Talk:Argus image types and conventions
Argus Image Types and Conventions
Review by David Huntley
This brief description of Argus image types outlines clearly the most widely used time-averaged and time series products.
The applications of some of the Argus products are not always made clear. For example, variance images can also be used to estimate underlying bar bathymetry, though not as often used as the time-averaged images. Cross-shore pixel time series arrays are primarily used to estimate underlying bathymetry.
It should perhaps be made clear that the quantitative correlation between a pixel intensity time series and a simultaneous wave height time series (as in the example in figure 4) is dependent on ambient light intensity and direction so there is no universal correlation function. In practice this means that, whilst wave period can be relatively accurately determined, only estimates of wave height can be obtained.
I suspect that figure 5 may be a negative of the actual intensity time stack. Certainly the wave trajectories are clear bright slightly curved lines, rather than dark lines, as described in the text.
A more comprehensive and up to date review of Argus image types can be found in Holman and Stanley (2007), who add the option of ‘brightest’ and ‘darkest’ time-averaged products: Huntley et al. (2010) used ‘brightest’ images in a comparison between Argus-derived and modelled breaker heights. The article by Holman and Stanley (2007) also describes other pixel time series arrays such as the ‘alpha’ arrays, designed to obtain wave directional spectra, and ‘tess’ arrays of tessellated alpha arrays, to measure changes in wave spectra over complex shallow bathymetry.
Holman, R. and J. Stanley (2007). The history and technical capabilities of Argus. Coastal Engineering, 54, 477-491.
Huntley, D, A. Saulter, K. Kingston and R. Holman (2010). Use of video imagery to test model predictions of surf heights. Proc. Coastal Processes 2009. 320 pp. WIT Press, Southampton, UK.