14 research outputs found
Image databases: Problems and perspectives
With the increasing number of computer graphics, image processing, and pattern recognition applications, economical storage, efficient representation and manipulation, and powerful and flexible query languages for retrieval of image data are of paramount importance. These and related issues pertinent to image data bases are examined
An Architecture for distributed multimedia database systems
In the past few years considerable demand for user oriented multimedia information systems has developed. These systems must provide a rich set of functionality so that new, complex, and interesting applications can be addressed. This places considerable importance on the management of diverse data types including text, images, audio and video. These requirements generate the need for a new generation of distributed heterogeneous multimedia database systems. In this paper we identify a set of functional requirements for a multimedia server considering database management, object synchronization and integration, and multimedia query processing. A generalization of the requirements to a distributed system is presented, and some of our current research and developing activities are discussed
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
Automated interpretation of digital images of hydrographic charts.
Details of research into the automated generation of a digital database of hydrographic charts is presented. Low level processing of digital images of hydrographic charts provides image line feature segments which serve as input to a semi-automated feature extraction system, (SAFE). This system is able to perform a great deal of the building of chart features from the image segments simply on the basis of proximity of the segments. The system solicits user interaction when ambiguities arise. IThe creation of an intelligent knowledge based system (IKBS) implemented in the form of a backward chained production rule based system, which cooperates with the SAFE system, is described. The 1KBS attempts to resolve ambiguities using domain knowledge coded in the form of production rules.
The two systems communicate by the passing of goals from SAFE to the IKBS and the return of a certainty factor by the IKBS for each goal submitted. The SAFE system can make additional feature building decisions on the basis of
collected sets of certainty factors, thus reducing the need for user interaction. This thesis establishes that the cooperating IKBS approach to image interpretation offers an effective route to automated image understanding
Image Retreival Using Weighted Color Co-occurrence Histogram
Color image retrieval is to search color images using queries represented by image descriptors, which usually describe color distribution and relation of color pixels in an image. A color co-occurrence histogram (CCH) among the descriptors captures information on the spatial layout of colors within an image. It has shown excellent performance on color image retrieval, but requires many bins to describe contents of images and has bad effect on the similarity of same contents images, in which the size of homogeneous color regions are highly different.
To resolve these problems and to improve retrieval performance, this thesis proposes a weighted CCH and two image retrieval methods using it. Generally the process of image retrieval using a CCH has three steps. The first step is to get the CCH from a query image. The second step is to compute similarity between CCHs of the query image and reference images. The last step is to sort reference images by the similarities and to visualize them. The proposed retrieval methods weight main diagonal and off-diagonal elements of a CCH in the first and/or the second steps mentioned above.
Experiments have shown that the proposed methods with a few bins outperform some conventional methods when large weight is given on off-diagonal elements regardless of color quantization levels. We believe that the effectiveness of the method is caused by the characteristics describing the size and the coherence of homogeneous color regions and being robust to size variation of the color regions. Moreover, the image retrieval performance is little affected by the threshold, which is an energy level of valid bins, regardless of color quantization levels.
The proposed methods use contents of images effectively, so they can be effectually used in the other content-based applications such as color image classification, color object tracking, and video cut detection.์ ๏ผ์ฅ ์ ๋ก = 1
1.1 ์ฐ๊ตฌ์ ๋ฐฐ๊ฒฝ = 1
1.2 ์ ์ํ ๋ฐฉ๋ฒ = 3
์ ๏ผ์ฅ ๋ด์ฉ๊ธฐ๋ฐ ์์๊ฒ์์ ์ํ ์ปฌ๋ฌ ๊ธฐ์ ์ = 6
2.1 ๋ด์ฉ๊ธฐ๋ฐ ์์๊ฒ์ ์์คํ
= 6
2.2 ์ปฌ๋ฌ์์์ ์ํ ๊ธฐ์ ์ = 7
์ ๏ผ์ฅ ์ปฌ๋ฌ ๋์๋ฐ์ ํ์คํ ๊ทธ๋จ์ ์ํ ์์๊ฒ์ = 19
3.1 ์ปฌ๋ฌ ๋์๋ฐ์ ํ์คํ ๊ทธ๋จ์ ๋ฌธ์ ์ = 19
3.2 ๋๊ฐ์ฑ๋ถ๊ณผ ๋น๋๊ฐ์ฑ๋ถ์ ์์๊ธฐ์ = 24
3.3 ๋๊ฐ์ฑ๋ถ๊ณผ ๋น๋๊ฐ์ฑ๋ถ์ ์์๊ฒ์ ์ฑ๋ฅ = 29
์ ๏ผ์ฅ ๊ฐ์ค์น๋ฅผ ๋ ์ปฌ๋ฌ ๋์๋ฐ์ ํ์คํ ๊ทธ๋จ์ ์ด์ฉํ ์์๊ฒ์ = 36
4.1 ๋๊ฐ์ฑ๋ถ ๋ฐ ๋น๋๊ฐ์ฑ๋ถ์ ๊ฐ์ค์น๋ฅผ ๋ ์์๊ฒ์ = 38
4.1.1 ๋๊ฐ์ฑ๋ถ ๋ฐ ๋น๋๊ฐ์ฑ๋ถ์ ๊ฐ์ค์น๋ฅผ ๋ CCH = 38
4.1.2 ๋น ๊ฐ์ ์ถ์์ ์ ์ฌ๋ ์ธก์ = 42
4.2 ๋๊ฐ์ฑ๋ถ, ๋น๋๊ฐ์ฑ๋ถ ๋ฐ ๊ฐ์ค์น์ ์ํ ์์๊ฒ์ = 46
4.2.1 CCH์ ํ๋๊ณผ ๋น ์ ๊ฑฐ = 46
4.2.2 ์ ์ฌ๋ ์ธก์ = 48
์ ๏ผ์ฅ ์คํ ๋ฐ ๊ณ ์ฐฐ = 52
5.1 ์คํํ๊ฒฝ ๋ฐ ์ฑ๋ฅํ๊ฐ ๋ฐฉ๋ฒ = 52
5.2 ์คํ๊ฒฐ๊ณผ ๋ฐ ๊ณ ์ฐฐ = 55
์ ๏ผ์ฅ ๊ฒฐ ๋ก = 79
์ฐธ๊ณ ๋ฌธํ = 8
Design and evaluation of a shape retrieval system
PhD ThesisWhile automated storage and retrieval systems for textual and numeric data are now
commonplace, the development of analogous systems for pictorial data has lagged behind
- not through the lack of need for such systems, but because their development involves
a number of significant problems.
The aim of this project is to investigate these problems by designing and evaluating an
information retrieval system for a specific class of picture, 2-dimensional engineering
drawings. This involves consideration of the retrieval capabilities needed by suchยท a
system, what storage structures it would require, how the salient features of each drawing
should be represented, how query and stored shapes should be matched, what features
were of greatest importance in retrieval, and the interfaces necessary to formulate queries
and display results.
A form of hierarchical boundary representation has been devised for stored shapes, in
which each boundary can be viewed as a series of levels of steadily increasing
complexity. A set of rules for boundary and segment ordering ensures that as far as
possible, each shape has a unique representation. For each level at which each boundary
can be viewed, a set of invariant shape features characterizing that level is extracted and
added to the shape representation stored in the database. Two classes of boundary feature
have been defmed; global features, characteristic of the boundary as a whole, and local
features, corresponding to individual fragments of the boundary. To complete the shape
description, position features are also computed and stored, to specify the pattern of inner
boundaries within the overall shape.
Six different tYPes of shape retrieval have been distinguished, although the prototype
system can offer only three of these - exact shape matching, partial shape matching and
similarity matching. Complete or incomplete query shapes can be built up at a terminal,
and subjected to a feature extraction process similar to that for stored drawings, yielding
a query fIle that can be matched against the shape database. A variety of matching
techniques is provided, including similarity estimation using global or local features, tests
for the existence of specified local features in stored drawings, and cumulative angle vs
distance matching between query and stored shape boundaries. Results can be displayed
in text or graphical form.
The retrieval performance of the system in similarity matching mode has been evaluated
by comparing its rankings of shapes retrieved in response to test queries with those
obtained by a group of human subjects faced with the same task. Results, expressed as
normalized recall and precision, are encouraging, particularly for similarity estimation
using either global or local boundary features. While the detailed results are of limited
significance until confrrmed with larger test collections, they appear sufficiently
promising to warrant the development of a more advanced prototype capable of handling
3-D geometric models. Some design aspects of the system would appear to be applicable
to a wider range of pictorial information systems
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Image database retrieval using neural networks
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The broad objective of this work has been to achieve retrieval of images from large unconstrained databases using image content. The problem is typified by the need to locate a target image within a database where no numerical indexing terms exist. Here, retrieval is based on important features within in an image and uses sample images or user sketches to specify a query. A typical query might be framed as "Find all images similar to this one", for example. The aim of this work has been to show how neural networks can provide a practical, flexible and robust solution to this problem. A neural network is basically an adaptive information filter which can be used to extract the salient characteristics of a data set during a training phase. The transformation learnt by the network can map the images into compact indices which support very rapid fuzzy matching of images across the database. This learning process optimises the performance of the code with respect to the contents of the database. We assess the applicability of several neural network architectures and learning rules for a practical coding scheme and investigate how the system parameters affect the performance of the system. We introduce a novel learning law which has a number of advantages over existing paradigms. In-depth mathematical analysis and extensive empirical tests are used to corroborate the arguments presented throughout. This thesis aims to show the nature of the image retrieval problem, how current research trends attempt to tackle it and how neural networks can offer us a real alternative to conventional approaches
COOPERATIVE QUERY ANSWERING FOR APPROXIMATE ANSWERS WITH NEARNESS MEASURE IN HIERARCHICAL STRUCTURE INFORMATION SYSTEMS
Cooperative query answering for approximate answers has been utilized in various problem domains. Many challenges in manufacturing information retrieval, such as: classifying parts into families in group technology implementation, choosing the closest alternatives or substitutions for an out-of-stock part, or finding similar existing parts for rapid prototyping, could be alleviated using the concept of cooperative query answering. Most cooperative query answering techniques proposed by researchers so far concentrate on simple queries or single table information retrieval. Query relaxations in searching for approximate answers are mostly limited to attribute value substitutions. Many hierarchical structure information systems, such as manufacturing information systems, store their data in multiple tables that are connected to each other using hierarchical relationships - "aggregation", "generalization/specialization", "classification", and "category". Due to the nature of hierarchical structure information systems, information retrieval in such domains usually involves nested or jointed queries. In addition, searching for approximate answers in hierarchical structure databases not only considers attribute value substitutions, but also must take into account attribute or relation substitutions (i.e., WIDTH to DIAMETER, HOLE to GROOVE). For example, shape transformations of parts or features are possible and commonly practiced. A bar could be transformed to a rod. Such characteristics of hierarchical information systems, simple query or single-relation query relaxation techniques used in most cooperative query answering systems are not adequate. In this research, we proposed techniques for neighbor knowledge constructions, and complex query relaxations. We enhanced the original Pattern-based Knowledge Induction (PKI) and Distribution Sensitive Clustering (DISC) so that they can be used in neighbor hierarchy constructions at both tuple and attribute levels. We developed a cooperative query answering model to facilitate the approximate answer searching for complex queries. Our cooperative query answering model is comprised of algorithms for determining the causes of null answer, expanding qualified tuple set, expanding intersected tuple set, and relaxing multiple condition simultaneously. To calculate the semantic nearness between exact-match answers and approximate answers, we also proposed a nearness measuring function, called "Block Nearness", that is appropriate for the query relaxation methods proposed in this research