Real-Time Depth Estimation

Semester Project

A lightweight monocular depth estimation model for UAVs, capable of real-time performance.


Abstract


Obstacle avoidance is vital for unmanned aerial vehicles (UAVs). In this lab report, we present an approach for real-time metric depth estimation using unlabeled drone data. Initially, a pretrained depth estimator generates relative pseudo ground-truth depth maps. Consecutively, a lightweight model with real-time capabilities utilizes this training data to estimate depth maps up to a scaling factor that is subsequently eliminated through a final optmization scheme. Our evaluation explores various loss formulations, training approaches, and incorporation of temporal context, aiming to enhance baseline results. We improved on the baseline result and made our model runnable on a DJI Mini 3 Pro drone at up to 60 FPS. Moreover, we assess the capabilities of our scale estimation approach and the impact of different components. While our method proves efficient with ground-truth depths, it exhibits limitations when applied to imperfect predicted depth maps and requires further adjustments to be applicable in real-time scenarios


Method



RGB Image, Pseudo Ground Truth, and ours

DJI Mini 3 Pro
  • Depth Anything was used to generate pseudo ground-truth depth maps, given our unlabeled drone data
  • A lightweight depth estimator based on FastDepth was trained on the generated depth maps
  • The trained model was deployed on a DJI Mini 3 Pro drone using the ONNX Runtime

Results


Left: RGB input

Middle: GT depth map

Right: Predicted depth map

Depth estimation on data captured in our lab.

Depth estimation on data captured in the university.

Depth estimation on data provided by Deutschen Rettungsrobotik-Zentrums.


References


  1. Depth anything: Unleashing the power of large-scale unlabeled data, CVPR 2024.
  2. Fastdepth: Fast monocular depth estimation on embedded systems, ICRA 2019.