Util2Physical.RdConvert intrinsic RSM parameters \(lambda_i\) and \(nu_i\) correspond to the physical RSM parameters \(lambda_i'\) and \(nu_i'\). The physical parameters are more meaningful but they depend on \(mu\). The intrinsic parameters are independent of \(mu\). See book for details.
Util2Physical(mu, lambda_i, nu_i)The mean of the Gaussian distribution for the ratings of latent LLs, i.e. continuous ratings of lesions that were found by the search mechanism ~ N(\(\mu\),1). The corresponding distribution for the ratings of latent NLs is N(0,1).
The intrinsic Poisson lambda_i parameter.
The intrinsic Binomial nu_i parameter.
A list containing \(\lambda\) and \(\nu\)
RSM is the Radiological Search Model described in the book.
See also Util2Intrinsic.
Chakraborty DP (2006) A search model and figure of merit for observer data acquired according to the free-response paradigm, Phys Med Biol 51, 3449–3462.
Chakraborty DP (2006) ROC Curves predicted by a model of visual search, Phys Med Biol 51, 3463–3482.
Chakraborty DP (2017) Observer Performance Methods for Diagnostic Imaging - Foundations, Modeling, and Applications with R-Based Examples, CRC Press, Boca Raton, FL. https://www.routledge.com/Observer-Performance-Methods-for-Diagnostic-Imaging-Foundations-Modeling/Chakraborty/p/book/9781482214840
mu <- 2;lambda_i <- 20;nu_i <- 1.1512925
lambda <- Util2Physical(mu, lambda_i, nu_i)$lambda
nu <- Util2Physical(mu, lambda_i, nu_i)$nu
## note that only the physical values are only constrained to be positive
## the physical variable nu must obey 0 <= nu <= 1