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Дата изменения: Sat Apr 16 02:46:21 1994 Дата индексирования: Sun Dec 23 20:17:20 2007 Кодировка: Поисковые слова: star |
The first criterion used to evaluate the restoration techniques is the ability to detect stars in the restored image without ``detecting'' noise and restoration artifacts. We used a simple detection algorithm which finds the local maximum in the restored image above a user-supplied threshold. Fig. 4 shows how the number of stars detected (solid line) increases as the threshold decreases. At the same time, the number of false detections (dashed line) also increases. As the threshold is decreased below 100, more than half of the additional detections are spurious.
Table 1 gives the results for various percentages of false detections. The
first two methods (both linear) show very poor results. Numerous artifacts
around bright stars make star detection very difficult in the linear
restorations. The next three methods (all non-linear) give significantly better
results. The R-L/Snyder method gives slightly better results than the R-L and
MEM methods. Some improvement in star detection is seen in the hybrid method
when is large (0.1). However, as
decreases, artifacts begin
to show up in the solution.