Image Enhancement Using the IRAS Survey Data
Abstract
A completely new calibration scheme using the zodiacal light emission as a standard candle has been designed and implemented. The standard IRAS data products presently available, that were produced at the IRAS Processing and Analysis Center, were all calibrated using the point-source-like response of the calibration flashes. Our calibration is better suited for smaller spatial frequencies. Comparison of the zodiacal light calibration and that of IPAC, for point sources, gives very satisfactory results (< 10%) at the wavelengths 12, 25, and 60 micrometers, but a 50% error at 100 micrometers. Also scans making an angle larger than 5 deg with the plane perpendicular to the line Sun-IRAS cannot be calibrated properly; there are only few of such scans. An iterative least squares (ILSQ) routine has been prepared that makes it possible to enhance the resolution of an IRAS image to slightly better than 2 arc minutes, for most regions of sky. The output of this routine is directly traceable to the input and the method is rather straightforward and, because of that, a lot faster than other non-linear methods developed to restore IRAS images: e.g. FIER. FIER produces higher-resolution images than ILSQ, but the method needs verification. Our ILSQ program is ideal for creating large spatial resolution enhanced images, and for checking e.g. FIER results.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1989
- Accession Number
- ADA223039
Entities
People
- P. R. Wesselius