# plotRoc

## PURPOSE

Function for display of rocs (receiver operator characteristic curves).

## SYNOPSIS

function [h,det] = plotRoc( D, varargin )

## DESCRIPTION

     Function for display of rocs (receiver operator characteristic curves).

     Displays nice clearly visible curves. Consistent usage ensures uniform
     look for rocs. The input D should have n rows, each of which is of the
     form [false-positive rate true-positive rate]. D is generated, for
     example, by scanning a detection threshold over n values from 0 (so first
     entry in D is [1 1]) to 1 (so last entry is [0 0]). Alternatively D can
     be a cell vector of rocs, in which case an average ROC will be shown with
     error bars.

     USAGE
      [h,det] = plotRoc( D, prm )

     INPUTS
      D    - [nx2] n data points along roc (falsePos/truePos)
      prm  - [] param struct
       .color    - ['g'] color for curve
       .lineSt   - ['-'] linestyle (see LineSpec)
       .lineWd   - [4] curve width
       .logx     - [0] use logarithmic scale for x-axis
       .logy     - [0] use logarithmic scale for y-axis
       .marker   - [''] marker type (see LineSpec)
       .mrkrSiz  - [12] marker size
       .nMarker  - [5] number of markers (regularly spaced) to display
       .lims     - [0 1 0 1] axes limits
       .smooth   - [0] if T compute lower envelop of roc to smooth staircase
       .fpTarget - [-1] if>0 plot line and return detection rate at given fp

     OUTPUTS
      h    - plot handle for use in legend only
      det  - detection rate at fpTarget (if fpTar specified)

     EXAMPLE
      k=2; x=0:.0001:1; data1 = [1-x; (1-x.^k).^(1/k)]';
      k=3; x=0:.0001:1; data2 = [1-x; (1-x.^k).^(1/k)]';
      hs(1)=plotRoc(data1,struct('color','g','marker','s'));
      hs(2)=plotRoc(data2,struct('color','b','lineSt','--'));
      legend( hs, {'roc1','roc2'} ); xlabel('fp'); ylabel('fn');

     See also

     Piotr's Image&Video Toolbox      Version 2.41
     Copyright 2009 Piotr Dollar.  [pdollar-at-caltech.edu]
     Please email me if you find bugs, or have suggestions or questions!
     Licensed under the Lesser GPL [see external/lgpl.txt]

## CROSS-REFERENCE INFORMATION

This function calls:

- getPrmDflt Helper to set default values (if not already set) of parameter struct.

This function is called by: