Patent ID: 7187498

Claim:
An aircraft surveillance system comprising: a wall separating a cockpit of an aircraft from the cabin of the aircraft; a cockpit door disposed within an opening within the wall, the wall having an aperture located proximate to the cockpit door; a window disposed within the aperture; a camera disposed on the cockpit side of the wall in a position adjacent to the window so as to receive light that passes through the window; the window comprising: a first circular polarizer having a linear polarizer side and a quarter-waveplate side, the linear polarizer side facing the cabin, the quarter-waveplate side facing the cockpit; a second circular polarizer attached to the first circular polarizer, the second circular polarizer having a linear polarizer side and a quarter-waveplate side, the linear polarizer side facing the quarter-waveplate side of the first circular polarizer, the quarter-waveplate side being oriented toward the cockpit, the camera being located between the cockpit and the second circular polarizer.