Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Upsampling01:22

Upsampling

Managing signal sampling rates is essential in digital signal processing to maintain signal integrity. A decimated signal, characterized by a reduced frequency range due to its lower sampling rate, can be upsampled by inserting zeros between each sample. This upsampling process expands the original spectrum and introduces repeated spectral replicas at intervals dictated by the new Nyquist frequency. To refine this zero-inserted sequence, it is passed through a lowpass filter with a cutoff...
Phase-lead and Phase-lag Controllers01:22

Phase-lead and Phase-lag Controllers

Understanding the working function of different types of controllers can be illustrated with practical analogies, such as adjusting a stereo's volume equalizer. Cranking up the bass involves a phase-lead controller, which functions as a high-pass filter, while increasing the treble uses a phase-lag controller, which acts as a low-pass filter. PD controllers, similar to high-pass filters, enhance the system's response to high-frequency components. PI controllers, akin to low-pass filters, manage...
Time and frequency -Domain Interpretation of Phase-lead Control01:24

Time and frequency -Domain Interpretation of Phase-lead Control

Phase-lead controllers are commonly used in various control systems to enhance response speed and stability. Adjusting the brightness on a television screen offers a practical example of phase-lead control. When contrast is enhanced, a phase-lead controller is employed. Mathematically, phase-lead control is identified when the first parameter is smaller than the second.
The design of phase-lead control involves the strategic placement of poles and zeros to balance steady-state error and system...
Time and frequency -Domain Interpretation of Phase-lag Control01:21

Time 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,...
Aliasing01:18

Aliasing

Accurate signal sampling and reconstruction are crucial in various signal-processing applications. A time-domain signal's spectrum can be revealed using its Fourier transform. When this signal is sampled at a specific frequency, it results in multiple scaled replicas of the original spectrum in the frequency domain. The spacing of these replicas is determined by the sampling frequency.
If the sampling frequency is below the Nyquist rate, these replicas overlap, preventing the original signal...
Downsampling01:20

Downsampling

When considering a sampled sequence with zero values between sampling instants, one can replace it by taking every N-th value of the sequence. At these integer multiples of N, the original and sampled sequences coincide. This process, known as decimation, involves extracting every N-th sample from a sequence, thereby creating a more efficient sequence.
The Fourier transform of the decimated sequence reveals a combination of scaled and shifted versions of the original spectrum. This...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

[Case of stage IVb gastric cancer in which favorable anti-tumor effect and good QOL were observed due to UFTP therapy after low-dose CDDP-tegafur therapy].

Gan to kagaku ryoho. Cancer & chemotherapyยท1999
Same author

Vitreous surgery for traumatic macular holes.

Retina (Philadelphia, Pa.)ยท1999
Same author

Clinical evaluation of diagnostic methods using plasma and/or serum for three mycoses: aspergillosis, candidosis, and pneumocystosis.

Nihon Ishinkin Gakkai zasshi = Japanese journal of medical mycologyยท1999
Same author

Balloon catheter snared by Palmaz stent placed in an arteriovenous fistula.

Nephronยท1999
Same author

Characterization of monomeric and dimeric B domain of Staphylococcal protein A.

The journal of peptide research : official journal of the American Peptide Societyยท1999
Same author

Interleukin-6 and transforming growth factor-beta regulate the expression of monocyte chemoattractant protein-1 and colony-stimulating factors in human thyroid follicular cells.

Life sciencesยท1999

Related Experiment Video

Updated: Jun 16, 2026

Shaping the Amplitude and Phase of Laser Beams by Using a Phase-only Spatial Light Modulator
08:39

Shaping the Amplitude and Phase of Laser Beams by Using a Phase-only Spatial Light Modulator

Published on: January 28, 2019

Speckle noise reduction by random phase shifters.

M Matsumura

    Applied Optics
    |February 6, 2010
    PubMed
    Summary

    A random phase shifter effectively reduces speckle noise in coherent imaging systems. This technique mitigates optical defects like scratches and dust, improving image quality in holographic systems.

    Area of Science:

    • Optics
    • Image Processing
    • Holography

    Background:

    • Coherent imaging systems, such as holographic systems, are susceptible to speckle noise.
    • Optical defects like scratches and dust on optical components or media cause significant image degradation.
    • Speckle noise reduces the clarity and resolution of images in various applications.

    Purpose of the Study:

    • To investigate the effectiveness of a random phase shifter (RPS) in reducing speckle noise.
    • To evaluate the performance of RPS in coherent and holographic imaging systems.
    • To demonstrate a method for mitigating image artifacts caused by optical defects.

    Main Methods:

    • An RPS composed of small transparent blocks was designed.
    • Each block imparts a specific phase shift (0 or pi) to transmitted light.

    More Related Videos

    Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source
    12:19

    Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source

    Published on: April 4, 2017

    Live Cell Imaging of F-actin Dynamics via Fluorescent Speckle Microscopy (FSM)
    19:16

    Live Cell Imaging of F-actin Dynamics via Fluorescent Speckle Microscopy (FSM)

    Published on: August 5, 2009

    Related Experiment Videos

    Last Updated: Jun 16, 2026

    Shaping the Amplitude and Phase of Laser Beams by Using a Phase-only Spatial Light Modulator
    08:39

    Shaping the Amplitude and Phase of Laser Beams by Using a Phase-only Spatial Light Modulator

    Published on: January 28, 2019

    Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source
    12:19

    Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source

    Published on: April 4, 2017

    Live Cell Imaging of F-actin Dynamics via Fluorescent Speckle Microscopy (FSM)
    19:16

    Live Cell Imaging of F-actin Dynamics via Fluorescent Speckle Microscopy (FSM)

    Published on: August 5, 2009

  • The phase shifts were arranged in a two-dimensional random distribution.

    • Main Results:

    • Experimental results confirmed that the RPS significantly reduces speckle noise.
    • The technique proved effective in coherent imaging systems, including holographic imaging.
    • The random phase shifting successfully counteracted the effects of optical defects.

    Conclusions:

    • Random phase shifters are a viable solution for speckle noise reduction.
    • RPS technology enhances image quality in systems affected by optical imperfections.
    • This method offers a practical approach to improving coherent and holographic imaging.