The quality of the displayed image during minimal-invasive operations (endoscopy) may be low due to highlights and water vapor in front of the camera lens. In some cases, image processing like temporal color vector median filtering may enhance the visual quality of the images [8]. In this contribution we present a new technique of ordering, filtering and re-ordering of color image pixels that i...

This work presents a method for estimation of the acoustic intensity, the energy density and the associated sound field diffuseness around the origin, when the sound field is weighted with a spatial filter. The method permits energetic DOA estimation and sound field characterization focused in a specific angular region determined by the beam pattern of the spatial filter. The formulation of the...

An investigation into the ability of different spatial filters to reduce the amount of crosstalk in a surface electromyography measurement was conducted. A simulation model was implemented to compare the performance of four spatial filters under dynamic muscle contractions. Two parameters of a dynamic muscle contraction, namely muscle shortening and varying contraction force, were evaluated sep...

This Paper presents an efficient algorithm for median filtering with a 3x3 filter kernel with only about 9 comparisons per pixel using spatial coherence between neighbouring filter computations. The basic algorithm calculates two medians in one step and reuses sorted slices of three vertical neighbouring pixels. An extension of this algorithm for 2D spatial coherence is also examined, which cal...

This paper presents a Gaussian noise filter that uses a sigmoid shaped membership function to model image information in the spatial domain. This function acts as a tunable smoothing intensification operator. With a proper choice of two sigmoid parameters ‘t’ and ‘a’, the filter strength can be tuned for removal of Gaussian noise in intensity images. An image information measure, Total Compatib...

The theory of zero-crossing detection is extended to include the first and second spatial derivative of the gaussian distribution. On the premise that phase contains a considerable proportion of the information content in an unknown signal, we show that phase can be extracted from the first and second derivatives of an appropriate filter. It is shown that the spatial gradient of phase can be us...

Spatial or modal filters are essential parts of highly rejecting nulling interferometers. We review the principle of operation of both types of filters and explain the fundamental physical difference. We point out the filter’s individual properties and potentials, and analyze practical limitations. For modal filters we discuss implementation alternatives, also with regard to their suitability f...