01633naa a2200169 a 450000100080000000500110000800800410001902200140006010000200007424501430009426000090023752011170024665000200136365000240138365300110140777300450141816326402023-05-31       1993    bl uuuu     u00u1 u    #d  a0191-29171 aBLAZQUEZ, C. H.  aCorrelation of densitometric measurements of aerial color infrared photography with visual grades of citrus groves.h[electronic resource]  c1993  aAerial color infrared photographs taken in April 1986 were used to select three blocks of a citrus grove for image anlysis. In ground surveys, trees were counted and classified according to percent stress and canopy growth. Measurements, made on the positive color infrared transparencies with a scanning densitometer over the 500- to 520-nm and 600- to 620-nm spectral ranges, correlated with visual grades assigned in surveys. Ratios of the spectral range integrals and the spectral range integrals and the peak transmittances of the two spectral curves showed significant correlations with the visual grades. In the 1989 photographs, significat correlations were found between visual grades and the integral and transmittance of the first peak. Visual grades assi gned through photointerpretation were comparable with densitometric measurements of both years, suggesting that the the scanning densitometer may be a good tool for interpretation because it was not affected by the different color balance or the hue found in the 1986 and 1989 aerial color infrared photographs while measuring stress and growth.  aCitrus Sinensis  aFotointerpretação  aCitros  tPlant Diseasegv.77, n.5, p.477-479,1993