Introduction: One of the major problems in the development of nuclear medicine images is the presence of noise. The noise level in nuclear medicine images is usually reduced by the analysis of imaging data in a Fourier transform environment. The main drawback of this environment belongs to low signal to noise ratio in high frequencies because removing noise frequencies may remove data and times...

The human visual system demonstrates powerful image processing functionalities. Inspired by the visual system, a spiking neural network is proposed to segment visual images. The network is constructed in the two parts. The first part is a spiking neural network which is composed of photon receptors, cone and rod cells, and ON/OFF ganglion cells. Colour features can be extracted and passed throu...

Introduction. Waveguides have been successfully used to generate magnetic resonance images at 7 Tesla for whole-body systems [1]. From these results, it has been established that waveguides are only suitable for 7T systems with wide bores of al least 60 cm. This is mainly due to the cut-off frequency of the cylindrical waveguides used. To overcome this limitation a parallel-plate waveguide was ...

Although images are defined both by the amplitude and phase of their Fourier components, it is phase structure that is the major determinant of their appearance [1–3]. Rainer et al. [4] recently examined how phase structure impacts on cortical activity by measuring the BOLD fMRI signal in anaesthetized monkeys that were shown stimuli containing a blend of phases from images and noise. They show...

Natural images appear blurred when imperfect lens focus reduces contrast energy at higher spatial frequencies. Here, we present evidence that perceived blur also depends on asymmetries between On (positive contrast polarities) and Off (negative contrast polarities) image signals. Psychophysical matching experiments involving natural and artificial stimuli suggest that attenuating Off signals at...

Nowadays, with huge progress in digital imaging, new image processing methods are needed to manage digital images stored on disks. Image retrieval has been one of the most challengeable fields in digital image processing which means searching in a big database in order to represent similar images to the query image. Although many efficient researches have been performed for this topic so far, t...