SUMMARY

Using migration algorithm to
determine velocities
in high frequency
electromagnetic prospecting

Nguyễn
Thành Vấn,
Nguyễn Văn
Thuận, Đặng Hoài Trung, Võ Nguyễn Như Liễu,
Võ Minh Triết, Nguyễn Tiến Hóa

Electromagnetic wave velocity is the most crucial parameter in
processing high frequency electromagnetic prospecting (ground penetrating
radar: GPR) data. Migration techniques that strongly depend on velocity
parameter have been used to refocus the scattered signals from the x-t domain
or image space back to their true spatial location in the object space. To
optimize migration algorithms, we propose using entropy as a criterion of
looking for the correct propagation velocity. The goal of this article is to
present the theoretical basis, the procedure as well as the necessity for
combining migration with entropy. Using mathematical models, we demonstrated
the need of having the migrated sections and the similarity between the
estimated velocities and the root mean square ones up to the top of objects.
The results verified on field data show that migrated images with true velocity
have the best quality and minimum entropy, thus the size as well as the depth
of anomalies is determined with high reliability.

Người biên tập: TS. Nguyễn Văn