Image Processing and Digital Typography

本研究对计算机生产文件的几个方面进行了研究。中心焦点是在离散设备中字符的表示方式，如CRT屏幕、激光打印机和数字照相排字机。图像处理技术，如数字滤波和光谱分析与增量扫描转换算法一起应用，以选择在表示给定字符时要打开的像素。这些技术可以为彩色和灰度CRT生成灰度字体，也可以为打印机和排字机生成二进制字体。该研究试图确定哪种数字过滤器，并根据这些参数，产生最清晰的字体。由此产生的算法可用于打印机或排版系统，用于从轮廓进行字符的实时扫描转换，允许根据需要从有限的轮廓集合中产生无限数量的大小和方向的类型。本研究的第二部分试图从人类视觉初始阶段的各种图像处理模型的角度来分析文本中的图像。这样做的目的是将类似的数字过滤器应用于字符的生成，就像人类视觉系统所假定的那样。反过来，这可能意味着对字体设计者和扫描转换算法应该做出的选择有更深入的了解，以提高计算机输出的易读性和速度。

This research studies several aspects of the production documents by computers. The central focus is on the manner in which characters are represented for discrete devices such as CRT screens, laser printers, and digital phototypsetters. Image processing techniques such as digital filtering and spectral analysis are applied along with incremental scan conversion algorithms to select the pixels which are to be turned on in representing a given character. These techniques can produce both gray scale fonts for color and gray scale CRT's and binary fonts for printers and typesetters. The study attempts to ascertain which digital filters, and with that parameters, produce the most legible type. The resulting algorithms could be used in printers or composition systems for real time scan conversion of characters from outlines, permitting type in an infinite number of sizes and orientation to be produced on demand from a finite collection of outlines. A second part of the study attempts to analyze the images present in text in terms of various image processing models of the initial stages of human vision. The aim of this is to apply similar digital filters to the production of characters as is presumed to be applied by the human visual system. This, in turn may point to greater understanding of choices which should be made by font designers and by scan conversion algorithms to improve the legibility and speed of computerized output.