Studies of populations of supernova remnants (SNRs) in different galaxies provide a more representative picture of their importance for feedback and metal enrichment in a wide variety of galactic environments. We present our results on the SNRs populations in a sample of nearby spiral galaxies (NGC 7793, NGC 55 ,NGC 45, NGC 1313), based on deep narrow-band Hα and [S II] images. We find a total of 180 candidate SNRs. We derive the Hα and excitation distributions of the SNRs, both of which are proxies of the energy deposition on the galactic interstellar medium (ISM). In our analysis we develop methods to account for selection effects that allow us to directly compare results between different galaxies. We also present a new, efficient, diagnostic tool for identifying SNRs and measuring their shock velocities based on narrow-band imaging. Through the effective differentiation from H II regions this diagnostic provides more complete samples of SNRs including those in later evolutionary phases with slower shocks.