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Squared Differences (squared + difference)
Selected AbstractsA Fast Stereo Matching Algorithm for Sewer Inspection RobotsIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 4 2008Alireza Ahrary Non-member Abstract In this paper, we present a fast stereo matching algorithm for sewer inspection robots. Conventional algorithms such as the sum of squared difference (SSD) and cross-correlation based on segmentation, graph cuts and so on have been proposed. However, most of them are computationally expensive. In order to solve the problem, we propose a fast stereo matching algorithm using interpolation in this paper. In our algorithm, an image is initially divided into many blocks. Then, a matching measure combining SSD and the cross-correlation is calculated only at the corner points of each block. A down sampled sewer disparity image is composed of only the corner points. Because the disparities change continuously in the sewer environment, we use the cubic interpolation for extending the down sampled sewer disparity image into a regular-sized disparity image. The experimental results show that our algorithm outperforms the conventional algorithms in both accuracy and speed in the sewer environment. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Using Image and Curve Registration for Measuring the Goodness of Fit of Spatial and Temporal PredictionsBIOMETRICS, Issue 4 2004Cavan Reilly Summary Conventional measures of model fit for indexed data (e.g., time series or spatial data) summarize errors in y, for instance by integrating (or summing) the squared difference between predicted and measured values over a range of x. We propose an approach which recognizes that errors can occur in the x -direction as well. Instead of just measuring the difference between the predictions and observations at each site (or time), we first "deform" the predictions, stretching or compressing along the x -direction or directions, so as to improve the agreement between the observations and the deformed predictions. Error is then summarized by (a) the amount of deformation in x, and (b) the remaining difference in y between the data and the deformed predictions (i.e., the residual error in y after the deformation). A parameter, ,, controls the tradeoff between (a) and (b), so that as ,,, no deformation is allowed, whereas for ,= 0 the deformation minimizes the errors in y. In some applications, the deformation itself is of interest because it characterizes the (temporal or spatial) structure of the errors. The optimal deformation can be computed by solving a system of nonlinear partial differential equations, or, for a unidimensional index, by using a dynamic programming algorithm. We illustrate the procedure with examples from nonlinear time series and fluid dynamics. [source] Structural refinement by restrained molecular-dynamics algorithm with small-angle X-ray scattering constraints for a biomoleculeJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2004Masaki Kojima A new algorithm to refine protein structures in solution from small-angle X-ray scattering (SAXS) data was developed based on restrained molecular dynamics (MD). In the method, the sum of squared differences between calculated and observed SAXS intensities was used as a constraint energy function, and the calculation was started from given atomic coordinates, such as those of the crystal. In order to reduce the contribution of the hydration effect to the deviation from the experimental (objective) curve during the dynamics, and purely as an estimate of the efficiency of the algorithm, the calculation was first performed assuming the SAXS curve corresponding to the crystal structure as the objective curve. Next, the calculation was carried out with `real' experimental data, which yielded a structure that satisfied the experimental SAXS curve well. The SAXS data for ribonuclease T1, a single-chain globular protein, were used for the calculation, along with its crystal structure. The results showed that the present algorithm was very effective in the refinement and adjustment of the initial structure so that it could satisfy the objective SAXS data. [source] Brief analysis of the retention process in RP-HPLC systems with a C30 bonded stationary phaseJOURNAL OF SEPARATION SCIENCE, JSS, Issue 13 2008Wojciech Zapa Abstract The influence of the mobile-phase composition on the retention of eight model substances in different RP-HPLC systems with a C30 alkyl bonded stationary phase has been studied. The aim of this study was to compare the performance of four valuable retention models assuming the partition and adsorption mechanism of retention. All the models were verified for different experimental data by four criteria: the sum of squared differences between the experimental and theoretical data; the approximation of the standard deviation; the Fisher test; and the F-test ratio. [source] Optimal approximations of nonlinear payoffs in static replication,THE JOURNAL OF FUTURES MARKETS, Issue 11 2010Qiang Liu Static replication of nonlinear payoffs by line segments (or equivalently vanilla options) is an important hedging method, which unfortunately is only an approximation. If the strike prices of options are adjustable (for OTC options), two optimal approximations can be defined for replication by piecewise chords. The first is a naive minimum area approach, which seeks a set of strike prices to minimize the area enclosed by the payoff curve and the chords. The second improves on the first by taking the conditional distribution of the underlying into consideration, and minimizes the expected area instead. When the strike prices are fixed (for exchange-traded options), a third or the approach of least expected squares locates the minimum for the expected sum of squared differences between the payoff and the replicating portfolio, by varying the weights or quantities of the options used in the replication. For a payoff of variance swap, minimum expected area and least expected squares are found to produce the best numerical results in terms of cost of replication. Finally, piecewise tangents can also be utilized in static replication, which together with replication by chords, forms a pair of lower or upper bound to a nonlinear payoff. © 2010 Wiley Periodicals, Inc. Jrl Fut Mark [source] High-definition Fourier domain OCT: non-invasive assessment of BRB changesACTA OPHTHALMOLOGICA, Issue 2009R BERNARDES Purpose To demonstrate the possibility of using a non-invasive imaging technique, the high-definition spectral domain optical coherence tomography, as a surrogate detector of blood-retinal barrier (BRB) breakdown. Methods Healthy volunteers and diabetic patients with diabetic retinopathy, age- related macular degeneration, choroidal neo-vascularisation and cystoid macular edema, underwent optical coherence tomography by Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA, USA). Profiles of reflectivity distribution between the inner-limiting membrane and the retinal pigment epithelium were built, normalized, aligned and compared. Patients underwent retinal leakage analyzer (RLA) to identify areas of retinal fluorescein leakage into the vitreous as areas of blood-retinal barrier breakdown. Results The comparison between healthy volunteers' and patients' reflectivity distribution demonstrates these profiles differ. Moreover, when comparing reflectivity distribution within the same eye between areas of leakage and areas of non-leakage, the sum of the squared differences is over one decade relatively to the comparison between two similar areas (leakage/leakage or non-leakage/non-leakage). Conclusion These findings suggest that high-definition OCT may be useful in identifying areas of retinal leakage/BRB breakdown and therefore to be used as surrogate for fluorescein angiography and retinal leakage analyzer. [source] | ||||||||||