算法评价指标 - FAR,FRR,ERR (TP/FP/FN/TN)

TP/FP/FN/TN

• True positive: having the condition and tested positive with the condition
• False positive: not having the condition but tested positive with the condition
• True negative: not having the condition and tested negative with the condition
• False negative: having the condition but tested negative with the condition

• Sensitivity (True positive rate, TPR): measures the proportion of positives that are correctly identified
• Specificity (True negative rate,TNR): measures the proportion of negatives that are correctly identified

FAR, FRR, ERR

FAR

FAR (False Accept Rate) refers to the possibility that an imposter is accepted by the system incorrectly, which may lead to security breach.

FAR(误接受率)指冒名顶替者被系统错误接受的可能性，这可能致使安全漏洞.

FRR

The FRR (False Reject Rate) is the possibility that a legitimate user is rejected by the system when requesting protected resources.

FRR(误拒绝率)是合法用户请求受保护资源时被系统拒绝的可能性。

ERR

在理想状况下，FAR和FRR均为零。可是在现实中这是不可能的，由于这两种偏差是相互矛盾的，一种偏差的减小会致使另外一种偏差的增长。所以，须要用EER (Equal Error Rate)来评估击键动力学认证系统的总体性能。

ERR是FRR等于FAR时的错误率，能够将FAR和FRR统一为一个参数，更好地表明系统的综合性能。通常来讲，ERR越低，识别系统的性能越好。