Banding is a printer artifact perceived as one dimensional luminance variations across the print-out caused by different mechanical problems such as vibration of different printer components in laser electrophotographic (EP) printers or media advance errors in inkjet printers. In the printing industry, banding is considered to be one of the worst defects that dominates overall perceived image quality. Understanding the visibility of banding will help us in developing strategies to reduce the banding artifact. We developed a soft-copy environment to conduct various experiments for investigating the visibility of banding in laser EP printers. This environment includes the methodology to duplicate the print on the monitor, and a banding extraction technique. This technique enables us to freely adjust the magnitude of banding of any printer. We validated the accuracy of this methodology by conducting a banding matching experiment. We used this platform to conduct banding visibility assessment experiments. One of them was a banding discrimination experiment. The results showed that for the printers investigated, a reduction of 6.5% in the banding magnitude will be just noticeable by an average observer. We were also able to find the detection thresholds of banding in grayscale images for three laser electrophotographic printers. The detection threshold of the best printer was about 50% of its original banding. So there is still plenty of room to reduce the visibility of the banding artifact. We were also able to compare the banding visibility of different printers quantitatively by conducting a cross-platform experiment. This methodology can form the basis for a metric for visibility of banding in laser EP printers. With some modifications, these techniques could also be adapted to other printer technologies such as ink jet printers.
Osman Arslan, Zygmunt Pizlo, Jan Allebach, "Softcopy Banding Visibility Assessment" in Journal of Imaging Science and Technology, 2007, pp 271 - 281, https://doi.org/10.2352/J.ImagingSci.Technol.(2007)51:3(271)