`get_cf_dens` takes the target (expected) number, baseline density, and power density, and generates a hyperframe with counterfactual densities.
get_cf_dens(expected_number, base_dens, power_dens = NA, window)an im object of a counterfactual density
the expected number of observations.
baseline density (im object)
power density (im object)
owin object
There are two ways of generating counterfactual densities. First, users can keep the locations of observations as they are and change the expected number of observations. In this case, users do not have to set `power_dens` and simply modify `expected_number`. Alternatively, users can shift the locations as well. In this case, `power_dens` must be specified. To obtain power densities, refer to [get_power_dens()].