An improved median window-filter to provide rounding of extreme values

The automatic recording of geophysical field information, and the automatic unloading of the information into a computer for processing, can speed up the entire task of geophysical field surveying. Unfortunately, undetected spurious values (glitches) can contaminate the data and have deleterious effects on the final calculated results. The non-linear median-value window-filter method of conditioning data is highly efficacious for the removal of glitches. The advantage of the method is in not degrading significantly the signal compared with other filtering methods. An undesirable feature of the median-filter is the clipping of each maximum and minimum. However, the clipping has been overcome by the addition of a rounding process to the program, thereby improving the appearance of the conditioned waveform. A computer program, written in BASIC, is provided.