ECoDepth: Effective Conditioning of Diffusion Models for Monocular Depth Estimation
Authors: Suraj Patni, Aradhye Agarwal, Chetan Arora

In the absence of parallax cues a learning-based single image depth estimation (SIDE) model relies heavily on shading and contextual cues in the image. While this simplicity is attractive it is necessary to train such models on large and varied datasets which are difficult to capture. It has been shown that using embeddings from pre-trained foundational models such as CLIP improves zero shot transfer in several applications. Taking inspiration from this in our paper we explore the use of global image priors generated from a pre-trained ViT model to provide more detailed contextual information. We argue that the embedding vector from a ViT model pre-trained on a large dataset captures greater relevant information for SIDE than the usual route of generating pseudo image captions followed by CLIP based text embeddings. Based on this idea we propose a new SIDE model using a diffusion backbone which is conditioned on ViT embeddings. Our proposed design establishes a new state-of-the-art (SOTA) for SIDE on NYUv2 dataset achieving Abs Rel error of 0.059(14% improvement) compared to 0.069 by the current SOTA (VPD). And on KITTI dataset achieving Sq Rel error of 0.139 (2% improvement) compared to 0.142 by the current SOTA (GEDepth). For zero-shot transfer with a model trained on NYUv2 we report mean relative improvement of (20% 23% 81% 25%) over NeWCRFs on (Sun-RGBD iBims1 DIODE HyperSim) datasets compared to (16% 18% 45% 9%) by ZoeDepth. The project page is available at https://ecodepth-iitd.github.io