Two- and three-dimensional works Digitization

- The preservation of the valuable information contained in images, photographs, works of art, books, newspapers, drawings, maps, posters, manuscripts, cinematographic works, etc. Some of the above-mentioned objects are destroyed by the ravages of time or an event, while others are altered. Intangible cultural goods, such as traditions and myths, are lost over time. Digitisation creates digital substitutes for tangible and intangible assets, preserving the valuable information they contain.  

- The role of cultural goods is enhanced, since the information they contain can be found more easily and in combination from different sources and is available for research, study, education, etc. 

- The promotion (which also makes a decisive contribution to the aforementioned reinforcement) of cultural goods, through the Internet, but also through the production of electronic publications (CDs, DVDs, applications, special offers) on education and culture, the production of printed material (e.g. books and posters) and other presentations/events. 

- Economic development through both the promotion of cultural goods and the exploitation of cultural content in vast markets such as education, entertainment and tourism.

In more detail, the digitisation lifecycle is all the necessary actions that an organisation takes to achieve the digitisation of its cultural content. The cycle starts with the initial planning, extends to the digitisation of the objects themselves and ends with issues of promotion, long-term preservation and re-use of the digital content. The stages of the life cycle are discussed below:  

- Planning the digitisation project: This is the first step in any digitisation project. Each project must have clearly defined objectives, sufficient resources, appropriately trained staff, and a plan for implementation (whether to outsource, how to deal with potential risks, etc.).  

- Choice of content: In the majority of projects it is not feasible to digitise all the objects of an organisation. It is therefore necessary to select the objects to be digitised. The criteria for selection vary according to the objectives of the digitisation project, the sensitivity of the content, geographical criteria, etc.  

- Preparation for digitisation: An appropriate hardware and software infrastructure and an environment with suitable conditions should be in place before the digitisation process starts. The elements that make up such an environment include equipment for the digitisation process itself (for example scanners, digital cameras, audio and moving image digitisation equipment, etc.), a computer system to which these devices will be linked, image processing software, software for managing the digitised material, etc. The environment in which the digitisation process will take place must be suitable for the objects to be digitised, for example it must meet specific lighting and humidity conditions.  

- Treatment of originals: This stage in the life cycle of the digitisation process may seem obvious, but a detailed presentation is unavoidable, since many digitisation projects involve objects that are rare or fragile. It is therefore necessary to ensure that the negative consequences of digitisation are minimised.

- Digitization: This stage refers to the digitisation process itself, i.e. the scanning, digital photography and generally the digital capture of the originals in combination with any digital processing they may undergo. In the context of this thesis, the digitisation of almost all categories of cultural objects (2D and 3D objects, audio and moving image documents) held by Greek cultural organisations is covered. 

- Preservation of digital content: An important objective of any digitisation project is to protect and ensure access to the digital content created. To achieve this, it is necessary to address issues such as obsolete file types and storage media, but also to protect digital content from natural disasters, environmental factors and human interference. At the same time, the issue of long-term preservation has also been the subject of research in recent years.  

- Metadata: Metadata is an issue under continuous research activity in the field of digitisation, content management, reuse and search of digitised content, interoperability, etc. The set of metadata selected for a project is of particular importance for its progress, since the characteristics to be recorded for the description of the originals depend on it.

 

- Actions of promotion - visibility: The project has now reached the stage where the creation and storage of the digital copy and its metadata has been completed. The next stage is the presentation and promotion of the digitised content. Before the digital objects can be displayed, they must be properly processed. The display of the content may involve displaying it on the Internet, on a CD-ROM or DVD-ROM, etc., and the processing involves downgrading the quality, and therefore reducing the size, of the image, sound and animation files so that users can access the digital content via the Internet. Copyright: The publication of digitised content should be accompanied by a broad analysis of the copyright situation of the material. For publicly available material the issue is not very complex. However, many cultural organisations benefit from the publication of cultural material, so that they have to be particularly careful about copyright, which may belong to third parties. Copyright protection and management technologies support institutions in this process. 

- Management of digitisation projects: The success of a digitisation project, like any project, depends to a large extent on its management. A well-organised project management plan makes a major contribution to the success of the project. 

The digitisation process for two-dimensional objects can be divided into two methods that require different equipment: scanning and digital photography. Similarly, there is appropriate equipment for three-dimensional digitisation and digitisation of sound and moving images. Specific guidelines and good practices on the choice of each of the above-mentioned types of equipment are given below.
 

Three-dimensional digitisation systems  

 

3D digitisation requires specific systems based on different techniques. Each of them has specific advantages and weaknesses. Most commercially available systems can be categorised as follows: 

1. Laser beam scanners: These are the most popular 3D digitizing systems, as they give very accurate geometric results and can be applied in many situations. 

2. Pattern projection scanners: These scanners can automatically digitise objects that provide both geometric and textural information and are ranked as the second most popular systems. 

3. Photographic scanners: There are very few commercial systems available, but some of them allow free photography of objects up to a few metres in size.  

4. Coordinate measuring systems with touch sensors: As in the above category, commercially available systems are scarce. However, they have the advantage that their effectiveness is unaffected by transparent and reflective surfaces. On the other hand, they face problems in capturing complex objects, as there are points where the sensors cannot reach.