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The object of research is the process of searching and analyzing images of raster graphics. In the context of this work, the problem of the lack of an effective and fast procedure for determining the similarity of images was solved. The technology for improving the construction of a software tool for determining the similarity of raster graphics images by devising a procedure for determining the similarity of images using a hash code that corresponds to all variants of the image, regardless of size and aspect ratio, is reported. The image features of raster graphics were systematized. A procedure for determining the similarity of images using a hash code is proposed. This procedure makes it possible to process all possible variants of the image, regardless of the size and aspect ratio. The resulting indicator of the proposed procedure is the value of the hash codes. It is proposed to use the mathematical apparatus of fuzzy logic by introducing linguistic variables to estimate the similarity index. A comparison of the numerical values of similarity, obtained on the basis of the use of information systems, and the linguistic values revealed in the survey process was carried out. Threshold values were obtained that make it possible to assess the degree of similarity of the images. Based on the proposed algorithm, a prototype of the information system for determining the similarity of images of raster graphics has been designed. As a result of the calculation of the numerical characteristics of the improvement of the technology of constructing a software tool for determining the similarity of images of raster graphics, the value of the precision indicators was approximately 0.89 and the completeness was 0.8. The advantage of the proposed technology for determining the similarity of images over known analog technologies is illustrated by the amount of RAM of the developed software, which is 210 MB. [ABSTRACT FROM AUTHOR]

An innovative and simple design for a weaving loom was proposed to simplify the pattern design and the decoding process of weaving. Using the structural analysis of the existing looms and based on the concepts of weaving, a creative open-type rigid heald was developed to replace the traditional one and generate warp shedding. Corresponding to the raster graphics of the designed pattern, the heald shape had convex–concave features to control warping in shedding. The pattern design was integrated into the heald design using mechanical coding. [ABSTRACT FROM AUTHOR]

A key advantage of vector graphics over raster graphics is their editability. For example, linear gradients define a spatially varying color fill with a few intuitive parameters, which are ubiquitously supported in standard vector graphics formats and libraries. By layering regions filled with linear gradients, complex appearances can be created. We propose an automatic method to convert a raster image into layered regions of linear gradients. Given an input raster image segmented into regions, our approach decomposes the resulting regions into opaque and semi-transparent linear gradient fills. Our approach is fully automatic (e.g., users do not identify a background as in previous approaches) and exhaustively considers all possible decompositions that satisfy perceptual cues. Experiments on a variety of images demonstrate that our method is robust and effective. [ABSTRACT FROM AUTHOR]

This paper proposes a method for changing pixel shape by converting a CMYK raster image (pixel) to an HSB vector image, replacing the square cells of the CMYK pixels with different vector shapes. The replacement of a pixel by the selected vector shape is done depending on the detected color values for each pixel. The CMYK values are first converted to the corresponding RGB values and then to the HSB system, and the vector shape is selected based on the obtained hue values. The vector shape is drawn in the defined space, according to the row and column matrix of the pixels of the original CMYK image. Twenty-one vector shapes are introduced to replace the pixels depending on the hue. The pixels of each hue are replaced by a different shape. The application of this conversion has its greatest value in the creation of security graphics for printed documents and the individualization of digital artwork by creating structured patterns based on the hue. [ABSTRACT FROM AUTHOR]

Today, the objective of applying shadow theory to architectural drawing is usually to obtain one (or several) bitmap images. This a priori innocuous fact leads to vector images being conspicuous by their absence when lighting factors come into play during the modelling and parametric design of architecture and its environment. The present article sets out a methodology to calculate shadows by placing vector drawing not only at the heart of the process but also of the obtained results. We found that in today's context of university excellence, it is essential to apply knowledge, control, as well as possible editing and postproduction of the effects generated by rendering process lighting calculations. Such interventions are also generally useful and effective in our profession. [ABSTRACT FROM AUTHOR]

Various web-based image-editing tools and web-based collaborative tools exist in isolation. Research focusing to bridge the gap between these two domains is sparse. We respond to the above and develop prototype groupware for real-time collaborative editing of raster and vector images in a web browser. To better understand the requirements, we conduct a preliminary user study and establish communication and synchronization as key elements. The existing groupware for text documents or presentations handles the above through well-established techniques. However, those cannot be extended as it is for raster or vector graphics manipulation. To this end, we develop a document model that is maintained by a server and is delivered and synchronized to multiple clients. Our prototypical implementation is based on a scalable client–server architecture: using WebGL for interactive browser-based rendering and WebSocket connections to maintain synchronization. We evaluate our work qualitatively through a post-deployment user study for three different scenarios. For quantitative evaluation, we perform a thorough performance measure on both client and server side, thereby identifying design recommendations for future concurrent image-editing software(s). [ABSTRACT FROM AUTHOR]

In this study, the effect of dietary Spirulina (Arthrospira platensis) on color intensity, growth performance, total ammonia–nitrogen excretion (TAN), and profitability of common clownfish (Amphiprion ocellaris) was investigated. Three isoproteic (46%) and isolipidic (13%) diets were formulated as one control (C) and two different levels (15 and 30%) of Spirulina (SP15 and SP30) substituted for fish meal and cornmeal. Ten clownfish (initial body weight of 0.55 ± 0.04 g) per aquarium were distributed to nine glass aquariums (60 L) with three replicates. Fish were hand-fed a day to the satiation thrice. Clownfish were weighed in bulk, and the photographs were taken biweekly during the 12-week experiment. The determined regions of the images were standardized with a raster graphics editor and recorded the color parameters by considering both CMYK (cyan magenta yellow key) and RGB (red green blue) models. After the feeding trial, fish were starved for 3 days, and the total ammonia–nitrogen (TAN) was analyzed with the ammonia salicylate method on the next day for 12 h. At the end of the trial, the final mean weights (FMW) and specific growth rates (SGR) of SP15 (FMW: 1.95 ± 0.18 g, SGR: 1.75 ± 0.04%/day) and SP30 (FMW: 2.05 ± 0.14 g, SGR: 1.81 ± 0.05%/day) were significantly higher than the C (FMW: 1.68 ± 0.12 g, SGR: 1.58 ± 0.06%/day) group (P < 0.05). Both color models have proved the enhancement of the skin coloration (significant improvements were recorded in the colors, including red, green, magenta, and key, P < 0.05). Also, it was determined that the TAN was decreased with the increase of the Spirulina level (29.8, 22.9, and 17.6 mg-N/100 g fish/12 h for C, SP15, and SP30, respectively) in the diet (P < 0.05). However, a high level of Spirulina in the diet negatively affected profitability. Consequently, common clownfish's growth, color, and TAN improved with the dietary Spirulina. Considering that Spirulina is an expensive raw material, adding it into the diet at medium levels (15%) is recommended. [ABSTRACT FROM AUTHOR]

Vector image representation methods that can faithfully reconstruct objects and color variations in a raster image are desired in many practical applications. This article presents triangular configuration B-spline (referred to as TCB-spline)-based vector graphics for raster image vectorization. Based on this new representation, an automatic raster image vectorization paradigm is proposed. The proposed framework first detects sharp curvilinear features in the image and constructs knot meshes based on the detected feature lines. It iteratively optimizes color and position of control points and updates the knot meshes. By using collinear knots at feature lines, both smooth and discontinuous color variations can be efficiently modeled by the same set of quadratic TCB-splines. A variational knot mesh generation method is designed to adaptively introduce knots and update their connectivity to satisfy the local reconstruction quality. Experiments and comparisons show that our framework outperforms the existing state-of-the-art methods in providing more faithful reconstruction results. In particular, our method is able to model undetected features and subtle or complicated color variations in-between features, which the previous methods cannot handle efficiently. Our vectorization representation also facilitates a variety of editing operations performed directly over vector images. [ABSTRACT FROM AUTHOR]

The presented study addresses the characterization of nanometer sized defects acting as damage precursors in nanosecond laser pulse duration regime. Two approaches are used to extract distributions of localized damage precursors, namely, damage probability and damage density measurements. Testing is performed on uncoated and SiO2 monolayer film deposited fused silica substrate exposed with pulsed UV irradiation (355 nm, 4.8 ns). Then, a direct comparison of damage precursor ensembles obtained from both methods is carried out. Our analysis indicates apparent differences between both methods that are discussed in detail. Contamination by ablation products is identified as one of the key factors that influence damage density measurements. [ABSTRACT FROM AUTHOR]

With the advent of advances in imaging and computing technologies, large-scale data acquisition and processing have become commonplace in many science and engineering disciplines. Conventional workflows for large-scale data processing usually rely on in-house or commercial software that are designed for domain-specific computing tasks. Recent advances in MapReduce, which was originally developed for batch processing textual data via a simplified programming model of the map and reduce functions, have expanded its applications to more general tasks in big-data processing, such as scientific computing, and biomedical image processing. However, as shown in previous work, volume rendering and visualization using MapReduce is still considered challenging and impractical owing to the disk-based, batch-processing nature of its computing model. In this article, contrary to this common belief, we show that the MapReduce computing model can be effectively used for interactive visualization. Our proposed system is a novel extension of Spark, one of the most popular open-source MapReduce frameworks, which offers GPU-accelerated MapReduce computing. To minimize CPU-GPU communication and overcome slow, disk-based shuffle performance, the proposed system supports GPU in-memory caching and MPI-based direct communication between compute nodes. To allow for GPU-accelerated in-situ visualization using raster graphics in Spark, we leveraged the CUDA-OpenGL interoperability, resulting in faster processing speeds by several orders of magnitude compared to conventional MapReduce systems. We demonstrate the performance of our system via several volume processing and visualization tasks, such as direct volume rendering, iso-surface extraction, and numerical simulations with in-situ visualization. [ABSTRACT FROM AUTHOR]

In this paper, we present two approaches for recording a quasi-hologram on the steel surface by femtosecond laser pulses. The recording process is done by rotating the polarization of the laser beam by a half-wave plate or a spatial light modulator (SLM), so we can control the spatial orientation of the formed laser-induced periodic surface structures (LIPSS). Two different approaches are shown, which use vector and bitmap images to record the hologram. For the first time to our knowledge, we managed to record a hologram of a bitmap image by continuously adjusting the laser beam polarization by SLM during scanning. The developed method can substantially improve hologram recording technology by eliminating complex processing procedures, which can lead to increasing the fabrication speed and reducing the cost. [ABSTRACT FROM AUTHOR]

There is growing interest in voxelated matter that is designed and fabricated voxel by voxel.sup.1-4. Currently, inkjet-based three-dimensional (3D) printing is the only widely adopted method that is capable of creating 3D voxelated materials with high precision.sup.1-4, but the physics of droplet formation requires the use of low-viscosity inks to ensure successful printing.sup.5. By contrast, direct ink writing, an extrusion-based 3D printing method, is capable of patterning a much broader range of materials.sup.6-13. However, it is difficult to generate multimaterial voxelated matter by extruding monolithic cylindrical filaments in a layer-by-layer manner. Here we report the design and fabrication of voxelated soft matter using multimaterial multinozzle 3D (MM3D) printing, in which the composition, function and structure of the materials are programmed at the voxel scale. Our MM3D printheads exploit the diode-like behaviour that arises when multiple viscoelastic materials converge at a junction to enable seamless, high-frequency switching between up to eight different materials to create voxels with a volume approaching that of the nozzle diameter cubed. As exemplars, we fabricate a Miura origami pattern.sup.14 and a millipede-like soft robot that locomotes by co-printing multiple epoxy and silicone elastomer inks of stiffness varying by several orders of magnitude. Our method substantially broadens the palette of voxelated materials that can be designed and manufactured in complex motifs. Voxelated soft matter is designed and fabricated using multimaterial multinozzle three-dimensional printing, which switches between different viscoelastic inks along the same print filament to print multiple materials simultaneously., Author(s): Mark A. Skylar-Scott [sup.1] [sup.2] , Jochen Mueller [sup.1] [sup.2] , Claas W. Visser [sup.1] [sup.2] , Jennifer A. Lewis [sup.1] [sup.2] Author Affiliations: (1) Harvard John A. Paulson [...]

Copyright of New Architecture is the property of New Architecture Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We introduce a differentiable rasterizer that bridges the vector graphics and raster image domains, enabling powerful raster-based loss functions, optimization procedures, and machine learning techniques to edit and generate vector content. We observe that vector graphics rasterization is differentiable after pixel prefiltering. Our differentiable rasterizer offers two prefiltering options: an analytical prefiltering technique and a multisampling anti-aliasing technique. The analytical variant is faster but can suffer from artifacts such as conflation. The multisampling variant is still efficient, and can render high-quality images while computing unbiased gradients for each pixel with respect to curve parameters. We demonstrate that our rasterizer enables new applications, including a vector graphics editor guided by image metrics, a painterly rendering algorithm that fits vector primitives to an image by minimizing a deep perceptual loss function, new vector graphics editing algorithms that exploit well-known image processing methods such as seam carving, and deep generative models that generate vector content from raster-only supervision under a VAE or GAN training objective. [ABSTRACT FROM AUTHOR]

Forty years ago, the first General Purpose Raster Graphics Processor made the transition from research project to commercial product. This is the story of the creation of a new graphics system and the startup company that produced it in the early days of raster computer graphics. [ABSTRACT FROM AUTHOR]

Glaciers depicted on old maps reveal their historical extents, before the advent of aerial and satellite remote sensing. Digital glacier inventories produced from these maps can be employed in assessments of centennial-scale glacier change. This study reconstructs the ~1899 (covering the period 1882–1916) glacier extent in Nordland, northern Norway, from historical gradteigskart maps, with an emphasis on examining the accuracy of the mapped glaciers. Glacier outlines were digitised from georectified scans of the analogue maps in a raster graphics editor and were subsequently inventoried in a GIS. The accuracy of the historical glacier extent was established from written descriptions and landscape photographs created during the original field surveys, and further validated against independent glacier outlines of (1) the maximum Little Ice Age extent derived from geomorphological evidence, and (2) the 1945 extent derived from vertical aerial photographs. An overall uncertainty of ±17% is associated with our inventory. Nordland's glaciers covered an area of 1712 ± 291 km2 in 1899. By 2000, total ice cover had decreased by 47% (807 ± 137 km2) at a rate of 6% 10 a−1 (80 ± 14 km2 10 a−1). The approach presented here may serve as a blueprint for future studies intending to derive glacier inventories from historical maps. [ABSTRACT FROM AUTHOR]

We report the preliminary results of a meta-analysis conducted to examine possible biases in the uncertainty values published in papers by ATLAS and CMS experiments. We have performed this analysis using two independent techniques: a vectoral analysis of the vector graphics files and a bitmap analysis of the raster graphic files of the exclusion plots from various physics searches. In both procedures, the aim is to compute the percentages of the data points scattered within 1σ and 2σ bands of the plots and verify whether the measured percentages agree with statistical norms, assuming unbiased estimations of the uncertainties. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Technology & Information Education is the property of Palacky University in Olomouc and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The plastic forming properties of metal depend on the nature of the metal and on the deformation conditions. However, in the process of grating mechanical scribing, the flow of materials, the distribution of stress and strain fields, and the tool loading can be hardly detected and controlled. In order to obtain a better groove shape and ensure the quality of the grating geometry, the metal flow inside the material during the scratching process was studied. The equivalent strain map, stress distribution, and metal flow rate of the scratching process can be clearly obtained from the simulation results of the grating scribe, and the flow law of the metal material can be grasped. By analyzing the equivalent strain map and stress distribution of the grating scribing process, the force distribution and size of the aluminum film are obtained, which is reflected in the stress of each side of the extended pyramid knife and each blade. To provide the theoretical basis and test data for the design of diamond-like tool design and its process, so as to improve the design quality and efficiency of the tool and provide scientific basis for the orientation and development of such diamond scribe tool. [ABSTRACT FROM AUTHOR]

This paper describes the collection of a large dataset (6930 measurements) on dimensional error in the fused deposition modeling (FDM) additive manufacturing process for full-density parts. Three different print orientations were studied, as well as seven raster angles (0°, 15°, 30°, 45°, 60°, 75°, and 90°) for the rectilinear infill pattern. All measurements were replicated ten times on ten different samples to ensure a comprehensive dataset. Eleven polymer materials were considered: acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), high-temperature PLA, wood-composite PLA, carbon-fiber-composite PLA, copper-composite PLA, aluminum-composite PLA, high-impact polystyrene (HIPS), polyethylene terephthalate glycol-enhanced (PETG), polycarbonate, and synthetic polyamide (nylon). The samples were ASTM-standard impact-testing samples, since this geometry allows the measurement of error on three different scales; the nominal dimensions were 3.25mmthick, 63.5 mm long, and 12.7 mm wide. This dataset is intended to give engineers and product designers a basis for judging the accuracy and repeatability of the FDM process for use in manufacturing of end-user products. [ABSTRACT FROM AUTHOR]

Bitmap-based indexes are known to be the most effective indexing method for retrieving and answering selective queries in a read-only environment. Various types of encoding bitmap indexes significantly improve query time efficiency by utilizing fast Boolean operations directly on the index before retrieving the raw data. In particular, the dual bitmap index improves the performance of equality queries in terms of the space vs. time trade-off. However, the performance of range queries is unsatisfactory. In this paper, an optimizing algorithm is proposed to improve the range query processing for the dual bitmap index. The results of the experiment conducted show that the proposed algorithm, called Dual-simRQ, reduces the number of bitmap vectors scanned and the Boolean operations performed, which impacts the overall performance for range query processing. [ABSTRACT FROM AUTHOR]

Piezoelectric actuators are widely used in scanning platforms of scanning probe microscopes (SPMs). However, the hysteresis of piezoelectric actuators reduces positioning accuracy and results in distorted SPM images. When regular raster scanning of SPM starts, the piezoelectric actuators move repeatedly at the same scanning range and frequency once the scanning parameters are set. In this study, a practical and simple mathematical model derived from experimental phenomenon, which is the combination of sinusoidal and linear functions, was proposed to describe the hysteresis behavior of piezoelectric actuators with repeated scanning. The model parameter was calculated from the coordinates of matched feature points in the trace and retrace images of ordinary sample obtained with an atomic force microscope (AFM). Experimental results show that the hysteresis of the scanned images is decreased from 107.46 pixels to 2.50 pixels after correction, with a width of 800 pixels. Hysteresis in other scanned images with different scanning frequencies and ranges was also corrected effectively using this model. The proposed model can be used to correct the hysteresis of AFM images without using any expensive displacement sensors or standard samples. The model is suitable and easy to be integrated into the scanning program of AFM without requiring hardware modifications. [ABSTRACT FROM AUTHOR]

Highlights • Two joint image compression and encryption schemes based on JPEG are proposed. • A trade-off between encryption power and compression ability is considered. • The first encryption scheme has better compression performance. • The second encryption scheme has stronger security level. Abstract Joint image encryption and compression schemes have shown their great potential values in protecting compressed images. To achieve the protection, a trade-off between encryption power and compression ability needs to be considered. In this paper, we propose two new joint encryption and compression schemes, where one scheme emphasizes compression performance, another highlights protection performance. For a given plain-image, we first raster scan it into non-overlapping 16 × 16 blocks, then apply various encryption techniques to it. In the first scheme, encryption operations are conducted at the transformation stage and quantization stage of JPEG. As for the second scheme, we add the run/size and value (RSV) pairs' shuffling operation at JPEG's entropy coding stage after first scheme's encryption operations. Performance evaluations using various criteria are conducted to show that the first scheme has better compression efficiency, while the second scheme has better defense ability against the statistical attack. [ABSTRACT FROM AUTHOR]

Novel fault leveling techniques based on address remapping (AR) are proposed in this paper. We can change the logical-to-physical address mapping of the page buffer such that faulty cells within a flash page can be evenly distributed into different codewords. Therefore, the adopted ECC scheme can correct them effectively. Based on the production test or on-line BIST results, the fault bitmap can be used for executing the heuristic fault leveling analysis (FLA) algorithm and evaluating control words used to steer fault leveling. A new page buffer architecture suitable for address remapping is also proposed. According to experimental results, repair rate, yield, and reliability can be improved significantly with negligible hardware overhead. [ABSTRACT FROM AUTHOR]

Scalability is a key issue in datacenter multicast as it needs to support a large number of groups in commodity switches with limited fast memory. Previous in-packet Bloom filter-based datacenter multicast schemes have been proposed to address the scalability issue. They encode a multicast tree in a Bloom filter carried in each packet. However, these schemes induce high bandwidth overhead due to the false positives inherent in Bloom filters, and cannot scale well to the increasing variety of group sizes. In this paper, we propose an in-packet bitmap-based approach towards scalable datacenter multicast, improving the bandwidth efficiency. We use a bitmap to encode switch ports of a multicast tree in the packet header, eliminating false positive forwarding. In addition, we use a clustered Golomb coding method to compress in-packet bitmaps for further reducing the bandwidth overhead. Experimental results on simulations and a Click-based switch prototype demonstrate that our scheme achieves up to several orders of magnitude reductions in bandwidth overhead compared to previous schemes. [ABSTRACT FROM AUTHOR]

Fidelity has been a critical concern of researchers throughout the history of driving simulation. Understanding the limits of a driving simulation system is a prerequisite for conducting valid driving simulator studies. This paper proposes a novel and interdisciplinary methodology to ensure validity of studies using driving simulators (primarily for traffic control devices and other object detection tasks) based on the visual limits of human sensory and perceptual capabilities, and the characteristics of raster graphics. This methodology decomposes the perceptual issues of a stimulus into perceptual issues of different visual properties like luminance, hue, or text of the stimulus. By systematically analyzing the mechanism of human vision in driving simulators, the perceptual principle is proposed to ensure perceivable visual details in human-in-the-loop driving simulation systems. Additionally, the graphic principle is proposed to ensure perceivable features of a target object in the virtual driving environment. Both principles quantify the minimum requirements of visual fidelity with two measurements: angular resolution and matrix dimensions. The enriched results from existing pertinent studies are analyzed and organized to yield support of both principles. This research focuses on the minimum requirements for four factors; namely the visual acuity of drivers, the specifications of display systems, the configurations of graphics systems, and the design of virtual scenarios, as well as the relationship among all these factors to assess the visual fidelity in driving simulation systems. Within the realm of human perception, this work can provide criteria for proper design, calibration, and usage of driving simulators. [ABSTRACT FROM AUTHOR]

The paper proposes a novel method for detecting indicators of image forgery by locating grid alignment abnormalities in JPEG compressed image bitmaps. The method evaluates multiple grid positions with respect to a fitting function, and areas of lower contribution are identified as grid discontinuities and possibly tampered areas. An image segmentation step is introduced to differentiate between discontinuities produced by tampering and those that are attributed to image content, making the output maps easier to interpret by suppressing non-relevant activations. Our evaluations, on both synthetically produced datasets and real world tampering cases against seven methods from the literature, highlight the effectiveness of the proposed method in its ability to produce output maps that are clear and readable, and which can achieve successful detections on cases where other algorithms fail. [ABSTRACT FROM AUTHOR]

In this paper, we present techniques for offsetting spherical curves represented in vector or raster form. Such techniques allow us to efficiently determine and visualize the region within a given distance of a spherical curve. Our methods additionally support multiresolution representations of the underlying data, allowing the initial coarse offsets to be provided quickly, which may then be iteratively refined to the correct result. An example application of offsetting is also specifically explored in the form of improving the performance of inside/outside tests in the vector case. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we present a method to vectorize raster images of line art. Inverting the rasterization procedure is inherently ill‐conditioned, as there exist many possible vector images that could yield the same raster image. However, not all of these vector images are equally useful to the user, especially if performing further edits is desired. We therefore define the problem of computing an instance segmentation of the most likely set of paths that could have created the raster image. Once the segmentation is computed, we use existing vectorization approaches to vectorize each path, and then combine all paths into the final output vector image. To determine which set of paths is most likely, we train a pair of neural networks to provide semantic clues that help resolve ambiguities at intersection and overlap regions. These predictions are made considering the full context of the image, and are then globally combined by solving a Markov Random Field (MRF). We demonstrate the flexibility of our method by generating results on character datasets, a synthetic random line dataset, and a dataset composed of human drawn sketches. For all cases, our system accurately recovers paths that adhere to the semantics of the drawings. [ABSTRACT FROM AUTHOR]

Raster map viewers can be used by various entities, including public administration units. They are used in particular when there is no economic justification for creating extended and comprehensive mapping services, or when there is a need to quickly publish the given map. These viewers can be made using one of many available components. However, not all of them are optimal for such applications. Selected raster map viewers may be inefficient, which may make it difficult or even impossible to view the map. The aim of the present work was to conduct a comparative analysis of the performance of selected raster map viewers. The prototype applications were used to test the implementation of selected designing tools. The efficiency measurement was made using tools for test automation. The value of the ESSCORE (Estimated Speed Score) synthetic performance meta-index has been determined. It has been shown that the application created with the use of the ImageViewer component (jQuery JavaScript) was objectively the best of the tests tested for the presentation of raster graphics (according to the adopted testing scheme). [ABSTRACT FROM AUTHOR]

Computer architectures have evolved into parallel and heterogeneous systems with multi-core CPUs, many-core GPUs, and vector instructions. Meanwhile, advances in data collection technologies have led to a rapid increase in the spatial and temporal resolution of geographic data. Efficiently dealing with large volumes of geographic data demands, now more than ever, an effective use of modern parallel computers. However, parallel programming is distinctly more challenging than writing sequential scripts. Moreover, parallelism is not the only issue; data locality is critical, too. This work addresses the issues of data escalation and parallel transition using a compiler approach to map algebra. More specifically, we design and implement a framework that uses compiler techniques to automatically speed up raster spatial analysis. In this way, users simply write sequential map algebra scripts in Python, which are translated into a graph where optimizations are applied. Then the scripts are parallelized, reordered for locality, and executed on OpenCL devices such as multi-core CPUs and GPUs. The novelty of our approach resides in the efficient organization of the execution, which we achieve via compilation. Unlike interpreters, our framework reorders the raster operations to maximize data reuse and minimize memory movements. The reordering occurs at two hierarchical levels and is controlled by a scheduler and a fusion technique. This strategy targets data locality, which, as we show, is key to the performance of raster spatial analysis. The experiments report speed-ups of one to two orders of magnitude compared to traditional interpreters. [ABSTRACT FROM AUTHOR]

We introduce a graphical method originating from the computer graphics domain that is used for the arbitrary placement of cells over a two-dimensional manifold. Using a bitmap image whose luminance provides cell density, this method guarantees a discrete distribution of the positions of the cells respecting the local density. This method scales to any number of cells, allows one to specify arbitrary enclosing shapes and provides a scalable and versatile alternative to the more classical assumption of a uniform spatial distribution. The method is illustrated on a discrete homogeneous neural field, on the distribution of cones and rods in the retina and on the neural density of a flattened piece of cortex. [ABSTRACT FROM AUTHOR]

The existing image authentication methods for absolute moment block truncation coding (AMBTC) modify the bits of quantitation levels or bitmaps to embed the authentication code (AC). However, the modification of the bits in these methods is equivalent to the LSB replacement, which may introduce undesirable distortions. Besides, the modification of bitmap for embedding AC reduces the image quality significantly, especially at image edges. Moreover, the existing methods might not be able to detect some special modifications to the marked image. In this paper, we propose an efficient authentication method for the AMBTC compressed image. AC is obtained from the bitmap and the location information, and is embedded into the quantization levels using the adaptive pixel pair matching (APPM) technique. Since the bitmap is unchanged and the APPM embedment is efficient, a high image quality can be achieved. The experimental results reveal that the proposed method not only significantly reduces the distortion caused by embedding but also provides a better authentication result when compared to the prior state-of-art works. [ABSTRACT FROM AUTHOR]