Shape-Enhanced Surgical Visualizations and Medical Illustrations
with Multi-Flash Imaging
Kar-Han Tan,
James Kobler,
Rogerio Feris,
Paul Dietz, and
Ramesh Raskar
In many medical applications like minimally invasive surgery with
endoscopes it is often difficult to capture images that convey the 3D
shape of the organs and tissues being examined. Perhaps for the same
reason, medical textbooks and articles frequently resort to hand drawn
illustrations when depicting organs and tissues.
We propose the use of multi-flash imaging to address this problem. We
present a novel approach for enhancing images and video used in endoscopic
surgery so that they are better able to convey shape. Multi-flash imaging
utilizes multiple light sources strategically positioned to cast shadows
along depth discontinuities. We describe designs for achieving multi-flash
imaging using multiple endoscopes as well as in single endoscopes.
Multi-flash photography can also be used for creating medical
illustrations. By highlighting the detected edges, suppressing unnecessary
details, or combining features from multiple images, the resulting images
convey more clearly the 3D structure of the subject. The method is easy to
implement both in software and hardware, and can operate in realtime.
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Building Multi-Flash Cameras
Capturing Depth Edges with Multi-Flash Imaging
Depth Edge-Enabled Visualizations
The image sequence captured with multi-flash cameras can be used to create a shadowless image. The depth edges recovered not only spatially localize the depth discontinuities, but are also signed to indicated the direction of the depth change. Approximate 3D surface normals can also be hallucinated by interpolation from the edges.
Multi-Flash Imaging With a Single Endoscope
Endoscopes with fiber optic illuminators can be converted into multi-flash devices by selectively turning on and off subsets of the fiber bundle. On the right, a simulated lesion was highlighted with
depth edges.
Medical Illustrations
Multi-Flash Cameras based on handheld consumer digital cameras can be used to
easily create comprehensible, realistic medical illustrations. Depth Edges are
generally more meaningful than intensity edges as they correspond to actual 3D shape features.
References
1. K.-H. Tan, J. Kobler, R. Feris, P. Dietz, and R. Raskar. Shape-Enhanced Surgical Visualizations and
Medical Illustrations with Multi-Flash Imaging. In Proceedings International Conference on Medical
Image Computing and Computer-assisted Intervention (MICCAI). 2004.
PDF
2. R. Raskar, K.-H. Tan, R. S. Feris, J. Yu, M. Turk. Non-photorealistic Camera: Automatic Stylization with Multi-Flash Imaging. In Proceedings SIGGRAPH 2004, and ACM Transactions on
Graphics 23(3) July 2004. PDF:
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