Measuring the line spacing and density of high-resolution images from capstan and drum output scanners

Robert E. MacDonald

doi:10.1117/12.207585

27 April 1995 Measuring the line spacing and density of high-resolution images from capstan and drum output scanners

Robert E. MacDonald

Proceedings Volume 2413, Color Hard Copy and Graphic Arts IV; (1995) https://doi.org/10.1117/12.207585
Event: IS&T/SPIE's Symposium on Electronic Imaging: Science and Technology, 1995, San Jose, CA, United States

Abstract

Minor defects in line spacing and/or density variations can cause visual artifacts in images generated by output scanners. This paper presents a method to quantify such errors using a measurement station that characterizes both the line spacing and the relative density of lines printed at 1200 to 2400 lines/inch. While other measurement methods exist (e.g., grabbing single frames of data from a micro-densitometer), possibly most restricting is the limited number of lines that can be measured due to the trade-off between field of view and resolution. Moire effects may also be utilized for spacing checks, but the results are not sufficiently quantized. The method being presented does not limit the number of lines that can be measured at one time, therefore large regions can be used to perform spatial frequency analysis. In 1- on/1-off line patterns, variations of only 2-3% in line spacing (approximately equals 40 microinches in 1200 LPI) are perceptible. Very minor variations in density can also cause visual artifacts. Distinguishing between a spacing error and a density error is critical to the troubleshooting process. This measurement system was designed to have a theoretical positional resolution of 0.417 microinches. Repeatability of line space measurements for this type of pattern is typically better than 10 microinches.

Citation Download Citation

Robert E. MacDonald "Measuring the line spacing and density of high-resolution images from capstan and drum output scanners", Proc. SPIE 2413, Color Hard Copy and Graphic Arts IV, (27 April 1995); https://doi.org/10.1117/12.207585

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available