Poling of calcium and zirconium modified lead titanate pyroelelectric thin films has been studied, Poling temperature and electrical field were optimized to achieve high figure of merits. It was found that thermal activation is important to obtain highly poled films. Defect-dipole complexes are supposed to play a major role to retain the polarization and also to enhance it. Porous calcium substituted films achieved an up to three times higher voltage response than zirconate substituted thin films, because porosity decreased the dielectric constant significantly.