In this work, we address the problem of building recognition across two camera views with large changes in scales and viewpoints. The main idea is to construct a semantically rich sketch-based representation for buildings which is invariant under large scale and perspective changes. After multi-scale maximally stable extremal regions (MSER) detection, the proposed approach finds repeated structural components of buildings, such as window, doors, and facades, and extracts semantically rich features, which are organized into a sketch-based representation of buildings. These descriptors are then clustered in association with different planes of the building and matched across video frames using spectral graph analysis. Our experiments demonstrate that the proposed approach outperforms SIFT-based matching schemes, especially for images with large viewpoint changes.

In this work, we study how continuous video monitoring and intelligent video processing can be used in eldercare to assist the independent living of elders and to improve the efficiency of eldercare practice. More specifically, we construct an advanced silhouette extraction and tracking algorithm for indoor environments. An adaptive learning method was developed to estimate the physical location and moving speed of a person from a single camera view without calibration. Then hierarchical decision tree and dimension reduction methods were used for human action recognition. We extract important ADL (activities of daily living) statistics for automated functional assessment. Our extensive tests over these massive video datasets demonstrate that the proposed automated activity analysis system is very efficient.

Global motion estimation (GME) is the enabling step for many important video exploitation tasks. In this work, we focus on indirect GME methods which have low computational complexity. Typically, an indirect GME method has two major steps. The first step is to find point correspondence between frames through local motion search or feature matching. Then, the second step determines global motion parameters using optimal model fitting, such as least mean-squared error (LMSE) fitting or RANSAC. However, due to image noise and inherent ambiguity in point correspondence, local motion estimation often suffers from relatively large errors, which degrade the performance and reliability of GME. In this work, we propose a method to characterize the reliability of local motion estimation results and use this reliability measure as a weighting factor to determine the importance level of each local motion estimation result during global motion estimation. Our simulation results demonstrate that the proposed scheme is able to significantly improve the accuracy and robustness of global motion estimation with a very small computational overhead.

In this work, we study how continuous video monitoring and intelligent video processing can be used in eldercare to assist the independent living of elders and to improve the efficiency of eldercare practice. More specifically, we develop an automated activity analysis and summarization for eldercare video monitoring. At the object level, we construct an advanced silhouette extraction, human detection and tracking algorithm for indoor environments. At the feature level, we develop an adaptive learning method to estimate the physical location and moving speed of a person from a single camera view without calibration. At the action level, we explore hierarchical decision tree and dimension reduction methods for human action recognition. We extract important ADL (activities of daily living) statistics for automated functional assessment. To test and evaluate the proposed algorithms and methods, we deploy the camera system in a real living environment for about a month and have collected more than 200 hours (in excess of 600 G bytes) of activity monitoring videos. Our extensive tests over these massive video datasets demonstrate that the proposed automated activity analysis system is very efficient.

Moving objects detection and tracking is the first and enabling step for many high-level UAV surveillance tasks, including cooperative UAV path planning, navigation control, and automated information analysis. In this work, we develop a low-complexity and reliable moving object detection algorithm by exploring the ideas of uncertainty analysis and spatiotemporal activity clustering. More specifically, the authors develop a fast and efficient algorithm to estimate the global vehicle-camera motion. Image regions (blocks) with local motion was detected using statistical hypothesis testing. Using spatiotemporal clustering, the authors group these moving blocks into moving objects with physical meanings, such as moving vehicles or persons. Our extensive experimental results demonstrate the efficiency of the proposed algorithm.