component_contrast      Contrast between the two exposure components
exposure_em             Fit a two-component exposure model by EM
exposure_em_control     Control parameters for exposure-component EM
                        fitting
exposure_fit            Fit a two-component exposure model using EM,
                        Marquardt, or both
exposure_marquardt_control
                        Control parameters for direct Marquardt fitting
posterior_components    Posterior latent-component probabilities
predict.exposure_em_fit
                        Predict from a fitted exposure model
