Paper
30 December 1994 Filtering remote sensing data in the spatial and feature domains
Freddy Fierens, Paul L. Rosin
Author Affiliations +
Abstract
We present a comparative study of the effects of applying pre-processing and post-processing to remote sensing data both in the spatial image domain and the feature domain. We use a neural network for classification since it is not biased by a priori assumptions about the distributions of the spectral values of the classes. Spatial smoothing was applied both as pre- and post-processing steps. Pre-processing involved smoothing the image spectral values by means of anisotropic diffusion, whereas iterative majority filtering was applied as a post- processing step to improve spatial coherence by reclassifying pixels. While it is common practice to filter the image before classification (smoothing) or after classification (iterative majority filtering) it is less obvious what happens if pre-processing is applied to the training or image data in feature space. To minimize the effect of noisy training pixels we applied a k- nearest neighbor filtering algorithm to the training data. This involved reclassifying each training pixel by the majority class of the set of k closest training pixels (in terms of Euclidean distance) in feature space. The procedure eliminates isolated training pixels and tends to produce more compact class clusters. The effects of all spatial and spectral filtering methods were validated by applying them to three different testcases.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Freddy Fierens and Paul L. Rosin "Filtering remote sensing data in the spatial and feature domains", Proc. SPIE 2315, Image and Signal Processing for Remote Sensing, (30 December 1994); https://doi.org/10.1117/12.196747
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CITATIONS
Cited by 8 scholarly publications.
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KEYWORDS
Image filtering

Optical filters

Neural networks

Remote sensing

Image classification

Anisotropic diffusion

Spatial coherence

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