iJiao

Exhibition by: City University of Hong Kong (CityU), Applied Laboratory for Interactive Visualization and Embodiment (ALiVE).
Exhibition period: 9-27 October 2011.
Exhibition venue: Gallery, Hong Kong Central Library.

The following briefly documents some of the technical aspects of the playback system for the iJiao exhibition, created by the Applied Laboratory for Interactive Visualization and Embodiment (ALiVE) at the City University of Hong Kong (CityU), and exhibited at gallery at the Hong Kong Central Library. An overview, by Sarah Kenderdine (exhibition manager), of the iJiao exhibition is given below.

About iJiao

In October 2011 City University will contribute an exceptional interactive panoramic video installation to a major exhibition at the Central Library focused on Mainland and Hong Kong Intangible Cultural Heritage, Genesis and Spirit: A Showcase of Intangible Cultural Heritage of China.

iJiao incorporates 360-degree videos sequences from a series of Taiping Qingjiao (also known as dajiao or Jiao Festival) into the iDome hemispherical projection system. The festivals, held throughout Hong Kong, appease the ghosts and give thanks to the deities for their protection. They take place every year or every five, eight, or ten years, depending on local customs. The religious rituals involved are meant to purge a community and prepare it for a new beginning. iJiao encapsulates a unique record of these auspicious events and allows the visitor to the installation experiences of the rich cultural activities that surround dajiao.

Conceived and produced in 2011 by City University of Hong Kong Applied Laboratory for Interactive Visualization and Embodiment (ALiVE) in conjunction with the Hong Kong Heritage Museum. Production team: Paul Bourke, H.W. Chau, Li Chongyu, Dr Robert Ellis-Geiger, Dr Sarah Kenderdine, Joe Leung, Dr Cedric Maridet, Alex Ngan, Beatrice Wong, William Wong, Tiffany Yu.


The thanksgiving performances of shengongxi performed
during the Jiao Festival are primarily Chinese operas.
iJiao © CityU ALiVE 2011.

About the Exhibition

The "Genesis and Spirit - Intangible Cultural Heritage of China" exhibition will be jointly presented by the MoC and HAB, and co-organized by the China National Center for Safeguarding Intangible Cultural Heritage and LCSD. It sets out to strengthen exchange and cooperation between the Mainland and Hong Kong in safeguarding of ICH and to showcase the richness of the country's living heritage. The exhibition looks at the historical development and safeguarding measures for the Mainland's intangible cultural heritage and introduces the safeguarding work undertaken in Hong Kong since the enforcement of UNESCO's Convention for the Safeguarding of the Intangible Cultural Heritage in April 2006. Exhibits from both the Mainland and Hong Kong will be on display. National intangible cultural heritage bearers () will also perform live demonstrations at the exhibition venue. The exhibition has been earmarked one of the major programmes of ACCF 2011 and it will be staged in the exhibition galleries of HKCL from 9-27 October 2011.

The filmed material for iJiao is captured using the LadyBug-3 camera, namely 360 x 150 degree video capture. Sample frame shown below, note the lower 40 degrees are cropped off the movie frames in the interest of performance, the lower 40 degrees are not visible in the iDome.


Sample frame from the LadyBug-3 camera, truncated at -40 degree latitude.

The spherical panoramic movies are presented in the iDome, the imagery is corrected so as to present an undistorted view using the techniques presented here. The user can freely pan around within the video [Quartz Composer composition by Paul Bourke]. The ambisonic audio recordings are processed using VBAP (Vector Base Amplitude Panning) such that they track the panning [MaxMSP implementation by Cedric Maridet].


View of the iDome (during development)

Quartz Composer (QC) was chosen for the playback due to its support for a number of required features.

  • The realtime mapping from spherical panoramas to warped fisheye is supported by a QC patch called pbmesh.

  • The panning of the ambisonic audio recordings is accomplished with MaxMSP, the angle of the view is transmitted to MAXMSP by the Quartz Composer OSC patch.

  • Realtime graphics performance to playback 4000 pixel wide movies.

  • Support for the Space Navigator 6DOF mouse. The SpaceNavigator is used to pan horizontally and to select the next movie sequence.


View of the Quartz Composer patch generating the warped fisheye for the iDome projection environment.