Noncrystalline film of As2S3 is used as a nonlinear recording material of the joint transform optical processor. Real-time cross-correlation between two transparencies has been demonstrated using the optical processor. In this processor an argon laser beam (λ1 = 4880 A) is used to record the Fourier transform spectrum of a reference object and of a test piece; a He-Ne laser beam (λ2 = 6828 A) is used to read a dynamic phase volume hologram simultaneously. The crosscorrelation peaks between two photographs of identical words hav? been observed. The set-up can bo applied to compare finger-prints.