International cooperation and technology transfer

Fras, Mojca Kosmatin

Bibliographic data

Monograph

Persistent identifier:: 856490555

Author:: Fras, Mojca Kosmatin

Title:: International cooperation and technology transfer

Sub title:: Ljubljana, Slovenia, February 2 - 5, 2000 : proceedings of the workshop

Scope:: VI, 163 Seiten

Year of publication:: 2000

Place of publication:: London

Publisher of the original:: RICS Books

Identifier (digital):: 856490555

Illustration:: Illustrationen, Diagramme

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: SOME ASPECTS OF CARTOGRAPHIC VISUALISATION OF THE SCREEN - MUTUAL RELATION OF SCAN PIXELS ANS SCREEN PIXELS. Dr. sc. Brankica Malic

Document type:: Monograph

Structure type:: Chapter

114 SOME ASPECTS OF CARTOGRAPHIC VISUALISATION OF THE SCREEN - MUTUAL RELATION OF SCAN PIXELS ANS SCREEN PIXELS Dr.sc. Brankica Malic Civil engineering Faculty of University J.J. Strossmayer Osijek, Croatia KEY WORDS: scan pixel, screen pixel, hardware zoom, transformation matrix ABSTRACT: This paper analyses the raster graphics on two types of Cathode Ray Tube (CRT) screens with shadow mask and with tension mask, regarding hardware zoom (pixel replication zoom). The results can be generalized through mathematical description of the transformation of scan pixel to screen pixel matrix. KURZFASSUNG: Dieser Artikel analysiert Rastergraphiken an zwei Typen des Kathodenstrahl-Bildschirms, am Streifenmasken- und Lochmasken-Bildschirm, durch die Anwendung eines reinen Hardware-Zooms, sog. „pixel replication zoom“. Diese Erkenntnisse werden durch die mathematische Beschreibung der Abbildung einer Bildmatrix in die Bildschirmpixelmatrix verallgemeinert. 1. INTRODUKTION Computer graphics are classified as two types, as raster graphics and as vector graphics. Raster graphics, which are, for example, acquired through the scanning of the maps, are made up of individual dots of the image, the so- called pixels arranged in the raster form. Vector graphics are made up of dots, i.e., of a sequence of coordinates which are then, through mathematical formulae, connected to form lines, curves or surfaces. This paper will discuss the relation between scan pixels and screen pixels within raster graphics. 2. THE FORM AND THE SIZE OF SCREEN PIXELS IN CRT SCREENS The construction of CRT (Cathode Ray Tube) computer screens, both with shadow mask (with “delta” electron gun arrangement) and with tension mask (with “in-line” electron gun arrangement) depends on the selected screen resolution. Screen resolution is the most important feature of image quality: the lower the resolution, the coarser the image. Since the screen image is made up of many individual screen dots, the so-called screen pixels, which are arranged in columns and in rows, the resolution is declared as columns x rows. Common resolutions are 640 x 480; 800 x 600; ...; 1600 x 1200. Each screen pixel on a color screen is made up of three phosphorus dots glowing in red, green and blue (RGB) colors when they are hit with an electron beam. Details on the image structure on CRT screens can be found in professional literature (Foley, 1994, Lang, 1995, Moers, 1996). The form and the size of a screen pixel depend on the type of the screen (CRT with shadow mask or CRT with tension mask), on screen size and on selected resolution. Rectangular screen pixels are found in screens with tension masks, whereas the screens with shadow mask have triangular screen pixels, which always have the same, constant dimensions, regardless of the selected resolution (see Figure 1). 7 ©y©*®^ ,®_©v®, Figure 1: Formation of screen pixels in screens with a tension mask and in 17”- screens with a shadow mask. With the tension mask screens the dimension of the electron beam changes depending on the selected resolution. Here the width of the electron beam is constant due to the construction of the mask (so-called aperture grill pitch) and the phosphorus stripes, and only the vertical stretching of the electron beam changes. Thus the height of the screen pixel is changed as well (marked with b in the table 2), whereas the width of the screen pixel remains constant (marked with a in the table 2). The measured sizes of screen pixels in 15” and 20” screens with tension masks are contained in table 2 (Malic, 1998). Due to the change in the vertical stretching of the electron beam in screens with tension masks, there is a change in the length of the way that the electron beam must pass, depending on the resolution selected. At the resolution of 640 x 480, the electron beam, with maximum height, must pass only through 480 rows to fully form the screen image. To achieve the same effect with the resolution of 1280 x 1024, the electron beam must pass through 1024 rows.

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