Adequate Video Research Articles

Close Range Stereophotogrammetry and Video Imagery Analyses in Soil Ecohydrology Modelling

AbstractEcohydrology is an emerging discipline in the environmental sciences. Soil micro‐relief is of relevance to various ecohydrological processes such as rainwater redistribution, seed displacement through water runoff, water erosion and plant competition for water. Mechanical–optical methods to characterise the soil surface and its incidence in these processes are time consuming and can produce modifications of soil relief. This research explores a methodology combining non‐contact techniques (close range stereophotogrammetry and geostatistical modelling) for microtopographic description with video imagery analysis to formulate quantitative determination of surface water movement and infiltration in undisturbed field plots. The numerical quality of the results obtained was tested with ad hoc laboratory models representing various elementary landforms (basin, hill and ridge), as well as with infiltration runoff experiments in undisturbed field plots. The requirements to define a minimum set of properly oriented digital images to attain target precision thresholds in modelling soil microtopography for ecohydrological applications are shown as well as the conditions and experimental arrangement to obtain adequate video imagery of water movement on the soil surface. The use of geostatistical algorithms to analyse ecohydrological processes occurring at the soil surface is illustrated with results obtained from field plots. The methodology presented serves to characterise and quantify water‐related ecological processes occurring at the soil surface while preserving undisturbed soil conditions. Potential applications are in ecohydrology, soil erosion science and environmental material transport studies.

(Semi)authentic audio-visual materials for the A2 level in the online language learning environment FRANEL: Pitfalls and challenges

The importance of the use of (semi)authentic audio-visual materials in electronic learning environments in general (Mayer, 2001) as well as in CALL environments (Hirschprung, 2005) has been clearly shown. There is at the same time a substantial demand for electronic language learning environments based on authentic video materials and which are adapted to the A2 target group. Franel is an electronic language learning platform for French and Dutch as foreign languages, which is based on authentic audiovisual materials and which is available for free on the Internet. Important issues in the development of the platform are the selection and creation of adequate video materials and the technological and pedagogical parameters this entails, the integration of the video materials into the pedagogical scenario and the creation of adequate learning tasks based on the video materials and focusing on the A2 level. All these language learning activities are offered in order to improve the learners’ communication skills in the target language.

Innovations in Video Error Resilience and Concealment

Router buffer overflow and random bit errors have always been a problem in the Internet. The growth in multimedia applications in mobile extensions of the Internet has increased the threat from error bursts, random errors, and packet erasures that are a manifestation of wireless channels. Source-coded error resilience has come to prominence in the H.264/AVC codec standard, and this paper reviews such innovations surrounding this codec. Some innovations are new variants of an existing technique such as datapartitioning and some are entirely new such as the powerful dispersed-mode flexible macroblock ordering. Other techniques, such as reversible variable length coding, were not be transferred to H.264 from earlier codecs and, hence, innovations are proposed to still provide robust entropy coding. Other variants such as adaptive intra-refresh are still being experimented with. When error resilience or other protection methods fail to present an adequate video frame then error concealment can be brought to bear. This paper reviews error concealment which is important to commercial companies as they are able to distinguish their codec from others. The paper considers spatial, temporal and hybrid error concealment methods. Though this paper contains over one hundred references it can only provide a slice through this rich field.

Innovations in Video Error Resilience and Concealment

Router buffer overflow and random bit errors have always been a problem in the Internet. The growth in multimedia applications in mobile extensions of the Internet has increased the threat from error bursts, random errors, and packet erasures that are a manifestation of wireless channels. Source-coded error resilience has come to prominence in the H.264/AVC codec standard, and this paper reviews such innovations surrounding this codec. Some innovations are new variants of an existing technique such as data-partitioning and some are entirely new such as the powerful dispersed-mode flexible macroblock ordering. Other techniques, such as reversible variable length coding, were not transferred to H.264/AVC from earlier codecs and, hence, innovations are proposed to still provide robust entropy coding. Other variants such as adaptive intra-refresh are still being experimented with. When error resilience or other protection methods fail to present an adequate video frame then error concealment can be brought to bear. This paper reviews error concealment which is important to commercial companies as they are able to distinguish their codec from others. The paper considers spatial, temporal and hybrid error concealment methods. Though this paper contains over one hundred references and relevant patents have been discussed, it can only provide a slice through this rich field.

Study of Rating Scales for Subjective Quality Assessment of High-Definition Video

With the constant evolution of video technology and the deployment of new video services, content providers and broadcasters always face the challenge of delivering an adequate video quality which meets end-users expectations. The development of reliable quality testing and quality monitoring tools that can be used by broadcasters ultimately requires reliable objective video quality metrics. In turn, the validation of these objective models requires reliable subjective assessment, the most accurate representation of the quality perceived by end-users. Many different subjective assessment methodologies exist, and each has its advantages and drawbacks. One important element in a subjective testing methodology is the choice of the rating scale. In this paper, we make a direct comparison between four scales, which are either included in existing international standards or proposed to be used in future standardization activities related to video quality. We examine the subjective data from the points of view of response behavior from participants, similarity and variability of subjective scores. We discuss these results within the context of the subjective quality assessment of high-definition video compressed and transmitted over error-prone networks. Our experimental data show no overall statistical differences between the different scales. Results also show that the single-stimulus presentation provides highly repeatable results even if different scales or groups of participants are used.

A zero-overhead implicit error correction nVoD schema for scalable video in wireless mesh networks

In a previous paper we presented a new near Video on Demand (nVoD) schema with error correcting capabilities, without any bandwidth overhead. In this paper, we compare this schema with the recent proposal by Jenkac in order to determine which one has better characteristics to be used on wireless mesh networks. After this, we extend our schema to support scalable video, allowing clients to adapt video quality in the case of unrecoverable errors. If the lowest quality layer is available, continuous playback is guaranteed. Finally, we analyze our nVoD schema on wireless mesh networks with unpredictable behavior, so that the clients can select the most adequate video quality depending on their context.

Selecting a Video Format to Support Teaching of Swimming

A computer application that supports the teaching and learning of sportingtechniques is presented. It was developed as a tool to assist sports trainers in identifying,analyzing, relating, and evaluating the learning of sporting techniques. At times trainers fail tovisualize all the details of an athlete’s technical gestures, mainly because of the speed of themovements. Based on this concept of observational method, the developed software is simpleto use and includes digital videos in a natural form for trainers who are not computer experts.To select an adequate video format for analyzing sporting techniques, compression tests andvideo compression with different codecs were made. Once the format had been chosen, itscompression was tested at different video qualities with the selected codec. To verify thefunctionalities of the developed tool, the chosen sport was swimming. The results obtainedwith the tool had excellent usability, since most of the functions were mastered withoutproblems by the trainers.

La méthodologie de l'image peut-elle être utile à la recherche en sciences sociales?

Si l'image n'a pas encore toute la place qui devrait lui revenir dans le champ des méthodologies en Sciences Sociales, c'est d'abord parce que son langage utilise un système de signes qui lui est spécifique, distinct de l'oral et de l'écrit. La méthodologie de l'image doit forger ses propres règles de collecte de données audiovisuelles, ses codes d'analyse et d'interprétation, afin de donner un sens sociologique à la " banalité " de ce qui est observé et enregistré. Elle doit aussi se plier aux conditions d'un média audiovisuel pour montrer des résultats de recherche dans un montage cohérent. L'article montre comment la réflexion s'alimente en particulier des apports de la Sémiologie et de ceux de l'Ecole de Palo Alto. Par sa nature épistémologique ce travail pousse la recherche sociologique à interroger ses catégories de collecte de données visuelles, à réajuster ses indicateurs, à préciser les objectifs de ce qu'elle veut transmettre. La méthodologie de l'image est donc utile à la production de connaissances en Sociologie. A partir d'exemples tirés des réalisations de l'auteure, l'article montre comment le corps, l' espace et le temps sont des catégories de la pratique sociale particulièrement adaptées aux approches audiovisuelles. Le corps au "Travail Domestique" ou en "Télétravail", l'espace dans "La gestion ordinaire de la vie en deux", "L'apprentissage du temps", au fondement de la prime socialisation.

Real-time Internet connections: implications for surgical decision making in laparoscopy.

To determine whether a low-bandwidth Internet connection can provide adequate image quality to support remote real-time surgical consultation. Telemedicine has been used to support care at a distance through the use of expensive equipment and broadband communication links. In the past, the operating room has been an isolated environment that has been relatively inaccessible for real-time consultation. Recent technological advances have permitted videoconferencing over low-bandwidth, inexpensive Internet connections. If these connections are shown to provide adequate video quality for surgical applications, low-bandwidth telemedicine will open the operating room environment to remote real-time surgical consultation. Surgeons performing a laparoscopic cholecystectomy in Ecuador or the Dominican Republic shared real-time laparoscopic images with a panel of surgeons at the parent university through a dial-up Internet account. The connection permitted video and audio teleconferencing to support real-time consultation as well as the transmission of real-time images and store-and-forward images for observation by the consultant panel. A total of six live consultations were analyzed. In addition, paired local and remote images were "grabbed" from the video feed during these laparoscopic cholecystectomies. Nine of these paired images were then placed into a Web-based tool designed to evaluate the effect of transmission on image quality. The authors showed for the first time the ability to identify critical anatomic structures in laparoscopy over a low-bandwidth connection via the Internet. The consultant panel of surgeons correctly remotely identified biliary and arterial anatomy during six laparoscopic cholecystectomies. Within the Web-based questionnaire, 15 surgeons could not blindly distinguish the quality of local and remote laparoscopic images. Low-bandwidth, Internet-based telemedicine is inexpensive, effective, and almost ubiquitous. Use of these inexpensive, portable technologies will allow sharing of surgical procedures and decisions regardless of location. Internet telemedicine consistently supported real-time intraoperative consultation in laparoscopic surgery. The implications are broad with respect to quality improvement and diffusion of knowledge as well as for basic consultation.

Error concealment by data partitioning

This paper presents an error concealment strategy for improving the quality of compressed video data when transmitted over noisy communication channels. Data partitioning is used to enable the recovery of motion information when the compressed bit stream is corrupted by channel errors. At low bit-rates the motion data is a significant part of the entire video stream and its recovery enables the decoder to perform motion compensated error concealment and hence maintain adequate video quality. The technique is shown to provide superior decode video quality over wide variety of channel errors, bit-rates and test sequences. In order to enable effective error concealment the partitioned motion and texture data are separated by a motion marker. The motion marker needs to be unique from any valid combination of the motion VLC data. In this paper, we also present an efficient search algorithm to identify such a motion marker with good error resilience properties. This error concealment technique was proposed to the ISO MPEG4 standard and based on its performance, it has been accepted as part of the evolving standard definition.

A New Approach to the Teaching of Foreign Language by using Films

The use of video films in foreign language teaching in schools is as yet not firmly established, at least in the Federal Republic of Germany. This is especially true for the teaching of French as a foreign language. One of the reasons for this blind spot as to the use of this medium is the lack of adequate video films for the communicative foreign language classroom. A new series of video films for second year French classes and the corresponding exercises are to be introduced. I should like to concentrate on two aspects of this production: (1) the alternative design of the films proper, and (2) the implications for exercises in order to ensure that the films are used as media in their own right, thus adding a new dimension to the foreign language classroom.

Film-Based Videodisc System

This paper summarizes the current results of an effort to develop a video-disc system of reasonable simplicity and low cost with adequate video storage capability. The system uses silver halide films or their equivalent as the basic storage medium for the video signals. These film media offer numerous well-known advantages such as archival image quality, ease of duplication and low cost. A prime advantage of the film media is the possibility of storing video information on numerous layers of one disc, increasing the capacity of a disc. The video data on any given layer may be less densely packed, easing the requirements of the retrieval process; the total video information store and hence the playing time can be increased in direct proportion to the number of layers bonded into one disc. Film has other advantages in the recording and playback operations. Recording can be carried out in real time and subsequent processing of the master disc utilizes standard darkroom techniques with duplication accomplished by standard contact print techniques. Playback of the recorded information involves no material contact with the film surface; only a light beam, from a lasing or a normal light source, touches the disc. In the simplest playback configuration, a white light source illuminates the region of interest on the film. This region is projected by a lens system that presents an optical image which is directly accessible to detection and processing by well-known electronic means. The alignment of the light source, the objective, and the detector is noncritical, allowing the use of mechanical components of reasonable tolerance.