Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
131 words
A method for removing sinusoidal noise from a data trace comprising the steps of: determining a line frequency for said sinusoidal noise; determining an exact autocorrelation function for said sinusoidal noise of said determined frequency; producing a convolutional filter from said exact autocorrelation function; and applying said filter to said data trace to remove said sinusoidal noise; and wherein the step of determining an exact autocorrelation function for said sinusoidal noise of said determined frequency further comprises the steps of: producing a frequency domain amplitude spectrum for said data trace; determining a notch width from said amplitude spectrum; determining a filter order comprised of a plurality of filter weights from said notch width; and determining the exact autocorrelation function for said sinusoidal noise of said determined frequency from said filter order.
Claim 2
Independent Claim
131 words
A method for removing sinusoidal noise from a data trace comprising the steps of: determining a line frequency for said sinusoidal noise; determining an exact autocorrelation function for said sinusoidal noise of said determined frequency; producing a convolutional filter from said exact autocorrelation function; and applying said filter to said data trace to remove said sinusoidal noise; and wherein the step of determining an exact autocorrelation function for said sinusoidal noise of said determined frequency further comprises the steps of: producing a frequency domain amplitude spectrum for said data trace; determining a notch width from said amplitude spectrum; determining a filter order comprised of a plurality of filter weights from said notch width; and determining the exact autocorrelation function for said sinusoidal noise of said determined frequency from said filter order.
Claim 3
Dependent Claim
28 words
The method according to claim 1 wherein said notch width is determined by a pair of 3 dB down locations, one on each side of said line frequency.
Claim 4
Dependent Claim
54 words
The method according to claim 1 further comprising the steps of: determining a notch depth from said amplitude spectrum; determining a white noise parameter from said filter order and said notch depth; and modifying said produced convolutional filter by applying said white noise parameter prior to applying said convolutional filter to said data trace.
Claim 5
Dependent Claim
23 words
The method according to claim 1 further comprising the step of producing a nomogram numerically relating said notch width and said filter order.
Claim 6
Dependent Claim
84 words
The method according to claim 4 wherein the step of producing a nomogram numerically relating said notch width and said filter order further comprises the steps of: selecting a sample interval for said data trace; selecting a plurality of filter orders for said sample interval; producing a filter amplitude spectrum for each of said plural filter orders; determining a filter notch width for each of said plural filter amplitude spectrums; and plotting said filter notch widths versus said filter orders to produce said namogram.
Claim 7
Dependent Claim
23 words
The method according to claim 3 further comprising the step of producing a nomogram numerically relating said notch depth and said filter order.
Claim 8
Dependent Claim
74 words
The method according to claim 6 wherein the step of producing a nomogram numerically relating said notch depth and said filter order further comprises the steps of: selecting a white noise parameter for said data trace; selecting a plurality of filter orders for said white noise parameter; determining a filter notch depth for each of said plural filter amplitude spectrums; and plotting said filter notch depths versus said filter orders to produce said nomogram.
Claim 9
Dependent Claim
50 words
The method of claim 1 wherein the step of determining said line frequency for said sinusoidal noise further comprises the steps of: transforming said data trace into the frequency domain to produce an amplitude spectrum for said data trace; and determining said line frequency from said frequency domain amplitude spectrum.
Claim 10
Dependent Claim
42 words
The method according to claim 1 wherein the step of applying said filter to said data trace to remove said sinusoidal noise further comprises the step of convolving said data trace with said filter to produce said sinusoidal noise removed data trace.
Claim 11
Dependent Claim
217 words
In seismic exploration wherein seismic sources are activated at spaced locations along a line of exploration and the amplitude of reflections are recorded as a function of time along said line to produce a series of seismic traces, said seismic traces comprised of a seismic data component and a plurality of sinusoidal noise components, a method of processing said seismic traces to remove said plural sinusoidal noise components comprising the steps of: determining a frequency for each of said sinusoidal noise components; determining an autocorrelation function for each of said sinusoidal noise frequencies; summing said determined autocorrelation functions; producing a convolutional filter from said summed autocorrelation functions; and applying said filter to said data trace to remove said plurality of sinusoidal noise components; and wherein the step of determining a summed autocorrelation function for said plural sinusoidal noise components of said determined frequencies further comprises the steps of: producing a frequency domain amplitude spectrum for said data trace; determining a notch width from said amplitude spectrum for each of said frequencies corresponding to said plurality of sinusoidal noise components; determining a filter order comprised of a plurality of filter weights for one of said notch widths; and determining the exact autocorrelation function for each of said sinusoidal noise components of said determined frequencies for said filter order.
Claim 12
Dependent Claim
217 words
In seismic exploration wherein seismic sources are activated at spaced locations along a line of exploration and the amplitude of reflections are recorded as a function of time along said line to produce a series of seismic traces, said seismic traces comprised of a seismic data component and a plurality of sinusoidal noise components, a method of processing said seismic traces to remove said plural sinusoidal noise components comprising the steps of: determining a frequency for each of said sinusoidal noise components; determining an autocorrelation function for each of said sinusoidal noise frequencies; summing said determined autocorrelation functions; producing a convolutional filter from said summed autocorrelation functions; and applying said filter to said data trace to remove said plurality of sinusoidal noise components; and wherein the step of determining a summed autocorrelation function for said plural sinusoidal noise components of said determined frequencies further comprises the steps of: producing a frequency domain amplitude spectrum for said data trace; determining a notch width from said amplitude spectrum for each of said frequencies corresponding to said plurality of sinusoidal noise components; determining a filter order comprised of a plurality of filter weights for one of said notch widths; and determining the exact autocorrelation function for each of said sinusoidal noise components of said determined frequencies for said filter order.
Claim 13
Dependent Claim
30 words
The method according to claim 10 wherein each said notch width is determined by a pair of 3 dB down locations, one on each side of each said line frequency.
Claim 14
Dependent Claim
98 words
The method according to claim 10 further comprising the steps of: determining a notch depth from said amplitude spectrum for each said line frequency; determining a white noise parameter from said filter order and said notch depth for one of said line frequencies; summing the total number of line frequencies at which sinusoidal noise is to be removed; scaling said white noise parameter by said line frequency sum; and modifying said convolutional filter produced by summing said autocorrelation functions by applying said scaled white noise parameter prior to producing said convolutional filter for application to said data trace.
Claim 15
Dependent Claim
23 words
The method according to claim 10 further comprising the step of producing a nomogram numerically relating said notch width and said filter order.
Claim 16
Dependent Claim
84 words
The method according to claim 13 wherein the step of producing a nomogram numerically relating said notch width and said filter order further comprises the steps of: selecting a sample interval for said data trace; selecting a plurality of filter orders for said sample interval; producing a filter amplitude spectrum for each of said plural filter orders; determining a filter notch width for each of said plural filter amplitude spectrums; and plotting said filter notch widths versus said filter orders to produce said nomogram.
Claim 17
Dependent Claim
23 words
The method according to claim 12 further comprising the step of producing a nomogram numerically relating said notch depth and said filter order.
Claim 18
Dependent Claim
74 words
The method according to claim 15 wherein the step of producing a nomogram numerically relating said notch depth and said filter order further comprises the steps of: selecting a white noise parameter for said data trace; selecting a plurality of filter orders for said white noise parameter; determining a filter notch depth for each of said plural filter amplitude spectrums; and plotting said filter notch depths versus said filter orders to produce said nomogram.
Claim 19
Dependent Claim
167 words
A seismic exploration system comprising: means for generating seismic energy into the earth's subsurface; means for recording reflections of said seismic energy from subsurface reflecting interfaces, said reflected seismic energy recorded as seismic traces; and means for removing sinusoidal noise from at least one frequency from said recorded seismic traces, said noise removal means including: means for determining said at least one frequency of said sinusoidal noise; means for determining an exact autocorrelation function for said sinusoidal noise of at least one frequency; means for producing a filter from said autocorrelation function; and means for convolving said filter and said seismic trace; and means for producing a frequency domain amplitude spectrum for said seismic trace; means for determining a notch width for each of said at least one frequencies; means for determining a filter order comprised of a plurality of filter weights from said notch width; and means for determining said autocorrelation function for said sinusoidal noise of said at least one frequency for said filter order.
Claim 20
Dependent Claim
167 words
A seismic exploration system comprising: means for generating seismic energy into the earth's subsurface; means for recording reflections of said seismic energy from subsurface reflecting interfaces, said reflected seismic energy recorded as seismic traces; and means for removing sinusoidal noise from at least one frequency from said recorded seismic traces, said noise removal means including: means for determining said at least one frequency of said sinusoidal noise; means for determining an exact autocorrelation function for said sinusoidal noise of at least one frequency; means for producing a filter from said autocorrelation function; and means for convolving said filter and said seismic trace; and means for producing a frequency domain amplitude spectrum for said seismic trace; means for determining a notch width for each of said at least one frequencies; means for determining a filter order comprised of a plurality of filter weights from said notch width; and means for determining said autocorrelation function for said sinusoidal noise of said at least one frequency for said filter order.
Claim 21
Dependent Claim
22 words
Apparatus according to claim 17 further comprising means for summing said autocorrelation functions determined for each of said at least one frequencies.
Claim 22
Dependent Claim
80 words
Apparatus according to claim 17 further comprising: means for determining a notch depth for each of said at least one frequencies; means for determining a white noise parameter from said filter order and one of said notch depths; means for summing the total number of line frequencies at which sinusoidal noise is to be removed; and means for scaling said white noise parameter by said line frequency sum; and means for applying said white noise parameter to said autocorrelation function.
Claim 23
Dependent Claim
121 words
Apparatus for removing sinusoidal noise from a seismic trace comprising: means for determining said at least one frequency of said sinusoidal noise; means for determining an autocorrelation function for said sinusoidal noise of at least one frequency; means for producing a filter from said autocorrelation function; and means for convolving said filter and said seismic trace; and means for producing a frequency domain amplitude spectrum for said seismic trace; means for determining a notch width for each of said at least one frequencies; means for determining a filter order comprised of a plurality of filter weights from said notch width; and means for determining said autocorrelation function for said sinusoidal noise of said at least one frequency for said filter order.
Claim 24
Dependent Claim
121 words
Apparatus for removing sinusoidal noise from a seismic trace comprising: means for determining said at least one frequency of said sinusoidal noise; means for determining an autocorrelation function for said sinusoidal noise of at least one frequency; means for producing a filter from said autocorrelation function; and means for convolving said filter and said seismic trace; and means for producing a frequency domain amplitude spectrum for said seismic trace; means for determining a notch width for each of said at least one frequencies; means for determining a filter order comprised of a plurality of filter weights from said notch width; and means for determining said autocorrelation function for said sinusoidal noise of said at least one frequency for said filter order.
Claim 25
Dependent Claim
22 words
Apparatus according to claim 20 further comprising means for summing said autocorrelation functions determined for each of said at least one frequencies.
Claim 26
Dependent Claim
80 words
Apparatus according to claim 20 further comprising: means for determining a notch depth for each of said at least one frequencies; means for determining a white noise parameter from said filter order and one of said notch depths; means for summing the total number of line frequencies at which sinusoidal noise is to be removed; and means for scaling said white noise parameter by said line frequency sum; and means for applying said white noise parameter to said autocorrelation function.