Inproceedings,
New Measurement Method of Banding using Spatial Features for Laser Printers
Image Quality and System Performance VII, 7529, page 1--7. (2010)
DOI: 10.1117/12.840480
Abstract
The techniques of one-dimensional projection in the spatial domain and contrast sensitivity function (CSF) are generally used to measure banding. Due to the complex printing process of laser printers, hardcopy prints contain other 2D nonuniformities such as graininess and mottle besides banding. The method of 1D projection is useful for extracting banding, but it induces the confounding effect of graininess or mottle on the measurement of perceived banding. The appearance of banding in laser printers is more similar to the sum of various rectangular signals having different amplitudes and frequencies. However, in many cases banding is modeled as a simple sinusoidal signal and the CSF is frequently applied. In this paper, we propose new measurement method of banding well correlated with human perception. Two kinds of spatial features give a good performance to banding measurement. First the correlation factor between two adjacent 1D signals is considered to obtain banding power which reduces the confounding effect of graininess and mottle. Secondly, a spatial smoothing filter is designed and applied to reduce the less perceptible low frequency components instead of using the CSF. By using moving window and subtracting the local mean values, the imperceptible low frequency components are removed while the perceptible low frequency components like the sharp edge of rectangular waves are preserved. To validate the proposed method, psychophysical tests are performed. The results show that the correlations between the proposed method and the perceived scales are 0.96, 0.90, and 0.95 for black, cyan, and magenta, respectively.
