Hyperspectral models for non-invasive analysis of Indigenous Australian rock art

Indigenous Australian rock art is significant cultural heritage that requires non-invasive analysis methods to ensure that analysis does not compromise cultural sensitivities. Often rock art analysis requires physical sampling, which is destructive, and unsuitable for preserving the fabric of this cultural heritage. Through deep history and into the present, people have employed cultural knowledge through use of particular ochre and other mineral pigments, composed of iron oxides (red), iron hydroxides (yellow), carbon (black), and aluminosilicate clays (white).

Analysing the relationships between pigments and the ways they are applied can help us understand pigment composition, age, origins, and complex modes of cultural exchange between communities. However, differentiating colours and layers in Australian rock art is hindered by available data analysis methods, especially when pigments are faint, faded or a similar colour to the underlying rock base.

In collaboration with Traditional Owners, this project aims to further develop hyperspectral imaging techniques to document and analyse rock art on Balanggarra and Martu Country in Western Australia. Hyperspectral imaging offers a non-invasive alternative, capturing detailed spectral information in an image. However, interpreting this complex data requires advanced analytical approaches.

The research team will develop novel methods for analysing hyperspectral images of rock art produced by the Specim IQ camera. This includes creating models to non-invasively document rock art, ‘virtually untangling’ complex pigment layers and identifying the sequence of pigment application.

These techniques will provide insights into the cultural use, history, and preservation of ochre and related mineral pigments in Aboriginal Australian rock art – revealing the history of rock art over time, showing how it was originally created, how it was modified, and how environmental factors have affected preservation and appearance.

MDAP's expertise in data analytics is crucial for developing spectral unmixing models and analysing large hyperspectral datasets. This will allow us to obtain further information from existing data sets and develop models for future data collection and partnerships.

The project's outcomes will benefit Traditional Owners and communities, archaeologists, cultural heritage professionals, educators and the public. It will produce new imaging and data analysis methods for imaging of rock art on Country, and lab-based approaches and analytical models applicable to rock art analysis worldwide.