Ionogram Scaling: ARTIST autoscaler version 4.5

ARTIST4.5 belongs to the family of ARTIST (Automatic Real-Time Ionogram Scaler with True height) software systems for Digisondes. Version 4.5 was designed and implemented in the early 2000s based on a new concept of trace extraction that replaced previous classic Reinisch and Huang 1983 signal tracer algorithm. The new concept used a best-fit Hough computation that overlayed on the ionogram image a set of the echo traces restored from a candidate pool of synthesized vertical Ne profiles. The best-fit approach demonstrated superior performance to version 4 at mid-latitudes, especially during periods of disturbed ionosphere.