Monitoring Horizontal Movement of Top of a Spire in Saint Mary Cathedral of Burgos via Computer Vision

ABSTRACT

Long-term monitoring of horizontal movement of the top of vertical elements, such as towers of historical monuments or chimneys, remains a challenge with current solutions. In such structures, which are usually of high historical and cultural value, ageing and structural degradation directly impact their horizontal movement. This study presents a novel solution based on computer vision that allows the monitoring of horizontal movements with very good accuracy (uncertainty less than ±0.26 mm), high measurement speed (up to 5 Hz), and reduced cost. A real-life validation was carried out on the south spire of the Saint Mary Cathedral in Burgos, Spain. Its horizontal movements were monitored for more than a year, and some relevant events were recorded, including high-range thermal variations, strong wind events, and ringing of the bells. The results showed that the proposed solution was particularly robust for long-term monitoring of slow movements, such as those produced by thermal events or those derived from structural degradation. The white noise of the sensor was small and, for long-term measurements and small reading frequencies, it could obtain field accuracies of the order of ±0.1 mm at a recording frequency of 1/10 Hz, which further improved at lower recording frequencies.

KEYWORDS:

• Computer vision
• historical heritage
• horizontal movement
• structural health monitoring

6. Acknowledgments

The authors are grateful for the financial support provided by the University of Burgos, Spain, through the VII Edition of the Convocatoria Prueba Concepto: Impulso a la valorización y explotación de resultados de investigación (Acronym: LASARTVIEW). They are also grateful to the chapter of the Cathedral of Saint Mary of Burgos for providing access to the south spire for the work and their logistical support.

Disclosure statement

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

Additional information

Funding

A Spanish patent (patent no: ES 2 684 134 B2) was granted (Vicente et al., 2019);Universidad de Burgos [VII Edition of the ”Convocatoria Prueba Concepto”];