AN OBJECT MODEL FOR THE MANAGEMENT OF

DIGITAL IMAGES

S. Khaddaj and A. Hoppe

Faculty of Computing, Information System and Mathematics, Kingston University

Kingston upon Thames KT1 2EE, U.K.

Keywords: Object Oriented Modelling, Object Versioning, Image Management Systems.

Abstract: With digital image volumes rising dramatically there exists an important and urgent need for novel

techniques and mechanisms that provide efficient storage and retrieval facilities of the voluminous data

generated daily. It is already widely accepted that the use of data abstraction in object oriented modelling

enables real world objects to be well represented in information systems. In this work we are particularly

interested with the use of object oriented techniques for the management of digital images. Object

orientation is well suited for such systems, which require the ability to handle multiple type content. This

paper aims to investigate a conceptual model, based on object versioning techniques, which will represent

the semantics in order to allow the continuity and pattern of changes of images to be determined over time.

1 INTRODUCTION

Digital imaging management systems, in which

images are collected, organised and categorised to

facilitate their preservation, retrieval and use are

becoming an essential part of many organisations

particularly in visual surveillance and medical

imaging sectors.

Object oriented techniques have been used

successfully in many different applications that

range from numerical modelling to web applications.

The main benefits, apart from the abstraction power

to represent real objects, are the provision for the

extensibility needed to create new models and the

semantic needed to construct complex objects of

similar states (Yourdon, 1994; Bertrand, 1997

The use of object oriented techniques in

information management has been given

considerable attention in the past decade (Cattell,

1991; Loomis, 1995

). Recent research works have

used temporal information and object oriented

techniques to explicitly define the relationship

between object behaviour over time (Khaddaj,

2004

). The ability to examine the continuity of

object changes is important for many different

applications.

The object oriented approach provides the

flexibility to make the changes to attributes and/or

behaviour of objects independent of one another, in

order to allow the examination of detailed

information of object application model. Therefore,

it can be used to identify the pattern of changes

within the objects. The simplest way to store

changes to objects is that every time a change occurs

the whole object is stored again, but this can be

prohibitively costly in terms of storage space, and

might compromise system performance particularly

if objects are updated regularly (fast changes). An

alternative is to use object versioning techniques in

order to track the evolution of objects. This paper

aims to investigate an object model for the

management of digital images that will represent the

semantics to allow the continuity and pattern of

changes of image objects to be determined over

time.

In this work we start by considering object

orientation’s major concepts and information

management. Then, object versioning is considered

for the development of the proposed model and is

used for the determination of the continuous links

between different versions of objects and

maintaining the metadata of those objects. An object

oriented image management model is then

considered together with an object-oriented

environment for system implementation. Finally, we

present some conclusions and suggestions for future

works.

Khaddaj S. and Hoppe A. (2009).

AN OBJECT MODEL FOR THE MANAGEMENT OF DIGITAL IMAGES.

In Proceedings of the 11th International Conference on Enterprise Information Systems - Databases and Information Systems Integration, pages 25-30

DOI: 10.5220/0001861000250030

 SciTePress

2 OBJECT ORIENTATION AND

INFORMATION

MANAGEMENT

The object-oriented approach has the abstraction

power to represent real objects. It represents space as

a domain populated with independently existing

objects that encapsulate attributes and operations.

Therefore, this encourages modularity within

information systems, while entity relationship

models will not show these properties. For example,

changes in an object do not necessarily affect the

properties of any other object in the system.

The object-oriented approach provides the

extensibility needed to create new models through

“inheritance” which also promotes hierarchies of

objects. It also provides the semantic power needed

to construct complex objects of similar states,

through “polymorphism”, for handling complex

attributes and behaviour changes, and the flexibility

needed to develop simulation models that can adapt

to the changing states of information systems. This

approach makes it easier to develop new software

from existing ones, thus, promoting reusability.

The object-oriented approach has been used

successfully for the unification of temporal and other

information related to objects. It is supported by

efficient design tools such as UML (Universal

Modelling Language), programming tools such as

Java, C# and C++, and Object Oriented Database

Management Systems (ODBMS) such as Objectivity

and Versant. The choice of a particular database,

however, clearly depends on the actual application.

A relational database is a better choice for a project

where relationships among objects are fairly fixed

and well known. Object-oriented databases can

outperform relational databases at handling complex

relationships among objects (Loomis, 1995

). The

problem becomes acute, however, when the changes

are too fast for a database to be redesigned so it can

rapidly deliver necessary information.

An object-oriented database could model the

presented changes based on a mix of objects and

their relationships. For example, if a real life object

is represented in object oriented form, rather than as

an entry in a database table, associations with other

objects (to which it is linked) can automatically

"inherit" any changes made, making it easier to track

later. At this point it is important to mention that the

Enhanced ER Model supports generalisation,

aggregation and composition. Moreover, many

object oriented features are provided by object-

relational database management systems

(ORDBMS) and are supported by SQL3 standard.

However, an ORDBMS does not represent a true

object oriented database, since it still represents a

data-centric system as a relational database.

The ORDBMSs, which have now been supported

by most vendors, are much larger and have huge

entrenched marketing infrastructure. By comparison,

the ODBMS vendors are much smaller. It is clear

that in today's complex, rapidly changing world,

ODBMSs provide the more flexible, extensible

alternative for companies that must act quickly to

match the capabilities of their information systems

with the needs of their organizations. Users will

make choices of database vendors based on many

criteria, some of which are addressed here.

3 OBJECT VERSIONING

Associating additional temporal information with

individual objects provides a means of recording

object histories, and thereby allowing the histories of

objects and the types of objects to be easily traced

and compared. This means that the temporal aspects

can also be described by their temporal topological

relationships. The object-oriented approach has been

used in different ways to effectively track versions

of the original object and these include the use of

version management (Wachowicz, 1994) and the

identity-based method (Hornsby, 2000). Although in

this work we are concerned with object versioning,

other strategies such as schema versioning can also

be considered (Grandi, 2002).

There are a number of methods for dealing with

object versioning (Khaddaj, 2004). The first

technique stores the complete objects, and any of the

versions can be accessed simply by a reference to

the particular object. The second approach, which is

a relative technique, stores one version as a complete

object and the rest of the versions are presented as

differences between the current version and the

previous version. The method of storing the versions

as complete objects is relatively easy to implement

in existing database systems. But, this method

introduces problems, such as waste of storage space

as the number of versions increases. The technique

of storing only one complete version and the rest as

differences between the current and the previous

version is difficult to implement but is suitable for

representing continuous and dynamic changes; and it

solves the storage space problem of the previous

approach. These two approaches have been

examined for relational databases (Dadam, 1984).

ICEIS 2009 - International Conference on Enterprise Information Systems

Using the second approach, changes of objects

are handled using version management, starting with

a generic object; then first and subsequent changes

can be represented as versions. Each version of the

object reflects changes of attributes and/or

behaviour. Subsequent changes of the versions will

generate related dynamic attributes and temporal

links to be updated to respective versions. Version

management reduces the need for large storage

space, since only the generic object or the current

object holds the complete attributes and behaviour of

the object.

3.1 Complete Versions

The first approach can be stated using the following

equation (1):

Versions(x)=(CV

(n), CV

(n-1),….., CV

)) (1)

In equation (1), CV

(n) represents the complete

version, n indicates the number of the version, x is

the object and n

is the oldest version number. Each

version can be accessed directly by reference to the

number of the version, n. Although access to any

version is supported directly and all versions have

similar access time, storage space can be costly.

3.2 Linear Versioning

Using this technique one version is stored as a

complete object, and the rest of the versions are

presented as differences between the versions

Khaddaj, 2004). The relationship using this

approach is based on one-to-one versioning of

objects, which means any parent or base object will

have only one child or derived object. The technique

can be classified into two versioning strategies. The

first strategy allows the current version to be

calculated from the previous version and is referred

to as forward oriented versioning. The second

strategy enables the previous version to be evaluated

from the current version and is referred to as

backward oriented versioning. Using forward linear

versioning the temporal relationships between the

generic object and versions is given by:

Versions(x)=(

(n,n-1),

(n-1,n-2),.. .,

+1, n

), CV

))

(2)

Where CV

) indicates the generic version,

which holds the complete attributes and behaviour.

(k, k’) represents the difference between the

current version (k) and the previous version (k’) of

object x. As shown in equation (2) access to the

current version n requires n-1 iterations, which

means that this strategy provides faster access time

for the oldest version.

In backward linear versioning the current object

holds the complete attributes and behaviour. The

temporal relationships between the current object

and versions is given by:

Versions(x) = (CV

(n),

(n,n-1),

(n-1,n-2), . .,

+1, n

))

(3)

As shown in the equation (3), the rest of the

versions are expressed as delta to the successor-in-

time version, which means that this strategy

provides faster access time for the newest versions.

As a result, this strategy is bound to be more useful

than the previous one for most applications.

…

n-1

Figure 1: Object versioning.

3.3 Branching

This technique is also classified into two versioning

strategies. The branch forward oriented strategy is

based on one-to-many object versioning (object

splitting), which means any parent or base object

will have many children or derived objects. The

branch backward oriented strategy is based on

many-to-one object versioning (object merging)

which means any child or derived object will have

many parents or base objects. The relationship using

the first strategy provides the same access time for

all versions:

Versions(x) = (∆

(n,n

), ∆

(n-1,n

), . . . .,

∆

+1, n

), CV

) )

(4)

The relationship using the second strategy

provides a faster access time for the current version:

Versions(x) = (CV

(n),

(n,n-1), Δ

(n,n-2), . .,

(n, n

))

(5)

However, due to the relationships between the

current version and the previous ones the values of

the versions are re-calculated whenever a new

version is created.

= Generic version,

…V

= Versions of the generic object

= Temporal topology link

AN OBJECT MODEL FOR THE MANAGEMENT OF DIGITAL IMAGES

Figure 2: Composite classes of a video object.

4 MANAGEMENT OF DIGITAL

IMAGES

Video images can now be generated and distributed

easily, but what is still needed is support in

managing the information contained in those images.

This is vital because by putting pieces of

information from different images together, the user

can generate new knowledge. The ability to

efficiently collect, store, manage, analyse, and

retrieve digital images remains a major issue.

4.1 Object Oriented Model for the

Management of Digital Images

Although there has been some work on using object-

oriented databases for storing and retrieving images

(Dönderler, 2003; William, 2001) not much

investigation has been done using the object oriented

approach in conjunction with the concept of object

versioning. To show the potential benefit of the

approach, it is sufficient to consider a typical CCTV

monitoring a car park where the background of the

scene does not change and the background object

can be stored in the database as a generic object, any

changes to the scene, for instance a car entering a car

park, can be stored in the database as versions

instead of storing the whole object, background and

changes, again (for simplicity at this point we are

assuming stable weather conditions).

Thus, in this work we are concerned with a

generic digital image management, context

independent, object model reflecting the structure

and semantic linking for different types of images.

The model should take into account issues like

image versions, notification and propagation of

changes. Of particular interest in this approach, are

scenarios when images are changing fast, and new

versions are created whether there is a need for time

stamping or not. Clearly, it is more useful when time

stamping is required, i.e. where there is a need to

keep a history of activities.

The development of a working system, using this

model, requires an intelligent video database that

provides automatic method of indexing and content-

based retrieving of images or video shots generated

by video-cameras based on the time they have been

recorded and the analysis of their features and

content. This can be used to provide an intelligent

database solution to the continuous logging and

annotation of events in public spaces and

environments. To achieve this we propose a new

object oriented video model. According to the

proposed model a video consists of a number of

shots. A shot is consecutive sequence of frames,

which are the smallest unit of video data. A frame

consists of a number of physical objects, static like

building, car park etc. and dynamic objects such as

persons, cars etc. Considered classes include the

events, processes and the versions class which is

fundamental to the system (figure 2).

Physical

Temporal

Version, Events and Processes Classes

Aggregated Link

Associated Link

Frame Object Class

Clip Object Class

Video Object Class

Spatial

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Using the versioning approach a frame object is

represented as a generic object, the first object and

any subsequent changes can be represented as

versions. Each version of the object consists of

changes (involving an attribute or behaviour) of the

aggregated and the associated classes. Subsequent

changes of attributes of the versions will generate

related dynamic attributes and temporal links to be

updated to the respective versions. The relationships

between the generic object and the versions of the

object are represented by temporal version

management approach (Khaddaj, 2004). To avoid

the use of large storage space, only the generic

object or the current object holds the complete

attributes and behaviour of the object whiles the

other versions represents the changes of their

attributes and behaviour. While MPEG-7 defines a

large set of description classes for multimedia

content-encoding schemes, it is considered

complementary to, rather than competing with, data

models such as the one proposed in this project.

Moreover, the query technique of the system will

be classified into different parts in order to identify

the attribute and behaviour changes to the classes

and objects of the model. This will provide support

of different types of queries such as spatio-temporal,

semantic and low level features (color, shape etc.)

queries on video data.

4.2 System Implementation

A successful implementation of the model will

require an Object Oriented Programming

Environment (OOPE) and an Object Oriented

Database System (OODBS). This approach

eliminates the need for mapping the model to an

OODBS, since the class structure used in the model,

the OOPE and OODBS are consistent. The OODBS

considered in this work is based on Objectivity/DB

(Objectivity, 2000). The classes are defined in the

application schema file, called Data Definition

Language (DDL). The DDL processor generates the

schema header file and the schema source code

which are linked with the application source code. In

the application DDL and application source code

files, all the classes have their own representation.

Objectivity/DB has the capabilities to represent

the various versioning approaches: linear, splitting

and merging. Image objects persist by storing the

object within the container of the database.

Persistent objects are identified using the object

identifier (OID) which remains unique within a

federated database. Objectivity/DB uses an object

handling class to access persistent objects

automatically by the DDL process for every

persistence class found in the schema header. All the

objects can be determined by scanning through the

database using iterative scanning functions.

Schema

Application

atabase

Federated Database

DDL

ocessor

Compiler / Linker

Application Program

Application

Source Code

Figure 3: General architecture of the System implementation.

Schema

Header

Application DDL

Schema

Schema Source

Code

AN OBJECT MODEL FOR THE MANAGEMENT OF DIGITAL IMAGES

Aggregated relationships between the classes are

established in the application source code.

Moreover, in order to determine and analyse

dynamic changes, the model establishes a temporal

relationship between the versions, the event and the

manager classes. A dynamic function handles the

temporal relationships between the versions, the

event and the manager classes.

Moreover, the relationships between the versions

allow forward and backward movement. The

previous version and the next version to the current

version can be obtained by iteration using either

backward or forward movement functions. In order

to avoid the use of large storage space, only the

generic object or the current object holds the

complete attributes and behaviour of the object

while the other versions represents the changes of

their attributes and behaviour.

5 CONCLUSIONS

The applications of object oriented techniques to the

management of digital images have been discussed

in this paper. Particular attention was paid to the

concept of object versioning and its applications.

The presented object oriented approach provides an

integrated framework for effective tracking of the

evolution of image objects. It also promotes good

temporal modelling, because the temporal attributes

and behaviour of the versions are independent but

have relationships that enable the tracking of

patterns of change. Also, less data storage is

required since only the generic object and its

versions are stored.

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