Journal ArticleDOI
Adaptive restoration of images with speckle
TLDR
This work model the speckle according to the exact physical process of coherent image formation and accurately represents the higher order statistical properties of speckel that are important to the restoration procedure.Abstract:
Speckle is a granular noise that inherently exists in all types of coherent imaging systems. The presence of speckle in an image reduces the resolution of the image and the detectability of the target. Many speckle reduction algorithms assume speckle noise is multiplicative. We instead model the speckle according to the exact physical process of coherent image formation. Thus, the model includes signal-dependent effects and accurately represents the higher order statistical properties of speckle that are important to the restoration procedure. Various adaptive restoration filters for intensity speckle images are derived based on different model assumptions and a nonstationary image model. These filters respond adaptively to the signal-dependent speckle noise and the nonstationary statistics of the original image.read more
Citations
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Journal ArticleDOI
Speckle reducing anisotropic diffusion
Yongjian Yu,Scott T. Acton +1 more
TL;DR: This paper provides the derivation of speckle reducing anisotropic diffusion (SRAD), a diffusion method tailored to ultrasonic and radar imaging applications, and validates the new algorithm using both synthetic and real linear scan ultrasonic imagery of the carotid artery.
Journal ArticleDOI
An unsupervised approach based on the generalized Gaussian model to automatic change detection in multitemporal SAR images
TL;DR: Experiments carried out on two sets of multitemporal images acquired by the European Remote Sensing 2 satellite SAR sensor confirm the effectiveness of the proposed unsupervised approach, which results in change-detection accuracies very similar to those that can be achieved by a manual supervised thresholding.
Journal ArticleDOI
Automated breast cancer detection and classification using ultrasound images: A survey
TL;DR: Generally, a CAD system consists of four stages: preprocessing, segmentation, feature extraction and selection, and classification, and their advantages and disadvantages are discussed.
Journal ArticleDOI
Structure detection and statistical adaptive speckle filtering in SAR images
TL;DR: In this paper it is shown that the filtering process can be controlled both by the coefficient of variation and by various geometrical ratio detectors, which allow the use of large window sizes for better speckle reduction while preserving spatial resolution and structural features.
Journal ArticleDOI
A Nonlocal SAR Image Denoising Algorithm Based on LLMMSE Wavelet Shrinkage
TL;DR: A novel despeckling algorithm for synthetic aperture radar (SAR) images based on the concepts of nonlocal filtering and wavelet-domain shrinkage, which compares favorably w.r.t. several state-of-the-art reference techniques, with better results both in terms of signal-to-noise ratio and of perceived image quality.
References
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Journal ArticleDOI
Some fundamental properties of speckle
TL;DR: In this paper, the distribution of scale sizes in a speckle pattern (i.e., the Wiener spectrum) is investigated from a physical point of view, and it is shown that adding M uncorrelated speckles on an intensity basis can reduce the contrast by 1/√M.
Journal ArticleDOI
A Model for Radar Images and Its Application to Adaptive Digital Filtering of Multiplicative Noise
TL;DR: A model for the radar imaging process is derived and a method for smoothing noisy radar images is presented and it is shown that the filter can be easily implemented in the spatial domain and is computationally efficient.
Journal ArticleDOI
Adaptive Noise Smoothing Filter for Images with Signal-Dependent Noise
TL;DR: The adaptive noise smoothing filter is a systematic derivation of Lee's algorithm with some extensions that allow different estimators for the local image variance and its easy extension to deal with various types of signal-dependent noise.
Book
Laser speckle and related phenomena
TL;DR: Dainty et al. as mentioned in this paper described statistical properties of laser speckle patterns and proposed a method to reduce the number of sparseness of the laser beam in Partially Coherent Light (PCL).
Journal ArticleDOI
Speckle analysis and smoothing of synthetic aperture radar images
TL;DR: This paper develops a statistical technique to define a noise model, and then successfully applies a local statistics noise filtering algorithm to a set of actual SEASAT SAR images, resulting in smoothed images that permit observers to resolve fine detail with an enhanced edge effect.