texture image analysis is one of the most important working realms of imageprocessing in medical sciences and industry. up to present, different approacheshave been proposed for segmentation of texture images. in this paper, we offeredunsupervised texture image segmentation based on markov random field (mrf)model. first, we used gabor filter with different parameters’ (frequency,orientation) va...

this paper presents a modified digital image watermarking method based on nonnegative matrix factorization. firstly, host image is factorized to the product of three nonnegative matrices. then, the centric matrix is transferred to discrete cosine transform domain. watermark is embedded in low frequency band of this matrix and next, the reverse of the transform is computed. finally, watermarked ...

controlling the electromagnetic waves propagation using optical transformation is a topic that finds many applications in recent years. one of the most important applications of these transformations is hiding the objects from radar waves, i.e. cloaking. hiding under the carpet or carpet cloak is a special type of cloaking that hides the objects situated between a metal sheet and the ground. in...

objective: in this research, a new approach termed as “evolutionary-based brain map” is presented as a diagnostic tool to classify schizophrenic and control subjects by distinguishing their electroencephalogram (eeg) features. methods: particle swarm optimization (pso) is employed to find discriminative frequency bands from different eeg channels. by deploying the energy of those selected frequ...

the helicopter-borne electromagnetic (hem) frequency-domain exploration method is an airborne electromagnetic (aem) technique that is widely used for vast and rough areas for resistivity imaging. the vast amount of digitized data flowing from the hem method requires an efficient and accurate inversion algorithm. generally, the inverse modelling of hem data in the first step requires a precise a...

This paper presents a modified 32-bit ROM-based Direct Digital Frequency Synthesizer (DDFS). Maximum output frequency of the DDFS is limited by the structure of the accumulator used in the DDFS architecture. The hierarchical pipeline accumulator (HPA) presented in this paper has less propagation delay time rather than the conventional structures. Therefore, it results in both higher maximum ope...

The presence of part-through cracks with limited length is one of the prevalent defects in the plate structures. Due to the slight effect of this type of damages on the frequency response of the plates, conventional vibration-based damage assessment could be a challenging task. In this study for the first time, a recently developed state-space method which is based on the chaotic excitation is ...