COMPUTER VISION AND IMAGE UNDERSTANDING

Vol. 72, No. 2, November, pp. 99–100, 1998ARTICLE NO. IV980731

GUEST EDITORS’ INTRODUCTION

Automatic Building Extractionfrom Aerial Images

We are pleased to present this Special Issue on the topic of “Automatic Building Ex-traction from Aerial Images.” The generation and use of 3-D city models (“Cybercity”) isbecoming a task of increasing importance. Buildings are the most important elements ofthese models. Having accurate 3-D models of man-made objects is important for a variety ofapplications. These include urban planning, environmental studies, telecommunication, riskassessment, transportation, energy production and consumption, simulation, video games,marketing, mission planning, and change detection. Primary data to support such appli-cations is becoming increasingly available from a variety of platforms and sensors, suchas aerial and space optical images, radar images and InSar data, and laser scanning data.However, quick and accurate construction of the required 3-D geospatial databases fromthis data remains a tedious and expensive process. It is widely recognized that automaticdetection and description of buildings would go a long way to making more wide use ofavailable imagery possible.

The task of automated building detection and reconstruction is difficult for many reasons.The most common source of data are 2-D images which lack direct 3-D information,though range sensors are also coming into use. Aerial images may differ from each otherwith respect to scale, spectral range of recording, sensor geometry, image quality, imagingconditions (weather, lighting), etc. Buildings can be rather complex structures with manyarchitectural details. They may be surrounded by other disturbing man-made and naturalobjects. Occlusion of parts is common and the geometrical resolution may be limited.Therefore the corresponding images are of very complex content and highly unstructured.Solving the problem of building detection and reconstruction under these conditions notonly is of great practical importance but also provides an excellent testbed for developingcomputer vision and image understanding techniques.

The six papers in this Special Issue describe different approaches to the problem of fullyautomated building detection and reconstruction. The input sources vary for the differentapproaches: One uses only a single intensity image, another two (stereo) images, and severaluse multiple images. One makes use of color and another uses DSM data from laser scanneror image matching in combination with existing 2-D map data. As the results show, theproblem of building detection and reconstruction is likely to be with us for a while. However,the papers indicate that substantial progress is being made and that some of the techniques arealmost ready for practical use, under limited conditions. The papers also show that the bestresults can be achieved by appropriate combination of computer vision and photogrammetricconcepts and know-how.

The idea of assembling this Special Issue arose in conjunction with the preparation ofthe second workshop on “Automatic Extraction of Man-Made Objects from Aerial andSpace Images,” held at the Centro Stefano Franscini, Monte Verita, Ascona, Switzerlandin May 1997. Many of the papers in this issue were first presented at the workshop, butin a much shorter form and largely different in content. While the workshop papers werebased on invitation only, these CVIU contributions underwent a rather strict triple reviewingprocedure.

991077-3142/98 $25.00

Copyright c© 1998 by Academic PressAll rights of reproduction in any form reserved.

100 GUEST EDITORS’ INTRODUCTION

We thank the many reviewers for their time-consuming and competent work and AviKak, Editor of CVIU, for allowing us to edit this Special Issue. We hope that the readerswill find it enjoyable and useful reading!

A. GruenR. Nevatia

Guest Editors