Solving linear systems or least-squares problems related to Toeplitz matrices is often required in the context of signal and image processing; Conjugate-Gradient-like methods are well-suited for solving such problems. The recent preconditioning technique involving the discrete sine transform is presented: convergence properties are reported and suitable generalizations to block matrices, nonsym...

We propose a novel approach to sufficient di­ mension reduction in regression, based on es­ timating contour directions of negligible vari­ ation for the response surface. These di­ rections span the orthogonal complement of the minimal space relevant for the regression, and can be extracted according to a mea­ sure of the variation in the response, lead­ ing to General Contour Regression (GCR)...

where ∇It+1 is the image gradient at W(x; u). ∂W ∂u denotes the Jacobian of the warp. Writing the partial derivatives in ∂W ∂u with respect to a column vector as row vectors, this simply becomes the 2 × 2 identity matrix for the case of optical flow. There is a closed-form solution for parameter update ∆u using a least-squares formulation. Setting to zero the partial derivative of eq. (3) with ...

This paper presents an approach to full-vehicle simulator control which accounts for nonlinearities in a vehicle/simulator system. The control scheme presented is based on the estimation of the system inverse dynamics. A composite linear/nonlinear approach to inverse system identification (SYS-ID) is presented. The linear portion of the SYS-ID uses time-domain methods to estimate the impulse re...

A method is described for the inverse calibration of a manipulator or robot. Inverse calibration is defined to be finding the joint angles necessary to drive a robot to a desired endpoint location. The joint angles recommended by the robot controller's internal model will not, in general, drive the robot to the desired location because of inaccuracies in this model. Inverse calibration seeks to...

Multiple reflections contain subsurface reflectivity information which often complements that found in primary reflections. Previous attempts to combine the additional information by summing prestack images of the primaries and multiples have generally failed because of crosstalk leakage between the images. We present a general linear least-squares inversion method, Least-Squares Joint Imaging ...

In this paper we consider nonlinear least squares fitting of the three-parameter inverse Weibull distribution to the given data (wi, ti, yi), i = 1, . . . , n, n ≥ 3. As the main result, we show that the least squares estimate exists provided that the data satisfy just the following two natural conditions: (i) 0 < t1 < t2 < . . . < tn and (ii) 0 < y1 < y2 < . . . < yn < 1. To this end, an illus...

In its basic formulation, the inverse kinematics (IK) problem seeks to compute a set of joint angles such that the end of a given joint chain coincides with a certain position in space. Further constraints, such as orientation, velocity, and preferences for curvature, are possible, but beyond the scope of this project. In this report, we describe the basic forward and inverse kinematics problem...

Error-contaminated systems Ax ≈ b, for which A is ill-conditioned, are considered. Such systems may be solved using Tikhonov-like regularized total least squares (RTLS) methods. Golub, Hansen, and O’Leary [SIAM J. Matrix Anal. Appl., 21 (1999), pp. 185–194] presented a parameter-dependent direct algorithm for the solution of the augmented Lagrange formulation for the RTLS problem, and Sima, Van...

A theoretical and a field study were performed for the interpretation of the vertical component magnetic anomalies from dipping dike model with infinite depth extent. Damped least squares inverse solution, Hilbert transform and power spectrum methods were used in interpretation. The parameters affecting the power spectrum of the analytical model response were determined and discussed. Damped le...