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  2. Speckle (interference) - Wikipedia

    en.wikipedia.org/wiki/Speckle_(interference)

    The Mitsubishi Laser TV appears to use such a screen which requires special care according to their product manual. A more detailed discussion on laser speckle reduction can be found here. [37] Synthetic array heterodyne detection was developed to reduce speckle noise in coherent optical imaging and coherent differential absorption LIDAR.

  3. Median filter - Wikipedia

    en.wikipedia.org/wiki/Median_filter

    The median filter is a non-linear digital filtering technique, often used to remove noise from an image, [1] signal, [2] and video. [3] Such noise reduction is a typical pre-processing step to improve the results of later processing (for example, edge detection on an image).

  4. Noise reduction - Wikipedia

    en.wikipedia.org/wiki/Noise_reduction

    Noise reduction is the process of removing noise from a signal. Noise reduction techniques exist for audio and images. Noise reduction algorithms may distort the signal to some degree. Noise rejection is the ability of a circuit to isolate an undesired signal component from the desired signal component, as with common-mode rejection ratio.

  5. Fixed-pattern noise - Wikipedia

    en.wikipedia.org/wiki/Fixed-pattern_noise

    The term "fixed pattern noise" usually refers to two parameters. [1] One is the dark signal non-uniformity (DSNU), which is the offset from the average across the imaging array at a particular setting (temperature, integration time) but no external illumination and the photo response non-uniformity (PRNU), which describes the gain or ratio ...

  6. Optical heterodyne detection - Wikipedia

    en.wikipedia.org/wiki/Optical_heterodyne_detection

    The primary remaining source of noise is photon shot noise from the nominally constant DC level, which is typically dominated by the Local Oscillator (LO). Since the shot noise scales as the amplitude of the LO electric field level, and the heterodyne gain also scales the same way, the ratio of the shot noise to the mixed signal is constant no ...

  7. Electronic speckle pattern interferometry - Wikipedia

    en.wikipedia.org/wiki/Electronic_speckle_pattern...

    Electronic speckle pattern interferometry (ESPI), [1] also known as TV holography, is a technique that uses laser light, together with video detection, recording and processing, to visualise static and dynamic displacements of components with optically rough surfaces. The visualisation is in the form of fringes on the image, where each fringe ...

  8. Noise (signal processing) - Wikipedia

    en.wikipedia.org/wiki/Noise_(signal_processing)

    Noise reduction, the recovery of the original signal from the noise-corrupted one, is a very common goal in the design of signal processing systems, especially filters. The mathematical limits for noise removal are set by information theory .

  9. Total variation denoising - Wikipedia

    en.wikipedia.org/wiki/Total_variation_denoising

    The regularization parameter plays a critical role in the denoising process. When =, there is no smoothing and the result is the same as minimizing the sum of squares.As , however, the total variation term plays an increasingly strong role, which forces the result to have smaller total variation, at the expense of being less like the input (noisy) signal.