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Fusion of Visual and Thermal Face Recognition Techniques: A ...

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In face recognition, the shortest distance between the gallery <strong>and</strong> subject can be<br />

measured <strong>and</strong> the first matched for verification or the first 10 or 100 can be matched the<br />

identification. The Euclidean distance, D , is used to compared two feature sets,<br />

where N in the number <strong>of</strong> the features <strong>and</strong> Pi<br />

<strong>and</strong><br />

∑ N 2<br />

D = || Pi - Qi<br />

|| , (6)<br />

i= 1<br />

Q<br />

i<br />

is the matrix <strong>of</strong> the feature sets.<br />

Since the features <strong>of</strong> the faces have different degrees <strong>of</strong> significance <strong>and</strong> reliability<br />

for representing a face, the weighted Euclidean distance, Dw , should be used to compare<br />

two feature sets. If we choose different feature sets, they will contribute differently in the<br />

recognition process. The main problem is how to find each weight.<br />

Dw =<br />

N<br />

∑<br />

i=<br />

1<br />

where ki<br />

is the weighting factors for Pi<br />

<strong>and</strong> Q i .<br />

2<br />

k || P − Q || , (7)<br />

i<br />

i<br />

Figure 24 shows the performance <strong>of</strong> different sets <strong>of</strong> l<strong>and</strong>mark points <strong>and</strong><br />

geometrical distances, while Figure 25 shows <strong>Face</strong>It® outperform our experimental<br />

results. This indicates that the features what we extract is not a good features for face<br />

recognition than <strong>Face</strong>It® has. A plot <strong>of</strong> probabilities <strong>of</strong> correct match versus the number<br />

<strong>of</strong> best similarity scores called a cumulative match characteristic curve (CMC) is mainly<br />

used in this paper for the evaluation <strong>of</strong> performance <strong>of</strong> face identification. Another<br />

performance method called a receiver characteristic curve (ROC), a plot <strong>of</strong> numerous<br />

false acceptance rate <strong>and</strong> false rejection rate combinations, which <strong>of</strong>ten is used for the<br />

evaluation <strong>of</strong> face verification, will be included in the future.<br />

i<br />

41

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