Related Experiment Video
Updated: Jan 30, 2026
10:46
Doppler Optical Coherence Tomography of Retinal Circulation
Published on: September 18, 2012
19.2K
Automated phase unwrapping in Doppler optical coherence tomography
Shaohua Pi1, Acner Camino1, Xiang Wei1
1Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States.
Journal of Biomedical Optics
|February 1, 2019
Summary
An automated phase-unwrapping technique for Doppler optical coherence tomography (OCT) overcomes phase wrapping issues. This method enables accurate quantification of retinal blood flow, accelerating clinical ophthalmology applications.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Medical Imaging
Background:
- Phase wrapping in Doppler optical coherence tomography (OCT) hinders automated quantification of retinal blood flow.
- Manual phase unwrapping is time-consuming and not suitable for clinical settings.
Discussion:
- This study introduces an automated phase-unwrapping algorithm for Doppler OCT.
- The technique leverages the parabolic blood flow velocity profile within vessels.
- It detects and corrects phase wrapping by analyzing phase shift gradients and adjacent flow directions.
Key Insights:
- The algorithm successfully validated on both rodent and human retinal OCT data.
- It automates the detection and correction of phase wrapping artifacts.
- Enables precise measurement of total retinal blood flow.
Outlook:
- This signal processing advancement is expected to accelerate clinical adoption of Doppler OCT.
- Facilitates improved diagnosis and monitoring of ocular diseases.
- Potential for integration into commercial Doppler OCT systems for enhanced clinical utility.
Related Concept Videos
00:56Doppler Effect - I
6.4K
The Doppler effect and Doppler shift were named after the Austrian physicist and mathematician Christian Johann Doppler in 1842, who conducted experiments with both moving sources and moving observers. Consider an observer standing on a street corner, observing an ambulance with a siren sound passing by at a constant speed. The observer experiences two characteristic changes in the sound of the siren. Initially, the sound increases in loudness as the ambulance approaches and decreases in...
6.4K
01:05Doppler Effect - II
4.7K
The Doppler effect has several practical, real-world applications. For instance, meteorologists use Doppler radars to interpret weather events based on the Doppler effect. Typically, a transmitter emits radio waves at a specific frequency toward the sky from a weather station. The radio waves bounce off the clouds and precipitation and travel back to the weather station. The radio frequency of the waves reflected back to the station appears to decrease if the clouds or precipitation are moving...
4.7K
02:39Phase Diagrams
50.1K
A phase diagram combines plots of pressure versus temperature for the liquid-gas, solid-liquid, and solid-gas phase-transition equilibria of a substance. These diagrams indicate the physical states that exist under specific conditions of pressure and temperature and also provide the pressure dependence of the phase-transition temperatures (melting points, sublimation points, boiling points). Regions or areas labeled solid, liquid, and gas represent single phases, while lines or curves represent...
50.1K
02:31Phase Transitions
23.1K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
23.1K
01:28Inductance: Single-Phase And Three-Phase Line
623
Understanding the inductance of transmission lines is crucial for efficient design and operation in electrical power systems. This discussion delves into the inductance characteristics of single-phase two-wire and three-phase three-wire transmission lines with equal phase spacing.
Single-Phase Two-Wire Line:
A single-phase line consists of two solid cylindrical conductors, denoted as x and y. Each conductor carries phasor currents ix and iy, respectively. Given that the sum of these currents is...
Single-Phase Two-Wire Line:
A single-phase line consists of two solid cylindrical conductors, denoted as x and y. Each conductor carries phasor currents ix and iy, respectively. Given that the sum of these currents is...
623
01:25Capacitance: Single-Phase And Three-Phase Line
603
In electrical power systems, understanding the capacitance of transmission lines is fundamental for efficient operation.
Single-Phase Lines
Consider a single-phase, two-wire transmission line with equal phase spacing energized by a voltage source. One conductor carries a uniform positive charge, while the other carries an equal negative charge. The capacitance C of the line can be derived from the voltage V between the conductors. For a one-meter section of the line, the capacitance is given...
Single-Phase Lines
Consider a single-phase, two-wire transmission line with equal phase spacing energized by a voltage source. One conductor carries a uniform positive charge, while the other carries an equal negative charge. The capacitance C of the line can be derived from the voltage V between the conductors. For a one-meter section of the line, the capacitance is given...
603