Mapping of the Indoor Conditions by Infrared Thermography

We present an instrumentation devoted to the mapping of indoor ambient conditions by an infrared camera. In addition to a measurement grid composed of several spherical sensors, an infrared camera is used to visualize and quantify the spatial distribution of the air temperature, the air speed, and the mean radiant temperature. A suitable procedure is developed so that from its temperature history recorded by the infrared camera, each sensor can measure, after solving an inverse heat transfer problem, all the three cited parameters. As the sensors are all imaged at the same time by the camera, an interpolation is done with the values they provide; the 2D distribution of each parameter is then obtained. By using a pair of stereoscopic cameras, it is possible to determine the 3D coordinates of each sensor of the measurement grid; consequently, the 3D mapping of the indoor ambient conditions is possible. Two steps are followed and allow us to achieve our goal: the validation of the performance of the sensor in terms of accuracy and reliability, and the validation of the complete experimental procedure which relies on digital image processing and on inverse heat transfer.