Temperature variations have strong effects on structure vibrations, urging the need for accurate real-time temperature identification. The work presented here deals with the reconstruction of the thermal field inside a structure, given pointwise temperature measurements. This is achieved by reconstructing both the initial and boundary conditions. The numerical procedure uses the adjoint method, which is unable, in its usual L-2 setting, to provide accurate results at the end of the observation period. This paper shows how the introduction of regularity assumptions yields an accurate and stable real-time temperature reconstruction while keeping the generality and flexibility of the usual adjoint method. (C) 2011 Elsevier Ltd. All rights reserved.