  We analyse the unravelling of the quantum optical master equation at finite
temperature due to direct, continuous, general-dyne detection of the
environment. We first express the general-dyne Positive Operator Valued Measure
(POVM) in terms of the eigenstates of a non-hermitian operator associated to
the general-dyne measurement. Then, we derive the stochastic master equation
obtained by considering the interaction between the system and a reservoir at
thermal equilibrium, which is measured according to the POVM previously
determined. Finally, we present a feasible measurement scheme which reproduces
general-dyne detection for any value of the parameter characterising the
stochastic master equation.
