GlaucomaM {ipred}R Documentation

Glaucoma Database

Description

The GlaucomaM data has 196 observations in two classes. 62 variables are derived from a confocal laser scanning image of the optic nerve head, describing its morphology. Observations are from normal and glaucomatous eyes, respectively.

Usage

data(GlaucomaM)

Format

This data frame contains the following predictors describing the morphology of the optic nerve head and a membership variable:

ag
area global.
at
area temporal.
as
area superior.
an
area nasal.
ai
area inferior.
eag
effective area global.
eat
effective area temporal.
eas
effective area superior.
ean
effective area nasal.
eai
effective area inferior.
abrg
area below reference global.
abrt
area below reference temporal.
abrs
area below reference superior.
abrn
area below reference nasal.
abri
area below reference inferior.
hic
height in contour.
mhcg
mean height contour global.
mhct
mean height contour temporal.
mhcs
mean height contour superior.
mhcn
mean height contour nasal.
mhci
mean height contour inferior.
phcg
peak height contour.
phct
peak height contour temporal.
phcs
peak height contour superior.
phcn
peak height contour nasal.
phci
peak height contour inferior.
hvc
height variation contour.
vbsg
volume below surface global.
vbst
volume below surface temporal.
vbss
volume below surface superior.
vbsn
volume below surface nasal.
vbsi
volume below surface inferior.
vasg
volume above surface global.
vast
volume above surface temporal.
vass
volume above surface superior.
vasn
volume above surface nasal.
vasi
volume above surface inferior.
vbrg
volume below reference global.
vbrt
volume below reference temporal.
vbrs
volume below reference superior.
vbrn
volume below reference nasal.
vbri
volume below reference inferior.
varg
volume above reference global.
vart
volume above reference temporal.
vars
volume above reference superior.
varn
volume above reference nasal.
vari
volume above reference inferior.
mdg
mean depth global.
mdt
mean depth temporal.
mds
mean depth superior.
mdn
mean depth nasal.
mdi
mean depth inferior.
tmg
third moment global.
tmt
third moment temporal.
tms
third moment superior.
tmn
third moment nasal.
tmi
third moment inferior.
mr
mean radius.
rnf
retinal nerve fiber thickness.
mdic
mean depth in contour.
emd
effective mean depth.
mv
mean variability.
Class
a factor with levels glaucoma and normal.

Details

All variables are derived from a laser scanning image of the eye background taken by the Heidelberg Retina Tomograph. Most of the variables describe either the area or volume in certain parts of the papilla and are measured in four sectors (temporal, superior, nasal and inferior) as well as for the whole papilla (global). The global measurement is, roughly, the sum of the measurements taken in the four sector.

The observations in both groups are matched by age and sex to prevent any bias.

Note

GLaucomM overlaps in some parts with GlaucomaMVF.

Source

Torsten Hothorn and Berthold Lausen (2003), Double-Bagging: Combining classifiers by bootstrap aggregation. Pattern Recognition, 36(6), 1303–1309.

Examples

data(GlaucomaM)
errorest(Class ~ ., data=GlaucomaM, model=rpart, 
         predict=function(obj, newdata) 
                   predict(obj, newdata, type="class"), 
         control=rpart.control(xval=0))
glbagg <- bagging(Class ~ ., data=GlaucomaM, coob=TRUE)
glbagg


[Package ipred version 0.8-1 Index]