Spatial shape error concealment method based on cubic B-spline interpolation

In this paper, we propose a novel spatial image error concealment (EC) method based on deep neural network. Considering that the natural images have local correlation and non-local self-similarity, we use the local information to predict the missing pixels and the non-local information to correct the predictions. The deep neural network we utilize can be divided into two parts: the prediction part and the auto-encoder (AE) part. The first part utilizes the local correlation among pixels to predict the missing ones. The second part extracts image features, which are used to collect similar samples from the whole image. In addition, a novel adaptive scan order based on the joint credibility of the support area and reconstruction is also proposed to alleviate the error propagation problem. The experimental results show that the proposed method can reconstruct corrupted images effectively and outperform the compared state-of-the-art methods in terms of objective and perceptual metrics.

A new spatial and temporal error concealment method for three-dimensional discrete wavelet transform (3D DWT) video coding is analyzed. 3D DWT video coding employing dispersive grouping (DG) and two-step error concealment is an efficient method in a packet loss channel [20], [21]. In the two-step error concealment method, the interpolations are only spatially applied however, higher efficiency of the interpolation can be expected by utilizing spatial and temporal similarities. In this paper, we propose an enhanced spatial and temporal error concealment method in order to achieve higher error concealment (EC) performance in packet loss networks. In the temporal error concealment method, structural similarity (SSIM) index is employed for inter group of pictures (GOP) EC and minimum mean square error (MMSE) is used for intra GOP EC. Experimental results show that the proposed method can obtain remarkable performance compared with the conventional methods.

Error concealment at a decoder is an efficient method to reduce the degradation of visual quality caused by channel errors. In this paper, we propose a novel spatio-temporal error concealment algorithm based on the spatial-temporal fading (STF) scheme which has been recently introduced. Although STF achieves good performance for the error concealment, several drawbacks including blurring still remain in the concealed blocks. To alleviate these drawbacks, in the proposed method, hybrid approaches with adaptive weights are proposed. First, the boundary matching algorithm and the decoder motion vector estimation which are well-known temporal error concealment methods are adaptively combined to compensate for the defect of each other. Then, an edge preserved method is utilized to reduce the blurring effects caused by the bilinear interpolation for spatial error concealment. Finally, two concealed results obtained by the hybrid spatial and temporal error concealment are pixel-wisely blended with adaptive weights. Experimental results exhibit that the proposed method outperforms conventional methods including STF in terms of the PSNR performance as well as subjective visual quality, and the computational complexity of the proposed method is similar to that of STF.

Rapid tools for the prediction of the spatial distribution of flood depths within inundated areas are necessary when the implementation of complex hydrodynamic models is not possible due to time constraints or lack of data. For example, similar tools may be extremely useful to obtain first estimates of flood losses in the aftermath of an event, or for large-scale river basin planning. This paper presents RAPIDE, a new GIS-based tool for the estimation of the water depth distribution that relies only on the perimeter of the inundation and a digital terrain model. RAPIDE is based on a spatial interpolation of water levels, starting from the hypothesis that the perimeter of the flooded area is the locus of points having null water depth. The interpolation is improved by (i) the use of auxiliary lines, perpendicular to the river reach, along which additional control points are placed and (ii) the possibility to introduce a mask for filtering interpolation points near critical areas. The reliability of RAPIDE is tested for the 2002 flood in Lodi (northern Italy), by comparing the inundation depth maps obtained by the rapid tool to those from 2D hydraulic modelling. The change of the results, related to the use of either method, affects the quantitative estimation of direct damages very limitedly. The results, therefore, show that RAPIDE can provide accurate flood depth predictions, with errors that are fully compatible with its use for river-basin scale flood risk assessments and civil protection purposes.

Multi-sided Bézier surfaces over concave polygonal domains

Corneal neovascularization (NV) is a sight-threatening condition often associated with infection, inflammation, prolonged contact lens use, corneal burns, and acute corneal graft rejection. Macrophages recruited to the cornea release nitric oxide (NO) and superoxide anion (O2(-)), which react together to form the highly toxic molecule peroxynitrite (ONOO(-)). The role of ONOO(-) in upregulating multiple angiogenic factors in cultured human corneal limbal epithelial (HCLE) cells was investigated. Human corneal limbal epithelial cells were incubated with 500 μM of ONOO(-) donor for various times. VEGF-A, BFGF, and hypoxic-inducible factor-alpha (HIF-1α) were investigated via Western blot and RT-PCR was performed for VEGF. Functional assays using human umbilical vein endothelial cells (HUVEC) used conditioned media from ONOO(-)-exposed HCLE cells. Secreted VEGF from conditioned media was detected and analyzed using ELISA. Increased angiogenic factors were observed as early as 4 hours after HCLE exposure to ONOO(-). HIF-1 expression was seen at 4, 6, and 8 hours post-ONOO(-) exposure (P < 0.05). BFGF expression was elevated at 4 hours and peaked at 8 hours after treatment with ONOO(-) (P < 0.005). Increased VEGF-A gene expression was observed at 6 and 8 hours post-ONOO(-) treatment. Functional assays using conditioned media showed increased HUVEC migration and tube formation. Exposure to elevated extracellular concentrations of ONOO(-) results in upregulation of angiogenic factors in HCLE cells. It is possible that, in the setting of inflammation or infection, that exposure to ONOO(-) could be one contributor to the complex initiators of corneal NV. Validation in vivo would identify an additional potential control point for corneal NV.

The positioning accuracy is critical for satellite-based topographic modeling in cases of exterior orientation parameters with high uncertainty and scarce ground control data. The integration of multi-sensor data can help to ensure precision topographical modeling in such situations. Presently, research on the combined processing of optical camera images and laser altimeter data has focused on planetary observations, especially on the Moon and Mars. This study presents an endeavor to establish a combined adjustment model with one constraint in image space for integration of ZY3-02 stereo images and laser altimeter data for improved Earth topographic modeling. The geometric models for stereo images and laser altimeter data were built first, and then, the laser ranging information was introduced to construct a combined adjustment model on the basis of the block adjustment model. One constraint that minimized the back-projection discrepancies in image space was incorporated into the combined adjustment. Datasets in several areas were collected as experimental data for the validation work. Experimental results demonstrated that the inconsistencies between stereo images and laser altimeter data for the ZY3-02 satellite can be reduced, and the elevation accuracy of stereo images can be significantly improved after applying the proposed combined adjustment. Experiments further proved that the improved height accuracy is insensitive to the number and relative position of laser altimeter points (LAPs) in stereo images. Moreover, additional plane control points (PCPs) were incorporated to achieve better planimetric accuracy. Experimental results in the Dengfeng area showed that the adjustment results derived by using LAPs and additional four PCPs were only slightly lower than those for the block adjustment with four ground control points (GCPs). Generally, the proposed approach can effectively improve the quality of Earth topographic model.

Refining reversal ages and improving reversal patterns for the geomagnetic polarity timescale are a major task for the paleomagnetic community. The Late Miocene is a period during which the geomagnetic field experienced frequent perturbations and which dramatic environmental changes occurred. Thus, improved (sub)chron definition during this period will enable to provide additional age control points for better understanding age of paleoenvironmental changes. A prior study of the Late Miocene C4n.2n magnetic polarity zone at Ocean Drilling Program Site 1092 in the sub‐Antarctic South Atlantic Ocean has revealed the potential existence of a subchron (C4n.2n‐1r). However, this subchron has not been incorporated into the geomagnetic polarity timescale yet because its existence has not been confirmed. Moreover, the low sediment accumulation rate of 1.32 cm/kyr at Site 1092 hampers a confident estimation of the age and duration of this subchron. Here we present a high‐resolution paleomagnetic data set covering C4n.2n from the Huaitoutala section in the eastern Qaidam Basin, Northwest China, with an average sediment accumulation rate of ~22 cm/kyr. Nine reversed declination/inclination data points define a subchron near the top of C4n.2n, similar to age of reported C4n.2n‐1r at Ocean Drilling Program Site 1092. Cyclostratigraphy of the magnetic susceptibility record of the Huaitoutala section suggests that the age and duration of the C4n.2n‐1r are 7.7612–7.7554 Ma and 5.8 ± 2.1 kyr, respectively. Confirming the existence of C4n.2n‐1r from a northern hemisphere terrestrial site suggests that two geomagnetic reversals bounding this subchron have global imprints and that this subchron can potentially serve as marker for stratigraphic correlation.

WIPLOAD Control has been proposed and evaluated as an effective job release control methodology. This paper presents a further simulation experimental study on two variations of WIPLOAD Control in semiconductor wafer fab environment. The first variation mechanism is to control separate WIPLOAD for each part type at a specified level under the situation when the type of job going to be released next can be controlled. The second variation is a mechanism with additional release control points along the production line. The performance of the WIPLOAD variations are compared with that of the original WIPLOAD Control and other existing release methods including CONWIP and Constant release in semiconductor manufacturing environment. The experimental results indicate that by breaking down the control of overall fab WIPLOAD into controlling WIPLOAD level for each part type, cycle time performance can be improved especially with respect to the standard deviation of cycle time.

H.264 adopts new coding tools such as intra-prediction, variable block size, motion estimation with quarter-pixel-accuracy, loop filter, etc. The adoption of these tools enables an H.264-coded bitstream to have more information compared with previous standards. In this paper we proposed an effective spatial error concealment method with low complexity. Among the information included in an H.264-coded bitstream, we use prediction modes of intra-blocks for recovering a damaged block. This is because a prediction direction in each prediction mode is highly correlated to the edge direction. We first estimate the edge direction of a damaged block using prediction modes of intra-blocks adjacent to a damaged block and classify the area inside a damaged block into the edge and the flat area. And then our method recovers pixel values in the edge area using edge-directed interpolation, and recovers pixel values in the flat area using weighted interpolation. Simulation results show the proposed method yields better video quality than conventional approaches.

In this paper, we present Bezier curves method to solve Volterra delay-integro-differential equations. Also, this paper is concerned with a linear system with distributed input delay and input saturation. The approximation process by Bezier curves method is done in two steps. First we divide the time interval into 2k subintervals, second approximate the trajectory and control functions in each subinterval by Bezier curves. We have chosen the Bezier curves as piecewise polynomials of degree n, and determine Bezier curves on any subinterval by \(n+1\) control points. Also, we have used Bezier curves method to solve linear and nonlinear Volterra-Fredholm integral equations, numerically. The proposed method is simple and computationally advantageous. Some numerical examples demonstrate the validity and applicability of the technique.

An Adaptive Spatio-Temporal Error Concealment (ASTEC) scheme based on H.264/AVC is proposed in the paper to improve the quality of the rebuilt frame in H.264/AVC decoder side. Combining the spatial error concealment method with the temporal one, a new scheme is proposed to conceal an erroneous macro block according to its encoded mode. The temporal error concealment scheme adopts the weighted Boundary Matching Algorithm to recover the erroneous macro block. The spatial error concealment scheme recovers the erroneous macro block by exploiting the directional interpolation which subdivides the macro block according to the number and the direction of edges going through it. Experiments show that the proposed concealment scheme can restrain the diffusion of erroneous macro block and improve the quality of the rebuilt frame subjectively as well as objectively.

In [M. M. Malakiyeh, S. Shojaee and S. Hamzehei-Javaran, Development of a direct time integration method based on Bezier curve and 5th-order Berstein basis function, Comput. Struct. 194 (2108) 15–31] an unconditionally stable implicit time-integration method using the Bezier curve was proposed for solving structural dynamic problems. In this study, a new class of the previous algorithm is presented by using the Bernstein polynomials and the Bezier curve as the interpolation functions for solving the equations of motion with the possibility of using large time steps. The spectral radius, period elongation, amplitude decay and overshooting of the present method are investigated and compared with some other methods. To show the high-performance, robustness and validity of this method, five numerical examples are presented. The theoretical analysis and numerical examples show that the proposed method has low dissipation in the lower modes and high dissipation in the higher modes in comparison with the other methods reported in the literature.

We propose a novel image interpolation scheme based on prescribed tangent of cubic B-spline curve. Firstly a cubic B-spline interpolation curve is constructed by discrete pixels. Then a straight line is constructed by joining two points on the B-spline curve with respect to two neighboring pixels. The value of the interpolation point between the two points is determined based on the tangent of the B-spline curve, whose slope is equal to that of the above straight line. Finally, we use the Sobel operator to estimate the edge direction of the interpolation point. Experiments results indicate that the proposed method can greatly maintain the basic information of the original image, reduce the effects of image smoothing and edge blurring caused by the traditional cubic B-spline interpolation, and improve the sharpness of the edges.

An unavoidable problem of most existing skeletonization algorithms for handwriting images is the production of undesired artifacts or pattern distortions. This paper presents a method of identifying these unreliable segments to improve the skeletons of handwriting images. In this method, a novel feature called iteration time is exploited, by which each unreliable segment can be treated as a set of points with exceptional iteration times. First, the iteration time of each skeleton point is calculated, and an undirected graph is built from the skeleton whose edges are weighted by defining a distance measurement between each pair of connected nodes based on iteration time. Then the set of unreliable segments is achieved by a graph clustering algorithm with an effective clustering quality function. Finally, the probability of two jointed reliable segments belonging to a continuous pair is estimated by a best-matched method, and a cubic B-spline interpolation is applied to reconstruct unreliable parts of the skeleton. Experimental results show that the proposed method can detect unreliable segments effectively and produce a skeleton that is closer to the original writing trajectory.