4 Results

  

Figure 2: DETSP test - lp31r frame

  

Figure 3: DETSP test - a53em frame

The DETSP procedure tests have been run in the Astronomical Institute under MIDAS-96NOV environment on a Hewlett-Packard HP-C160 workstation with 64-bit CPU, 64MB RAM, and operating system HP-UX 10.20. We used two frames from digitized high-quality copies of spectral plates taken with the 1.2 UK Schmidt Telescope in Australia. The one is a $2048 \times 2048$ pixels frame lpr31r from an image scanned by the Super-COSMOS facility at the Royal Observatory of Edinburgh. The other is the a53em frame of $3001 \times 1601$ pixels from an image digitized by a PDS 1010A microdensitometer at the Trieste Observatory. Experts detected spectra in these frames using standard methods of detection on direct and spectral plates.

Applying the DETSP procedure, we had 553 detections (Fig. 2) and 13 undetected spectra (error $<2.5\%$) for the frame lpr31r. For the frame a53em, we had 427 detections (Fig. 3) and 17 undetected spectra (error $<4\%$). A careful analysis showed that the missed spectra are in majority too faint, so they are unusable for further processing (e.g. automated classification). Applying the described method, a very significant number of spectra were automatically detected (True-Positive detections $\gt 96\%$). It is worth to point out that despite the presence of M-type and Carbon star spectra on the frames, there were no false detections. In both cases, the processing took about 20 min without displaying supporting plots and images and about twice more with them. Implementation of this MIDAS procedure in a C language program will significantly reduce this processing time. The results are very encouraging for this procedure as well as for the next steps, extraction and classification, of the OBJPR context for automated processing of objective prism spectra.

Acknowledgements

This research has been supported by a grant from the General Secretariat of Research and Technology of Greece, PENED programme. The authors are grateful to the UK Schmidt Telescope Plate Library (ROE) for the loan of the observational material.