Browsing by Author "Sepúlveda, Marcela"

Now showing 1 - 5 of 5
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    Color-based discrimination of color hues in rock paintings through Gaussian mixture models: a case study from Chomache site (Chile)
    (2024) Cerrillo-Cuenca, Enrique; Sepúlveda, Marcela; Cabello Baettig, Gloria Andrea; Bastías Croudo Fernando Daniel
    The article explores advanced image processing techniques for pigment discrimination in rock art paintings, emphasizing color separation using RGB (red, green, blue) and LHCUv (Luminance, Hue, Chroma) imagery. It highlights the use of dimensionality reduction methods such as Principal Components Analisys PCA and Independent Component Analysis (ICA), with a focus on Gaussian Mixture Models (GMM) for probabilistic classification of image elements. This approach, applied to the Chomache archaeological site on the northernmost coast of the Atacama Desert in Chile, reveals previously undetected motifs and details, offering a nuanced perspective in rock art documentation and analysis. This proposal reinforces the value of rock art panel not only as a finished product but as a process.
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    Colors and dyes of archaeological textiles from Tarapacá in the Atacama Desert (South Central Andes)
    (2021) Sepúlveda, Marcela; Lemp Urzúa, Cecilia Mariana; Cárcamo, José; Casanova-Gónzalez, Edgar; Gutiérrez, Sebastián; Maynez-Rojas, Miguel Á.; Ballester, Benjamín; Ruvalcaba-Sil, José L.
    Abstract This work concerns the study of colors and dyes identified on archaeological textiles from the Atacama Desert. The different garments and ornaments come from the excavation of two important pre-Columbian cemeteries of the Tarapacá region: Tarapacá-40 attributed to the Formative period (1100 BC–660 AD) and Pica-8 to the Late Intermediate period (900–1450 AD). For the first time, a multi-analytical approach with non-invasive techniques using FORS and SERS was applied on samples of less than 2 cm of length for physicochemical characterization of the raw materials and the dyes employed in the textile production of northern Chile. The fibers are from animal origin. Blue, green, and yellow are identified as indigo, but we cannot discard a mixture with other dyes to vary hue and shade; while carminic acid and alizarin—to a lesser extent—are found on red, orange, and brown samples. This research provides new elements for the discussion about the textile technology developed in this desertic region, its changes, and continuities along the history. Our results are compared to recent findings on neighboring regions from South-Central Andes, to improve the current knowledge and discuss the existence of dyeing textile cultural traditions.
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    El Condor mine : Prehispanic production and consumption of hematite pigments in the Atacama Desert, northern Chile
    (2019) Sepúlveda, Marcela; Gallardo Ibañez, Héctor Francisco; Ballester, Benjamín; Cabello, Gloria; Vidal, Estefanía
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    Fuegian Firestone Quarry : Iron Pyrite on Capitán Aracena Island, Magallanes Archipelago, Southern Chile
    (2018) Gallardo Ibañez, Héctor Francisco; Ballester, Benjamín; Prieto, Alfredo; Sepúlveda, Marcela; Gibbons, Jaime; Gutiérrez, Sebastián; Cárcamo, José
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    The Dry Puna as an ecological megapatch and the peopling of South America: Technology, mobility, and the development of a late Pleistocene/early Holocene Andean hunter-gatherer tradition in northern Chile
    (2017) Osorio, Daniela; Steele, James; Sepúlveda, Marcela; Gayo Hernández, Eugenia Monserrat; Capriles, José M.; Herrera, Katherine; Ugalde, Paula; De Pol-Holz, Ricardo; Latorre H., Claudio; Santoro, Calogero M.