The Italian company Studio Labing assisted the facade restoration of the century-old building, Palace of Justice in Messina by generating a vertical surface orthomosaic from Pix4Dmapper…

Project Description

In 1908, one of the most severe earthquakes in the history shook Messina, Italy, resulting in nearly 10,000 deaths and destroying the entire city.

 

With two primary hospitals collapsed, the government decided to build the Palace of Justice (Palazzo Piacentini) at their former location.

 

The original palace design was inspired by both the Doric Sicilian temples and Brandenburg Gate in Germany. On the top of the palace sits Minerva, the Roman Goddess of Wisdom, guiding the horses which pull her cart.

 

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Palace of Justice, Court of Messina

 

Palace plans were approved in 1912, but were subsequently suspended due to World War I. Construction resumed after the war, and took four years, from 1923 to 1927, to complete.

 

Last year, the century-old building, with obvious marks on its facades, needed immediate action taken in order to prevent more damage.

 

Italian company, Chiofalo Group, was in charge of the entire restoration, and Studio Labing SLRS supported the restoration process by surveying the main facade with non-invasive drone photogrammetry technology.

Data Acquisition

To perform the inspection work of the facade, Studio Labing chose a DJI Inspire 1, which as a rotary drone is an optimal solution for mapping a vertical surface. Th flight was conducted using manual control, ensuring a high sampling distance and sufficient overlap among images. Other materials acquired for this project were: ground-points surveyed with a Trimble S6 total station, to pin the precise global position, and 4K video from a GoPro camera.

 

pix4d-pix4dmapper-inspection-orthoplane-facade-orthomosaic-messina-data-acquisitionCamera positions and 3D point cloud of the main facade in Pix4Dmapper rayCloud

 

Achieved Results

Images from the Inspire 1 were processed with Pix4Dmapper desktop software, using the orthoplane feature. This feature allows users to generate a surface model and orthomosaic from any facade, by defining the inclination and coverage of the box tool with the facade surface being surveyed. Generated outputs are high resolution, with one pixel representing 0.5 centimeter on the facade. With the correct scale, these results were then used in CAD software for continued analysis.

 

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(Left )Defining an orthoplane in Pix4Dmapper rayCloud interface; (Right) Pix4Dmapper-generated facade orthomosaic was used in CAD software (CADPILLAR 5.0) for diagnosis and classifcation of damage

 

Based on the orthomosaic, facade damage was noted and classified into 16 categories, with the location of and area affected by each type of damage recorded. While the entire facade has surface deposit and patina coverage, the main columns suffer a lot from discoloration. This graph will be handed over to appropriate authorities to assist them in making the final decision.

 

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Damage types of the Messina Court facade, in scale 1:100, based on the Pix4D facade orthomosaic 

 

3D reconstruction from Pix4Dmapper

 

Advantage of New Technology

There are many historical buildings and monuments around the world which need to be monitored and preserved. In Italy, such ancient buildings have exceptionally high value from an artistic point of view. Using drones to take high resolution images for inspection has been a popular methodology lately, and the power of image processing software provides additional values to the output and analysis.

 

The combination of drones and photogrammetry is currently the most efficient and economic way to monitor historical building conditions in the long term, create a database for digital museums, and assist decision making for further damage recovery plans.

 

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This technology gives a high-resolution result at low cost and in less time. (Top) CAD drawing of building facade; (Bottom) Surface orthomosaic from Pix4Dmapper with a ground sampling distance of 0.5 cm 

 

 

Author: Gabriel Versaci