However, as dim objects can occupy larger areas, features need to be computed using the entire image of the object. All pixels inside the boundary were used to compute the features. The 51 features used in the classification of detectable objects are listed below. As before, new features are shown in bold face. Multiple classifiers based on brightness cutoffs.
Table summarizes the results of the multiple classifiers described above.
However, these numbers were also not very satisfactory to the astronomers. The features magnitude, sharpness and chisquare appear very powerful. Magnitude has an almost linear relation with the catalog magnitude of the objects in the simulated SDSS, as shown in Fig. . So it provides a better basis for brightness cutoffs than either peak intensity or peaksig . Sharpness estimates the intrinsic angular size of the measured object outside the atmosphere.