Fingerprints

Setup

The fingerprints are captured using a fingerprint reader which is a physical device that scans the finger. An Android app also needs to be installed on the device to interface to the reader.

Fingerprint Readers

Mantra MFS100

  • Produced by: Mantratec
  • Cost: Approximately 80 USD

This reader plugs into the USB port on the phone which is running fieldTask. Assuming this port on the phone is USB-C then you will also need a USB-C to USB-A adapter.

Website: https://www.mantratec.com/products/Fingerprint-Sensors/MFS100-Fingerprint-Scanner

Reader App

Smap Fingerprint reader can be downloaded onto the device from the server home page under the download menu. To do this use a browser on the device to go to the server home page and select the download menu.

The download menu on the smap server

Downloading the fingerprint reader

This app is an extension of the opensource Keppel app, the extension being to capture fingerprints as an image, Keppel only supports the ISO 19794-4 fingerprint template.

The form

An instruction to call the fingerprint reader can be added to either an image question or a text question as shown below.

survey
type name label appearance
image fp1 capture fingerprint image ex:uk.ac.lshtm.keppel.android.SCAN(type='image')
text fp2 capture fingerprint iso template ex:uk.ac.lshtm.keppel.android.SCAN(type='image')

The result will look like the following:

Field task screen showing the results of requesting an image, and an iso template fingerprint

Captured fingerprint data

Matching Fingerprints

Matching functionality will be increased progressively according to need.

On the console, if you select a record, a new button labeled “Links” will be shown. Click on this button to open a page that shows the image finger prints and any records that match. The default minimum score required for a match is 40.0. You can change this score and press the search button to redo the search. If you click on the link to a matching record it will open the record in a web form.

Matching Algorithm

Smap is using an open source fingerprint matching tool called SourceAFIS. Commercial alternatives offer more accurate matching however being open source results in a more sustainable system. Organisations collecting fingerprints should also investigate using fieldTask to collect fingerprints that can be used to train an Artificial Intelligence system to find matches.