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Bernal S D_2010.pdf - University of Plymouth

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4.2. ARCmm^TVRES<br />

S3<br />

I<br />

C2<br />

s<br />

f<br />

S2<br />

o o<br />

O I .<br />

P(C2 I S3)<br />

4 nodes<br />

I<br />

(= 60 objects)<br />

9 nodes<br />

Kc} states<br />

P(S2b„..«,».|C2)<br />

OS lo o|p jo o!0"lo OS "to oo to ojfl to o;6 lo o<br />

o-<br />

Ol Ol<br />

O:<br />

o o<br />

E „M<br />

o o<br />

E„ = 3<br />

0 O O O o o<br />

E i, = 8<br />

o b<br />

o o iu-* Ej=5<br />

2,253 nodes<br />

(=1000<br />

features)<br />

Figure 4.5: Bayesian network reprodueing the shaicture and functionality <strong>of</strong> a modified version<br />

ol' the :Mevel HMAX model (Serre c1 al. 2()()7c), The variation consisis <strong>of</strong> a<br />

reduced pooling range (RF size) at the lop layers C2 and S3 and was introduced<br />

to try to improve the recognition <strong>of</strong> the translated set <strong>of</strong> inpui objects. Only ihosc<br />

layers a hove S 2 are shown, as layers SI and CM are equivalent to the previous version.<br />

The numher <strong>of</strong> nodes at each layer and hand depends on the size <strong>of</strong> the input<br />

image and Ihe pooling (AN) and sampling (r) parameters. The figure shows ihe<br />

total numher <strong>of</strong> nodes at eaeli layer, assuming an input image ol 160x160 pixels<br />

and the parameters defined hy Table 4.:^. Fach nixle in Ihe network has an a-ssiKialed<br />

CPT which links it wiih ii.s parent nodes. Similarly, each node perform.s the<br />

same internal operations, shown in Figure 4.^. which correspond to the distributed<br />

implementation <strong>of</strong> belief propagation.<br />

154

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