Linguang Zhang will present his Pre FPO "Towards a Robust Local Feature Pipeline" on Tuesday, January 15, 2019 at 1pm in CS 302

Linguang Zhang will present his Pre FPO on Tuesday, January 15, 2019 at 1pm in CS 302. The members of his committee are as follows: Szymon Rusinkiewicz (advisor), Jia Deng, Adam Finkelstein, Thomas Funkhouser, and Olga Russakovsky. All are welcome to attend. Abstract follows below. Title: Towards a Robust Local Feature Pipeline Many computer vision applications including image matching, image-based reconstruction and localization rely on extracting and matching robust local features. A typical local feature pipeline first detects repeatable keypoints in the image (i.e., keypoint detector), and then computes a short vector to uniquely describe each keypoint (i.e., feature descriptor). Both the keypoint detector and the feature descriptor are conventionally hand-crafted based on what is intuitive to the designer. For example, corners or blobs are popular choices of keypoints, and the image gradient is a useful clue for descriptors. However, it is often difficult to define these principles to accommodate various applications. In this thesis, we study data-driven approaches which can more easily tailor the local feature pipeline for target applications. We start with a mobile robotics application that leverages local features extracted from ground texture images to achieve high-precision global localization. The second part of the thesis addresses the problem that existing keypoint detectors that are optimized for natural images suffer from sub-optimal performance on texture images. We therefore learn a keypoint detector specifically for each type texture using a deep neural network. Our detector automatically learns to identify keypoints that are distinctive in the target texture rather than relying on a set of pre-defined rules. Finally, we focus on a non-parametric approach for learning feature descriptors. Many well-performing local feature descriptors are trained using a triplet loss that includes a tunable margin, which limits its ability to generalize to other types of data and problems. We propose to replace the hard margin with a soft margin that self-tunes as learning progresses. To summarize, we first demonstrate through a novel visual-based localization system where a customized local feature pipeline is critical. Then, we tackle both the keypoint detector and the feature descriptor with generalizable data-driven approaches.
participants (1)
-
Nicki Gotsis