Size distribution of photopheric bright points in active region

Photospheric bright points (BPs) are a small-scale feature on the solar surface. Studying their characteristics may reveal the problems on coronal hearting, local dynamo theory and relation of magnetic field. In the present paper, an automatic algorithm, employing Laplacian and morphological dilation technique, is utilized to identify the BPs. Two data sets are derived from the Dutch Open Telescope (DOT) on July 19 2006 and September 24 2006. Their size distribution of BPs in the two data sets are investigated and analyzed. The size distributions of PBPs are consistent with log-normal statistics. Both peak distributions occur at about 230km.