# 4d isip: 4d implicit surface interest point detection

## TL;DR

This paper introduces 4D-ISIP, a novel method for detecting interest points on 4D implicit surfaces using a TSDF-based 3D volume, demonstrated on human motion data captured with a Kinect.

## Contribution

The paper presents a new approach for 4D interest point detection leveraging implicit surface representations and a system for capturing 3D human motion with a single Kinect.

## Key findings

- Effective detection of 4D interest points on human actions
- Uses TSDF for implicit surface representation
- Works with data from a single Kinect sensor

## Abstract

In this paper, we propose a new method to detect 4D spatiotemporal interest points though an implicit surface, we refer to as the 4D-ISIP. We use a 3D volume which has a truncated signed distance function(TSDF) for every voxel to represent our 3D object model. The TSDF represents the distance between the spatial points and object surface points which is an implicit surface representation. Our novelty is to detect the points where the local neighborhood has significant variations along both spatial and temporal directions. We established a system to acquire 3D human motion dataset using only one Kinect. Experimental results show that our method can detect 4D-ISIP for different human actions.