The Charter on the Preservation of Digital Heritage of UNESCO defines digital heritage as embracing “cultural, educational, scientific and administrative resources, as well as technical, legal, medical and other kinds of information created digitally, or converted into digital form from existing analogue resources”.
Cultural heritage is not just the traces of past society and past times, but also includes the evidence of the present ones, which needs to be preserved for our progeny as well. The digital technologies offer modern tools for cultural heritage preservation and also play a crucial role for key issues such as providing access, interaction and sharing knowledge.
Cultural Heritage can be distinguished into three types:
- Built Environment (Buildings, Townscapes, Archaeological remains)
- Natural Environment (Rural landscapes, Coasts, Agricultural heritage)
- Artefacts (Books & Documents, Objects & Pictures)
Role of Digital Image Processing
The use of image processing techniques for the analysis, diagnosis, and restoration of artworks remains a rare practice. However. recently there has been an interest in acquiring and processing digital data of artworks. The field of digital processing for cultural heritage encompasses a variety of topics:
- High resolution 2D and 3D digital capture and rendering of artworks.
- Digital Restoration, Enhancement, and Recognition of artworks.
- Classification of features, structures and content in cultural heritage visual data.
- Creation of large-scale multimedia databases.
Some of the major applications of image processing in preservation of cultural heritage are discussed briefly.
Cultural Heritage Image Acquisition
Archiving, retrieval and dissemination closely followed the exact replication of artworks being the biggest benefactor from the digital format. Most of the museums, archives, and libraries are engaged in direct digital image capture of cultural heritage.
Depending on the application’s requirements, the image acquisition devices use passive or active detection schemes and several kinds of sensors and radiation sources (lasers, LEOs, X-ray tubes). However, most of the current developments are concentrated on processing the visible and near IR range images.
Watermarking for Authentication and Compression of Cultural Heritage Images
Hard Authentication techniques often falsely identify data passed through diverse distribution chains and content-preserving operations such as compression, transcoding etc as inaccurate. Recently there has been a movement towards Soft-Authentication schemes which distinguish content-preserving processing from unlawful content-changing manipulations. One such tool-set is semi-fragile digital watermarking which provides authentication and compression of Cultural Heritage Images.
Virtual Restoration of Artworks
Image-processing techniques can either be used as a guide to the actual restoration of the artwork (computer-guided restoration), or they can produce a digitally restored version of the work (virtual restoration). However, on a virtual representation of the artwork, many more options are possible.
- The crack removal is a straightforward application which proved to improve the readability of the image to a significant extent.
- Virtual cleaning is another application, helping in the complicated removal task of varnish from the paintings which make paintings illegible as they age.
- The virtual recomposition of fragments of a painting, joining parts of paintings which are now hosted in different museums or are lost but reproduced in some old postcard.
Cultural Heritage Content Fruition
The birth of virtual art gallery and museums enable artists to showcase their masterpieces globally. Digital reproductions of artworks belong to the legal owner, similar to real artworks. But these images are at risk of illicit use, consequently arising the need of a simple yet effective way to counter it. Digital watermarking is one such possibility.
Preservation Challenges For Digital Collections
The Library faces challenges in digital preservation that are widely recognized and widespread. They include the following:
Fragile storage media: Digital materials are especially vulnerable to loss and deterioration owing to being stored on fragile magnetic and optical media susceptible to exposure to heat, humidity, airborne contaminants or man-made errors.
Technology obsolescence: Digital materials become unreadable and inaccessible if the playback devices or the digital to human- readable format translator become obsolete.
Legal questions surrounding copying and access: Libraries, archives, and other cultural institutions have limited rights to copy digital information for preservation purposes, to reformat information to remain accessible by current technology, and to provide public access.
Indian Digital Heritage
In 1972, the General Conference of UNESCO adopted a resolution, creating a ‘Convention concerning the protection of the World Cultural and Natural Heritage’. The main objectives were to enlist Sites and Monuments from the member countries which are of exceptional interest and universal value, and to preserve these universal treasures for future generations.
There are 32 World Heritage Properties in India, 25 of which are Cultural Properties and 7 are Natural Properties.
Recent Application in India
Indian Digital Heritage Project is a unique initiative of the Department of Science & Technology (DST), Government of India, supporting collaborative projects between researchers in the areas of Technology and Humanities for the digital documentation and interpretation of our heritage. The project highlights the art, architecture and cultural legacy of the world heritage site of Hampi in Karnataka, the medieval capital of the Vijayanagara dynasty.
In a first of its kind project, a team of experts from premier institutions like IIT made a 3D imagery of UNESCO World Heritage Site Hampi, enabling people to experience the rich cultural heritage of the ancient city in Karnataka. A mobile app has also been developed, the users of which can see the now ruined original Hampi Structures.
FUTURE : Smart cities in India
In the age of experience, digital heritage is a competitive advantage for cities. There is tremendous potential in India to build an effective ecosystem to enable its expanding urban areas to become smart and sustainable by using digital technology.
Cities are the most complex objects that man created. They can’t be treated simply as products. This is why, in the world of tomorrow, no city will be designed or managed without the help of virtual worlds.
This breakthrough is set to revolutionize all aspects of the way cities are developed and managed, including urban services, infrastructure, security and natural disaster mitigation. Dynamic digital models of cities make it possible to simulate scenarios and create experiences in order to find sustainable solutions to all these challenges.
The main obstacle to the application of image processing technologies to the art field is represented by a cultural distance between technical researchers and researchers belonging to the humanistic area. In spite of these difficulties, there is a clear demand for new computational tools to help know more about works of art. Hence the application of image processing to the study of artworks will be one of the most interesting image processing research areas in the coming years.