Multilevel halftoning: Extensions to binary methods and constant-contrast screen design and modulation transfer function characterization
Abstract
In the first Chapter, we propose and compare the multilevel halftoning technologies with Direct Binary Search(DBS) screen, Floyd and Steinberg Error Diffusion, Tone Dependent Error Diffusion and hybrid screen. Several different schedules are also explored and compared among these halftoning technologies. In addition, we exploit the smooth transition between different graylevels under multi-drop pens of dual-ink density capabilities. In Chapter 2, to overcome the limitation that the traditional approach to multilevel halftoning is hampered by the appearance of contouring in the vicinity of native tones of the output device, we propose a novel framework based on maintaining a consistent periodic, clustered-dot halftone texture across the tone scale. We develop metrics for granularity and structure dissimilarity, and show how these can be used to guide the manner in which the halftone texture evolves from native tone to native tone, across the tone scale. Experimental results confirm the benefits of our new approach. The modulation transfer function (MTF) characterization methods are discussed in the last chapter. MTF is a fundamental tool for assessing the performance of imaging systems. It has been applied to a range of capture and output devices, including printers and even the media itself. In this chapter, we consider the problem of measuring the MTF of image capture devices. Then, we examine three different approaches to this task based, respectively, on a Slant-edge target, a Sinewave target, and a grill pattern. We review the mathematical relations among the three different methods, and discuss their comparative advantages and disadvantages. Finally, we present experimental results for MTF measurement with some image capture devices including camera-based system, flat-bed scanner.
Degree
Ph.D.
Advisors
Allebach, Purdue University.
Subject Area
Electrical engineering
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.