Self-organization phenomenon in a helium dielectric barrier discharge generated by a piezoelectric transformer (PT) has been investigated. Time-resolved images taken by an intensified charge-coupled device camera reveals the temporal behavior of the microdischarge filaments that coincide with the homogeneous discharge in a cycle of the secondary voltage of the PT. We have succeeded in optically observing the traces of the accumulated charges on the dielectric surface as dark spots remained after the extinction of the microdischarge filaments. © 2006 IEEE.