cond.table: Compute a contingency table from an sre object

In davidavdav/ROC: Compute structures to compute ROC and DET plots and metrics for 2-class classifiers.

Compute a contingency table from an sre object

Description

For averaging detection trial lists that were obtained from different experimental conditions, the amounts of trials in these conditions should be weighted. This function computes a contingency table from an cst object.

Usage

cond.table(x, cond, target = F)

Arguments

x	An object of class cst, or compatible data frame or roc object
cond	A list of factors making up the various conditions
target	Is column target to be interpreted as a factor?

Details

This function produces a table of the number of trials for each condition in a trial list. Conditions are specified by all combinations of all levels of the factors specified in cond. Conditions with no trials are left out of the table.

This table can be used in equalizing the influence of different implicit conditions in a larger set of trials, such as NIST SRE-2008. In order to do this properly, the analysis needs to be carried out separately for target and non-target trials, this can be specified by target=TRUE.

This function is used by the functions det.sre() and plot.cond(), but can be used separately as well.

Value

A data.frame with a columns for each factor, specifying the condition, and the column Freq that indicated the trial count.

Author(s)

David van Leeuwen

References

David A. van Leeuwen, “Overal performance metrics for multi-condition Speaker Recognition Evaluations,” Proc. Interspeech, Brighton, September 2009, pp 908–911.

See Also

plot.cond

Examples

## a NIST 2008 SRE data set
data(tno.2008)
## Analyse by gender
cond.table(tno.2008, gender)
#  gender  Freq
#f      f 59343
#m      m 39433
## Analyse by acoustic condition
cond.table(tno.2008, list(mtype, mmic, ttype, tmic))
#       mtype mmic     ttype tmic  Freq
#1  interview  mic interview  mic 34181
#4  phonecall  phn interview  mic  7350
#8  phonecall  phn phonecall  mic  8454
#13 interview  mic phonecall  phn 11741
#16 phonecall  phn phonecall  phn 37050

davidavdav/ROC documentation built on Sept. 8, 2023, 2:39 p.m.