Biomedical Engineering Reference
In-Depth Information
1. A projection of the point P on the sensor plane in the circle relative to cone 1.
2. A projection of the point P on the sensor plane in the circle relative to cone 2.
3. Two projections of the point P on the sensor plane, that is, each twin laser beam makes
a projection of the particle on the CCD array detector.
The last situation is interesting because we demonstrate that it is possible to find the path of
a point P A ( C 1 ,
2 ) using the information on the projections' coordinates, by the
knowledge of the position of the two vertices C 1 , C 2 . Suppose that the projections' of P in
the two circles are the points P 1 ( x p 1 , y p 1 ,0) and P 2 ( x p 2 , y p 2 ,0), respectively, the point P can be
estimated as
Ω
1 )
-
( C 2 ,
Ω
P 5 C 1 P 1
-C 2 P 2
(10.5)
where AB denote the segment joining the points A ( x A , y A , z A ) and B ( x B , y B , z B ):
8
<
x 0 5 x A 1 l x t
y 0 5 y A 1 l y t
z 0 5 z A 1 l z t
(10.6)
:
where ðx 0 ; y 0 ; z 0 Þ A AB;
t A [0,1] and l ð U Þ 5 ð U Þ B 2 ð U Þ A .
(A)
Estimated path
Real path
(B)
200
200
100
100
0
0
-100
-100
-200
-200
-200
-200
-100
-100
-2.5
0
0
-2
-2
-1.5
0
× 10 4
× 10 4
100
100
-1
-0.5
2
x (pixels)
x (pixels)
200
z (pixels)
200
z (pixels)
0
Figure 10.9
Comparison between real and estimated path for (A) linear and (B) coil paths.
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