Assessing the Raspberry Pi as a low-cost alternative for acquisition of near infrared hemispherical digital imagery

Research output: Contribution to journalArticle

Abstract

Hemispherical imagery is used in many different sub-fields of climatology to calculate local radiation budgets via sky-view factor analysis. For example, in forested environments, hemispherical imagery can be used to assess the leaf canopy, (i.e. leaf area / gap fraction) as well as the radiation below the canopy structure. Nikon Coolpix cameras equipped with an FC-E8 fisheye lens have become a standard device used in hemispherical imagery analysis however as the camera is no longer manufactured, a new approach needs to be investigated, not least to take advantage of the rapid development in digital photography over the last decade. This paper conducts a comparison between a Nikon Coolpix camera and a cheaper alternative, the Raspberry Pi NoIR camera, to assess its suitability as a viable alternative for future research. The results are promising with low levels of distortion, comparable to the Nikon. Resultant sky-view factor analyses also yield promising results, but challenges remain to overcome small differences in the field of view as well as the present availability of bespoke fittings.

Details

Original languageEnglish
Pages (from-to)232-239
JournalAgricultural and Forest Meteorology
Volume259
Early online date15 May 2018
Publication statusPublished - 15 Sep 2018

Keywords

  • hemispherical fisheye , near infra-red , Raspberry Pi , sensors