检查数据库中的指纹 [英] Check a fingerprint in the database

问题描述

我将指纹保存在斑点"字段中，然后想知道比较这些印象的唯一方法是否是使用函数"identify_finger"检索数据库中保存的所有打印件，然后创建要检查的矢量?您可以使用SELECT直接从数据库中检查吗?

I am saving the fingerprints in a field "blob", then wonder if the only way to compare these impressions is retrieving all prints saved in the database and then create a vector to check, using the function "identify_finger"? You can check directly from the database using a SELECT?

我正在使用libfprint.在此代码中，验证是通过向量完成的:

I'm working with libfprint. In this code the verification is done in a vector:

def test_identify():
    cur = DB.cursor()
    cur.execute('select id, fp from print')
    id = []
    gallary = []
    for row in cur.fetchall():
        data = pyfprint.pyf.fp_print_data_from_data(str(row['fp']))
        gallary.append(pyfprint.Fprint(data_ptr = data))
        id.append(row['id'])
    n, fp, img = FingerDevice.identify_finger(gallary)

推荐答案

使用指纹数据库有两种根本不同的方法.一种是验证通过其他方式认识的人的身份，另一种是搜索身份未知的人.

There are two fundamentally different ways to use a fingerprint database. One is to verify the identity of a person who is known through other means, and one is to search for a person whose identity is unknown.

简单的库(例如libfprint)仅适用于第一种情况.由于您使用它来验证某人，因此您可以使用其身份从数据库中查找一行.也许您已经扫描了多个手指，或者每个手指存储了多个扫描，但是仍然会返回少量的数据库Blob.

A simple library such as libfprint is suitable for the first case only. Since you're using it to verify someone you can use their identity to look up a single row from the database. Perhaps you've scanned more than one finger, or perhaps you've stored multiple scans per finger, but it will still be a small number of database blobs returned.

必须从头开始设计一种指纹搜索算法，以缩小搜索空间，进行快速比较，对结果进行排名并处理假阳性.正如Google搜索可能会找到与您要查找的内容完全不相关的页面一样，指纹搜索也是如此.有些公司全力以赴解决这个问题.

A fingerprint search algorithm must be designed from the ground up to narrow the search space, to compare quickly, and to rank the results and deal with false positives. Just as a Google search may come up with pages totally unrelated to what you're looking for, so too will a fingerprint search. There are companies that devote their entire existence to solving this problem.

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