Non-uniformity assessment of digital prints based on noise power spectrum

Uniformity of the prints is one of the important quality elements. However, the large tint and solid areas of digital prints such as electrophotography outputs are often uneven. With the analysis for the causes of the non-uniformity of digital prints and summary for the existing methods of non-uniformity evaluation, a simple non-uniformity assessment method for the prints based on noise power spectrum is proposed, and a non-uniformity metric of the prints on the basis of the total noise amount is developed. The experiment on the analysis and evaluation of the black patches of the digital prints verifies the validity and practicability of the method.