Processing of visual illusions in the frequency and spatial domains

In the results we report here, complex periodic and aperiodic illusions are revealed by filtering with filters containing one or more straight edges. Positive definite filters are used both in the frequency domain and in the space domain to reveal each illusion. Rotating slit and half-plane filters are used in the frequency domain, while processing is done in the spatial domain by convolution with a rotating slit. These two schemes show similar results in revealing the illusory patterns. The implications for human visual processing are discussed.