Printer resolution measurement based on slanted edge method

Printer resolution is an important attribute for determining print quality, and it has been frequently referred to hardware optical resolution. However, the spatial addressability of hardcopy is not directly related to optical resolution because it is affected by printing mechanism, media, or software data processing such as resolution enhancement techniques (RET). The international organization ISO/IEC SC28 addresses this issue, and makes efforts to develop a new metric to measure this effective resolution. As the development process, this paper proposes a candidate metric for measuring printer resolution. Slanted edge method has been used to evaluate image sharpness for scanners and digital still cameras. In this paper, it is applied to monochrome laser printers. A test chart is modified to reduce the effect of halftone patterns. Using a flatbed scanner, the spatial frequency response (SFR) is measured and modeled with a spline function. The frequency corresponding to 0.1 SFR is used in the metric for printer resolution. The stability of the metric is investigated in five separate experiments: (1) page to page variations, (2) different ROI locations, (3) different ROI sizes, (4) variations of toner density, and (5) correlation with visual quality. The 0.1 SFR frequencies of ten printers are analyzed. Experimental results show the strong correlation between a proposed metric and perceptual quality.