Analyze the Water-Sensitive Paper

Evaluate the spray quality by analyzing an RGB-image of the water-sensitive paper.

analyzePaper(x, paper_dim = c(76, 26), distance = 0.7, display.it = TRUE)

Arguments

x	Either an object of class Image from package EBImage or a character indicating the path to the image file (.jpg, .jpeg, .png, .tif).
paper_dim	A numeric vector of length 2 indicating the length and width (in mm) of the water-sensitive paper.
distance	A numeric value indicating the distance from the nozzle(s) to the target, in order to estimate the spray drift (%) using the 'German model' for field crops.
display.it	(Logical) Should the image with the bounding box of the paper be displayed? Default is TRUE.

Value

Am object of class hydropaper, consisting of a list of the following:

ndrops

An integer indicating the number of droplets found.

coverage

The percentage of wet area of the paper.

density

The number of droplets per squared centimeter.

vol

The volume of product deposited in the paper. If paper_dimis given in milimeters, then vol is given in microliters.

vol_ha

The extrapolation of volume deposited for one hectare. If paper_dim is given in milimeters, then vol_ha is given in L/ha.

md

The mean diameter of droplets. If paper_dim is given in milimeters, then md is given in micrometers.

nmd

The numeric median diameter of droplets. If paper_dim is given in milimeters, then nmd is given in micrometers.

vmd

The volumetric median diameter of droplets. If paper_dim is given in milimeters, then vmd is given in micrometers.

d1

The 10th percentile of the volumetric median diameter of droplets. If paper_dim is given in milimeters, then d1 is given in micrometers.

d9

The 90th percentile of the volumetric median diameter of droplets. If paper_dim is given in milimeters, then d9 is given in micrometers.

RA

The relative amplitude: (d9 - d1)/vmd.

maxdrop

The maximum diameter of droplets. If paper_dim is given in milimeters, then maxdrop is given in micrometers.

mindrop

The minimum diameter of droplets. If paper_dim is given in milimeters, then mindrop is given in micrometers.

size_class

The percentage of droplets in each of the following three classes of diameter: <200, 200-400, >400 micrometers.

CVa

The coeficient of variation (%) of droplet areas.

CVd

The coeficient of variation (%) of droplet diameters.

r

A character giving a naive recomendation of which products are suitable to be sprayed, based on density.

drift

A prediction of drift (%) based on the 'German model' for field crops (Rautmann et al., 2001), as function of distance. This quantifies a 90th percentile of the drift values.

areas

A numeric vector containing area of each droplet found. If paper_dim is given in milimeters, then areas is given in squared milimeters.

diams

A numeric vector containing the diameter of each droplet found. If paper_dim is given in milimeters, then diams is given in squared micrometers.

binary

The binary mask of the segmentation, a numeric matrix.

References

Rautmann, D., M. Streloke, R. Winkler (2001) New basic drift values in the authorization procedure for plant protection products. In: R. Forster & M. Streloke, Workshop on Risk Assessment and Risk Mitigation measures in the context of the authorization of plant protection products (WORMM) 27.-29. September 1999. Mitteilungen aus der Biologischen Bundesanstalt für Land- und Forstwirtschaft, Berlin-Dahlem, Heft 381. 2001. 133-141.

See also

detectPaper()

Examples

path <- system.file('images', 'field1.jpg', package = 'hydropaper')
p1 <- detectPaper(path)


a <- analyzePaper(p1)

print(a)
#> 
#>               Water-Sensitive Paper Analysis
#>  
#>                             N drops: 1394 
#>                  Spray coverage (%): 18.1 
#>                 Density (drops/cm2): 71 
#>          Vol. applied (microliters): 213.44 
#>                    L/ha (predicted): 1080.15 
#>        Mean diameter (micronmeters): 462 
#>                   NMD (micrometers): 357 
#>                   VMD (micrometers): 1042 
#>                   D.1 (micrometers): 608 
#>                   D.9 (micrometers): 1456 
#>                  Relative amplitude: 0.81 
#>          Largest drop (micrometers): 1553 
#>         Smallest drop (micrometers): 113 
#> Diam. class % (<105, 105-340, >340): 0 49 51 
#>                         CV area (%): 135.2 
#>                        CV diam. (%): 72.8 
#>                       Good to spray: 
#>                           Drift (%): 96.1 
#> 
plot(a)