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Artificial Intelligence and Soft Computing: Behavioral ... - Arteimi.info

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2<br />

µshade(bj k) = e -a x , where x = σ 2 , a>>0<br />

2<br />

µedge(bj k) = 1-e -b x , where x = σ 2 , b>0<br />

µmixed-range(bj k) = cx 2 / (d+ex 2 +fx 3 ), where x = σ 2 , <strong>and</strong> c, d, e, f > 0.<br />

The membership distributions with respect to Gdiff <strong>and</strong> Gavg have also been<br />

defined analogously. Table 23.1 below presents the list of membership<br />

functions used in this chapter.<br />

PARAMETERS<br />

Gavg<br />

Gdiff<br />

σ 2<br />

Table 23.1: Membership functions for features.<br />

Mixed Range<br />

Membership<br />

(ηx 2 )<br />

(ρ+θx 2 +ϕx 3 )<br />

η,ρ,θ,ϕ > 0<br />

αx 2<br />

(β+λx 2 +δx 3 )<br />

α,β,λ,δ >0<br />

cx 2<br />

(d+ex 2 +fx 3 )<br />

c,d,e,f > 0<br />

Edge<br />

Membership<br />

-8 x<br />

1-e<br />

2<br />

1-e -bx<br />

2<br />

1-e -bx<br />

b>0<br />

Shade<br />

Membership<br />

e<br />

2<br />

-a x<br />

4<br />

e -ax<br />

-a x<br />

e<br />

a>>0<br />

The membership values of a block b[j, k] containing edge, shade <strong>and</strong><br />

mixed-range can be easily estimated if the parameters <strong>and</strong> the membership<br />

curves are known. The fuzzy production rules, described below, are<br />

subsequently used to estimate the degree of membership of a block b [j, k] to<br />

contain edge (shade or mixed-range) by taking into account the effect of all<br />

the three parameters together.<br />

Fuzzy Production Rules: A fuzzy production rule is an If-Then relationship<br />

representing a piece of knowledge in a given problem domain. For the<br />

estimation of fuzzy memberships of a block b [j, k] to contain, say, edge, we<br />

need to obtain the composite membership value from their individual<br />

parametric values. The If-Then rules represent logical mapping functions from<br />

the individual parametric memberships to the composite membership of a

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