Thermal imaging of the human body skin surface requires a set of standardized conditions. There are many factors and influences on the skin that will determine the actual temperature distribution that is under investigation. Environmental conditions and levels of physical activity are both strong influences. Medical imaging often involves exposure to some form of energy or radiation. It should be made clear that infrared imaging is passive, and only detects natural heat emitted by the skin. As is all medical imaging protocols, there are particular recommendations in the way in which the subject to positioned for regional imaging. A range of suitable room temperatures have been established, depending on the type of examination. When images are recorded of the human body, the size of the image is dependent on the distance between the camera and the subject.