Friday, November 22, 2024
11/22/2024
Abstract Visually discriminating and identifying materials (such as judging whether a cup is made of plastic or glass) is crucial for everyday tasks, such as walking on different surfaces, using tools, and selecting food; and yet material perception remains poorly understood. The main challenge is that a given material can take an enormous variety of appearances depending on the 3D shape, lighting, and object class, and humans must untangle these to achieve perceptual constancy. Previous research revealed useful image cues and found that 3D geometry interacts with the material perception in intricate ways. The discovered image cues, however, do not generalize across materials and scenes. The proposed work will combine unsupervised generative models with human psychophysics to identify a representation that can disentangle physical properties and discover diagnostic image features without labeled image data. The specific Aim 1 is to identify a latent representation that predicts human material discrimination, using unsupervised deep neural networks trained with computer rendered images. The specific Aim 2 is to characterize high-level semantic material perception, the effects of high-level recognition as well as individual differences on attribute rating and recognition tasks. To discover a representation of real-world materials, the PI and the team will train a unsupervised style-based Generative Adversarial Network (StyleGAN) on real-world photographs. The preliminary results show that StyleGAN can generate realistic and diverse images of materials. Collectively, these studies will explore how the semantic-level material perception process relates to the statistical structure of the natural environment learned from unsupervised models. The proposed work will also uncover the task-dependent interplay between high-level vision and mid-level representations, and provide guidance for seeking neural correlates of material perception. The methods developed in this proposal, such as discovering perceptual dimensions with limited human labeled data and characterizing individual variability, have impact for other research in cognition. The AREA proposal provides a unique multidisciplinary training opportunity to engage diverse undergraduate students at American University in the research of psychophysics, machine learning, and image processing. The PI and students will also investigate a novel method of recruiting under-represented human subjects using "peer-recruiting." Finally, the expected findings of this proposal will have implications for the long-standing debate about the degree to which perceptual representations are predetermined by evolution or learned via experience.
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