Applying Multifractal Analysis to Remotely Sensed Data for Assessing PYVV Infection in Potato (Solanum tuberosum L.) Crops

Abstract

Multispectral reflectance imagery and spectroradiometry can be used to detect stresses affecting crops. Previously, we have shown that changes in spectral reflectance and vegetation indices detected viral infection 14 days before visual symptoms were noticed by the trained eye. Herein we present evidence that shows that the application of multifractal analysis and wavelet transform to spectroradiometrical data improves the diagnostic power of the remote sensing-based methodology proposed in our previous work. The diagnosis of viral infection was effectively enhanced, providing the earliest detection ever reported, as anomalies were detected 29 and 33 days before appearance of visual symptoms in two experiments

Investigating the Utility of Wavelet Transforms for Inverting a 3-D Radiative Transfer Model Using Hyperspectral Data to Retrieve Forest LAI

“…The discrete wavelet transform (DWT) has been increasingly used in recent years in the processing of hyperspectral images for a variety of purposes [33][34][35][36][37][38][39]. These studies have shown its importance as an effective tool for reducing the dimensionality of hyperspectral data while maintaining information content for a variety of applications.…”

Detection of bacterial wilt infection caused by Ralstonia solanacearum in potato (Solanum tuberosum L.) through multifractal analysis applied to remotely sensed data

“…Using this method, Chiwaki et al (2005) were able to determine bacterial infection in plants 4 days earlier than the visual identification of symptoms, as the invasion of vascular bundles by multiplying bacteria reduced transpiration and caused a raised leaf temperature. Another promising technique is remote sensing and spectroradiometry of plant reflectance as it allows the early detection of morphological and anatomical changes even if these changes are small, as shown for virus infection (Chávez et al 2009(Chávez et al , 2010. Our own unpublished work provides evidence that the technique is also able to detect changes caused by water stress in plants.…”

“…Hence, the objective of this work was to test the feasibility of using the multispectral light reflectance of plants, supported by conventional and wavelet-based multifractal analyses of the reflectance signal, for detecting R. solanacearum infection in potato crops, aiming at developing a practical field monitoring method for the spatial assessment of the health condition of the crop. Although this work is methodologically similar to that reported in Chávez et al (2009Chávez et al ( , 2010, it is different in the sense that it tries to look for a general application of the diagnostic tool to different stresses which generally cause different physiological and morphological changes in affected plants. The general hypothesis is that different plant reactions, caused by a diversity of stressors (e.g.…”

“…However, the effects of biotic or abiotic stressors disrupt the normal timing and pattern change of reflectance that occurs in a healthy plant along its development from emergence to maturity. This departure from a normal reflectance pattern along time, difficult to be visually noticed at early stages, calls for the development of a reliable method for the early detection of stress responses to agents such as bacteria, viruses, and drought periods, based on non-conventional data processing techniques (Chávez et al 2010). In this work, the wavelet-based multifractal approach was used.…”

Remote Monitoring of Wheat Streak Mosaic Progression Using Sub-Pixel Classification of Landsat 5 TM Imagery for Site Specific Disease Management in Winter Wheat

“…Results from greenhouse and field studies have shown that it is possible to observe and quantify changes in crop health using remote sensing over the course of a growing season [27][28][29][30][31][32][33]. The presence of a disease or insect feeding leads to reductions in green leaf area and chemical and pigment concentrations, and alteration of cell structure, water and nutrient uptake, and gas exchange, which is known to modify canopy reflectance characteristics.…”