Related Experiment Video
Updated: Jul 7, 2026
08:39
Shaping the Amplitude and Phase of Laser Beams by Using a Phase-only Spatial Light Modulator
Published on: January 28, 2019
Demodulation of a single interferogram by use of a two-dimensional regularized phase-tracking technique
Applied Optics
|July 1, 1997
Summary
This study introduces a novel 2D regularized phase-tracking technique for fringe pattern demodulation. The method provides continuous phase detection, eliminating the need for phase unwrapping.
Area of Science:
- Optics and Photonics
- Image Processing
- Metrology
Background:
- Fringe projection profilometry is a widely used 3D measurement technique.
- Phase unwrapping is a critical but challenging step in fringe analysis.
- Existing methods often struggle with complex fringe patterns or require multiple patterns.
Purpose of the Study:
- To develop a robust and efficient phase demodulation technique for single fringe patterns.
- To eliminate the need for traditional phase unwrapping algorithms.
- To enable continuous phase detection from both open and closed fringe patterns.
Main Methods:
- A two-dimensional regularized phase-tracking algorithm was developed.
- The technique processes a single fringe pattern.
- It incorporates regularization to enhance phase estimation accuracy.
Main Results:
- The proposed technique successfully demodulates single fringe patterns, including those with open and closed fringes.
- Continuous phase maps were generated directly, without requiring a separate phase unwrapping step.
- Accurate phase detection was achieved, demonstrating the effectiveness of the regularization approach.
Conclusions:
- The presented regularized phase-tracking technique offers a significant advancement in fringe pattern analysis.
- It simplifies the 3D measurement workflow by removing the need for phase unwrapping.
- This method holds potential for various optical metrology applications requiring efficient and accurate phase retrieval.
Related Concept Videos
01:10Reconstruction of Signal using Interpolation
Signal processing techniques are essential for accurately converting continuous signals to digital formats and vice versa. When a continuous signal is sampled with a period T, the resulting sampled signal exhibits replicas of the original spectrum in the frequency domain, spaced at intervals equal to the sampling frequency. To handle this sampled signal, a zero-order hold method can be applied, which creates a piecewise constant signal by retaining each sample's value until the next sampling...
01:26Linear Approximation in Frequency Domain
Linear systems are characterized by two main properties: superposition and homogeneity. Superposition allows the response to multiple inputs to be the sum of the responses to each individual input. Homogeneity ensures that scaling an input by a scalar results in the response being scaled by the same scalar.
In contrast, nonlinear systems do not inherently possess these properties. However, for small deviations around an operating point, a nonlinear system can often be approximated as linear.
In contrast, nonlinear systems do not inherently possess these properties. However, for small deviations around an operating point, a nonlinear system can often be approximated as linear.
02:18Interference and Diffraction
Interference is a characteristic phenomenon exhibited by waves. When two electromagnetic waves interact with their peaks and troughs coinciding, a resulting wave with enhanced amplitude is produced. This is known as constructive interference. In this case, the two waves interacting are in phase with each other.
01:21Linear Approximation in Time Domain
Nonlinear systems often require sophisticated approaches for accurate modeling and analysis, with state-space representation being particularly effective. This method is especially useful for systems where variables and parameters vary with time or operating conditions, such as in a simple pendulum or a translational mechanical system with nonlinear springs.
For a simple pendulum with a mass evenly distributed along its length and the center of mass located at half the pendulum's length, the...
For a simple pendulum with a mass evenly distributed along its length and the center of mass located at half the pendulum's length, the...
01:21Time and frequency -Domain Interpretation of Phase-lag Control
Phase-lag controllers are widely used in control systems to improve stability and reduce steady-state errors. A dimmer switch controlling the brightness of a light bulb serves as a practical example of phase-lag control, gradually adjusting the bulb's brightness. Mathematically, phase-lag control or low-pass filtering is represented when the factor 'a' is less than 1.
Phase-lag controllers do not place a pole at zero, but instead influence the steady-state error by amplifying any finite,...
Phase-lag controllers do not place a pole at zero, but instead influence the steady-state error by amplifying any finite,...
01:10Interference: Path Lengths
Consider two sources of sound, that may or may not be in phase, emitting waves at a single frequency, and consider the frequencies to be the same.
Two special sources may be considered when they are in phase. This can be easily achieved by feeding the two sources from the same source. An example would be synchronizing the two speakers by feeding them with the same source, such as the sound waves produced by a tuning fork. This setup ensures that the two sources have the same frequency and are...
Two special sources may be considered when they are in phase. This can be easily achieved by feeding the two sources from the same source. An example would be synchronizing the two speakers by feeding them with the same source, such as the sound waves produced by a tuning fork. This setup ensures that the two sources have the same frequency and are...