Digitisation of cultural heritage

Chapter 4: Processing for precision

Digitisation of cultural heritage

Processing for precision
The challenge of the processing of the accumulated data was to develop a workflow that processes automated laser scan and photogrammetry data. The solution had to be able to also handle the large data volume. 

A mutually-beneficial cooperation with an external start-up company called Capturing Reality began in order to process huge volumes of data in reasonable time. STUDIO 727 provided the data samples to test Capturing Reality’s innovative algo-rithms on the big-data and create needed functionality. The software product is today known as RealityCapture.

“We were able to process astonishing amounts of laser scans and images thanks to the RealityCapture software in very reasonable time,” said Dedik.

TLS data was pre-processed with the Leica Cyclone modelling software. With Cyclone, the laser scan data was de-referenced, merging the required point clouds and converting the data into the required .ptx data type. 

Cyclone distinguishes the highest possible level of automation. The software offers the possibility that point clouds can be exported in CAD and be processed there directly, such as for ground plans or 3D drawings.

With the RealityCapture software, the georeferenced point clouds and pictures are merged in an automated process. For this, the most suitable data (laser and image data) will be selected. From this data, textural polygonal model with high accuracy were generated. The resulting 3D models combines the advantages of both methods. 

The further processing of data occurs in JTSK coordinate system, the default coordinate system in the Slovak Republic. From this, the textural polygonal model can then be processed into highly accurate and detailed:
  • ortho-images
  • 3D models
  • technical documentation

In the table below are three different sized monuments that were digitised related to data volume and processing time. The time includes alignment, meshing and colouring for final models

Monument   Scan positions  Images  Processing time
 Virgin Mary Assumption church in Banska Stiavnica  70  80.000  1 months
 Church and chapel in Spissky Stvitok  150  50.000  4 months
 Historic town Banska Stiavnica  400  400.000  5 months

“The advantages of this workflow of the digitisation of cultural monuments over the classical geodetic methods are the temporal factor with the data collection as well as the highly detailed degree in connection with a high accuracy,” said Dedik. “It is no longer necessary to pre-define the output, because all required documentation can be created from the collected data.”

Back to Reporter 77 article overview

Story: Digitisation of cultural heritage
Chapter 1: Introduction
Chapter 2: Merging sensors for the best results
Chapter 3: Flying high for detail
Chapter 4: Processing for precision

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