Paper
19 March 2013 Preliminary investigation of the frequency response and distortion properties of nonlinear image processing algorithms
Author Affiliations +
Proceedings Volume 8668, Medical Imaging 2013: Physics of Medical Imaging; 86681H (2013) https://doi.org/10.1117/12.2008549
Event: SPIE Medical Imaging, 2013, Lake Buena Vista (Orlando Area), Florida, United States
Abstract
Assessment of the resolution properties of nonlinear imaging systems is a useful but challenging task. While the modulation transfer function (MTF) fully describes contrast resolution as a function of spatial frequency for linear systems, an equivalent metric does not exist for systems with significant nonlinearity. Therefore, this preliminary investigation attempts to classify and quantify the amount of scaling and distortion imposed on a given image signal as the result of a nonlinear process (nonlinear image processing algorithm). As a proof-of-concept, a median filter is assessed in terms of its principle frequency response (PFR) and distortion response (DR) functions. These metrics are derived in frequency space using a sinusoidal basis function, and it is shown that, for a narrow-band sinusoidal input signal, the scaling and distortion properties of the nonlinear filter are described exactly by PFR and DR, respectively. The use of matched sinusoidal basis and input functions accurately reveals the frequency response to long linear structures of different scale. However, when more complex (multi-band) input signals are considered, PFR and DR fail to adequately characterize the frequency response due to nonlinear interaction effects between different frequency components during processing. Overall, the results reveal the context-dependent nature of nonlinear image processing algorithm performance, and they emphasize the importance of the basis function choice in algorithm assessment. In the future, more complex forms of nonlinear systems analysis may be necessary to fully characterize the frequency response properties of nonlinear algorithms in a context-dependent manner.
© (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jered R. Wells and James T. Dobbins III "Preliminary investigation of the frequency response and distortion properties of nonlinear image processing algorithms", Proc. SPIE 8668, Medical Imaging 2013: Physics of Medical Imaging, 86681H (19 March 2013); https://doi.org/10.1117/12.2008549
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Cited by 2 scholarly publications.
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KEYWORDS
Distortion

Signal processing

Spatial frequencies

Nonlinear image processing

Modulation transfer functions

Double positive medium

Image processing

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