Does Audio help in deep Audio-Visual Saliency prediction models?

Ritvik Agrawal

Abstract

The task of saliency prediction focuses on understanding and modeling human visual attention (HVA), i.e., where and what people pay attention to given visual stimuli. Audio has ideal properties to aid gaze fixation while viewing a scene. There exists substantial evidence of audio-visual interplay in human perception, and it is agreed that they jointly guide our visual attention. Learning computational models for saliency estimation is an effort to inch machines/robots closer to human cognitive abilities. The task of saliency prediction is helpful in many digital content-based applications like automated editing, perceptual video coding, human-robot interactions,etc. The field has progressed from using hand-crafted features to deep learning-based solutions. Efforts on static image saliency prediction methods are led by convolutional architectures. The ideas were extended to videos by integrating temporal information using 3D convolutions or LSTM’s. Many sophisticated multimodal, multi-stream architectures have been proposed to process multimodal information for saliency prediction. Despite existing works of Audio-Visual Saliency Prediction (AVSP) models claiming to achieve promising results by fusing audio modality over visual-only models, most of these models only consider visual cues and fail to leverage auditory information that is ubiquitous in dynamic scenes. In this thesis, we investigate the relevance of audio cues in conjunction with the visual ones and conduct extensive analysis to analyse the cause of AVSP models being superior by employing well-established audio modules and fusion techniques from diverse correlated audio-visual tasks. Our analysis on ten diverse saliency datasets suggests that none of the methods worked for incorporating audio. Our endeavour suggests that augmenting audio features ends up learning a predictive model agnostic to audio . Furthermore, we bring to light, why AVSP models show a gain in performance over visual-only models, though the audio branch is agnostic at inference. Our experiments clearly indicate that visual modality dominates the learning; the current models largely ignore the audio information. The observation is consistent while using three different audio backbones and four different fusion techniques and contrasts with the previous methods, which claim audio as a significant contributing factor. The performance gains are a byproduct of improved training and the additional audio branch seems to have a regularizing effect. We show that similar gains are achieved while sending random audio during training. Overall our work questions the role of audio in current deep AVSP models and motivates the community to a clear avenue for reconsideration of the complex architectures by demonstrating that simpler alternatives work equally well.

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