The In composition is investigated in GaN/InGaN multi-quantum wells (QWs) by measurement of the local lattice distortion in high-resolution electron microscopy (HREM) images taken along the [1120] zone axis by image processing. The direct peak-finding procedure is more adequate for analysing images taken in the [1120] zone axis in comparison with the geometric-phase method since the information from different beams must be averaged. The finite element (FE) modelling and image simulation were combined in order to determine the error bars of the composition evaluation. (C) 2003 Elsevier Science B.V. All rights reserved.