Rational-operator-based depth-from-defocus approach to scene reconstruction

This paper presents a rational-operator-based approach to depth from defocus (DfD) for the reconstruction of three-dimensional scenes from two-dimensional images, which enables fast DfD computation that is independent of scene textures. Two variants of the approach, one using the Gaussian rational operators (ROs) that are based on the Gaussian point spread function (PSF) and the second based on the generalized Gaussian PSF, are considered. A novel DfD correction method is also presented to further improve the performance of the approach. Experimental results are considered for real scenes and show that both approaches outperform existing RO-based methods

Developing a method for elaboration the scenarios related with sustainable products lifecycle

This article aims at presenting our objective that is to use DfD rules earlier during the design process. Indeed, during the conceptual design phase, designers don't have simple qualitative tools or methods to evaluate their products. There are guidelines that are very useful in a first approach to give some objectives, but there is no quantitative indicators associated to these rules to consider the disassembly aspects when the first choices are realised for the product. So we will present that to use DfD rules during the conceptual design phase, we first have: ?to identify which kind of rules can be applied when designers only have a functional representation of their product. ?to create the necessary indicators to evaluate these rules depending on designers choices. We think that this approach is usable for many DfX rules either if we only consider in this paper DfD rules.Comment: 10 Pages; 1st International Engineering Sciences Conference 2008, Aleppo : Syrian Arab Republic (2008

The bounce-splash of a viscoelastic drop

This is an entry for the Gallery of Fluid Motion of the 61st Annual Meeting of the APS-DFD (fluid dynamics videos). This video shows the collision and rebound of viscoelastic drops against a solid wall. Using a high speed camera, the process of approach, contact and rebound of drops of a viscoelastic liquid is observed. We found that these drops first splash, similar to what is observed in Newtonian colliding drops; after a few instants, the liquid recoils, recovering its original drop shape and bounce off the wall.Comment: Small manuscript that goes along with a video submission for the Gallery of Fluid Motion of the 61 anual meeting of the APS-DFD, November 200

DFD based scene segmentation for H.263 video sequences

Content based indexing and retrieval of video is becoming increasingly important in many applications. Identifying scene changes and special effects in a video scene is an essential pre-requisite for indexing. In this paper, a sudden scene change detection algorithm for H.263 video sequences is proposed. This method uses the number of intra-coded macroblocks and Displaced Frame Difference (DFD) signal of the video signal. Experimental results show that the performance of this algorithm is independent of the encoder threshold. Furthermore, this algorithm is capable of detecting abrupt scene changes accurately even the video sequence contains special effects