scholarly journals Retinal axial motion analysis and implications for real-time correction in human retinal imaging

2022 ◽  
Author(s):  
Yao Cai ◽  
Kate Grieve ◽  
Pedro Mecê
Keyword(s):  
Retinal Imaging ◽  
Breath Holding ◽  
High Temporal Resolution ◽  
Axial Motion ◽  
Full Field ◽  
Stabilization Control ◽  
Typical Data ◽  
Ophthalmic Imaging ◽  
Time Correction

High-resolution ophthalmic imaging devices including spectral-domain and full-field optical coherence tomography (SDOCT and FFOCT) are adversely affected by the presence of continuous involuntary retinal axial motion. Here, we thoroughly quantify and characterize retinal axial motion with both high temporal resolution (200,000 A-scans/s) and high axial resolution (4.5 um), recorded over a typical data acquisition duration of 3 s with an SDOCT device over 14 subjects. We demonstrate that although breath-holding can help decrease large-and-slow drifts, it increases small-and-fast fluctuations, which is not ideal when motion compensation is desired. Finally, by simulating the action of an axial motion stabilization control loop, we show that a loop rate of 1.2 kHz is ideal to achieve 100% robust clinical in-vivo retinal imaging.

scholarly journals High-resolution in-vivo human retinal imaging using full-field OCT with optical stabilization of axial motion

2019 ◽  
Vol 11 (1) ◽  
pp. 492 ◽  
Author(s):  
Pedro Mecê ◽  
Jules Scholler ◽  
Kassandra Groux ◽  
Claude Boccara
Keyword(s):  
High Resolution ◽  
Retinal Imaging ◽  
Axial Motion ◽  
Full Field

Adaptive glasses wavefront sensorless Full-Field OCT for high-resolution in vivo retinal imaging over a wide FOV

2021 ◽  
Author(s):  
Yao Cai ◽  
Jules Scholler ◽  
Kassandra Groux ◽  
Olivier Thouvenin ◽  
Claude Boccara ◽  
...  
Keyword(s):  
High Resolution ◽  
Retinal Imaging ◽  
Full Field ◽  
Wide Fov

scholarly journals Coherence gate shaping for wide field high-resolution in vivo retinal imaging with full-field OCT

2020 ◽  
Vol 11 (9) ◽  
pp. 4928
Author(s):  
Pedro Mecê ◽  
Kassandra Groux ◽  
Jules Scholler ◽  
Olivier Thouvenin ◽  
Mathias Fink ◽  
...  
Keyword(s):  
High Resolution ◽  
Retinal Imaging ◽  
Wide Field ◽  
Full Field

scholarly journals In vivo high-resolution human retinal imaging with wavefront-correctionless full-field OCT

Optica ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 409 ◽  
Author(s):  
Peng Xiao ◽  
Viacheslav Mazlin ◽  
Kate Grieve ◽  
Jose-Alain Sahel ◽  
Mathias Fink ◽  
...  
Keyword(s):  
High Resolution ◽  
Retinal Imaging ◽  
Full Field

Adaptive glasses wavefront sensorless full-field OCT for high-resolution in-vivo retinal imaging over a wide field-of-view

2021 ◽  
Author(s):  
Yao Cai ◽  
Jules Scholler ◽  
Kassandra Groux ◽  
Olivier Thouvenin ◽  
Claude Boccara ◽  
...  
Keyword(s):  
High Resolution ◽  
Retinal Imaging ◽  
Field Of View ◽  
Wide Field ◽  
Full Field ◽  
Wide Field Of View

In-vivo retinal imaging with off-axis full-field time-domain optical coherence tomography

2016 ◽  
Vol 41 (21) ◽  
pp. 4987 ◽  
Author(s):  
Helge Sudkamp ◽  
Peter Koch ◽  
Hendrik Spahr ◽  
Dierck Hillmann ◽  
Gesa Franke ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Time Domain ◽  
Retinal Imaging ◽  
Optical Coherence ◽  
Full Field

Optically pumped magnetometers enable a new level of biomagnetic measurements

2020 ◽  
Vol 9 (5) ◽  
pp. 247-251
Author(s):  
Tilmann Sander ◽  
Anna Jodko-Władzińska ◽  
Stefan Hartwig ◽  
Rüdiger Brühl ◽  
Thomas Middelmann
Keyword(s):  
Quantum Interference ◽  
High Sensitivity ◽  
High Temporal Resolution ◽  
Optically Pumped ◽  
New Class ◽  
Magnetic Shields ◽  
Highly Sensitive ◽  
Electric And Magnetic Fields ◽  
Auditory Evoked Fields

AbstractThe electrophysiological activities in the human body generate electric and magnetic fields that can be measured noninvasively by electrodes on the skin, or even, not requiring any contact, by magnetometers. This includes the measurement of electrical activity of brain, heart, muscles and nerves that can be measured in vivo and allows to analyze functional processes with high temporal resolution. To measure these extremely small magnetic biosignals, traditionally highly sensitive superconducting quantum-interference devices have been used, together with advanced magnetic shields. Recently, they have been complemented in usability by a new class of sensors, optically pumped magnetometers (OPMs). These quantum sensors offer a high sensitivity without requiring cryogenic temperatures, allowing the design of small and flexible sensors for clinical applications. In this letter, we describe the advantages of these upcoming OPMs in two exemplary applications that were recently carried out at Physikalisch-Technische Bundesanstalt (PTB): (1) magnetocardiography (MCG) recorded during exercise and (2) auditory-evoked fields registered by magnetoencephalography.

scholarly journals Multimodal in vivo recording using transparent graphene microelectrodes illuminates spatiotemporal seizure dynamics at the microscale

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Nicolette Driscoll ◽  
Richard E. Rosch ◽  
Brendan B. Murphy ◽  
Arian Ashourvan ◽  
Ramya Vishnubhotla ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
Spatial Scales ◽  
Epileptic Seizures ◽  
Therapeutic Interventions ◽  
State Transitions ◽  
Integrated Analysis ◽  
High Temporal Resolution ◽  
Seizure Onset ◽  
Acute Seizures

AbstractNeurological disorders such as epilepsy arise from disrupted brain networks. Our capacity to treat these disorders is limited by our inability to map these networks at sufficient temporal and spatial scales to target interventions. Current best techniques either sample broad areas at low temporal resolution (e.g. calcium imaging) or record from discrete regions at high temporal resolution (e.g. electrophysiology). This limitation hampers our ability to understand and intervene in aberrations of network dynamics. Here we present a technique to map the onset and spatiotemporal spread of acute epileptic seizures in vivo by simultaneously recording high bandwidth microelectrocorticography and calcium fluorescence using transparent graphene microelectrode arrays. We integrate dynamic data features from both modalities using non-negative matrix factorization to identify sequential spatiotemporal patterns of seizure onset and evolution, revealing how the temporal progression of ictal electrophysiology is linked to the spatial evolution of the recruited seizure core. This integrated analysis of multimodal data reveals otherwise hidden state transitions in the spatial and temporal progression of acute seizures. The techniques demonstrated here may enable future targeted therapeutic interventions and novel spatially embedded models of local circuit dynamics during seizure onset and evolution.

scholarly journals Raman and Infrared Thermometry for Microsystems

2013 ◽  
Vol 5 (3) ◽  
Author(s):  
Leslie M. Phinney ◽  
Wei-Yang Lu ◽  
Justin R. Serrano
Keyword(s):  
Data Collection ◽  
Spatial Resolution ◽  
Infrared Imaging ◽  
Silicon On Insulator ◽  
Pixel Size ◽  
Full Field ◽  
Infrared Thermometry ◽  
Full Field Measurement ◽  
Typical Data ◽  
Field Temperature

This paper reports and compares Raman and infrared thermometry measurements along the legs and on the shuttle of a SOI (silicon on insulator) bent-beam thermal microactuator. Raman thermometry offers micron spatial resolution and measurement uncertainties of ±10 K. Typical data collection times are a minute per location leading to measurement times on the order of hours for a complete temperature profile. Infrared thermometry obtains a full-field measurement so the data collection time is on the order of a minute. The spatial resolution is determined by the pixel size, 25 μm by 25 μm for the system used, and infrared thermometry also has uncertainties of ±10 K after calibration with a nonpackaged sample. The Raman and infrared measured temperatures agreed both qualitatively and quantitatively. For example, when the thermal microactuator was operated at 7 V, the peak temperature on an interior leg is 437 K ± 10 K and 433 K ± 10 K from Raman and infrared thermometry, respectively. The two techniques are complementary for microsystems characterization when infrared imaging obtains a full-field temperature measurement and Raman thermometry interrogates regions for which higher spatial resolution is required.

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