XVIIIth Congress: XVIIIth Congress

kraus, karl; waldhäusl, peter

Bibliographic data

Multivolume work

Persistent identifier:: 1667435949

Title:: XVIIIth Congress

Sub title:: Vienna, Austria 1996

Year of publication:: 1996

Place of publication:: Vienna

Publisher of the original:: Austrian Society of Surveying and Geoinformation

Identifier (digital):: 1667435949

Language:: English

Editor:: Kraus, Karl; Waldhäusl, Peter

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing

Document type:: Multivolume work

Volume

Persistent identifier:: 1667437070

Title:: XVIIIth Congress

Scope:: 230 Seiten

Year of publication:: 1996

Place of publication:: Vienna

Publisher of the original:: Austrian Society of Surveying and Geoinformation

Identifier (digital):: 1667437070

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(31,B1)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist anhand des Copyrightjahrs ermittelt.

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

Editor:: Kraus, Karl; Waldhäusl, Peter

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 18., 1996, Wien; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: QUALITY ANALYSIS AND CALIBRATION OF DTP SCANNERS Emmanuel P. Baltsavias, Barbara Waegli

Document type:: Multivolume work

Structure type:: Chapter

and the actually | board of asic data such as rmed by too great f the A/D 1 be said z an A/D y as uld be olling | only t accel- accel- ional rs are o, da- num- ed as 1g, since amera is mera is ut using urveying QUALITY ANALYSIS AND CALIBRATION OF DTP SCANNERS Emmanuel P. Baltsavias, Barbara Waegli Institute of Geodesy and Photogrammetry, Swiss Federal Institute of Technology (ETH) ETH-Hoenggerberg, CH-8093 Zurich, Switzerland Commission I, Working Group 5 KEY WORDS: Scanner, Film, Digitization, Scanner Quality Analysis, Scanner Test Patterns, Scanner Calibration. ABSTRACT Scanners have been used as input devices in photogrammetric and cartographic applications mainly for digitisation of aerial images and maps. This paper deals with the use and applicability of DeskTop Publishing (DTP) scanners for photogrammetric/cartographic applications, their quality analysis and calibration. The motivation of the paper is the investigation as to what extent low-priced DTP scanners, which are rapidly improving during the few last years, can be used for such applications. The paper will mainly concentrate on flatbed scanners with aim the scanning of films. However, many of the topics mentioned in the paper are also valid for drum scanners. The paper gives a review of recent technological developments with respect to these scanners, describes advantages and disadvantages, presents characteristics and problems of such scanners, and investigations on their geometric and radiometric accuracy. Test patterns for calibration of such scanners and a novel, simple and generic geometric calibration method are presented. Results using five different scanners show that a geometric accuracy of 4 - 7 uum can be achieved. 1. INTRODUCTION Scanners are an essential component in photogrammetric and cartographic applications. They have been used for scanning of aerial and satellite images, as well as digitisation of topographic and thematic maps, plans, charts and atlases. Aerial and satellite imagery has been used to derive Digital Terrain Models, orthoimages, and for digital mapping (new generation or update of existing map data). A trend is the use of digital orthoimages for generation and update of databases, generation of orthoimage maps, integration with other raster and vector data and visualisation. Although the developments in direct digital data acquisition have been enormous in the last decade, film-based systems are used in all fields of photogrammetry. In aerial photogrammetry film-based systems will provide the main data input for many years to come. The scanning requirements depend on the document to be scanned and the application. Aerial images are scanned in grey levels or colour, require a format of 25 x 25 cm, a geometric resolution of at least 600 - 1200 dpi, a geometric accuracy of 2 - 5 um (for high accuracy applications), a radiometric resolution of 10 - 12 bit and a density range of 2.5 D (panchromatic images) to 3.5 D (colour images). Satellite images often require a larger scan format (up to 30 x 45 cm). Maps/plans pose some additional requirements: opaque scanning, large scan format (e.g. A1), bilevel and multilevel (usually 1 - 4 bit) and halftone scanning. There is no single scanner, that can fulfil all these requirements. High-end, A3 DTP scanners come close to fulfilling these requirements with the main problems being in the geometric accuracy and resolution, and the scan format. A classification of scanners is given in Baltsavias and Bill, 1994. DTP scanners can be divided in flatbed and drum scanners, or low (1,000 - 20,000 SFr. with few exceptions) and high cost (> 50,000 SFr.). Although drum scanners have a high geometric resolution (2000 - 4000 dpi), and high density range (3D - 4D), they are generally more expensive than their flatbed counterparts, 13 and most importantly they have low geometric accuracy due to drum inaccuracies, unflatness of film on drum etc. and because of the same problems and the inability to scan glass plates an accurate geometric calibration is not feasible. Here, mainly only lost cost flatbed scanners will be treated. 2. OVERVIEW OF DTP SCANNERS DTP scanners have been developed for applications totally different than the photogrammetric/cartographic ones. However, since they constitute the largest sector in the scanner market, they are subject to rapid developments and improvements. Flatbed scanners typically employ one or more linear CCDs, and move in direction vertical to the CCD to scan a document in one swath. Usually the stage is stationary, and the sensor/optics/illumination move. They can scan binary, halftone, grey level and colour data (with one or three passes), may have good and cheap software for setting the scanner parameters, image processing and editing, and can be connected to many computer platforms (mainly Macs and PCs, but also Unix workstations) via standard interfaces. They can usually scan A4 format, but some can scan up to A3 or even more. Some do not scan transparencies, others do so but only of smaller format (for A4 scanners the maximum transparency scan width is 8°- 8.5””). Such a width suffices to scan aerial films with 8 fiducials (5 fiducials are visible). Flatbed scanners have a resolution of up to 1200 dpi (21 um pixel size) over the whole scan width. Few scanners offer the option to increase the resolution by projecting a document portion (smaller than the full width) on the CCD. Their price range, with few exceptions, is 1,000 - 20,000 SFr. The big price jump occurs when going from A4 to A3 format. The transition from 600 dpi to 1200 dpi costs less. A3 scanners with 600 x 1200 dpi start at ca. 19,000 SFr. A4 scanners with 600 x 1200 dpi and transparency options cost much less (2,000 - 5,000 SFr.). Their radiometric resolution and quality, and scanning speed can be comparable to or even exceed that of the more expensive photogrammetric film International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B1. Vienna 1996

Access restriction

Copyright

fullscreen: XVIIIth Congress (Part B1)

Multivolume work

Volume

Chapter

Table of contents

Cite and reuse

Volume

Chapter

Image

Image fragment

Citation links

Citation recommendation