초록 ▼

To measure the distance to targets, local maxima exceeding a threshold (ε) and being associated with a correlation function (f) are determined, the reference values of which are obtained from scalar products of a received signal (e), produced by reflections of an optical pulse by the targets, and nu

To measure the distance to targets, local maxima exceeding a threshold (ε) and being associated with a correlation function (f) are determined, the reference values of which are obtained from scalar products of a received signal (e), produced by reflections of an optical pulse by the targets, and number of comparison functions, copies of a reference function (r) which are shifted as a function of time, and the transit times of the reflections are derived from the time-related shifts of the corresponding comparison functions. By interpolation with respect to the time-related shifts or optimization thereof, for example by adjusting them so that the orthogonal distance of the received signal (e) from the vector space which is spanned by the corresponding comparison functions is a minimum, the transit times can be determined even more accurately.

대표청구항 ▼

To measure the distance to targets, local maxima exceeding a threshold (ε) and being associated with a correlation function (f) are determined, the reference values of which are obtained from scalar products of a received signal (e), produced by reflections of an optical pulse by the targets, and nu

To measure the distance to targets, local maxima exceeding a threshold (ε) and being associated with a correlation function (f) are determined, the reference values of which are obtained from scalar products of a received signal (e), produced by reflections of an optical pulse by the targets, and number of comparison functions, copies of a reference function (r) which are shifted as a function of time, and the transit times of the reflections are derived from the time-related shifts of the corresponding comparison functions. By interpolation with respect to the time-related shifts or optimization thereof, for example by adjusting them so that the orthogonal distance of the received signal (e) from the vector space which is spanned by the corresponding comparison functions is a minimum, the transit times can be determined even more accurately. of duration approximately equal to or greater than one second. 5. The method of claim 1, wherein the frequency spectrum is estimated from a selection of adjacent seismic traces of number approximately equal to or greater than 100. 6. The method of claim 1, wherein the step of applying the compensation filter to the seismic data comprises: selecting a seismic trace from the seismic data, generating an input trace; extracting a plurality of overlapping data segments from the input trace; deriving the compensation filter corresponding to the velocity and offset at the center of each data segment, generating a plurality of corresponding segment filters; applying the segment filter to the corresponding segments, generating a plurality of corresponding filtered segments; combining the filtered segments by linear interpolation, generating an output trace; and repeating the preceding steps for each seismic trace from the seismic data. 7. The method of claim 6, wherein the step of combining the filtered segments by linear interpolation comprises: selecting a time t on the output trace; selecting a first filtered segment wherein the time t1 at the center is greater than the time t; selecting a second filtered segment wherein the time t2 at the center is less than the time t; determining the seismic data value a1 at the center time t1; determining the seismic data value a2 at the center time t2; measuring the time interval dt1=t1-t; measuring the time interval dt2=t-t2; measuring the time interval dt=t1-t2; calculating the output sample value a at time t by the following equation: a=a1*(dt2/dt)+a2*(dt1/dt); and repeating the preceding steps for each time t on the output trace. 8. The method of claim 7, wherein the first and second filtered segments are derived from neighboring traces in the plurality of overlapping data segments. 9. The method of claim 6, wherein the length of the data segments is approximately equal to or greater than 200 milliseconds. 10. The method of claim 6, wherein the interval between the centers of neighboring data segments is approximately equal to or greater than 4 milliseconds and approximately equal to or less than 100 milliseconds.