement, resolving the contradiction between speed and data quality
2Manufacturing precision
If large optical aperture size of AO deflectors is used to achieve large scanning volumes with high spatial resolution, then scanning volume and resolution are improved, but sampling rate is limited by the time required to fill the large aperture with acoustic wave
Solution Approach 1:
The system uses periodic chirp signals to drive the acousto-optic deflectors, allowing the large optical aperture to be filled efficiently with acoustic waves. The periodic nature of the chirp signals enables rapid scanning while maintaining high spatial resolution, overcoming the sampling rate limitation
Solution Approach 2:
The invention makes the acoustic wave parameters dynamic by using time-varying chirp signals instead of static frequencies. This allows the system to adaptively fill the large optical aperture, achieving both high spatial resolution and improved sampling rate through dynamic parameter adjustment
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 method effectively corrects motion artifacts, increases measurement speed, and allows for uninterrupted fluorescence signal collection, overcoming the limitations of traditional 3D random-access AO microscopy.
Implementation Method 1
3D laser scanning microscope having acousto-optic deflectors for focusing a laser beam within a 3D space
Implementation Method 2
providing chirp signals for the acoustic frequencies in the deflectors for continuously moving the focus spot along the given scanning line
Implementation Method 3
the quantity of Ca2+ present in the neural cells increases which can be detected by fluorescent dyes
Data Source
AI summary
A method for correcting motion artifacts of in vivo fluorescence measurements using a 3D laser scanning microscope containing two pairs of orthogonally arranged acousto-optic deflectors, the method including: selecting a region of interest; selecting a plurality of guiding points along the region of interest; extending the guiding points to objects selected from scanning lines and/or surface elements and/or volume elements which, together, substantially cover the region of interest; repeatedly scanning the objects by generating continuous drifts to cover the objects; projecting the obtained scanning data to frames and obtaining a time series of the frames; correcting motion artifacts by shifting the data of the successive frames with respect to each other so as to maximize fluorescence cross correlation between the data of the frames.