Harnessing oversampling in correlation-coded OTDR

High performance and highly reliable Raman-based distributed temperature sensors based on correlation-coded OTDR and multimode graded-index fibers

The performance of distributed temperature sensor systems based on spontaneous Raman scattering and coded OTDR are investigated. The evaluated DTS system, which is based on correlation coding, uses graded-index multimode fibers, operates over short-to-medium distances (up to 8 km) with high spatial and temperature resolutions (better than 1 m and 0.3 K at 4 km distance with 10 min measuring tim...

Oversampling in Wavelet Subspaces

Recently, several extensions of classical Shannon sampling theory to wavelet subspaces have been reported. This paper is devoted to uniform and periodic nonuniform oversampling in wavelet subspaces. Specifically, we provide a stability analysis and we introduce a technique for calculating the condition number of wavelet subspace sampling operators. It is shown that oversampling results in impro...

MEASUREMENT GUIDE OTDR - Optical Time Domain Reflectometer

Oversampling Expansion in Wavelet Subspaces

We find necessary and sufficient conditions for (shifted) oversampling expansions to hold in wavelet subspaces. In particular, we characterize scaling functions with the (shifted) oversampling property. We also obtain L and L∞ norm estimates for the truncation and aliasing errors of the oversampling expansion.

Tridimensional invariant correlation based on phase-coded and sine-coded range images

New methods for recognition of range images based on correlation are presented. The techniques allow the detection of a range image of a tridimensional pattern whatever its position along the x , y and z axes. The first method uses the phase-coding of the range image in order to obtain invariance along the z -axis in the correlation process. The second method uses the sine-coding of the range i...