A new spatial filtering technique is proposed for improving image contrast and depth of focus in projection photolithography. The technique is based on fractional Fourier domain filtering. Unlike the current pupil filtering method, the fractional filter can be placed at any location along the projection optical path other than the pupil plane. The theory of partial coherent diffraction combined...

UNLABELLED Removal of electrocardiographic (ECG) contamination of electromyographic (EMG) signals from torso muscles is often attempted by high-pass filtering. This study investigated the effects of the cut-off frequency used in this high-pass filtering technique on the resulting EMG signal. Surface EMGs were recorded on five subjects from the rectus abdominis, external oblique, and erector spi...

Independent component analysis (ICA) is a suitable method for decomposing functional magnetic resonance imaging (fMRI) activity into spatially independent patterns. Practice has revealed that low-pass filtering prior to ICA may improve ICA results by reducing noise and possibly by increasing source smoothness, which may enhance source independence; however, it eliminates useful information in h...

Three different implementations of the 3-pass algorithm of image and volume data rotation are illustrated and discussed. The three protocols use interpolation in real domain, with a peculiar implementation of the Shannon reconstruction, or phase shifts in Fourier domain. Accuracy and speed of the three methods are compared with corresponding values obtained with a 1-pass method. The results ind...

The temporal waveform of neural activity is commonly estimated by low-pass filtering spike train data through convolution with a gaussian kernel. However, the criteria for selecting the gaussian width sigma are not well understood. Given an ensemble of Poisson spike trains generated by an instantaneous firing rate function lambda(t), the problem was to recover an optimal estimate of lambda(t) b...

This paper addresses the problem of expressing a signal as a sum of frequency components (sinusoids) wherein each sinusoid may exhibit abrupt changes in its amplitude and/or phase. The Fourier transform of a narrow-band signal, with a discontinuous amplitude and/or phase function, exhibits spectral and temporal spreading. The proposed method aims to avoid such spreading by explicitly modeling t...

Graph signal processing has recently received considerable attention. Several concepts, tools, and applications in such as filtering, transforming, sampling have been extended to graph processing. One extension is the optimal filtering problem. The minimum mean-squared error estimate of an original can be obtained from its distorted noisy version. However, best separation noise, thus least erro...