Automatic Detection of Surface Damage in Round Brick Chimneys by Finite Plane Modelling from Terrestrial Laser Scanning Point Clouds. Case Study of Bragança Dukes’ Palace, Guimarães, Portugal

ABSTRACT

Chimneys are architectural elements of difficult access and analysis in heritage buildings. This paper presents a method for automatic modelling of round brick chimneys and analysing their inclination, straightness and surface. The method uses as input data point clouds acquired with a Terrestrial Laser Scanner. Four chimneys have been surveyed on the north face of Bragança Dukes’ Palace in Guimarães, Portugal. The method consists of two main processes. First, the point cloud of each chimney is segmented into circumferential sections and adjusted to cylinders by applying Maximum Likelihood Sample Consensus. From the set of centroids, the inclination and the straightness of the chimney is estimated. Second, the point cloud chimney is segmented longitudinally and adjusted to finite planes. The distance estimation between the input point cloud and the modelled planes allows detecting the lack of bricks or mortar erosions. The proposed method allows estimating characteristics in chimneys even if the chimneys have not been completely acquired.

KEYWORDS:

• Bricks
• point cloud processing
• round chimneys
• surface damage
• terrestrial laser scanning

Acknowledgments

Authors would like to thank the Xunta de Galicia given through human resources grant (ED481B-2019-061, ED481D 2019/020) and competitive reference groups (ED431C 2016-038), the Ministerio de Ciencia, Innovación y Universidades -Gobierno de España- (RTI2018-095893-B-C21) and COST CA15201 - Archaeological practices and knowledge work in the digital environment. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 769255. This document reflects only the views of the author(s). Neither the Innovation and Networks Executive Agency (INEA) or the European Commission are in any way responsible for any use that may be made of the information it contains. The statements made herein are solely the responsibility of the authors. The authors would also like to thank all the institutions and companies that have been involved in supporting and contributing to the development of this study, in particular, Isabel Fernandes and Flávio Vieira, director and staff member of Bragança Ducal Palace. This work was also partly financed by FCT/MCTES through national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020

Disclosure of potential conflicts of interest

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Xunta de Galicia [ED481B-2019-061, ED481D 2019/020].