Citizen science

Knuckle Down ID

A three year PhD project, assessing human variation in knuckle creases.

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Start date

February 2021

Completion date

June 2022

About this activity

Knuckle Down ID was part of a three year PhD project, assessing human variation in the knuckle creases on the back of the fingers and the impact of finger bending on their appearance in digital images.

The images collected through this citizen science project will be used to develop a suitable AI algorithm to replicate the process of identifying perpetrators from digital images using knuckle creases. 

Between March 2021 – June 2022, 84 citizen scientists took images of their hands for Knuckle Down ID database. Thank you to all our citizen scientists who contributed!

We collected:

  • 1008 different hand images
  • 6 images of each hand
  • 12 images from each citizen scientist


Participants were asked to complete a questionnaire and then take images of their hands positioned around a round cup or mug with a smartphone through the Knuckle Down ID app.

What happens now?

The database will be made available via controlled access once the images and associated data have been further anonymised via the removal of unique identification numbers.

An illustration of a hand focusing on the knuckles

If you have any questions about the project, please contact