The aim of paper is a non-touch experimental method for measure parameters of the specimen in a moment of high temperature deformation. The method is consist of a photo camera, a lamp into a furnace, an electronic system send a pulse to take a picture in each 0.1 mm stretching and a computer program for post processing. The specimen geometry was measured remotely, with pictures taken during the experiment. In a tension test the use of a developed noncontacting measuring system allowed us to see variations in the specimen shape and to estimate the true stress in various cross-sections on the time. In post processing stage we can fix localization time by a theoretical criterion automatically.