Evaluation of leukocyte dynamic in mouse retinal circulation with scanning laser ophthalmoloscopy (Video report)

http://bjo.bmj.com/content/suppl/2001/06/20/85.7.DC1 Leukocyte-endothelial cell interactions play an important role in the pathogenesis of various types of retinal vascular diseases, including diabetes, uveitis, and ischemic lesions. Over the last few years, several methods have been devised in which the scanning laser ophthalmoscope (SLO) is used to study leukocyte-endothelial interactions in vivo [1,2]. Previously we reported a noninvasive in vivo leukocyte tracking method using the SLO in rat. In this method, a nontoxic fluorescent agent (6-carboxyfluorescein diacetate, CFDA) was used to label leukocytes in vitro. Leukocyte velocities within the retinal and choroidal circulations were be quantified simultaneously [3]. None of the previous methods has been developed for imaging the murine fundus, mainly due to problems arising from the small size of the mouse eye. However, there are many advantages of using a murine model to study retinal vascular diseases such as enhanced genetic definition, increased range of reagents available for immunological studies and cost reduction. We have developed our SLO method such that we can track leukocytes in the mouse retinal and choroidal circulations.

The use of interactive video in teaching teachers: an evaluation of a link with a primary school

This paper presents an evaluation of the use of videoconferencing in learning and teaching in a United Kingdom higher education institution involved in initial teacher education. Students had the opportunity to observe naturalistic teaching practices without physically being present in the classroom. The study consisted of semi-structured interviews with the co-ordinator of the link, the head of ICT services in Stranmillis University College and the teacher of the classroom being observed. Students were invited to complete an online questionnaire. The views of the students, the co-ordinator of the link, the teacher of the classroom being observed and the head of ICT services in Stranmillis University College were then triangulated to gain an overall view of the effectiveness of the videoconferencing link. Interviews suggested students benefited in terms of pedagogy. In the early stages of the project, the teacher thought it acted as a form of classroom control. Technical problems were encountered initially and camera control was modified in the light of these. The online questionnaire suggested that students viewed this experience in a positive way and were impressed with the content, technical quality, and potential benefits of the use of this example of new technologies.

Behaviours in video

With a significant increment of the number of digital cameras used for various purposes, there is a demanding call for advanced video analysis techniques that can be used to systematically interpret and understand the semantics of video contents, which have been recorded in security surveillance, intelligent transportation, health care, video retrieving and summarization. Understanding and interpreting human behaviours based on video analysis have observed competitive challenges due to non-rigid human motion, self and mutual occlusions, and changes of lighting conditions. To solve these problems, advanced image and signal processing technologies such as neural network, fuzzy logic, probabilistic estimation theory and statistical learning have been overwhelmingly investigated.

A 64-point fourier transform chip for video motion compensation using phase correlation

Details of a new low power fast Fourier transform (FFT) processor for use in digital television applications are presented. This has been fabricated using a 0.6-µm CMOS technology and can perform a 64 point complex forward or inverse FFT on real-time video at up to 18 Megasamples per second. It comprises 0.5 million transistors in a die area of 7.8 × 8 mm and dissipates 1 W. The chip design is based on a novel VLSI architecture which has been derived from a first principles factorization of the discrete Fourier transform (DFT) matrix and tailored to a direct silicon implementation.

Reconfigurable full-search video motion estimation architecture

In this paper, a new reconfigurable multi-standard architecture is introduced for integer-pixel motion estimation and a standard-cell based chip design study is presented. This has been designed to cover most of the common block-based video compression standards, including MPEG-2, MPEG-4, H.263, H.264, AVS and WMV-9. The architecture exhibits simpler control, high throughput and relative low hardware cost and highly competitive when compared with excising designs for specific video standards. It can also, through the use of control signals, be dynamically reconfigured at run-time to accommodate different system constraint such as the trade-off in power dissipation and video-quality. The computational rates achieved make the circuit suitable for high end video processing applications. Silicon design studies indicate that circuits based on this approach incur only a relatively small penalty in terms of power dissipation and silicon area when compared with implementations for specific standards.

Error analysis of FFT architectures for digital video applications

This paper describes how worst-case error analysis can be applied to solve some of the practical issues in the development and implementation of a low power, high performance radix-4 FFT chip for digital video applications. The chip has been fabricated using a 0.6 µm CMOS technology and can perform a 64 point complex forward or inverse FFT on real-time video at up to 18 Megasamples per second. It comprises 0.5 million transistors in a die area of 7.8×8 mm and dissipates 1 W, leading to a cost-effective silicon solution for high quality video processing applications. The analysis focuses on the effect that different radix-4 architectural configurations and finite wordlengths has on the FFT output dynamic range. These issues are addressed using both mathematical error models and through extensive simulation.

The role of imitation in video-based interventions for children with autism.

Objective: The aim of this paper is to bridge the gap between the corpus of imitation research and video-based intervention (VBI) research, and consider the impact imitation skills may be having on VBI outcomes and highlight potential areas for improving efficacy.

Method: A review of the imitation literature was conducted focusing on imitation skill deficits in children with autism followed by a critical review of the video modelling literature focusing on pre-intervention assessment of imitation skills and the impact imitation deficits may have on VBI outcomes.

Results: Children with autism have specific imitation deficits, which may impact VBI outcomes. Imitation training or procedural modifications made to videos may accommodate for these deficits.

Conclusions: There are only six studies where VBI researchers have taken pre-intervention imitation assessments using an assortment of imitation measures. More research is required to develop a standardised multi-dimensional imitation assessment battery that can better inform VBI.