Browsing by Author "Demarco, Rodrigo"

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    Assessment of light environment conditions for reconstruction of multispectral images by conditional adversarial networks
    (2025) Arevalo Ramirez, Tito Andre; Menéndez, Oswaldo; Villacrés, Juan; Guevara, Javier; Guamán-Rivera, Robert; Demarco, Rodrigo; Auat Cheein, Fernando
    Understanding vegetation through its reflectance in the visible and near-infrared spectrum is vital for gaining biophysical and structural insights about vegetation. However, the spectral reflectance on meaningful bands (e.g., red-edge, near-infrared) is not always available because of the camera’s spectral response restrictions. In this context, previous research addresses the lack of multispectral information by reconstructing it using deeplearning approaches. Although there are promising outcomes, the influence of varying illumination conditions on this process still needs to be explored. Thus, this work examines if conditional Generative Adversarial Networks (cGANs) can infer environment illumination for achieving an appropriate multispectral image reconstruction. In particular, the spectral reconstruction performance of cGANs is investigated under six different scenarios with different illumination (occurring over a whole day), focusing on green, red-edge, and nearinfrared bands. Note that the dataset used for this research has become publicly available. These results indicated that illumination conditions influenced the performance of cGAN models in generating spectral images. Specifically, the cGANs could not infer the source image illumination to output a reliable reconstructed spectral image. Furthermore, although including samples under different illumination improved cGANs’ performance, the generated multispectral images tended to be darker than actual images.
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    Flammability features of native and non-native woody species from the southernmost ecosystems: a review
    (2024) Toy Opazo, Octavio Alexander; Fuentes Ramírez, Andrés; Palma Soto, Valeria; Garcia, Rafael A.; Moloney, Kirk A.; Demarco, Rodrigo; Fuentes Castillo, Andrés
    Background: Vegetation plays a crucial role in the ignition, propagation, and severity of fre, and understanding the relationship between plants and fre through fammability attributes has become a useful tool that is increasingly used in studies on fre dynamics worldwide. However, in the southern cone of South America, rather few studies have systematically and specifcally addressed the fammability of vegetation, and yet fewer have compared native and non-native species. Given the increasing interest in knowing the fammability characteristics of vegetation, this review aims to assess the potential diferences in fammability between native and non-native plant species that inhabit the southern cone and to identify the main methodologies and experiments used to analyze vegetation fammability. Results: Twenty-eight species were identifed, 18 native to the region and 10 non-native. Additionally, 64 experimental tests were revised to evaluate plant fammability. It was found that Cryptocarya alba, Acacia dealbata, Eucalyptus globulus, and Pinus ponderosa are the species with a high fammability index. By contrast, the species Araucaria araucana, Austrocedrus chilensis, Embothrium coccineum, and Persea lingue showed low fammability. The methodologies used to evaluate vegetation fammability were highly variable, with the use of epiradiators being the most frequent. Conclusions: Our review indicates that the geographic origin of vegetation (native vs. non-native in South America) is not a decisive factor in determining species-level diferences in fammability. Other relevant factors that contribute with the degree of plant fammability include fuel moisture, the morphology of the species, and its internal chemical compounds. We highlight the necessity of continuing the study of plant fammability and advance in the standardization of protocols and measurements, using uniform criteria and increasing comparative studies between species, particularly in the southern cone of South America where catastrophic wildfres are increasing.