Independent component analysis (ICA) of textured images is presented as a computational technique for creating a new data dependent filter bank for use in texture segmentation. We show that the ICA filters are able to capture the inherent properties of textured images. The new filters are similar to Gabor filters, but seem to be richer in the sense that their frequency responses may be more com...

A promising approach for LEBT systems are Gabor Plasma Lenses using a stable space charge cloud [1]. The confinement of the electrons by external fields leads to focusing of ion beams at drastically reduced magnetic and electric field strength compared to conventional ion optics. Therefore in former experiments the fundamental properties of the electron cloud so called nonneutral plasma were st...

The tracking of prominent oscillations with time-varying frequencies is a common task in many signal processing applications. Therefore, efficient methods are needed to meet precision and run-time requirements. We propose two methods that extract the energy of the time frequency plane along a cubic spline trajectory. To raise efficiency, a sparse sampling method with dynamically shaped atoms is...

The ModelFest Phase One dataset is a collection of luminance contrast thresholds for 43 two-dimensional monochromatic spatial patterns confined to an area of approximately two by two degrees. These data were collected by a collaboration among twelve laboratories, and were designed to provide a common database for calibration and testing of spatial vision models. Here I report fits of the ModelF...

How does our visual system detect prominent contours? Our investigation begins with the observation that neurons in the visual cortex have receptive fields similar to oriented Gabor filters. Unlike plain gray-level intensity histograms which greatly vary across images, we found that Gabor orientation-response (or orientation-energy) histograms of natural images have a fairly uniform shape. Base...

In this paper, we review most major filtering approaches to texture feature extraction and perform a comparative study. Filtering approaches included are Laws masks, ring/wedge filters, dyadic Gabor filter banks, wavelet transforms, wavelet packets and wavelet frames, quadrature mirror filters, discrete cosine transform, eigenfilters, optimized Gabor filters, linear predictors, and optimized fi...

Image segmentation is the foremost process in medical image processing. It aids the diagnostic and clinical analysis of MRI (Magnetic Resonance Imaging) images that were acquired through the most complex procedures of medical diagnostics. The earliest soft computing techniques in segmenting images were carried out through Fuzzy C-Means (FCM) and similar extensions of various clustering algorith...

We propose two texture-based approaches, one involving Gabor filters and the other employing log-polar wavelets, for separating text from non-text elements in a document image. Both the proposed algorithms compute local energy at some information-rich points, which are marked by Harris’ corner detector. The advantage of this approach is that the algorithm calculates the local energy at selected...

Models of spatial vision usually assume a "front-end" of spatial-frequency and orientation selective channels. Subthreshold-summation studies have provided some of the strongest support for this notion. We applied a single-channel energy model and a multiple-channels probability-summation model to explore subthreshold-summation phenomena. We measured the contrast thresholds for detection of two...