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Background: Adjectives are essential for communication, conceptual development and academic success. However, they are semantically and syntactically complex and can be particularly challenging for children with Developmental Language Disorder (DLD). Surprisingly, language interventions have not typically focused on this important word class. Aims: (1) To provide a supportive and accessible primer on adjectives for practitioners; (2) to explore how the SHAPE CODINGTM system can be adapted to support adjective learning in DLD; and (3) to provide practical recommendations on how to support adjective learning in clinical practice and education. Methods/Procedure: We synthesise linguistic and psychological research on adjective semantics, clinical insights into DLD and pedagogical practice supporting this population. Main Contribution: We address the lack of specific training in the nature and acquisition of adjectives for speech and language therapists (SLTs) by providing an accessible primer. We also provide an innovative guide detailing how an established metalinguistic intervention might be adapted to support adjective learning. Conclusions/Implications: Without targeted support for adjective learning, the communicative potential of children with DLD is compromised. Our recommendations can be used across a range of therapeutic and educational contexts to guide SLTs and teaching staff in developing practice in this area. What this paper adds: What is already known on the subject: Adjectives are an essential word class needed for effective communication. They are also vital to successfully achieve academic objectives across all curriculum areas. For example, most subjects require children to be able to describe, evaluate, compare and discriminate different events, objects or techniques. Children with Developmental Language Disorder (DLD) have deficits in various domains of language that can affect adjective learning and use. What this paper adds to existing knowledge: Despite the importance of adjectives, speech and language therapists (SLTs) and other professionals supporting language development rarely receive specific training regarding their structure and meanings, and how to teach and support their use. This article provides an accessible primer on the many subtypes of adjectives and how these behave syntactically and semantically. It explores how adjective teaching could be enhanced for children with DLD by adapting an established metalinguistic technique and provides practical recommendations for implementing this approach. What are the potential or actual clinical implications of this work?: By raising awareness of the complexities of adjectives and providing strategies to support their acquisition by children with DLD, this article will enable SLTs and teaching staff to improve their understanding and practice in this area and, with further research, to develop robust, effective interventions for children with DLD. This will contribute to enhancing the long‐term academic, social and employment success of children with DLD. [ABSTRACT FROM AUTHOR]

Visual shape perception is central to many everyday tasks, from object recognition to grasping and handling tools. 1,2,3,4,5,6,7,8,9,10 Yet how shape is encoded in the visual system remains poorly understood. Here, we probed shape representations using visual aftereffects—perceptual distortions that occur following extended exposure to a stimulus. 11,12,13,14,15,16,17 Such effects are thought to be caused by adaptation in neural populations that encode both simple, low-level stimulus characteristics 17,18,19,20 and more abstract, high-level object features. 21,22,23 To tease these two contributions apart, we used machine-learning methods to synthesize novel shapes in a multidimensional shape space, derived from a large database of natural shapes. 24 Stimuli were carefully selected such that low-level and high-level adaptation models made distinct predictions about the shapes that observers would perceive following adaptation. We found that adaptation along vector trajectories in the high-level shape space predicted shape aftereffects better than simple low-level processes. Our findings reveal the central role of high-level statistical features in the visual representation of shape. The findings also hint that human vision is attuned to the distribution of shapes experienced in the natural environment. • Prolonged viewing of shapes makes subsequent stimuli appear systematically distorted • Models of low-level visual processes cannot predict these aftereffects • A high-level model derived from statistical shape features can Morgenstern et al. probe shape representations in the human visual system by comparing perceptual aftereffects with computational models. A high-level model, based on the statistical features of natural shapes, outperforms low-level models, suggesting that human vision is attuned to the distribution of shapes in the natural environment. [ABSTRACT FROM AUTHOR]

The shape of a geospatial object is an important characteristic and a significant factor in spatial cognition. Existing shape representation methods for vector-structured objects in the map space are mainly based on geometric and statistical measures. Considering that shape is complicated and cognitively related, this study develops a learning strategy to combine multiple features extracted from its boundary and obtain a reasonable shape representation. Taking building data as example, this study first models the shape of a building using a graph structure and extracts multiple features for each vertex based on the local and regional structures. A graph convolutional autoencoder (GCAE) model comprising graph convolution and autoencoder architecture is proposed to analyze the modeled graph and realize shape coding through unsupervised learning. Experiments show that the GCAE model can produce a cognitively compliant shape coding, with the ability to distinguish different shapes. It outperforms existing methods in terms of similarity measurements. Furthermore, the shape coding is experimentally proven to be effective in representing the local and global characteristics of building shape in application scenarios such as shape retrieval and matching. [ABSTRACT FROM AUTHOR]

Compression of point clouds has so far been confined to coding the positions of a discrete set of points in space and the attributes of those discrete points. We introduce an alternative approach based on volumetric functions, which are functions defined not just on a finite set of points, but throughout space. As in regression analysis, volumetric functions are continuous functions that are able to interpolate values on a finite set of points as linear combinations of continuous basis functions. Using a B-spline wavelet basis, we are able to code volumetric functions representing both geometry and attributes. Attribute compression is addressed in Part I of this paper, while geometry compression is addressed in Part II. Geometry is represented implicitly as the level set of a volumetric function (the signed distance function or similar). Experimental results show that geometry compression using volumetric functions improves over the methods used in the emerging MPEG Point Cloud Compression (G-PCC) standard. [ABSTRACT FROM AUTHOR]

Shape is a popular way to define objects and shape coding is a key technique for object-based 3D video applications. In this paper, the issue of efficient shape coding for object-based 3D video applications is addressed, and a novel contour-based and chain-represented scheme is proposed. For a given 3D shape video, contour extraction and preprocessing are first implemented followed by chain-based representation. Then, to achieve high coding efficiency, a chain-based prediction and compensation technique is developed based on joint motion-compensated prediction and disparity-compensated prediction to effectively exploit the intra-view temporal correlation and the inter-view spatial correlation. Experiments are conducted, and the results demonstrate that the proposed scheme is more efficient than the existing methods, including state-of-the-art methods. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Image & Graphics is the property of Editorial Office of Journal of Image & Graphics 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.)

Children with Developmental Language Disorder are likely to experience difficulties with morphosyntax, especially regular past tense marking. Few studies have evaluated the effectiveness of intervention to improve morphosyntax in young school-aged children with DLD. This study investigated the efficacy of combined explicit and implicit intervention techniques delivered by a speech pathologist to improve receptive and expressive grammar, including the use of past tense morphosyntax, using a multiple baseline single case experimental design. Participants were aged six to seven years and received two 1:1 45 minute sessions per week for five weeks (total 7.5 hours) using Shape Coding intervention techniques combined with implicit approaches. Two of the three participants made statistically significant gains on standardized tests of general receptive and expressive grammar. Two of the three children made statistically significant improvement on measures of expressive morphosyntax, with one participant continuing to improve five weeks post treatment. Findings suggest that this approach was efficacious. These findings warrant further investigation using larger group comparison research studies. [ABSTRACT FROM AUTHOR]

A high efficient lossless shape coding scheme was proposed based on the representation of contour and chain code. The object contours are firstly extracted and thinned to be single-pixel width. Then the object contours are trans-formed into chain-code-based representation and divided into different sub-segments based on link directions to make each sub-segment consist of up to two types of links. Thirdly, straightness detection is performed and long straight-line segments within contours are separated. Finally, different schemes are proposed to encode the straight-line sub-segments and ordinary curve sub-segments by employing the spatial correlations among contours aiming to acquire high coding performance. Experiments are conducted and the results show that the proposed scheme outperforms the existing tech-niques and can improve the compression efficiency by 36.5% on average compared with the state-of-the-art method.

We effortlessly recognize objects across changes in viewpoint, but we know relatively little about the features that underlie viewpoint invariance in the brain. Here, we set out to characterize how viewpoint invariance in monkey inferior temporal (IT) neurons is influenced by two image manipulations-silhouetting and inversion. Reducing an object into its silhouette removes internal detail, so this would reveal how much viewpoint invariance depends on the external contours. Inverting an object retains but rearranges features, so this would reveal how much viewpoint invariance depends on the arrangement and orientation of features. Our main findings are 1) view invariance is weakened by silhouetting but not by inversion; 2) view invariance was stronger in neurons that generalized across silhouetting and inversion; 3) neuronal responses to natural objects matched early with that of silhouettes and only later to that of inverted objects, indicative of coarse-to-fine processing; and 4) the impact of silhouetting and inversion depended on object structure. Taken together, our results elucidate the underlying features and dynamics of view-invariant object representations in the brain. NEW & NOTEWORTHY We easily recognize objects across changes in viewpoint, but the underlying features are unknown. Here, we show that view invariance in the monkey inferotemporal cortex is driven mainly by external object contours and is not specialized for object orientation. We also find that the responses to natural objects match with that of their silhouettes early in the response, and with inverted versions later in the response-indicative of a coarse-to-fine processing sequence in the brain. [ABSTRACT FROM AUTHOR]

An information hiding algorithm based on MPEG-4 texture coding was proposed. Hiding information in VOP motion texture codes could be realized by replacing the YUV value of non-VOP pixels in the DCT coding block with secret data, and modifying the transparence of the VOP. It was proved by the experiment that the proposed algorithm has much better fidelity and capacity. The algorithm is highly desirable in the situations that high capacity information hiding in MPEG-4 video streaming.

Our visual abilities are unsurpassed because of a sophisticated code for objects located in the inferior temporal (IT) cortex. This code has remained a mystery because IT neurons show extremely diverse shape selectivity with no apparent organizing principle. Here, we show that there is an intrinsic component to selectivity in IT neurons. We tested IT neurons on distinct shapes and their parametric variations and asked whether neurons selective along one dimension were also selective along others. Selective neurons responded to fewer shapes and were narrowly tuned to local variations of these shapes, both along arbitrary morph lines and along variations in size, position, or orientation. For a subset of neurons, selective neurons were selective for both shape and texture. Finally, selective neurons were also more invariant in that they preserved their shape preferences across changes in size, position, and orientation. These observations indicate that there is an intrinsic constraint on the sharpness of tuning for the features coded by each IT neuron, making it always sharply tuned or always broadly tuned along all dimensions. We speculate that this may be an organizing principle throughout visual cortex. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Image & Graphics is the property of Editorial Office of Journal of Image & Graphics 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.)

A new scheme for contour-based predictive shape coding is proposed aiming to acquire high coding efficiency, where the temporal correlations among object contours are effectively exploited. For a given binary shape image, the object contours are firstly extracted and thinned to be perfect single-pixel width followed by chain-based representation. Then a chain-based motion estimation and compensation technique is developed to remove temporal correlations among object contours to reduce the data to be encoded. Finally, by further exploiting the spatial correlations within chain links, a novel method is introduced to efficiently encode the residuals together with the motion displacements. Experiments are conducted and the results show that the proposed scheme is considerably more efficient than the existing techniques. [ABSTRACT FROM AUTHOR]

It has been suggested that difficulties with tense and agreement marking are a core feature of language impairment. Hence, studies are required that analyse the effectiveness of intervention in this area, including consideration of whether changes seen in therapy sessions generalize to spontaneous speech. This study assessed the effectiveness of therapy based around Shape Coding in developing the use of the regular past tense morpheme -ed in two school-aged children with language impairments. It also considered whether participants benefited from additional generalization therapy in order to start using target forms in their spontaneous speech. The former was assessed using a sentence completion task and the latter by a conversational task with blind assessors. One participant improved markedly in sentence completion but did not gain in the conversation task until after the generalization therapy. The other made more modest gains on the sentence completion task and seemed to generalize to the conversation task without recourse to the generalization therapy. Larger studies are required to confirm these interpretations and to determine whether they are applicable to the wider population of children with language impairments. [ABSTRACT FROM PUBLISHER]

The intention of shape coding in the MPEG-4 is to improve the coding efficiency as well as to facilitate the object-oriented applications, such as shape-based object recognition and retrieval. These require both efficient shape compression and effective shape description. Although these two issues have been intensively investigated in data compression and pattern recognition fields separately, it remains an open problem when both objectives need to be considered together. To achieve high coding gain, the operational rate-distortion optimal framework can be applied, but the direction restriction of the traditional eight-direction edge encoding structure reduces its compression efficiency and description effectiveness. We present two arbitrary direction edge encoding structures to relax this direction restriction. They consist of a sector number, a short component, and a long component, which represent both the direction and the magnitude information of an encoding edge. Experiments on both shape coding and hand gesture recognition validate that our structures can reduce a large number of encoding vertices and save up to 48.9% bits. Besides, the object contours are effectively described and suitable for the object-oriented applications. [ABSTRACT FROM AUTHOR]

Background Little evidence exists for the effectiveness of therapy for children with receptive language difficulties, particularly those whose difficulties are severe and persistent. Aims To establish the effectiveness of explicit speech and language therapy with visual support for secondary school-aged children with language impairments focusing on comprehension of coordinating conjunctions in a randomized control trial with an assessor blind to group status. Methods & Procedures Fourteen participants (aged 11;3-16;1) with severe RELI (mean standard scores: CELF4 ELS = 48, CELF4 RLS = 53 and TROG-2 = 57), but higher non-verbal (Matrices = 83) and visual perceptual skills (Test of Visual Perceptual Skills (TVPS) = 86) were randomly assigned to two groups: therapy versus waiting controls. In Phase 1, the therapy group received eight 30-min individual sessions of explicit teaching with visual support (Shape Coding) with their usual SLT. In Phase 2, the waiting controls received the same therapy. The participants' comprehension was tested pre-, post-Phase 1 and post-Phase 2 therapy on (1) a specific test of the targeted conjunctions, (2) the TROG-2 and (3) a test of passives. Outcomes & Results After Phase 1, the therapy group showed significantly more progress than the waiting controls on the targeted conjunctions ( d = 1.6) and overall TROG-2 standard score ( d = 1.4). The two groups did not differ on the passives test. After Phase 2, the waiting controls made similar progress to those in the original therapy group, who maintained their previous progress. Neither group showed progress on passives. When the two groups were combined, significant progress was found on the specific conjunctions ( d = 1.3) and TROG-2 raw ( d = 1.1) and standard scores ( d = 0.9). Correlations showed no measures taken (including Matrices and TVPS) correlated significantly with progress on the targeted conjunctions or the TROG-2. Conclusions & Implications Four hours of Shape Coding therapy led to significant gains on comprehension of coordinating conjunctions which were maintained after 4 months. Given the significant progress at a group level and the lack of reliable predictors of progress, this approach could be offered to other children with similar difficulties to the participants. However, the intervention was delivered one-to-one by speech and language therapists, thus the effectiveness of this therapy method with other methods of delivery remains to be evaluated. [ABSTRACT FROM AUTHOR]

In object-based video representation, video scenes are composed of several arbitrarily shaped video objects (VOs), defined by their texture, shape and motion. In error-prone communications, packet loss results in missing information at the decoder. The impact of transmission errors is minimized through error concealment. In this paper, we propose a spatial error concealment technique for recovering lost shape data. We consider a geometric shape representation consisting of the object boundary, which can be extracted from the \alpha-plane. Missing macroblocks result in a broken boundary. A B-spline curve is constructed to replace a missing boundary segment, based on a T-spline representation of the received boundary. We use T-splines because they produce shape-preserving approximations and do not change the characteristics of the original boundary. The representation ensures a good estimation of the first derivatives at the points touching the missing segment. Applying smoothing conditions, we manage to construct a new spline that joins smoothly with the received boundary, leading to successful concealment results. Experimental results on object shapes with different concealment difficulty demonstrate the performance of the proposed method. Comparisons with prior proposed methods are also presented. [ABSTRACT FROM AUTHOR]

Traditionally the sliding window (SW) has been employed in vertex-based operational rate distortion (ORD) optimal shape coding algorithms to ensure consistent distortion (quality) measurement and improve computational efficiency. It also regulates the memory requirements for an encoder design enabling regular, symmetrical hardware implementations. This paper presents a series of new enhancements to existing techniques for determining the best SW-length within a rate-distortion (RD) framework, and analyses the nexus between SW-length and storage for ORD hardware realizations. In addition, it presents an efficient bit-allocation strategy for managing multiple shapes together with a generalized adaptive SW scheme which integrates localized curvature information (cornerity) on contour points with a bi-directional spatial distance, to afford a superior and more pragmatic SW design compared with existing adaptive SW solutions which are based on only cornerity values. Experimental results consistently corroborate the effectiveness of these new strategies. [ABSTRACT FROM PUBLISHER]

Geometric distortion measurement and the associated metrics involved are integral to the Rate Distortion (RD) shape coding framework, with importantly the efficacy of the metrics being strongly influenced by the underlying measurement strategy. This has been the catalyst for many different techniques with this article presenting a comprehensive review of geometric distortion measurement, the diverse metrics applied, and their impact on shape coding. The respective performance of these measuring strategies is analyzed from both a RD and complexity perspective, with a recent distortion measurement technique based on arclength- parameterization being comparatively evaluated. Some contemporary research challenges are also investigated, including schemes to effectively quantify shape deformation. [ABSTRACT FROM AUTHOR]

Abstract: Selecting the incorrect control during the operation of underground bolting and drilling equipment causes serious injuries. Shape coding and the layout of dual control banks are two aspects of control design which require further examination. The aims of this research were: (i) to determine whether arbitrary shape coding was effective in reducing selection error rates in a virtual analogy of roof-bolting; and (ii) to determine whether any advantages exist for mirror or place layouts for dual control situations in this situation. Two experiments were conducted to address these questions. No benefits of arbitrary shape coding were evident while control location remained constant. When control location was altered, shape coding did provide a significant reduction in selection error rate. No differences between mirror or place arrangements were detected and this question remains open. [Copyright &y& Elsevier]

Shape masks are used in object-based video coding, such as MPEG-4 part 2, to specify the boundaries of a video object. The term "binary shape" is used to describe shape masks where each pixel is either completely inside the object or completely out- side it, i.e., there is no blending of pixels at object boundaries. In this paper, we present a new lossless block-based coding algorithm for binary shapes that combines a quad-tree structure with con- text-based arithmetic coding. Experimental results demonstrate that this new approach provides a saving in bits generated up to approximately 66% compared to the MPEG-4 binary shape coding algorithm. [ABSTRACT FROM AUTHOR]

In this paper, an operationally optimal joint shape and texture coding algorithm is proposed that uses shape-adaptive texture coding as well as texture-aware shape coding. The solution is optimal in the operational rate distortion sense, i.e, given the coding setup, the solution will guarantee the smallest possible distortion for a given rate. The shape is approximated using polygons or higher order curves. We also consider biasing the cost function to favor horizontal and vertical edges for the case of polygon approximation (biased polygon approximation). The texture is encoded using shape-adaptive discrete cosine transform or shape- adaptive discrete wavelet transform of the MPEG-4 video codec. A comparison is drawn between the two techniques. Both a fixed- width and a variable-width tolerance band for shape coding are considered. The variable width of the tolerance band is a function of the texture profile, i.e, the width is inversely proportional to the magnitude of the image gradient. Experimental results are presented and conclusions are drawn. [ABSTRACT FROM AUTHOR]

Abstract: An efficient contour-based method for the coding of binary shape information is described. Conventional chain coding techniques show high coding efficiency for lossless compression, but they exploit the coherence of the contour in only a restricted manner. Higher coding efficiency can be achieved by realising the neighbourhood relation as a Markov chain, and this is exploited in a new coding scheme, the directional grid chain coding (DGCC). The method is computationally efficient and the coding process adapts to the inherent changes in the contour. Two schemes are proposed, a lossless and a quasi-lossless method. The lossless scheme achieves 32% saving in bit rate compared with the conventional differential chain code (DCC). The second, quasi-lossless technique achieves 44% bit reduction compared with the DCC and the distortions present in the reconstructed contour are hardly noticeable to the human eye. [Copyright &y& Elsevier]

A novel scheme for coding gray-level alpha planes in object-based video is presented. Gray-level alpha planes convey the shape and the transparency information, which are required for smooth composition of video objects. The algorithm proposed is based on the segmentation of the alpha plane in three layers: binary shape layer, opaque layer, and intermediate layer. Thus, the latter two layers replace the single transparency layer of MPEG-4 Part 2. Different encoding schemes are specifically designed for each layer, utilizing cross-layer correlations to reduce the bit rate. First, the binary shape layer is processed by a novel video shape coder. In intra mode, the DSLSC binary image coder presented in [3] is used. This is extended here with an intermode utilizing temporal redundancies in shape image sequences. Then the opaque layer is compressed by a newly designed scheme which models the strong correlation with the binary shape layer by morphological erosion operations. Finally, three solutions are proposed for coding the intermediate layer. The knowledge of the two previously encoded layers is utilized in order to increase compression efficiency. Experimental results are reported demonstrating that the proposed techniques provide substantial bit rate savings coding shape and transparency when compared to the tools adopted in MPEG-4 Part 2. [ABSTRACT FROM AUTHOR]

In this paper, we propose a statistical learning-based approach to analyze the rate-distortion characteristics of MPEG-4 multiscale binary shape coding. We employ the polynomial kernel function and epsiv-insensitive loss function for our support vector regression. To improve the accuracy of the estimation, rate and distortion related features are incorporated in the statistical learning framework. Our experimental results show that the proposed approach can achieve good performance, e.g., modelling the rate-distortion curves accurately. [ABSTRACT FROM PUBLISHER]

This paper describes a unified framework of bit-rate control for binary and gray-level shape coding. An exponential rate-distortion model is proposed for binary shape and used in the bit-rate control. An approximation method is applied for finer distortion scale adjustment by adjusting the conversion ratio at the binary alpha block level. Since the gray-level shape is encoded as its support information and the alpha plane information, the rate-quantizer relationship of the alpha plane is modeled. The bit-rate control is then able to adjust the quantizer of the alpha plane for the bit-rate control purpose. The extension for video object (VO) coding is also studied. In this bit-rate control approach, a buffer feedback controller is employed to determine the target bit rates for different sources, i.e., binary shape, gray-level shape, and texture. Accordingly, the distortion scales of different sources are adjusted based on their rate-distortion relationships to maintain a stable encoder buffer. The advantages of the proposed method are demonstrated through various tests for different scenarios. Overall, the algorithm can efficiently encode the shape information and shows a good performance for VO coding. [ABSTRACT FROM AUTHOR]

This paper presents a new adaptive vertex-based coding scheme to improve the coding efficiency of the object shapes of a video sequence. We first smooth out the original contour using the property of perfect 8-connectivity, which reduces the number of vertexes without loss of quality. Then we propose top-down and bottom-up algorithms to select the vertex points. In the top-down scheme, we develop a new adjusting technique to measure the distortion. It is simple for both calculation and implementation, and the reconstructed shape has better quality. In the bottom-up scheme, we develop a new area-based measure that makes the insertion of a new vertex easy. Finally, we propose a scheme that employs multiple dynamic ranges to modify the object-adaptive vertex coding method. It improves the coding performance significantly. [Copyright &y& Elsevier]

This paper presents a fast binary motion estimation (BME) algorithm and its architecture for MPEG-4 shape encoding. The proposed algorithm explores the property of the binary-value in BMIE to quickly skip the unnecessary sum of absolute differences (SAD) computation. When comparing with the full search algorithm, simulation results show that it can efficiently save in the search positions to an average -99.58% of that in the full search algorithm with the same PSNR quality. Due to the algorithm's simplicity and regularity, the resulting hardware implementation also exhibits simple and regular control and data flow. It can achieve real-time encoding with only 11582 gate count. [ABSTRACT FROM AUTHOR]

This paper presents the enhanced frame-based video coding scheme. The input source video to the enhanced frame-based video encoder consists of a rectangular-sized video and shapes of arbitrarily shaped objects on video frames. The rectangular frame texture is encoded by the conventional frame-based coding technique and the video object's shape is encoded using the contour-based vertex coding. It is possible to achieve several useful content-based functionalities by utilizing the shape information in the bitstream at the cost of a very small overhead to the bit-rate. [ABSTRACT FROM AUTHOR]

In object-based video encoding, the encoding of the video data is decoupled into the encoding of shape, motion, and texture information, which enables certain functionalities, like content-based interactivity and content-based scalability. The fundamental problem, however, of how to jointly encode this separate information to reach the best coding efficiency has not been studied thoroughly. In this paper, we present an operational rate-distortion optimal scheme for the allocation of bits among shape, motion, and texture in object-based video encoding. Our approach is based on Lagrangian relaxation and dynamic programming. We implement our algorithm on the MPEG-4 video verification model, although it is applicable to any object-based video encoding scheme. The performance is accessed utilizing a proposed metric that jointly captures the distortion due to the encoding of the shape and texture. Experimental results demonstrate that the gains of lossy shape encoding depend on the percentage the shape bits occupy out of the total bit budget. This gain may be small or may be realized at very low bit rates for certain typical scenes. [ABSTRACT FROM AUTHOR]

MPEG-4 shape coding comprises context-based arithmetic encoding (CAE) as its centerpiece. Since the CAE algorithm has a complicated coding procedure and strong data dependency, it is hard to exploit its pipeline and parallel facilities. Furthermore, to encode multiple symbols within one clock cycle, it needs to overcome the issues of extracting multiple contexts of these symbols, deriving multiple probabilities from these contexts, and performing multiple multiplicative range update operations. This paper presents an efficient pipelined multisymbol CAE architecture for real-time MPEG-4 shape encoding. The proposed design is based on the inherent characteristics of binary alpha blocks as well as the numerical properties of the probabilities indexed by the contexts, and it is capable of encoding either a singe symbol or multiple symbols within each clock cycle. To overcome the aforementioned issues under the consideration of the hardware cost and the critical path delay, only symbols with a particular set of contexts are chosen to be processed simultaneously within the same clock cycle. Theoretical analysis shows that the majority of symbols have contexts belonging to this particular set, and there- fore CAE processing can be significantly accelerated. An example VLSI implementation of proposed architecture that encodes two symbols within each clock cycle without sacrificing the clock rate can achieve a speedup of 1.47 in comparison with traditional CAE architectures. This particular two-symbol design can support MPEG-4 Main Profile at levels 3 and 4 under extreme and typical conditions, respectively. When synthesized from Verilog RTL design by using TSMC 0.35-pm 1P4M CMOS technology, the design can run at 90 MHz. [ABSTRACT FROM AUTHOR]

This paper presents a fast binary motion estimation (BME) algorithm using diamond search pattern for MPEG-4 shape coding, which is the key technology for supporting the content-based video coding. Based on the properties of binary shape information, a boundary mask for efficient search positions can be generated. Therefore, a large number of search points can be skipped. Simulation results show that our algorithm combined with diamond shaped zones takes equal bit rate in the same quality but reduces the number of search points marvelously in BME to 0.6% compared with full search algorithm, which is described in MPEG-4 verification mode. The proposed algorithm will reduce computational complexity of shape coding significantly and be suitable for real-time software and hardware applications of MPEG-4 shape coding. [ABSTRACT FROM AUTHOR]

A major problem in object-oriented video coding and MPEG-4 is the encoding of object boundaries. Traditionally this problem is treated separately from the texture encoding problem. In this paper, we present a vertex-based shape coding method which is optimal in the operational rate-distortion sense and takes into account the texture information of the video frames. This is accomplished by utilizing a variable-width tolerance band whose width is a function of the texture profile. As an example, this width is inversely proportional to the magnitude of the image gradient. Thus, in areas where the confidence in the estimation of the boundary is low and/or coding errors in the boundary will not affect the application (e.g., object-oriented coding and MPEG-4) significantly, a larger boundary approximation error is allowed. We present experimental results which demonstrate the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

This paper proposes a modified shape coding algorithm called modified vertex-based shape coding (MVBSC) to encode the boundary of a visual object compactly by using a modified polygonal approximation approach which uses modified curvature scale space (CSS) theory to extract feature-points. [ABSTRACT FROM AUTHOR]

We review error resilience techniques for real-time video transport over unreliable networks. Topics covered include an introduction to today's protocol and network environments and their characteristics, encoder error resilience tools, decoder error concealment techniques, as well as techniques that require cooperation between encoder, decoder, and the network. We provide a review of general principles of these techniques as well as specific implementations adopted by the H.263 and MPEG-4 video coding standards. The majority of the article is devoted to the techniques developed for block-based hybrid coders using motion-compensated prediction and transform coding. A separate section covers error resilience techniques for shape coding in MPEG-4 [ABSTRACT FROM PUBLISHER]