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

Taking the maximum score across all matchers

Answer

Multiplying all matcher scores together

Answer

Selecting the score from the most reliable matcher

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

Min-Max normalization

Answer

Tanh estimator normalization

Answer

Decimal scaling

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

The second modality is always invoked for verification

Answer

The system automatically rejects due to suspicion of spoofing

Answer

Feature-level fusion is triggered

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

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

Answer

Lower False Reject Rate (FRR) compared to any single matcher only

Answer

Equal error rates across all participating matchers

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

Parallel fusion uses only one biometric modality at a time

Answer

Parallel fusion applies only to decision-level combination

Answer

Parallel fusion eliminates the need for score normalization

Question 6

Which of the following is a key challenge specific to multimodal biometric systems that is less prominent in unimodal systems?

Accepted Answer

Managing increased computational complexity and fusion strategy selection

Answer

Preventing feature drift over time

Answer

Ensuring sensors are calibrated correctly

Answer

Storing biometric templates securely

Question 7

Soft biometrics (e.g., height, gender, eye color) are most commonly incorporated into multimodal systems at which fusion level?

Accepted Answer

Score-level or decision-level fusion as supplementary evidence

Answer

Feature-level fusion only

Answer

Sensor-level fusion only

Answer

They cannot be used in biometric fusion