  We propose a systematic procedure to optimize quantum state tomography
protocols for continuous variable systems based on excitation counting preceded
by a displacement operation. Compared with conventional tomography based on
Husimi or Wigner function measurement, the excitation counting approach can
significantly reduce the number of measurement settings. We investigate both
informational completeness and robustness, and provide a bound of
reconstruction error involving the condition number of the sensing map. We also
identify the measurement settings that optimize this error bound, and
demonstrate that the improved reconstruction robustness can lead to an order of
magnitude reduction of estimation error with given resources. This optimization
procedure is general and can incorporate prior information of the unknown state
to further simplify the protocol.
