BACKGROUND The paper presents a method of linear time-varying filtering, with extremely low computational costs, for the suppression of baseline drift in electrocardiographic (ECG) signals. An ECG signal is not periodic as the length of its heart cycles vary. In order to optimally suppress baseline drift by the use of a linear filter, we need a high-pass filter with time-varying cut-off frequen...

Although LCL filters are used widely in the grid connected inverters to reduce high-orderharmonics, such a system increases system order and therefore sustainable design of closed-loopcontroller system will be complicated. Recently, the single-loop control strategy has beensuggested for L or LC filter based grid-connected inverters. However, the use of single-loopcontrol directly in LCL filter-...

Introduction:  Skin  sparing  is  one  of  the  most  desirable  characteristics  of  high  energy  photon  beams. However, the photons emerging from the target of linacs are contaminated by secondary  electrons  as  a  result  of  their  interactions  with  air,  collimators,  flattening  filter  and  any  other  objects in their path. This phenomenon tends to increase the skin dose received b...

Purpose: In the last years, some studies investigated dosimetric benefits of a free flattening filter for the photon mode in the radiotherapy field. This study aims to provide a theoretical study published and analysis of basic dosimetric properties for a Saturne 43 Linac head to implement free flattening filter beams clinically. Material and Methods: Thi...

Existing sinogram restoration methods cannot handle noises and nonstationary artifacts simultaneously. Although bilateral filter provides an efficient way to preserve image details while denoising, its performance in sinogram restoration for low-dosed X-ray computed tomography LDCT is unsatisfied. The main reason for this situation is that the range filter of the bilateral filter measures simil...

Background: In myocardial perfusion SPECT imaging, images are degraded by photon attenuation, the distance-dependent collimator, detector response and photons scatter. Filters greatly affect quality of nuclear medicine images Materials and Methods: A phantom simulating heart left ventricle was built. About 1mCi of 99mTc was injected into the phantom. Images were taken from this phantom. Some fi...

While depth of field is an important cinematographic means, its use in real-time computer graphics is still limited by the computational costs that are necessary to achieve a sufficient image quality. Specifically, color bleeding artifacts between objects at different depths are most effectively avoided by a decomposition into subimages and the independent blurring of each sub-image. This decom...

This paper presents the design of a sub-threshold CMOS G,„-C low-pass filter in a portable ECG detection system. The proposed filter is formed by cascading 6 stages of identical l^'-order low-pass sections. With a minimum number of active components in the l^'-order section, the noise contribution of the circuit can be kept low while minimizing the size of transistors and capacitors. The filter...

The acquisition of functional magnetic resonance imaging (fMRI) data in a finite subset of k-space produces ring-artifacts and 'side lobes' that distort the image. In this article, we explore the consequences of this problem for functional imaging studies, which can be considerable, and propose a solution. The truncation of k-space is mathematically equivalent to convolving the underlying "true...