Thermal imaging device for detecting and identifying a thermal object

A thermal imaging device for detecting and identifying a thermal object, said device comprising:

• an objective system;
• a rotating, infrared radiation-transmitting scanning polygon arranged on an optical axis behind the objective system;
• an infrared sensor array arranged on the optical axis behind the polygon such that radiation emerging from the polygon is incident on the infrared sensor array, said array producing electrical signals in response to the radiation;
• and
• a display for converting the electrical signals into optical signals, characterized in that:
• the scanning polygon rotates about the optical axis and rotates about another axis which is perpendicular to the optical axis, said latter rotation causing deflection of the infrared radiation radially with respect to the optical axis;
• the infrared sensor array is stationary;
• and the device further comprises:
• a correction lens, arranged on the optical axis between the objective system and the scanning polygon;
• a reversing optic, arranged on the optical axis between the polygon and the sensor array, said reversing optic rotating about the optical axis at half the angular frequency at which the polygon rotates about the optical axis;
• a multichannel summing amplifier for adding electrical signals produced by the sensor array, said amplifier producing further electrical signals;
• means for synchronizing the gain of said amplifier with the rotation of the scanning polygon about the axis perpendicular to the optical axis;
• and
• a picture tube for converting the electrical signals received from the amplifier into optical signals.