BS ISO IEC 19795-5:2011 pdf free download – Information technology – Biometric performance testing and reporting
5.4.2 Universality of the test
The rationale for using grade levels versus pass/fail relates to the “universality” or variety of user applications of the evaluation results. Each application is expected to have its own set of required metric grades. A pass/fail evaluation of a system against any particular set of metrics could be developed. However, the introduction of a grade level-based evaluation may provide several advantages. First, a standard test can be defined and used for several different applications. More importantly, the results of a single evaluation can be used by all potential users of the system to judge the suitability of the tested system to their specific application. The system supplier could theoretically reduce overall evaluation cost by submitting to one test, which would optimize the test organization’s time and resources. The overall cost for a single graded evaluation may be higher, but could apply to a variety of user applications.
5.4.3 Levels of effort and decision policies
The experimenter shall report enrolment and verification levels of effort and decision policies as follows. Minimum and maximum number of placements, attempts, and transactions required or permitted to enrol may be somewhat dependant on the enrolment subsystem under test. An enrolment subsystem may allow enrolment after one attempt, or may require multiple presentations, attempts, and transactions. Unless otherwise dictated, the following shall apply:
⎯ three enrolment transactions of up to three attempts each shall be allowed (if unable to enrol on the first or second transaction);
⎯ an enrolment transaction shall be defined by the supplier, consistent with their operational enrolment practices. For modalities with multiple instances (e.g. fingers, irises), the enrolment policy may include attempts with a primary instance (e.g. right index finger), and if that attempt fails, then secondary instances may be used to enrol;
⎯ three attempts shall be allowed for each verification transaction.
Minimum and maximum duration permitted or required to enrol within a given enrolment attempt or transaction may be somewhat dependant on the enrolment subsystem under test. A biometric subsystem may terminate an enrolment attempt or transaction after a fixed duration. This may be due to (1) inability to acquire sufficiently distinctive data or (2) inability to sense any biometric data input. Incident (1) means that a biometric subsystem has acquired and processed data but found it lacking; incident (2) means that the data was not acquired and processed. It is not feasible to allow a biometric subsystem to attempt to acquire data indefinitely; therefore for subsystems that do not time out, a time of 45 seconds shall be established as the default time-out.