3:30, IMDSP-P8.1
ANALYSIS OF MAMMOGRAPHIC MICROCALCIFICATIONS USING A COMPUTATIONALLY EFFICIENT FILTER BANK
T. GULSRUD
We present a new method for classification of malignant and benign clusters of microcalcifications in digital mammograms. A computationally efficient infinite impulse response (IIR) quadrature mirror filter (QMF) bank is used as a tool for extracting texture and shape features. The filter bank splits the input image into four subbands: low-low band, low-high band, high-low band and high-high band. Texture and shape features based on co-occurrence matrices are computed from the subsampled subbands. The low-low band extracts the information of spatial dependence and the higher frequency bands extract the shape information. The results of an experimental study demonstrate that our approach drastically improves the overall performance compared to a manual system.

3:30, IMDSP-P8.2
X-RAY IMAGES ENHANCEMENT USING HUMAN VISUAL SYSTEM MODEL PROPERTIES AND ADAPTIVE FILTERS
M. HADHOUD
X-Ray Images Enhancement using Human Visual System Model Properties and Adaptive Filters Mohiy M. Hadhoud , Ph D, Member IEEE Telecommunications Department, Faculty of Electronic Eng. Menoufia University, Menouf, 32952 , Egypt. Tel. 20-48-664062 ABSTRACT This paper proposes the use of an adaptive image enhancement system that implements the human visual (HVS) properties for the contrast enhancement of the X-Ray images. X-Ray images are of poor quality and usually interpreted visually. The HVS properties considered are the adaptive nature, multichannel, the highly non-linearity. The proposed method is adaptive, nonlinear, multichannel, and combins adaptive filters and homomorphic processing. Results presented illustrate the effectiveness of the proposed method.

3:30, IMDSP-P8.3
AUTOMATIC UNDERSTANDING OF SELECTED DISEASES ON THE BASE OF STRUCTURAL ANALYSIS OF MEDICAL IMAGES
M. OGIELA, R. TADEUSIEWICZ
The goal of this paper is a presentation of the possibilities of the application of syntactic methods to the recognition of the local stenoses of the lumen of coronary arteries, and to the detection of pathological signs in upper parts of ureter ducts and renal calyxes. An analysis of the correct morphology of these structures is possible thanks to the application of sequence and tree methods from the group of syntactic methods of pattern recognition. In the case of the analysis of coronary artery images, the main objective is a computer-aided early diagnosis of the different forms of cardiac ischemic diseases. In the analysis of kidney radiograms the main goal is the recognition of local irregularities in ureter lumens, and an examination of the morphology of renal pelvis and calyxes.

3:30, IMDSP-P8.4
A NOVEL METHOD FOR ADAPTIVE ENHANCEMENT AND UNSUPERVISED SEGMENTATION OF MRI BRAIN IMAGE
J. XUE, W. PHILIPS, A. PIZURICA, I. LEMAHIEU
This paper describes a novel global-to-local method for the adaptive enhancement and unsupervised segmentation of brain tissues in MRI (Magnetic Resonance Imaging) images. Three brain tissues are of interest: CSF (CerebroSpinal Fluid), GM (Gray Matter), WM (White Matter). Firstly, we de-noise the image using wavelet thresholding, and segment the image with minimum error thresholding. Both the thresholdings are global-wise. Subsequently, we combine locally adaptive weighted median and weighted average filters with FCM (Fuzzy C-Means) clustering to achieve a local-wise segmentation. The performance of the proposed method is quantitatively validated by four indices with respect to a MRI brain phantom.

3:30, IMDSP-P8.5
3-D IMAGE RECONSTRUCTION FROM EXPONENTIAL X-RAY PROJECTIONS USING NEUMANN SERIES
J. WAGNER, F. NOO
In two dimensions, the exponential X-ray transform has been well-studied due to its applications of correcting attenuation effects in Single Photon Emission Computed Tomography (SPECT). Explicit inversion formulas have been known for over 15 years. The three-dimensional (3D) case has not been as thoroughly examined, and inversion formulas are available for only a few of the wide range of possible 3D geometries. The Rotating Slant-Hole (RSH) SPECT geometry is a special case for which no inversion formula has yet appeared. This paper presents a general inversion formula for the 3D exponential X-ray transform using a Neumann series. The method applies to any geometry but convergence of the series depends on the exponential scalar and the size of the region-of-interest. The derivation is presented in the context of the RSH SPECT geometry. Results from computer simulations are given.

3:30, IMDSP-P8.6
RECONSTRUCTING SPATIO-TEMPORAL ACTIVITIES OF NEURAL SOURCES FROM MAGNETOENCEPHALOGRAPHIC DATA USING A VECTOR BEAMFORMER
K. SEKIHARA, S. NAGARAJAN, D. POEPPEL, Y. MIYASHITA
We have developed a method suitable for reconstructing spatio-temporal activities of neural sources using MEG data. Our method is based on an adaptive beamformer technique. It extends a beamformer originally proposed by Borgiotti and Kaplan to a vector beamformer formulation in which three sets of weight vectors are used to detect the source activity in three orthogonal directions. The weight vectors of this vector-extension of the Borgiotti-Kaplan beamformer are then projected onto the signal subspace of the measurement covariance matrix to obtain a final form of the proposed beamformer's weight vectors. Our numerical experiments demonstrated the effectiveness of the proposed beamformer.

3:30, IMDSP-P8.7
SAMPLING STRATEGIES AND RESOLUTION IN LIMITED DATA CONE-BEAM TOMOGRAPHY
F. NOO
This paper addresses the prediction of tomographic capabilities of limited-data cone-beam tomographic systems. We introduce the notion of ``local directional resolution'' to predict these capabilities and illustrate its usefulness in a simulation of SPECT breast imaging.