ARS | Publication request: Leaf Surface Wetness Detection Using Ground Based Multispectral Imaging

Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings/Symposium
Publication Acceptance Date: May 1, 2003
Publication Date: July 27, 2003
Reprint URL: http://asae.frymulti.com/request.asp?search=1&JID=5&AID=15325&CID=lnv2003&T=2
Citation: Ramalingam, R., Ling, P.P., Derksen, R.C. 2003. Leaf surface wetness detection using ground based multispectral imaging. ASAE Annual International Meeting. Paper No. 033130.

Technical Abstract: Most pesticide applications are made with using carrier volumes that are sufficiently high to result in some wetting of the leaf surfaces. This characteristic may be useful in detecting the quality and quantity of an application. The objectives of this research were to develop means for relatively simple approaches for extracting leaf surface wetness information and to perform sensitivity analysis for estimating the minimum detectable water film thickness on a leaf. The multispectral imaging system consisted of a monochrome tube camera and filters spanning the VIS, NIR, and MIR wavebands. Using these techniques, spatial and spectral information were simultaneously acquired. The performance of the multispectral imaging system was evaluated by comparing the calculated reflectances with those measured using a spectroradiometer. There was a high correlation between the calculated and measured reflectance values. There were no significant performance differences between the spectral and spatial approaches to leaf surface water assessment. Sensitivity analysis showed that the multispectral imaging system can be used to detect a layer of water as thin as 0.006 cm representing a delivery rate of 500 L/ha for a leaf area index of unity.