Patent ID: 8593694

Claim:
A printing apparatus for performing trapping comprising: an input unit configured to input image data; a determining unit configured to determine whether or not a pixel of interest of the input image data is a candidate for the trapping; and a trapping unit configured to perform the trapping on the pixel of interest in accordance with a determination result of the determination unit, wherein the determining unit comprises: a pixel determining unit configured to determine whether the pixel of interest is a light pixel or not; a pixel scanning unit configured to scan a first window centered on the pixel of interest to determine whether or not a dark pixel exists in a surround area of the pixel of interest; and a trapping determining unit configured to determine whether or not the pixel of interest is a candidate for the trapping, based on determination results of the pixel determining unit and the pixel scanning unit, wherein, in a first case where it is determined that the pixel of interest is the light pixel and the dark pixel exists in the first window, the trapping determining unit determines that the pixel of interest is a candidate for the trapping, wherein in a second case where it is determined that the pixel of interest is the light pixel and no dark pixel exists in the first window, the trapping determining unit controls the pixel scanning unit to scan a second window larger than the first window and centered on the pixel of interest so as to determine whether or not the dark pixel exists in the surround area of the pixel of interest, wherein in a third case where it is determined that the pixel of interest is the light pixel and the dark pixel exists in the second window, the trapping determining unit determines that the pixel of interest is a candidate for the trapping, and wherein in a fourth case where it is determined that the pixel of interest is the light pixel and no dark pixel exists in the second window, the trapping determining unit controls the pixel scanning unit not to scan a third window larger than the second window and centered on the pixel of interest, and the trapping determining unit determines that the pixel of interest is not a candidate for the trapping.