Abstracr Synthetic aperture processing yields an effective lateral r solution for intravascular ultrasound imaging. This processing is generally performed with time domain summation. In this paper, we derive a new synthetic aperture inversion method based on the Fourier domain. The analysis of the image formation shows that the frequency modulation of the PSF could be useful to improve the ...

We present a method for automatic program inversion of functional programs based on methods of LR parsing. We formalize the transformation and illustrate it with the inversion of a program for runlength encoding. We solve one of the main problems of automatic program inversion—the elimination of nondeterminism—by viewing an inverse program as a context-free grammar and applying to it methods of...

A statistical inversion method is presented in support to the application of kernel-based BRDF (Bi-directional Reflectance Distribution Function) models for the calculation of the surface albedo. We present an operational procedure for the inversion of kernel-driven BRDF model and further albedo retrieval to be applicable to the SEVIRI/MSG reflectance measurements. The processing steps applied ...

More than three decades the implementation of iterative methods for the simultaneous inclusion of polynomial zeros in circular complex interval arithmetic is carried out using the exact inversion of disks. Based on theoretical analysis and numerical examples, we show that the centered inversion gives smaller inclusion disks. This surprising result is the consequence of better convergence of the...

This paper discusses the effects of frequency selection on source localization and geoacoustic inversion methods that use frequency coherent objective functions. Matched-field processors based on frequency-coherent objective functions often have rapidly fluctuating range ambiguity surfaces. Insufficient sampling in frequency domain results in range aliasing terms that affect geoacoustic inversi...

We introduce an inversion algorithm for tomographic images of layered media. The algorithm is based on a multiscattering series expansion of the Green function that, unlike the Born series, converges unconditionally. Our inversion algorithm obtains images of the medium that improves iteratively as we use more and more terms in the multiscattering series. We present the derivation of the multisc...

This paper presents a parallel algorithm for matrix inversion on a torus interconnected MIMD-MC multi-processor. This method is faster than the parallel implementations of other widely used methods namely Gauss-Jordan, Gauss-Seidal or LU decomposition based inversion. This new algorithm also introduces a novel technique, called adaptive pivoting, for solving the zero pivot problem at no cost. O...

This paper presents an evaluation method for statistically based speech inversion, in which the estimated vocal tract shapes are classified into phoneme categories based on the articulatory correspondence with prototype vocal tract shapes. The prototypes are created using the original articulatory data and the classifier hence permits to interpret the results of the inversion in terms of, e.g.,...

RESUME A polarimetric and PolInSAR analysis has been conducted on the Nezer forest (Southern France) at L and P band on high resolution SAR data acquired with the ONERA RAMSES system in January 2004. The dataset was investigated for its potential for retrieval of forest parameters from SAR data using three different techniques: • Radiometric inversion from the cross-polarized term, • PolInSAR i...