Biomedical Engineering Reference
In-Depth Information
system and Micro Technica MTPCI-DC2 as video capture boards.
This enabled to load video frames of 640 × 480 pixels to a dynamic
memory array every 15 ms. The video frames were captured and
processed in different computers for each plane, and they were
synchronized through TCP/IP. For this analysis, we use a region of
interest of 640 × 260 pixels containing the entire blood vessel model
(Fig. 4.25).
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Top View
Polariscopes
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Target
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b)
a)
Figure 4.25 (a) Bi-planar vision system for real-time catheter trajectory
analysis adapted for a carotid artery vasculature model. (b)
Example of the captured images with the bi-planar vision
system, showing the catheter inserted from the start point to
the target branch.
4.11.2 Filtering
To distinguish between these three regions we use two static images
for each plane. For the XY-plane, L XY,i,k is the frame number k of a
trajectory video L XY,i ( i , k N ), the optical path length image D XY
and the irst frame of the studied trajectory L XY,i, 0 . The irst one is
used to calculate the stress value, D XY is deduced from the blue light
transmittance. For preventing noise in this image we calculate the
noise indicator S x,y for each pixel of D XY :
 
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