A heat imaging camera (3) for sensing convective conditions in boundary layer flows occurring on wind tunnel models (2), particularly at cryogenic temperatures, scans the model from the outside, thereby detecting the temperature distribution on the model surface. Detectors (9) that are sensitive to the long-wave infrared spectrum range are part of the camera and convert the heat information into electrical signals. The temperature distribution is displayed pictorially and graphically with the help of an evaluation unit (50). The detectors (9) are grouped in a detector mosaic (10) in the camera (3).