Video Depth-From-Defocus

TL;DR

This paper introduces a novel method to capture all-in-focus RGB-D video using a standard camera by exploiting defocus blur during focus shifts, enabling advanced post-processing effects like refocusing.

Contribution

It presents a new video-based depth-from-defocus algorithm that works with unmodified cameras and dynamic scenes, producing coherent depth maps and all-in-focus videos.

Findings

Effective depth maps and all-in-focus videos generated from defocus blur.

Enables compelling refocusing effects in post-processing.

Works with standard cameras without hardware modifications.

Abstract

Many compelling video post-processing effects, in particular aesthetic focus editing and refocusing effects, are feasible if per-frame depth information is available. Existing computational methods to capture RGB and depth either purposefully modify the optics (coded aperture, light-field imaging), or employ active RGB-D cameras. Since these methods are less practical for users with normal cameras, we present an algorithm to capture all-in-focus RGB-D video of dynamic scenes with an unmodified commodity video camera. Our algorithm turns the often unwanted defocus blur into a valuable signal. The input to our method is a video in which the focus plane is continuously moving back and forth during capture, and thus defocus blur is provoked and strongly visible. This can be achieved by manually turning the focus ring of the lens during recording. The core algorithmic ingredient is a new video-based depth-from-defocus algorithm that computes space-time-coherent depth maps, deblurred all-in-focus video, and the focus distance for each frame. We extensively evaluate our approach, and show that it enables compelling video post-processing effects, such as different types of refocusing.