Abstract: An apparatus known as a common module for converting a thermal scene into a visible image. The apparatus comprises an infrared objective, a pivotal mirror which can be pivoted back and forth about an axis, an infrared detection array comprising a plurality of detectors, and a linear display array which is connected to the infrared detection array via an amplifier arrangement. The radiation emitted by the display array is imaged in a plane of observation, preferably via the back of the pivotal mirror and via at least one diverting mirror. For omnidirectional viewing in the horizontal and the vertical direction the infrared objective, the pivotal mirror, the detector array and the display array are combined to form a constructional unit, which is arranged to be pivotable about a horizontal and about a vertical axis. Between the diverting mirror and the eyepiece an erecting prism is arranged. The erecting prism is rotated in conformity with the rotation of the constructional unit.