Various methods, carrier media, and systems for detecting defects on a specimen using a combination of bright field channel data and dark field channel data are provided. One computer-implemented method includes combining pixel-level data acquired for the specimen by a bright field channel and a dark field channel of an inspection system. The method also includes detecting defects on the specimen by applying a two-dimensional threshold to the combined data. The two-dimensional threshold is defined as a function of a threshold for the data acquired by the bright field channel and a threshold for the data acquired by the dark field channel.