Affordances of Scan Processing Methods

An INTRODUCTION to SCAN PROCESSING This survey inquires about the affordances of historic and contemporary implementations of scan processing technology. Scan processing, also known as raster manipulation, refers to the separation and independent manipulation of the horizontal, vertical, and brightness components of a video image. It is often associated with the Rutt/Etra Video Synthesizer, which was designed in the early 1970s and used extensively by Steina and Woody Vasulka, Gary Hill, and other pioneering video artists. Scan processing differs from other methods of video synthesis or processing in that it does not generate a normal video signal which can be displayed on a standard analog or digital video monitor. Rather, it outputs three independent signals (horizontal sweep, vertical sweep, and brightness) which must be rendered on an XY display of some kind (oscilloscope, vector monitor, ILDA laser, etc). The look of the scan processing effect can also be emulated by digital video software. Scan processing relies on an input image or video, and thus does not include other XY image techniques, such as Lissajous figures or vector line art and animations. THREE METHODS of SCAN PROCESSING The three methods of scan processing covered in this survey utilize the following technologies: 1) Analog scan processing hardware such as the Rutt/Etra Video Synthesizer, the Dave Jones Raster Manipulator, or the LZX Cadet series modules with output displayed on an analog Cathode Ray Tube monitor 2) Digital software designed to produce a set of analog horizontal, vertical, and brightness signals to be displayed on an analog Cathode Ray Tube monitor, such as the REWereHere or Vector Synthesis scan processing patches for Max and Pure Data. 3) Software which emulates the Rutt/Etra, scan processing, or Z-displacement effect entirely in the digital video domain, such as the v002 Rutt/Etra Quartz Composer plugin, the Rutt/Etra-Izer, or a number of filters and plugins for other softwares. ABOUT AFFORDANCES "Affordances" is a term from interface design which describes the various possibilities an object suggests or offers to its users. These possibilities may or may not be part of the object's intended design, and may also be specific to certain users. For example, a coffee mug is designed for drinking a hot beverage, but just as easily I can scoop dry rice out of a bag, hold a dozen pens ready for writing, or elevate another object such as my laptop off the table by using it. See: https://en.wikipedia.org/wiki/Affordance扫描处理技术导论 本综述旨在探究扫描处理技术（亦称光栅操作(raster manipulation)）的历史与当代实现形式的可供性(affordance)。扫描处理指对视频图像的水平、垂直与亮度分量进行分离及独立操作，其常与拉特/埃特拉视频合成器(Rutt/Etra Video Synthesizer)相关联——该设备于20世纪70年代初设计完成，被斯坦娜与伍迪·瓦苏尔卡、加里·希尔及其他先锋影像艺术家广泛使用。 扫描处理与其他影像合成或处理方法的核心差异在于，它无法生成可在标准模拟或数字影像显示器上播放的常规视频信号。与之相对，其输出三组独立信号：水平扫描信号、垂直扫描信号与亮度信号，需通过各类XY显示器（如示波器(oscilloscope)、矢量显示器(vector monitor)、ILDA激光器(ILDA laser)等）进行渲染呈现。扫描处理的视觉效果也可通过数字影像软件模拟。扫描处理依赖输入图像或视频，因此不包含其他XY影像技术，例如李萨如图形(Lissajous figures)或矢量线条艺术与动画。 扫描处理的三种实现方式 本综述涵盖的三种扫描处理实现方式依托以下技术： 1. 模拟扫描处理硬件：例如拉特/埃特拉视频合成器(Rutt/Etra Video Synthesizer)、戴夫·琼斯光栅操作器(Dave Jones Raster Manipulator)，或LZX Cadet系列模块，其输出信号可在模拟阴极射线管(Cathode Ray Tube, CRT)显示器上呈现。 2. 用于生成一组模拟水平、垂直与亮度信号并在模拟阴极射线管显示器上呈现的数字软件，例如适用于Max与Pure Data的REWereHere或Vector Synthesis扫描处理补丁。 3. 完全在数字影像领域内模拟拉特/埃特拉技术、扫描处理或Z位移(Z-displacement)效果的软件，例如v002 Rutt/Etra Quartz Composer插件、Rutt/Etra-Izer，以及多款面向其他软件的滤镜与插件。 关于可供性(affordance) “可供性(affordance)”是源自界面设计领域的术语，用于描述某一物体向使用者暗示或提供的各类可能性。这些可能性未必属于该物体的预设设计范畴，且可能仅针对特定使用者存在。举例而言，咖啡杯的设计用途是盛放热饮，但使用者也可以用它从袋中舀取干米、收纳十余支待书写的钢笔，或是将笔记本电脑等其他物体垫高以脱离桌面。 参考：https://en.wikipedia.org/wiki/Affordance