Chapter 8. 3D Interaction for Digital Libraries
8.4. Research collections and research interfaces
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exhibitions of precious texts (for example, the exhibition of Leonardo da Vinci’s manuscripts at the Louvre). A more sophisticated animation based on the physical characteristics of a bent piece of paper has been described in [CHU 04, WIT 03].
The page-turning associated with a 3D representation of pages remains to be studied.
Figure 8.8. The tripod in page-turning mode
The proposed design for the lectern is clearly arbitrary. Due to the performance of the 3D structure we have limited the design to basic geometrics, and the analogy with a conventional window on a computer screen. The main advantage of the device (in comparison to those suggested in [CAR 04] and [CHU 04]) makes it possible to have a large number of lecterns within the same work session. The device also completes the lecterns by adding research and navigation tools to the collections of books.
3D Interaction for Digital Libraries 135 (Library of Congress). None of these could satisfy a contemporary reader like Alberto Manguel [MAN 98]:
Whenever I choose a book to read in bed or to place on a lectern, to give to someone or to read on the train, my hands take into consideration the shape as much as the contents of the book. Depending on the occasion or the location where I have decided to read I prefer something small and intimate, or ample and substantial. Books assert themselves because of their titles, their authors, their positioning in catalogs and libraries, the illustrations on their covers and also by their size. Depending on the time period and place, I have become accustomed to seeing books appearing in all shapes and sizes, and as in all types of fashion these ever-changing aspects add a certain characteristic to the definition of what a book is. I judge a book by its cover, I judge a book by its shape.
Figure 8.9. An extract from three digitized libraries (pages of catalogs)
In practice, the search mode is always associated with a search engine, a function which has been judged as essential as soon as the corpus reaches a certain level. As sophisticated as this function is, it is only useful for the user who already has a preconceived idea of what they are going to research: it is therefore not possible to lounge around in a digital library.
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It is quite easy to complete the text interfaces of research tools by adding a much more graphic function, for example by digitizing the spine of a book to its respective dimensions, as can be seen in Figure 8.10. However, for the websites mentioned earlier this information was not gathered during the design of the websites. It is also believed that in most cases it is not possible to distinguish between books just by looking at the cover. From information that relates to the physical make-up of the books (page numbers, publication dates) it would perhaps be possible to construct a more abstract interface relying on a “grammar” of predefined shapes for which an inventory would need to be established. A similar approach was used in the Libviewer project [RAU 00]. In this system, the metadata is accessible and the result of the research requests is displayed in the shape of 3D bookshelves. These interfaces have the disadvantage of not being able to simultaneously display a large number of volumes. Of course, a zoom function is feasible but its use in a 2D graphic context does not allow for fluid navigation. Here we meet the limits of the WIMP process mentioned in the previous section.
Figure 8.10. An alternative visual interface (http://jasmin.cnam.fr:8081/REL/)
Carrying out a search in a library using virtual reality techniques has been investigated by several teams. One of the first 3D representations of an existing library (with VRMC) was created at The Institute of Research and Musical/Acoustic Co-ordination (L’Institut de Recherche et Coordination Acoustique/Musique or IRCAM) [FIN 00]. Similar experiments have taken place at the National School of Mining Engineering in Nantes [PLE 01] and at the University of Karlsruhe [CHR 02]. In these interfaces the organization of the actual library is respected (study and work rooms, shelving areas, even corridors and stairs). Beyond their undeniable asset as a communication tool, such processes also have limits. Navigation from one
3D Interaction for Digital Libraries 137 virtual room to another is time-consuming (it is impossible to imagine how such an interface would represent the François Mitterrand library in Paris). Furthermore, all of the collections which can be digitized are not strictly accessible to the public, nor are they linked to a specific establishment. In [FOX 97] a summary is given of the experiments carried out for the 3D navigation on a national scale of a large corpus of digitized theses.
In [CUB 98b] we have presented an interface of the same type for users of the CNUM. The users of this library can navigate in VRML scenes which represent large virtual bookshelves. Several structures have been studied: mainly linear or helicoid structures. A cylindrical-shaped structure is all that is required to ease navigation within a scene. In such a scene (Figure 8.11), the user can pivot the view point and move it in order to zoom towards the bookshelves. The organization of the collection of books can also be reconstructed according to the user’s needs. In this case the view point is positioned to the books or collections of books corresponding to the user’s request, whilst the remainder is placed “behind” the user. For requests with two criteria (for example, date of publication = 18th century AND subject = electricity) rotating the view point shows the books which answer the first criterion whilst the vertical axis enables the user to navigate through the collection according to the second criterion. These two movements can be easily carried out with an ordinary mouse.
Figure 8.11. A VRML scene for virtual shelves. The selected book appears in the foreground (on the left). Criteria of shelf classification (on the right)
The virtual bookshelf can be inserted into the general reading interface in several ways. However, a compromise must be found in order to try and avoid too much information appearing on the screen at once (which tends to disperse the objects from the scene), and reduce the navigation time in the scene (which gets longer if
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the objects on the shelves are far from one another). Figure 8.12 is a reproduction of the organization of the 3D scene which is quite similar to that of Web Forager [CAR 96].
Figure 8.12. The entire collection is shown and accessible at the back of the screen.
The favorite books or basket are available in the foreground
The collection of books is always visible in the background and zooming into the bookshelves does not affect the positioning of the lecterns. It is understood that with this layout the screen overloads as soon as some of the lecterns are activated and a large number of the bookshelves become invisible. A wider scene therefore needs to be defined. In Figure 8.13 the zone of movement of the lectern is organized in the shape of a disk around the user. By rotating the lectern 180° on the Y axis the screen moves from the area of the lectern to the area of the bookshelves. There is also the possibility of positioning the lecterns in front of the bookshelves. Other organizations are possible. In [CUB 01] and [CUB 02] alternative designs have been suggested.
A demonstration (based on Opengl) was presented to NITC professionals during the JFT 2003 and ECDL ’03 conferences; see [CUB 03] and [DUP 03] respectively.
A wider audience was attracted to the general public exhibition known as Image by Image (Montreuil, March 2003) and to the National Science days in which the CNAM participates. At each of these exhibitions we had a stall dedicated to the 3D workshop and another stall which enabled the general public to have access to the
3D Interaction for Digital Libraries 139 CNUM website. The sessions were limited to a few minutes by a timer and the users’ actions were recorded. From these demonstrations we have been able to conclude that the users are able to use and manipulate the lecterns within a short period of time. The page-numbering function was widely accepted by the general public and by librarians (but not always by professional computer scientists). Some modifications from the designer have been necessary. The extent to which the lecterns could be moved was limited: a lectern cannot be larger than the screen nor can the lectern be minimized on the screen. The detection of any collision between objects has improved, as has the lighting and the reproduction of shadows.
Figure 8.13. The organization of a workspace for reading and for carrying out research within a collection of books