Getting simultaneous red and near-infrared band data from a single digital camera for plant monitoring applications: Theoretical and practical study

Abstract

Multispectral images, including red and near-infrared bands, have proved efficient for vegetation-soil discrimination and agricultural monitoring in remote sensing applications. However, they remain little used in ground-based and unmanned aerial vehicle (UAV) imagery, due to a limited availability of adequate 2D imaging devices. A methodology is proposed to obtain simultaneously the near-infrared and red bands from a standard single RGB camera, after having removed the near-infrared blocking filter inside. Its ability to provide satisfactory NDVI computation for vegetation and soil has been assessed through spectral simulations. Application in field conditions with Canon 500 D and Canon 350D cameras have then been considered, taking into account signal noise and demosaicing concerns. The results obtained have proved the practical usability of this approach, opening new technical possibilities for crop monitoring and agricultural robotics.

Detecting tree water deficit by very low altitude remote sensing

“…To be cost effective, we adapted a method used in crop studies and used a modified digital camera and a non-modified digital camera (Rabatel et al 2014, Lebourgeois et al 2008, Jensen et al 2007) and a mobile darkroom. This technology has also been used for forest monitoring with Unmanned Aerial Vehicles (Lisein et al 2014).The results in Tab.…”

“…2), in order to record only visible wavelengths (red, green and blue). When this filter is removed, commercial cameras become sensitive to infrared wavelengths (Rabatel et al 2014). By photographing the same target with one modified and one nonmodified Canon ® EOS 350D digital camera, we recorded both near infrared (NIR) and red (from RGB) bands that could be used to calculate the NDVI.…”

Investigating the Potential of Low-Cost Remotely Piloted Aerial Systems for Monitoring the Alpine Snow Cover

“…The achieved better response for wavelengths above 700 nm should be a significant advantage when measuring snow surface reflectance, mainly for transformed snow like firn, aged snow and ice (Figure 8). However, these images are not calibrated and therefore only give a rough impression of the reflectivity of the snow and vegetation in these wavelengths, as opposed to a fully-calibrated multispectral camera (Rabatel et al, 2014;Lebourgeois et al, 2008). It has been shown in the relevant literature, that NIR-sensitivity does however have advantages for snow (Bühler et al, 2015b) and vegetation (Tucker, 1979) analysis, as well as in diffuse light conditions (Bühler et al, 2016a).…”

An Airborne Multispectral Imaging System Based on Two Consumer-Grade Cameras for Agricultural Remote Sensing

“…Therefore, it is possible to replace the blocking filter by a long-pass infrared filter on standard CCD or CMOS sensors for obtaining NIR images. Studies have been conducted on the use of NIR-converted digital cameras for monitoring plant conditions and results from these studies support their use as simple and affordable tools for plant stress detection and growth monitoring [20,21].…”