Figure 1: Postcards from Ayutthaya
Populating the City
Many virtual reality visualisations of heritage precincts present the site as a depopulated theatre set; indeed the addition of human figures, especially moving ones, presents many difficulties. Computer generated figures very often look computer generated, the level of realism needed to remain in context with the rendered scenes is difficult to obtain. However video production techniques used in television and computer games offer the opportunity to add 'live' actors into sequences of computer graphics. The opportunity arose to adopt this approach in this project.
The use of 'chroma-keying' is now commonplace in the video special effects industry, being used in such mundane applications as evening news broadcasts and high level applications like movie and computer games special effects. The process works on replacing one particular chroma or colour in one image or image sequence with another image. The colours used are commonly the blue or green channels as these two colours are very different to human skin tones. The foreground object or actors are filmed against the single colour background, and them 'matted' into another video sequence comprising either live footage or computer graphics. The most well known use is in television weather broadcasts where the presenter appears in front of the weather chart, in reality the presenter is in front of a blue wall and the weather details are mixed into the scene before broadcast.
This process has been used to add traditional dancers and musicians into the audience chamber of the Grand Palace at Ayutthaya. Two dancers, six musicians, a conductor, 3 make-up artists, 4 riggers, a catering crew, a producer and translator, and a person with the cans of blue paint were engaged for a filming session in a large photographic studio in Bangkok. Digital video was acquired of the dancers performing a dance from the Ayutthaya period against the blue screen, and CD quality audio of the accompanying music was recorded. This video was later transferred into a computer, and composited with rendered computer graphic sequences from the Ayutthaya model.
Figure 2: The chroma key studio
Figure 3: The dancers and orchestra at Ayutthaya
