SII-package: Calculate ANSI S3.5-1997 Speech Intelligibility Index

In SII: Calculate ANSI S3.5-1997 Speech Intelligibility Index

Description

This package calculates ANSI S3.5-1997 Speech Intelligibility Index (SII), a standard method for computing the intelligibility of speech from acoustical measurements of speech, noise, and hearing thresholds. This package includes data frames corresponding to Tables 1 - 4 in the ANSI standard as well as a function utilizing these tables and user-provided hearing threshold and noise level measurements to compute the SII score. The methods implemented here extend the standard computations to allow calculation of SII when the measured frequencies do not match those required by the standard by applying interpolation to obtain values for the required frequencies.

Author(s)

Gregory R. Warnes [e-mail]

References

ANSI S3.5-1997, "American National Standard Methods for Calculation of the Speech Intelligibility Index" American National Stan- dards Institute, New York.

Other software programs for calculating SII are available from http://www.sii.to/html/programs.html.

Examples

## Example C.1 from ANSI S3.5-1997 Annex C
sii.C1 <- sii(
              speech   = c(50.0, 40.0, 40.0, 30.0, 20.0,  0.0),
              noise    = c(70.0, 65.0, 45.0, 25.0,  1.0,-15.0),
              threshold= c( 0.0,  0.0,  0.0,  0.0,  0.0,  0.0),
              method="octave"
	      )
sii.C1                        # rounded to 2 digits by default
print(sii.C1$sii, digits=20)  # full precision
summary(sii.C1)               # full details
plot(sii.C1)                  # plot
## The value given in the Standard is $0.504$.

Example output

SII: 0.504 

[1] 0.5039555062499999627

Speech Intellibility Index
--------------------------

Call:

sii(speech = c(50, 40, 40, 30, 20, 0), noise = c(70, 65, 45, 
    25, 1, -15), threshold = c(0, 0, 0, 0, 0, 0), method = "octave")

Method: Octave band SII procedure 

Calculation table:

    Fi E'i N'i T'i Vi Bi Ci  Zi    Xi   X'i   Di   Ui Ji   Li   Ki   Ai    Ii
1  250  50  70   0 NA NA NA  70  -3.9  -3.9 70.0 34.8  0 0.97 0.00 0.00 0.062
2  500  40  65   0 NA NA NA  65  -9.7  -9.7 65.0 34.3  0 1.00 0.00 0.00 0.167
3 1000  40  45   0 NA NA NA  45 -12.5 -12.5 45.0 25.0  0 0.97 0.33 0.32 0.237
4 2000  30  25   0 NA NA NA  25 -17.7 -17.7 25.0 17.3  0 0.98 0.67 0.66 0.265
5 4000  20   1   0 NA NA NA   1 -25.9 -25.9  1.0  9.3  0 1.00 1.00 1.00 0.214
6 8000   0 -15   0 NA NA NA -15  -7.1  -7.1 -7.1  1.1  0 1.00 0.74 0.74 0.055
   IiAi
1 0.000
2 0.000
3 0.077
4 0.174
5 0.213
6 0.040

SII: 0.5 

SII documentation built on May 1, 2019, 8:48 p.m.