CBP Biometric Fusion and Multimodal Systems 2

Question 1

The Sum Rule in score-level fusion computes the final score by:

Accepted Answer

Adding the normalized scores from each matcher

Answer

The Sum Rule combines normalized matcher scores by addition, and has been shown to be robust and effective in practice even when score distributions are not ideal.

Question 2

Which score normalization technique uses the mean and standard deviation of match scores to map them to a standard distribution?

Accepted Answer

Z-score normalization

Answer

Z-score normalization (also called z-normalization) subtracts the mean and divides by the standard deviation to produce a zero-mean, unit-variance distribution.

Question 3

In a cascaded (sequential) multimodal biometric architecture, what happens when the first modality produces a high-confidence match?

Accepted Answer

Processing may stop and identity is accepted without querying further modalities

Answer

In cascaded fusion, subsequent modalities are only invoked when earlier stages produce uncertain results, saving processing time and resources when initial confidence is high.

Question 4

The OR rule in decision-level fusion is most likely to result in:

Accepted Answer

Higher False Accept Rate (FAR) compared to any single matcher

Answer

The OR rule accepts an identity claim if any single matcher accepts, which tends to raise FAR because more pathways exist for an impostor to be accepted.

Question 5

Parallel fusion architecture differs from cascaded (sequential) fusion in that:

Accepted Answer

All biometric modalities are processed simultaneously and results are combined

Answer

In parallel fusion, all matchers run concurrently and their outputs are combined afterward, maximizing accuracy at the cost of processing all modalities regardless of intermediate confidence.

(CBP) Certified Biometrics Professional Practice Test

(CBP) Certified Biometrics Professional Practice Test

CBP Biometric Fusion and Multimodal Systems 2