Prototyping a mini-radiometer for measuring reflected light from different types of land covers [articol]

Abstract

In this paper, we describe in detail the prototyping of a mini radiometer for spectral data measurements. It is based on three main parts: -1- an RGB + near-infrared leds for the emitted light and a photodiode for the reflected light. -2- An 8-bit microcontroller for automatic data acquisition, calibrating and storing. -3- A user interface with small keypad + LCD display. An optional serial link interface is also provided for a compatible PC/Windows platform, with an open source C++ application software, in order to handle and deal with the mass of data collected. This instrument is useful for measuring the spectral reflectance of different land covers, in the visible and near-infrared wavelengths, to allow the construction of a characteristic curve named spectral signature of the object. The study of spectral signatures for different types of surfaces such as water, bare ground or vegetation (to name a few) allows their automatic identification by remote sensing, as done, for instance, by the NOAA satellite system, using the AVHRR (Advanced very High Resolution Radiometer) data sensor of the freely distributed HRPT (High Resolution Picture Transmission) images.