We present pitch angle measurements of a nearly complete sample of nearby spiral galaxies. Using these results along with the relationship between supermassive black hole mass and the pitch angle of the host galaxy's spiral arms, we have determined the black hole mass function for local spiral galaxies. The pitch angle measurements were obtained by applying a two-dimensional fast Fourier transform to optical images. This technique can be extended to samples of spiral galaxies at higher redshifts in order to investigate how the black hole mass function has changed over time. Funding for this project was provided by NASA and NSF grants.