Combination head-protective helmet which includes a cap and an outwardly extending brim and thermal imaging apparatus which includes an infrared camera for producing an infrared image of a scene or object and a display system which generates a visible image of the scene or object from the infrared image, the camera is mounted underneath the brim of the protective helmet for protection against e.g. falling objects and the display system is mounted on the helmet in a position to permit a person wearing the combination to see the visible image.