A novel technique for estimating the distribution of the conduction velocity of peripheral nerve fibers is described in this paper. In order to overcome the sensitivity of present methods to noisy data, a regularized-least-squares (RLS) method with a smoothing constraint and a self-adaptation of regularization parameter was adopted. The simulation results demonstrated that the improved technique maybe applied in clinical diagnosis because it yielded reliable and almost undistorted results even when the simulated data are severely contaminated by noise.

Abstract-Vector field tomography has been proven to be a very powerful technique for the noninvasive determination of vector field distribution such as in the case of a fluid velocity field. We show that classical tomographic sampling conditions can essentially be applied to vector field tomography. Thus, essentially the same sampling schemes are obtained, and the interlaced scheme is also shown to be the most efficient scheme in vector field tomography. We then propose a Direct Algebraic approach for vector field tomography, with an efficient and robust algorithm for interlaced schemes. Numerical experiments showing the superiority of interlaced schemes are provided. tion. Theses articles describe the reconstruction problem using one of two different reconstruction methods. In the first type of method the problem of reconstructing the vector field is led back to reconstructing a scalar field from which the vector field can be calculated. In the second, using algebraic methods, the vector components are directly computed.In the first type of approach, the decomposition of vector fields into two parts is utilized, according to Helmholtz's theorem:(1) dW denotes the source-free (solenoidal) and Gq the curl-free (irrotational) part of the field. In the case of a 2-D field in a plane, each part is then described by a scalar field. The sourcefree components v', can be expressed by the vector potential w& and the curl-free components Zq by the scalar potential q: Here, e', denotes the unit vector normal to the investigated plane. In [2], it is shown that for vector tomography two types of interaction between the vector field and the ray used must be distinguished. The first, which is called the longitudinal interaction, is mathematically expressed by In both cases, R, which is the support of 17, is supposed to be compact. Reconstruction formulas of v' from (3) and (4) have 1053-587X/95$04.00 0 1995 IEEE

No abstract

No abstract