Time course of the integration of spatial frequency-based information in natural scenes.

It is known that visual information is processed separately and based on multiple spatial frequencies. Therefore, integration of information is important for categorization of natural scenes. To clarify the time course of visual integration, we examined categorization accuracies for spatially filtered images as a function of image exposure duration. Results indicated that, with image durations of 100-ms, accuracy was superior with spatially integrable images when compared with accuracy levels based upon the probability summation model estimated from accuracies of separately presented low- and high-frequency images. This finding suggests that spatial frequency integration begins earlier than 100-ms after the image onset.