A device for detecting at least one thermographic image including a thermal camera sensitive to infrared radiation for acquiring the thermographic image; a protective case, inside which the thermal camera is inserted, having a window through which the thermal camera is able to acquire the thermographic image; a screen, positioned outside the protective case and movable between a first operating position at which it is superposed on the window to protect it from environmental disturbances and a second operating position wherein it is shifted from the window, allowing the thermal camera to acquire the thermographic image; a pneumatic system for supplying air inside the protective case having an inlet outside the protective case; a computerized command and control unit; the pneumatic system includes means for adjusting and distributing the air operating inside the protective case and in communication with the external inlet controlled by the computerized command and control unit.