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Active Shadows: A Tool for Collaborative Rich Media Creation


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Collaboration is essential aspect of  rich media creation where many different talents from different sources can be fused together for a single purpose.  To have such varied individual working together, we need to have a way of transporting their work and the presence in their work over the network.  For this purpose, we invented the Active Shadows algorithm that produces a digital shadow of a real person that becomes their "digital" representation and integrate their presence into rich media communications. 

The Active Shadows algorithm produces low latency (under 200ms) and high quality video object segmentation of a person, occluding a computer-controlled display of any type (LCD, projector, CRT, plasma) in front of video camera device. This algorithm sets up a causal video feedback loop that can resolve ambiguous visual occlusions by adaptively modifying the displayed image in real-time. These real-time modifications to the display manifest themselves as if the camera were a virtual light source and was casting a reverse shadow onto the display. Active Shadows gives the same output as a chromakey system except that the user is physically interacting with the displayed image, instead of a colored background. With this setup, the system produces segmented video at approximately 5 fps and seamlessly composites presentation slides and segmented video of the speaker to create a multi-layered video representations.

For more technical details, please refer to the following paper:

I.J. Lin, "Active Shadows: Real-time Video Object Segmentation in a Camera-Display Space," IEEE International Conference on Multimedia and Expo (WIAMIS 2004), Lisboa, Portugal, June 2004.  


For more information about the technology, please contact I-Jong Lin (i-jong.lin @ hp.com) at New Media Group of Imaging Technology Dept., HP Labs.

Printing and Imaging Research Center
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Background Interaction Image

Raw Camera OutputReal Time Segmentation Output from Active Shadows

Rich Media Presentation Capture

Click here for a sample of Active Shadows output Click above for a sample of Active Shadows output (30MB MPEG)

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