TY - JOUR
T1 - Cleaning the USNO-B catalog through automatic detection of optical artifacts
AU - Barron, Jonathan T.
AU - Stumm, Christopher
AU - Hogg, David W.
AU - Lang, Dustin
AU - Roweis, Sam
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2008/1/1
Y1 - 2008/1/1
N2 - The USNO-B Catalog contains spurious entries that are caused by diffraction spikes and circular reflection halos around bright stars in the original imaging data. These spurious entries appear in the Catalog as if they were real stars; they are confusing for some scientific tasks. The spurious entries can be identified by simple computer vision techniques because they produce repeatable patterns on the sky. Some techniques employed here are variants of the Hough transform, one of which is sensitive to (two-dimensional) overdensities of faint stars in thin right-angle cross patterns centered on bright (<13 mag) stars, and one of which is sensitive to thin annular overdensities centered on very bright (<7 mag) stars. After enforcing conservative statistical requirements on spurious-entry identifications, we find that of the 1,042,618,261 entries in the USNO-B Catalog, 24,148,382 (2.3 percent) are identified as spurious by diffraction-spike criteria and 196,133 (0.02 percent) are identified as spurious by reflection-halo criteria. The spurious entries are often detected in more than two bands and are not overwhelmingly outliers in any photometric properties; they therefore cannot be rejected easily on other grounds, i.e., without the use of computer vision techniques. We demonstrate our method, and return to the community in electronic form a table of spurious entries in the Catalog.
AB - The USNO-B Catalog contains spurious entries that are caused by diffraction spikes and circular reflection halos around bright stars in the original imaging data. These spurious entries appear in the Catalog as if they were real stars; they are confusing for some scientific tasks. The spurious entries can be identified by simple computer vision techniques because they produce repeatable patterns on the sky. Some techniques employed here are variants of the Hough transform, one of which is sensitive to (two-dimensional) overdensities of faint stars in thin right-angle cross patterns centered on bright (<13 mag) stars, and one of which is sensitive to thin annular overdensities centered on very bright (<7 mag) stars. After enforcing conservative statistical requirements on spurious-entry identifications, we find that of the 1,042,618,261 entries in the USNO-B Catalog, 24,148,382 (2.3 percent) are identified as spurious by diffraction-spike criteria and 196,133 (0.02 percent) are identified as spurious by reflection-halo criteria. The spurious entries are often detected in more than two bands and are not overwhelmingly outliers in any photometric properties; they therefore cannot be rejected easily on other grounds, i.e., without the use of computer vision techniques. We demonstrate our method, and return to the community in electronic form a table of spurious entries in the Catalog.
KW - Astrometry
KW - Catalogs
KW - Methods: statistical
KW - Standards
KW - Techniques: image processing
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U2 - 10.1088/0004-6256/135/1/414
DO - 10.1088/0004-6256/135/1/414
M3 - Article
AN - SCOPUS:50849115208
VL - 135
SP - 414
EP - 422
JO - Astronomical Journal
JF - Astronomical Journal
SN - 0004-6256
IS - 1
ER -