xbob.measure.idmeasure 0.0.3

Installation

First, you have to install bob following the instructions there.

There are two options you can follow to get this package installed and operational on your computer: you can use automatic installers like pip (or easy_install) or manually download, unpack and use zc.buildout to create a virtual work environment just for this package. In both cases, the two dependences listed above will be automatically downloaded and installed.

$ pip install xbob.measure.idmeasure

$ easy_install xbob.measure.idmeasure

$ python bootstrap.py
$ ./bin/buildout

User Guide

It is assumed you have followed the installation instructions for the package and got this package installed.

Two functions, DIR and DIR_plot, are in this package to compute and plot the detection and identification rates by given the predefined false acceptance rates. The descriptions of these function are presented below:

DIR(cmc_scores, far_list):
==========================
Calculates the Detection and Identification Rate from the give input and
a vector of specified false acceptance rates

Keyword attributes:

cmc_scores
  List of two-element tuples. Each of the tuples contains the negative and
  the positive scores for one test item.

far_list
  Array of predefined false acceptance rates.

Return: List of two-element tuples, namely detection and identificatio rate.
  Each of the tuples contains the probability that the rank r of the
  positive score and the corresponding false acceptance rate. r is computed
  as the number of negative scores that are higher than the positive score.

DIR_plot(cmc_scores, far_list, logx = True, **kwargs):
======================================================
Plot the Detection and Identification Rate from the give input and a
vector of specified false acceptance rates

Keyword attributes:

cmc_scores
  List of two-element tuples. Each of the tuples contains the negative
  and the positive scores for one test item.

far_list
  Array of predefined false acceptance rates.

logx
  Boolean input, if it is true, the x-axis is in log scale.

kwargs
  A dictionary of extra plotting parameters, that is passed directly to
  matplotlib.pyplot.plot

Note: This function does not initiate and save the figure instance, it
      only issues the plotting commands.  Every user is responsible for
      setting up and saving the figure as it best fits his purpose.

Below, we provide an example of how to appy DIR_plot to plot the DIR curve, from the python universe:

>>> import idmeasure
# predefine a list of false acceptance rates
>>> FAR=[.01, 0.1, 1]
#Read The four column file needs to be in the same format as described in the
 five_column function, and the "test label" (column 4) has to contain the
 test/probe file name.  please refer the functions of
 bob.measure.load.cmc_four_column, bob.measure.load.cmc_five_column to load
 or generate the "cmc scores".
>>> idmeasure.DIR_plot(cmc_scores, FAR)
>>>pyplot.xlabel("Rank")
>>>pyplot.ylabel("Identification Rate (%)")
>>>pyplot.title("Detection and Identification Rate Identification Experiment")
>>>pyplot.grid()
>>>pyplot.savefig("eigenfaceDIR.png")
>>>pyplot.close()