Patent ID: 6820016
Filing Date: 2004-11-16
Classification: G01M

Abstract:
An apparatus for detecting a leak in a pipe, the apparatus comprising:a sensor located at a pipe configured to detect a signal from a pipe; converter means to convert the signal detected by the sensor into a digital signal; transform means for transforming the digital signal into a different orthogonal space; and a transmitter for transmitting the transformed digital signal back to a remote processor; wherein the transform means is configured to perform a wavelet transform in which the digital signal is transformed according to the general formula: f&af;(t)=&Sum;k=-âˆžâˆž&it;â€ƒ&it;ck&it;&varphi;&af;(t-k)+&Sum;k=-âˆžâˆž&it;&Sum;j=0âˆž&it;â€ƒ&it;dj,k&it;â€ƒ&it;Ïˆ&af;(2j&it;t-k)(1)where (ft) represents the digital signal outputted by the analogue to digital conversion means, t is the time, &phgr;(tâˆ’k) and &psgr;(2jtâˆ’k) functions represent the mother scaling functions and wavelet functions repsectively and the coeffricients ck and dj,k are calculated from the inner product of f(t) with the scaling functions and wavelet functions respectively such that: ck=âˆ«f(t)&phgr;(tâˆ’k)dt dj,k=âˆ«f(t)&psgr;(2jtâˆ’k)dt.