[EN] The estimation of the biophysical parameters of vegetation such as LAI (Leaf Area Index), FAPAR (Fraction of Absorbed Photosynthetically Active Radiation) and FCOVER (Fraction of Green Vegetation) have many climatic, hydrologic, ecosystem and silvo-agricultural applications. Despite the various satellite products that estimate these parameters continuously and globally, it’s necessary to continue generating in situ estimations to validate these remote data. It’s in this context where Digital Hemispheric Photography (DHP) technique stands out as being one of the most accurate an adaptable to operate continuously with diverse photographic equipment and field scenarios. The objective of this paper is to estimate effective LAI (LAIeff), true LAI (LAItrue), FAPAR and FCOVER through the DHP method on several agricultural land covers in Chile, between the years 2015 and 2016 using a GoPro camera and the CAN-EYE software to process hemispheric photographs. The results obtained were initially compared with those provided by a CANON EOS 6D camera mounted together with a SIGMA 8mm F3.5-EX DG fisheye lens and subsequently with satellite products provided by the Copernicus Global Land service, derived from PROBA-V mission at 333 m2 spatial resolution. The comparison between the CANON and GoPro shows similar values and R2 over 0,72 for all parameters. The comparison with PROBA-V resulted in values over 0,52 of R2 for the parameters, and similar multitemporal patterns. It’s concluded that it’s possible to estimates LAIeff, FAPAR and FCOVER like other fish eyes cameras. Concerning PROBA-V, except for FAPAR, the estimates with the GoPro do not show much correlation. In both campaigns significant discrepancies were observed in the LAItrue, which could be related to the calculation of CAN-EYE canopy clumping with the characteristics of the camera itself. 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Revista oficial de la Asociación Española de Teledetección [ES] La estimación de los parámetros biofísicos de la vegetación como el LAI (Leaf Area Index, FAPAR (Fraction of Absorbed Photosynthetically Active Radiation) y FCOVER (Fraction of Green Vegetation) tienen una gran cantidad de aplicaciones climáticas, hidrológicas, ecosistémicas y en sistemas silvoagropecuarios. A pesar de los diversos productos satelitales que estiman estos parámetros de forma continua y global, es necesario seguir generando estimaciones in situ para validar estos datos remotos. Es en este escenario en donde la técnica de Fotografía Digital Hemisférica (DHP) destaca por ser una de las más precisas y adaptables para funcionar de forma continua en diversos equipos fotográficos y escenarios de campo. El objetivo de este estudio es estimar el LAI efectivo (LAIeff), LAI verdadero (LAItrue), FAPAR y FCOVER a través del método DHP sobre diversas cubiertas agrícolas de Chile, entre los años 2015 y 2016 utilizando la cámara fotográfica GoPro y el software CAN-EYE para procesar las fotografías hemisféricas. Los resultados obtenidos se compararon inicialmente con los suministrados por una cámara CANON EOS 6D montada junto a un lente ojo de pez SIGMA 8mm F3.5-EX DG y posteriormente con productos satelitales proporcionados por el servicio Copernicus Global Land, derivado de la misión PROBA-V a 333 m2 de resolución espacial. La comparación entre las cámaras CANON y GoPro muestra estimaciones similares y valores de R2 sobre 0,72 para todos los parámetros. La comparación con PROBA-V dio lugar a valores sobre 0,52 de R2 para los parámetros y estimaciones multitemporales con patrones similares. Se concluye que con la cámara GoPro, es posible generar estimaciones de LAIeff, FAPAR y FCOVER de forma similar a otras cámaras ojos de pez. Respecto a PROBA-V, a excepción de FAPAR, las estimaciones con la GoPro no muestran mucha correlación. En ambas campañas se observaron discrepancias significativas del LAItrue lo que se podría relacionar al cálculo del agrupamiento de la canopia de CAN-EYE sobre las características propia cámara. Uribe, D.; Mattar, C.; Camacho, F. (2018). Estimación de parámetros biofísicos de la vegetación en praderas y cultivos en Chile mediante fotografía digital hemisférica obtenidas por una cámara GoPro. Revista de Teledetección. (52):1-15. doi:10.4995/raet.2018.9315 Latorre, C., Camacho, F., Mattar, C., Santamaría-Artigas, A., Leiva-Büchi, N., Lacaze, R. 2016. Obtención de mapas verdad-terreno de LAI, FAPAR y cobertura vegetal a partir de imágenes del satélite chileno FASat-C y medidas in-situ en la zona agrícola de Chimbarongo, Chile, para la validación de productos de satélite. Revista de Teledeteccion, 2016(47), 51- 64. https://doi.org/10.4995/raet.2016.5691 Martínez, B., Camacho-de Coca, F., García-Haro, F. 2005a. Estimación de parámetros biofísicos de la cubierta vegetal a alta resolución a partir de medidas in-situ obtenidas en SPARC'03. XI Congreso Nacional de Teledetección, 21-23. Martínez, B., García-haro, F., Camacho-de Coca, F. 2005b. Estimación de parámetros biofísicos de vegetación utilizando el método de la cámara hemisférica. Revista de Teledetección, 23, 13-26.

Estimation of vegetation biophysical parameters in grasslands and crops in Chile through hemispheric digital photography by a GoPro camera

Estimación de parámetros biofísicos de la vegetación en praderas y cultivos en Chile mediante fotografía digital hemisférica obtenidas por una cámara GoPro

Abstract