A new automatic quasar recognition technique based on PCA and the Hough transform

The main purpose of quasar recognition is to determine the observed quasar spectrum's redshift value. In the past, the template of the quasar rest frame was mainly constructed based on astronomers' inference. Due to the inaccuracy of such a template, it is hard to determine the redshift value by matching the observed quasar spectrum with the template directly. This paper's main contributions are two-fold. Firstly, the template in our paper is constructed by the principal component analysis (PCA) method from some selected spectra with known readshift values, hence the resulting template is more realistic. Secondly, a 2D Hough transform, rather than a 1D Hough transforms is used. In our 2D Hough transform, in addition to the redshift parameter, a new parameter, named scale parameter, is also introduced to enhance the discriminability. The experiments show that our proposed technique is workable and the correct recognition rate can reach about as high as 90%.