A two-stage filter for high density salt and pepper denoising

Image restoration is an important and interesting problem in the field of image processing because it improves the quality of input images, which facilitates postprocessing tasks. The salt-and-pepper noise has a simpler structure than other noises, such as Gaussian and Poisson noises, but is a very common type of noise caused by many electronic devices. In this article, we propose a two-stage filter to remove high-density salt-and-pepper noise on images. The range of application of the proposed denoising method goes from low-density to high-density corrupted images. In the experiments, we assessed the image quality after denoising using the peak signal-to-noise ratio and structural similarity metric. We also compared our method against other similar state-of-the-art denoising methods to prove its effectiveness for salt and pepper noise removal. From the findings, one can conclude that the proposed method can successfully remove super-high-density noise with noise level above 90%.

     

HEVC optimization based on human perception for real-time environments

High-Efficiency Video Coding (HEVC) is the new emerging video coding standard of the ITU-T Video Coding Experts Group (VCEG) and the ISO/IEC Moving Picture Experts Group (MPEG). The HEVC standard provides a significant improvement in compression efficiency in comparison with existing standards such as H264/AVC by means of greater complexity. In this paper we will examine several HEVC optimizations based on image analysis to reduce its huge CPU, resource and memory expensive encoding process. The proposed algorithms optimize the HEVC quad-tree partitioning procedure, intra/inter prediction and mode decision by means of H264-based methods and spatial and temporal homogeneity analysis which is directly applied to the original video. The validation process of these approaches was conducted by taking into account the human visual system (HVS). The adopted solution makes it possible to perform HEVC real time encoding for HD sequences on a low cost processor with negligible quality loss. Moreover, the frames pre-processing leverages the logic units and embedded hardware available on an Intel GPU, so the execution time of these stages are negligible for the encoding processor.

     

A graph coloring approach to the deployment scheduling and unit assignment problem

We address one of the external factors of personnel inventory behavior, deployments. The configuration of persistent unit deployments has the ability to affect everything from individual perceptions of service palatability to operational effectiveness. There is little evidence to suggest any analytical underpinnings to the U.S. Army deployment scheduling and unit assignment patterns. This paper shows that the deployment scheduling and unit assignment problem can be formulated as an interval graph such that modifications to traditional graph coloring algorithms provide an efficient mechanism for dealing with multiple objectives.     

Performance of dynamic texture segmentation using GPU

This work is focused on the assessment of the use of GPU computation in dynamic texture segmentation under the mixture of dynamic textures (MDT) model. In this generative video model, the observed texture is a time-varying process commanded by a hidden state process. The use of mixtures in this model allows simultaneously handling of different visual processes. Nowadays, the use of GPU computing is growing in high-performance applications, but the adaptation of existing algorithms in such a way as to obtain a benefit from its use is not an easy task. In this paper, we made two implementations, one in CPU and the other in GPU, of a known segmentation algorithm based on MDT. In the MDT algorithm, there is a matrix inversion process that is highly demanding in terms of computing power. We make a comparison between the gain in performance obtained by porting to GPU this matrix inversion process and the gain obtained by porting to GPU the whole MDT segmentation process. We also study real-time motion segmentation performance by separating the learning part of the algorithm from the segmentation part, leaving the learning stage as an off-line process and keeping the segmentation as an online process. The results of performance analyses allow us to decide the cases in which the full GPU implementation of the motion segmentation process is worthwhile.     

Real‐Time Isosurface Extraction With View‐Dependent Level of Detail and Applications

Volumetric scalar data sets are common in many scientific, engineering and medical applications where they originate from measurements or simulations. Furthermore, they can represent geometric scene content, e.g. as distance or density fields. Often isosurfaces are extracted, either for indirect volume visualization in the former category, or to simply obtain a polygonal representation in case of the latter. However, even moderately sized volume data sets can result in complex isosurfaces which are challenging to recompute in real time, e.g. when the user modifies the isovalue or when the data itself are dynamic. In this paper, we present a GPU‐friendly algorithm for the extraction of isosurfaces, which provides adaptive level of detail rendering with view‐dependent tessellation. It is based on a longest edge bisection scheme where the resulting tetrahedral cells are subdivided into four hexahedra, which then form the domain for the subsequent isosurface extraction step. Our algorithm generates meshes with good triangle quality even for highly non‐linear scalar data. In contrast to previous methods, it does not require any stitching between regions of different levels of detail. As all computation is performed at run time and no pre‐processing is required, the algorithm naturally supports dynamic data and allows us to change isovalues at any time.     

Industrial assay to assess the efficiency of vacuum pressure impregnation to eliminate the pinewood nematode from wood

An assay using the full-cell method in an industrial autoclave was performed to evaluate the efficiency of vacuum pressure impregnation treatment with a commercial wood preservative product to eliminate the pinewood nematode, Bursaphelenchus xylophilus, from infected Pinus pinaster wood trunks and sections. After treatment and wood incubation, no live nematodes were detected in the treated trunks and sections. This treatment revealed to be a good way to eliminate nematodes from wood and to reduce the risk of pinewood nematode dissemination.     

A 2.4 GHz high-performance CMOS differential quadrature relaxation oscillator

In this paper, the effects that limit the performance of practical implementations of RC relaxation oscillators are investigated. The insights gained are used to suggest a topology for high-frequency quadrature relaxation oscillators with closer-to-optimal performance. The proposed oscillator uses a modified latch to improve the switching speed without increasing the power consumption. Moreover, the new topology avoids static current sources, maximizes the voltage swing and has an active coupling structure without static power consumption that reduces the circuit phase-noise. Experimental results show that the oscillator operates in relaxation mode at 2.4 GHz and achieves a FoM of \(\mathrm {-162\,dBc/Hz}\), which is, as far as the authors know, the best FoM for relaxation oscillators operating in the GHz range.     

Satisfaction and switching intention in mobile services: Comparing lock-in and free contracts in the Spanish market

Switching costs are a relevant issue affecting market competition in the mobile services industry. However, customer switching costs have not disappeared, since numerous leading mobile services companies use lock-in strategies, such as obliged long-term contractual relationships. The present study provides and empirically test a conceptual model in order to analyze the creation of customer satisfaction and switching intention with mobile services, as well as to examine the differences between lock-in and free contracts in a South European mature market – Spain. For this purpose, drawing on a sample of 370 customers, we developed Structural Equation Modeling (SEM) through a multi-group analysis. Our findings suggest that service quality is one of the key determinants of satisfaction, while the availability of attractive alternatives is the main switching barrier. Moreover, some interesting differences were found between the two type of contracts analyzed. Consequently, we suggest shifting resources to customer retention through improved service quality for reducing customer churn rate.