2 research outputs found
Sketch-Based Spatial Queries for the Retrieval of Human Locomotion Patterns in Smart Environments
A system for retrieving video sequences created by tracking humans in a smart environment, by using spatial queries, is presented. Sketches made with a pointing device on the floor layout of the environment are used to form queries corresponding to locomotion patterns. The sketches are analyzed to identify the type of the query. Directional search algorithms based on the minimum distance between points are applied for finding the best matches to the sketch. The results are ranked according to the similarity and presented to the user. The system was developed in two stages. An initial version of the system was implemented and evaluated by conducting a user study. Modifications were made where appropriate, according to the results and the feedback, to make the system more accurate and usable. We present the details of the initial system, the user study and the results, and the modifications thus made. The overall accuracy of retrieval for the initial system was approximately 93%, when tested on a collection of data from a real-life experiment. This is improved to approximately 97% after the modifications. The user interaction strategy and the search algorithms are usable in any environment for automated retrieval of locomotion patterns. The subjects who evaluated the system found it easy to learn and use. Their comments included several prospective applications for the user interaction strategy, providing valuable insight for future directions
A study of spatial data models and their application to selecting information from pictorial databases
People have always used visual techniques to locate information in the space
surrounding them. However with the advent of powerful computer systems and
user-friendly interfaces it has become possible to extend such techniques to stored
pictorial information. Pictorial database systems have in the past primarily used
mathematical or textual search techniques to locate specific pictures contained
within such databases. However these techniques have largely relied upon complex
combinations of numeric and textual queries in order to find the required
pictures. Such techniques restrict users of pictorial databases to expressing what is
in essence a visual query in a numeric or character based form. What is required
is the ability to express such queries in a form that more closely matches the user's
visual memory or perception of the picture required. It is suggested in this thesis
that spatial techniques of search are important and that two of the most important
attributes of a picture are the spatial positions and the spatial relationships of
objects contained within such pictures. It is further suggested that a database
management system which allows users to indicate the nature of their query by
visually placing iconic representations of objects on an interface in spatially
appropriate positions, is a feasible method by which pictures might be found from
a pictorial database. This thesis undertakes a detailed study of spatial techniques
using a combination of historical evidence, psychological conclusions and practical
examples to demonstrate that the spatial metaphor is an important concept and that
pictures can be readily found by visually specifying the spatial positions and
relationships between objects contained within them