Comparison of lock-in correlation and a novel periodogram method for experimental multi-harmonic thermoelastic analysis

•Lock-in correlation and a periodogram method are evaluated for multi-harmonic TSA.•The proposed periodogram method solves the deficiencies of Fourier transform.•The resulting thermal maps and processing time were studied for the comparison.•Lock-in is more efficient for short thermal sequences and few frequency terms.•Periodograms are more efficient for long thermal sequences and many frequency terms.