Description of the 'Roughness Profile' Results Page

   

Clicking on the 'Roughness Profile' button will send your file to the application server for analysis and take you to the 'Results' page. The results will include a set of time/roughness pairs at the user-defined time interval (default: 250ms) by ascending time, followed by a list of the corresponding spectra (frequency and amplitude values by descending amplitude) . The first time/roughness pair and spectrum will be estimated on or after the time corresponding to half the length of the analysis window. To return from the 'Results' to the 'SRA' page, use the browser's 'Back' button or hit the 'Backspace' key on the keyboard.

The analysis window length will be determined by the frequency resolution setting (~320ms for 10Hz and ~160ms for 20Hz) and be centered at times determined by the time interval setting. This setting (default: 250ms) is not limited by the analysis window length and can be as short as 1ms, although such short time intervals may be both impractical (in terms of the amount of data reported) and meaningless (in terms or roughness changes). If the time-interval field is left blank, the analysis will return an error. The earliest (latest) point within a file for which a roughness value can be calculated is 158ms (for 10Hz frequency resolution; 79ms for 20Hz frequency resolution) from the beginning (end) of the submitted file.

The degree of precision of the spectral analysis (in terms of time, frequency, and amplitude estimates) is much finer than the one required for roughness calculation (read about the spectral analysis method). It captures fast, fine spectral time-variance that does not necessarily correspond to perceivable roughness variations.
To reduce this effect, the roughness value reported at any given time corresponds to the median of 5 roughness values calculated from 5 equally-spaced spectra within an 100ms window (i.e. at -50ms, -25ms, 0ms, +25ms, and +50ms), centered at the time reported. The precise time for each spectral distribution used to calculate the reported roughness values is recovered in the spectral distribution reports.

The sections below outline the segments of the 'Roughness Profile' Results page and include:
a) a report of the analysis parameters and the roughness profile of the submitted file (i.e. a list of time/roughness pairs by ascending time) and
b) the spectral profile of the submitted file [i.e. spectral distributions (by descending amplitude) corresponding to the analyses at the requested times].

Tip: Depending on the roughness profile time-interval selected and on the research question of interest, the roughness profile obtained may need to be modified by using 5- or 7-point running-average values in order to better reveal data trends.

   

REPORT OF THE ANALYSIS PARAMETERS - ROUGHNESS PROFILE

Figure 1: The results display an outline of the file and analysis parameters, followed by the file's roughness profile (i.e. list of time and roughness values, by ascending time). The "Normalizing Amplitudes" parameter will display only if it has been set to "Yes."

   

SPECTRAL PROFILE
(List of spectral distributions at the requested times)

Figure 2: The spectral profile that follows, consists of the spectral distributions (i.e. frequency and amplitude values of up to 50 'peaks' (components) with amplitudes > the amplitude determined by the amplitude threshold value, listed by descending amplitude) at the user-specified time intervals. Regardless of the decimal digits displayed, frequency and amplitude values are estimated at 32-bit, floating-point precision. Note that the roughness returned for a given point in time (e.g. 750ms) may have been computed at a slightly different point in time (e.g. 725ms). As already described, the roughness value reported at any given time corresponds to the median of 5 roughness values calculated from 5 equally-spaced spectra within an 100ms window (i.e. at -50ms, -25ms, 0ms, +25ms, and +50ms), centered at the time requested. See the top of this page for more.