Minutiae Structures in Nature

Manfred Bromba (http://www.bromba.com/contacte.htm)
First issue: 2008-02-06 - Last update: 2008-03-08
Permanent address for citation: urn:nbn:de:0125-2008042909
In biometric systems the individuality of fingerprint patterns is used to distinguish humans with surprising reliability. The reason for the uniqueness of the ridge structure of fingerprints is the random arrangement of bifurcations and line endings which deliver very characteristic image details. Aim of this standing document is to compile every known occurrence of minutiae patterns [Wikipedia] in nature to demonstrate the universality of it. For a more detailed consideration of minutiae patterns in flower and animal structures see [1] and [2].

Human fingerprints

Human fingerprint structure
Author: unknown
License: GFDL
Fingerprint-like patterns are bound to a surface. Additionally, fingerprint-like patterns comprise a stripe component such that the inverse structure also belongs the same pattern family. This enables additional structure elements when compared to vein-like structures [2]. While in vein-like patterns all lines are connected to something like a root line and thus have a common begin, fingerprint lines (which express as ridges and valleys in 3D), may begin anywhere and end anywhere. This is illustrated in the following binarized human fingerprint image:
Binarized fingerprint image
Author: Manfred Bromba
License: limited to this article
Origin: binar.png
It is well known that the very basic structures which define minutiae are the line endings and the line bifurcations (ramifications). This is shown in the following two images from the Optel homepage [4]:
Line ending (white lines) Bifurcations (white lines)
If the black lines are considered, the situation is inverted: line endings transform to bifurcations, and vice versa. All other line structures can be attributed to these two cases. For animal fingerprints, see the fingerprint pages of Jean-François Mainguet [8] and Hans van den Nieuwendijk [9].

Artificial Fingerprints

There are at least two different ways to try understand the creation of minutiae structures. The most obvious method is to analyze the underlying physical and chemical micro phenomena and then to build a (mathematical) model and compare the (numerical) solutions with the reality. This often is the most cumbersome way. Another possibility is to look for known solutions of (simple) models which accidently coincide with the natural phenomenon. Such a model can also be used to synthesize minutiae patterns. An example of fingerprint synthesis is given in the article of Wieslaw Bicz [4] where also a link to a sample software from Optel is given.
Artificial fingerprints with different coarse characteristics
Author: Wieslaw Bicz
License: personal permission
Origin: [4]

The Zebra

Zebra stripes are already binarized as they only comprise two colors with sharp borders. In comparison to human fingerprints, the line distance and width strongly depends on the location on the fur. Also the minutiae are unequally but nevertheless randomly distributed.
Zebra
Author: Manfred Bromba
License: Public Domain

Stapelia gigantea

Fingerprint patterns in plants is a rare phenomenon, but it exists as the following case shows! The photograph has been taken in the Botanical Garden of Munich [3].
Stapelia gigantea
Author: Manfred Bromba
License: cc-by-sa 3.0
Origin: this article
Stapelia gigantea zoomed
Author: Manfred Bromba
License: cc-by-sa 3.0
Origin: this article

Ripple Marks

The explanation of ripple marks at a beach, best viewed at low tide, have engaged scientists since more than 100 years [5]. Hertha Ayrton was one of the first researches able to build a (mechanical) model to successfully simulate the formation of ripple marks with its characteristic minutiae. Physical-mathematical models have been considered, e.g., by Ingo Rehberg [6]. It is shown that the main mechanism for creating ripples is the interaction of flowing fluids over sand in the presence of a disturbance.
Low tide at a beach of Borkum (Germany)
Author: Amanda77
License: GFDL
Origin: Ebbe.jpg
As the next two images show, ripple marks have even been conserved as fossils.
Fossil ripple marks from the Hassberge mountains (Germany)
Author: R. Kirchner
License: GFDL
Fossil ripple marks found in Capitol Reef National Park (USA)
Author: Daniel Mayer
License: cc-by-sa 2.5

Dunes

The next two examples of minutiae structures I found thanks to a book of Robert Laughlin [7] about emergence [Wikipedia]. To learn more about the term emergence I found in the German Wikipedia two images which clearly show fingerprint structures: dunes and cow trails [Wikipedia].
Dune in Morocco
Author: Rosino
License:  cc-by-sa 2.0
The formation of dune structures can be explained in the same way as in the case of water ripple marks. Here, the wind takes over the role of the flowing water.

Cow Trails

Top view on cow trails on a steep mountain meadow
Author: Herzi Pinki
License:  GFDL
On impassable grounds such as on steep meadows, cows - just like humans - prefer to use caved paths. This leads to a number of parallel paths which occasionally bifurcate. In contrast to fingerprints, there will be no endings. This restricts minutiae to one type only.

Clouds

Altocumulus clouds
Author: Ralph F. Kresge #1201
License: Public Domain
This example of a ridge structure in clouds suggest that as soon as nature shows a stripe pattern, the pattern will be broken by minutiae.

Cactus Ripples

Echinopsis huascha (?)
Author: Manfred Bromba
License: cc-by-sa 3.0
Origin: this article
This cactus shows two bifurcations in its ripples, see right hand side. The photograph has been taken in a garden in Mallorca.

Humpback Whale

Megaptera novaeangliae
Author: Merzperson
License: Public Domain
When viewing the documentary film "Earth" (2007) in our cinema, I saw that the dark and white stripe contours in the skin of humpback whales show beautiful minutiae structures. As shown in the image of a dead whale above, these 3d structures seem to be the largest ones for animals which are directly comparable with human fingerprints.

Acknowledgment

The author would like to thank all photographers for their personal or general permission to publish their photos in this article. All rights remain with the contributors.

Literature and Links

1]
Manfred Bromba, Biometric Animals (http://www.bromba.com/knowhow/BiometricAnimals.htm)
2]
Manfred Bromba, Individuality of Plants (http://www.bromba.com/knowhow/BiometricPlants.htm)
3]
Botanical Garden of Munich (http://www.botmuc.de/)
4]
Wieslaw Bicz, New numerical methods of fingerprints' recognition based on mathematical description of arrangement of dermatoglyphics and creation of minutiae (http://www.optel.pl/software/english/method.htm)
5]
Hertha Ayrton, The Origin and Growth of Ripple-mark. Proceedings of the Royal Society of London A84: 285 (1910) (http://cwp.library.ucla.edu/articles/ayrton/Ayrton_ripple/ripple.html)
6]
Research papers of Ingo Rehberg (http://www.staff.uni-bayreuth.de/~btp915/research.html)
7]
Laughlin, Robert (2005), A Different Universe: Reinventing Physics from the Bottom Down, Basic Books, ISBN 0-465-03828-X
8]
Mainguet, Jean-François; "Fingerprint", (http://perso.wanadoo.fr/fingerchip/biometrics/types/fingerprint.htm)
9]
van den Nieuwendijk, Hans; "FINGERPRINTS.TK" (http://www.fingerprints.tk/)