Depth estimation of metallic objects using multiwavelets scale-space representation

The problem of dimensional defects in aluminum die-castings is widespread throughout the foundry industry and their detection is of paramount importance in maintaining product quality. Due to the unpredictable factory environment and metallic with highly reflective nature, it is extremely hard to estimate true dimensionality of these metallic parts, autonomously. Some existing vision systems are capable of estimating depth to high accuracy, however are very much hardware dependent, involving the use of light and laser pattern projectors, integrated into vision systems or laser scanners. However, due to the reflective nature of these metallic parts and variable factory environments, the aforementioned vision systems tend to exhibit unpromising performance. Moreover, hardware dependency makes these systems cumbersome and costly. In this work, we propose a novel robust 3D reconstruction algorithm capable of reconstructing dimensionally accurate 3D depth models of the aluminum die-castings. The developed system is very simple and cost effective as it consists of only a pair of stereo cameras and a defused fluorescent light. The proposed vision system is capable of estimating surface depths within the accuracy of 0.5mm. In addition, the system is invariant to illuminative variations as well as orientation and location of the objects on the input image space, making the developed system highly robust. Due to its hardware simplicity and robustness, it can be implemented in different factory environments without a significant change in the setup. The proposed system is a major part of quality inspection system for the automotive manufacturing industry. <br /

Stereo correspondence estimation using multiwavelets scale-space representation-based multiresolution analysis

A multiresolution technique based on multiwavelets scale-space representation for stereo correspondence estimation is presented. The technique uses the well-known coarse-to-fine strategy, involving the calculation of stereo correspondences at the coarsest resolution level with consequent refinement up to the finest level. Vector coefficients of the multiwavelets transform modulus are used as corresponding features, where modulus maxima defines the shift invariant high-level features (multiscale edges) with phase pointing to the normal of the feature surface. The technique addresses the estimation of optimal corresponding points and the corresponding 2D disparity maps. Illuminative variation that can exist between the perspective views of the same scene is controlled using scale normalization at each decomposition level by dividing the details space coefficients with approximation space. The problems of ambiguity, explicitly, and occlusion, implicitly, are addressed by using a geometric topological refinement procedure. Geometric refinement is based on a symbolic tagging procedure introduced to keep only the most consistent matches in consideration. Symbolic tagging is performed based on probability of occurrence and multiple thresholds. The whole procedure is constrained by the uniqueness and continuity of the corresponding stereo features. The comparative performance of the proposed algorithm with eight famous existing algorithms, presented in the literature, is shown to validate the claims of promising performance of the proposed algorithm. <br /

Constructing artificial images of facial expressions

This paper presents a method for construction of artificial images of facial expressions. The proposed fractal-based synthesis procedure called pixel-based correspondence works on 2D images and does not require any depth information. This method can generate artificial images of an object when only a single image is given. Using the proposed method, effective example-based facial analysis systems can be trained and utilised in various applications.<br /

A simple solution of sound transmission through an elastic wall to a rectangular enclosure, including wall damping and air viscosity effects

A simple solution to the problem of the acoustical coupling between a rectangular structure, its air content, and an external noise source is presented. This solution is a mathematical expression for the normalized acoustic pressure inside the structure. Numerical results for the sound-pressure response for a specified set of parameters are also presented

Automotive can network response time analysis with variable jitter

Many methods to calculate message latencies for Controller Area Network (CAN) have previously been presented based upon the static worst-case behaviour of the system. With the use of modern simulation tools however, the behaviour of CAN networks can be simulated dynamically in order to find the likely worst-case response times for CAN messages. This paper shows the development of an automotive body control network model to be used as the basis for further simulations. A method to simulate the Worst-Case Response Time of this model is then presented, taking into account random queuing jitter.<br /

Optimal mapping of joint faults into healthy joint velocity space for fault-tolerant redundant manipulators

redundant manipulator

Dielectrophoretically tuneable optical waveguides using nanoparticles in microfluidics

We present a tuneable optical waveguide using dielectrophoretically controlled nanoparticles in microfluidics. Silicon dioxide nanoparticles of different sizes in de-ionized water are channelled through a microfluidic system. An array of microelectrodes generates the dielectrophoretic force to funnel nanoparticles, forming narrowbands at the center of the microfluidics at different applied voltages and frequencies. It is observed that these narrowbands either scatter or guide the coupled light under selected conditions. The realization of such a system offers exciting possibilities for the development of a new class of optofluidics, which are tuned by the positioning of nanoparticles on demand

Nitric oxide is protective against mercury induced depression

Introduction: Mercury is the second most metal pollutant in the world and has the potential to induce many pathologic conditions, especially in nervous system, such as depression. Here we tried to find out if nitric oxide has any possible role in the pathophysiology of depression induced by this metal. Although the role of nitric oxide has been shown in mood control, here we use specific doses of nitric oxide inducer and/or inhibitors which had no effect on normal rats. Methods: 120 male wistar rats weighting 200-250 gram were divided into two main groups: control and methyl mercury(MM) treated. Each main group was divided into four different sub-goups: Saline, L-Arginine, L-Name or 7-nitroindazole (7-NI) respectively. The duration of taking MM or saline was daily for 15 days for both. After the 15th injection a forced swimming test was done. This test shows behavioral immobility (BI) or latency of attempt to escape (LAE), as a depression indicator. Results: Our study showed that low dose L-arginine is protective against MM induced depression as it could turn behavioral immobility (BI) to normal levels in groups taking MM plus L-Arginine, while in group taking just MM, BI was much longer showing the intensity of depression. L-Name and 7-NI did aggravated depression in MM groups but not control ones, on the other hand just in the case of 7-NI the result was significant. Discussion: Our results showed 1) MM could induce depression in rat 2) L-Arginine could improve depression to normal situation in MM group, while in control group has no effec 3) 7-NI, a selective nNOS inhibitor can aggravate mental depression in intoxicated rats. These results showed the important role of nNOS in protection against MM induced depression

A microfluidic electroosmotic mixer and the effect of potential and frequency on its mixing efficiency

This paper presents the design and numerical simulation of a T-shape microfluidic electroosmotic micromixer. It is equipped with six microelectrodes that are embedded in the side surfaces of the microchannel. The electrode array consists of two sets of three 20 &Acirc;&iquest;m and 60 &Acirc;&iquest;m microelectrodes arranged in the form of two opposing triangles. Numerical analysis of electric potential and frequency effects on mixing efficiency of the micromixer is carried out by means of two sets of simulations. First, the electric potential is kept at 2 V while the frequency is varied within 10-50 Hz. The highest achieved mixing efficiency is 96% at 22 Hz. Next, the frequency is kept at 30 Hz whilst the electric potential is varied within 1-5 V. The best achieved mixing efficiency is 97% at 3 V.<br /