Manipulation of the geophysical measurements is necessary due to the small wavelength and small amplitude nature of the geophysical signals. Simple processing, such as equalization of the gray scales, amplification of the signal and noise reduction can be achieved with digital filtering. De-spiking of pointlike interference, crispening of the local brightness of an image, smoothing and high-pass filters, removal of geological trend, block matching, and edge detection are among the most common processing techniques of geophysical measurements. Potential field data can be further processed through downward or upward continuation algorithms, rectification techniques, or other more sophisticated filtering (e. g., spectral analysis, estimation of power spectrum, FFT, etc.). Inverse (finding the source based on the corresponding data) and forward (comparison of signals to the anomaly produced by a well defined target) modeling techniques can also be applied.
Other more specific data treatment procedures are required depending on the needs of the prospection technique. Image segmentation techniques and change-point analysis are applied for reducing background noise in soil phosphate data caused by postdepositional processes. Gain filters, trace averaging, and stacking and time slicing are commonly applied to GPR data. Aerial and satellite images are processed by usual image processing algorithms with emphasis to the classification of them based on the extraction and recognition of the spectral signatures of cultural and geomorphic characteristics.
Interpretation of geophysical anomalies depends on past experience and theoretical models, while it may be also influenced by geological or surface features. The refinement of the interpretation of the geophysical maps can be achieved with the cooperation of both archaeologists and geophysicists and the confirmation of a selected number of candidate targets.
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