NASA Scientific and Technical Aerospace Reports

procedure is effectively combined with an image differencing technique to obtain displacement vectors between two
successive frames. The resulting displacement field is dense, and leads to compact depth maps. The computational cost is
shown to be lower than in a simple correlation method. A maximum likelihood estimate is used to characterize the probability
of match which can give a local estimate of the noise distribution in the frame sequence. Such knowledge can be used
effectively for the determination of displacement vectors in subsequent frames of the image sequence.
Author
Algorithms; Estimating; Image Analysis; Probability Theory
20060001662 Minnesota Univ., USA
On the Statistical Sufficiency of the Coherently Averaged Covariance Matrix for the Estimation of the Parameters of
Wideband Sources
Hung, H.; Kaveh, M.; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP ‘87); Volume 1;
1987, pp. 2.2.1-2.2.4; In English; See also 20060001583
Contract(s)/Grant(s): N000I4-86-K-0410; Copyright; Avail.: Other Sources
In this paper we investigate the degree of sufficiency of the approximately coherently averaged covariance matrix via a
relative efficiency measure, termed the Relative Information Index (RII), for the estimation of the parameters of multiple
wideband sources. First, we prove that all the narrowband sample covariance matrices are minimal sufficient under the
asymptotic normality condition of the raw data samples. The asymptotic distribution and its associated first- and second-order
statistics of the approximately coherently averaged covariance matrix are derived. The Fisher’s Information matrices of the
statistic and the raw data are then evaluated for the computation of the RII’s.
Author
Asymptotic Series; Asymptotic Methods; Matrices (Mathematics); Broadband; Covariance
20060001667 Rhode Island Univ., Kingston, RI, USA
Statistically/Computationally Efficient Estimation of Non-Gaussian Autoregressive Processes
Kay, Steven; Sengupta, Debasis; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP ‘87);
Volume 1; 1987, pp. 2.5.1-2.5.4; In English; See also 20060001583
Contract(s)/Grant(s): N00014-84-K-0527; Copyright; Avail.: Other Sources
A new technique for the estimation of autoregressive filter parameters of a non-Gaussian autoregressive process is
proposed. The probability density function of the driving noise is assumed to be known. The new technique is a two-stage
procedure motivated by maximum likelihood estimation. It is computationally much simpler than the maximum likelihood
estimator and does not suffer from convergence problems. Computer simulations indicate that unlike the least squares or linear
prediction estimators, the proposed estimator is nearly efficient, even for moderately sized data records.
Author
Autoregressive Processes; Computerized Simulation; Statistics; Probability Theory
20060001679 Stanford Univ., Stanford, CA, USA
On the Stability of Adaptive Lattice Filters
Lev-Ari, H.; Chiang, K. F.; Kailath, T.; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP
‘87); Volume 1; 1987, pp. 395-398; In English; See also 20060001583; Copyright; Avail.: Other Sources
A new approach to stability of adaptive filters is presented. The notion of constrained-input constrained-output (CICO)
stability is introduced as a generalization of the standard notion of bounded-input/bounded-output (BIBO) stability. This new
notion involves a set of constraints on the filter data (i.e., signals and parameters) that, unlike boundedness, are specific to the
filter in consideration. The set of all data that satisfy the constraints is the feasibility domain of the adaptive filter. Three
particular adaptive lattice filters are analyzed: (i)Burg’s lattice, (ii)the unnormalized RLS lattice, and (iii)the normalized RLS
lattice. We derive the feasibility domains of these adaptive filters and prove that they are CICO stable.
Author
Adaptive Filters; Stability
20060001703 Bell Telephone Labs., Inc., Naperville, IL, USA
A Multivariate Voicing Decision Rule Adapts to Noise, Distortion, and Spectral Shaping
Thomson, David L.; IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP ‘87); Volume 1;
1987, pp. 6.10.1 - 6.10.4; In English; See also 20060001583; Copyright; Avail.: Other Sources
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