Faculty Information |

DOI Ryoichi Faculty of Sociology Department of Sociology Professor

■ Title
Doi et al., 2013. Quantitative use of luminosity-normalized grayscale images of greenness, redness and yellowness of a rice canopy derived from multi-temporally acquired digital photographs

■ Outline
  Comparison of spectral profiles of a crop in multi-temporally acquired digital photographs is effective in crop management. However, comparison has been difficult due to temporal changes in brightness of photographs and the absence of correlation among brightness and color components such as blue (B). To circumvent this problem, this study examined
luminosity-normalization of the entire area of grayscale images of green (G), red (R), and RGB yellow for a rice canopy in photographs multi-temporally acquired by a surveillance camera. After confirming the linear relationships between luminosity and the above color components using a rooftop invariant, all pixels in the grayscale images of the color components were luminosity 100-normalized. The maturity of rice was described as great intensity values of R, G and RGB yellow, an R/G value of 1.0 and great coefficients of variation of around 17 for the above color components. This was due to light yellowish mature rice grains and incomplete leaf senescence resulting in a color diversity of the canopy. With the luminosity 100-normalization of the entire area of the grayscale images of G, R and RGB yellow, comparison of the continuously and multi-temporarily acquired spectral profiles of the rice canopy was possible.
  Doi, R., Arif, C., Setiawan, B. I. and Mizoguchi, M.
  Collaboration   Int. J. Agric. Biol.   FS Publishers   15(4),pp.707   2013