Optimization of use-wear detection and characterization on stone tool surfaces

Abstract

Debates and doubt around the interpretation of use-wear on stone tools called for the development of quantitative analysis of surfaces to complement the qualitative description of traces. Recently, a growing number of studies showed that prehistoric activities can be discriminated thanks to quantitative characterization of stone tools surface alteration due to use. However, stone tool surfaces are microscopically very heterogeneous and the calculated parameters may highly vary depending on the areas selected for measurement. Indeed, it may be impacted by the effects from the raw material topography and not from the altered zones only, if non-altered part of the surface is included in the measurement. We propose here to discuss this issue and present a workflow involving the use of masks to separate worn and unworn parts of the surface. Our results show that this step of extraction, together with suitable filtering, could have a high impact on the optimization of the detection and thus characterization of use traces. This represents the basis for future automatic routines allowing the detection, extraction and characterization of wear on stone tools.

Scales of Analysis: the Usage of Appropriate Magnification in Use-Wear Studies

“…Polish produced by rubbing the bone specimen against another piece of unworked bone for 30 minutes viewed at different magnifications 2019). While digital masking applications may provide a way, they presuppose a visual distinction between use-wear features and taphonomic alterations (Borel et al 2021). Nor has the extent to which automated processes like RTI can distinguish between natural and anthropogenic alterations been demonstrated (see Desmond et al 2018).…”

“…One way around this problem is to use digital masking techniques to filter out those areas of the surface that ought not to be included in the surface roughness calculation (Borel et al 2021). Filtering out natural, unworked surfaces or surfaces affected by taphonomic alterations means that observational area is less important as one can select only those areas one wants to include in the calculation.…”