The TRIRADIUS in a fingerprint: how it develops, it's characteristics + a definition!

Martijn (admin) wrote:

Patti wrote:

Martijn (admin) wrote:

Patti wrote:

Martijn (admin) wrote:

Patti wrote:Yes, on page 8 the FBI mentions 'bifurcation'. Not in relationship to the delta, but in relationship to Type Lines.

The definition for the focal point, delta, is:

"The delta is that point on a ridge at or in front of and nearest the center of the divergence of the type lines."

Then comes the list. If bifurcation was so important, it would have been included in that sentence, but it isn't. It's one of many in a list of possibilities.

Patti, seen from the F.B.I. perspective: in far most fingerprints the 'delta' manifest in a 'bifurcation'.

And this simple fact illustrates why the 'bifurcation' is listed first in the 6 options for a delta. But since the 'delta' is not always found in a bifurcation... it actually perfectly makes sense that the bifurcation is not mentioned in that definition sentence!

The fact that it's listed first has no significance and you can't prove it does.

Patti, I already mentioned that it is confirmed by the 2nd delta rule: why else could they have 'chosen' that as a rule?

(Can you name any other argument regarding how the forumulates that 2nd delta rule? I can't.)

Do you mean the rule about 1 or more bifurcations. That I would see a 'sub rule'. When dealing with 2 bifurcations, what to do. It doesn't make the bifurcation special.

Yes, the 2nd sub-rule does make the bifurcation special:

"● When there is a choice between a bifurcation and another type of delta, the bifurcation is selected."


I think this sub-rule very, very, very explicitely describes that the 'bifurcation' is more important than the other 5 manifestations shapes for a 'delta'.

Patti, are you denying this as well???

(You should not... )

Patti wrote:Read Page 121:

Personal identification: methods for the identification of individuals ... By Harris Hawthorne Wilder, Bert Wentworth

http://books.google.com/books?id=CDoiAAAAMAAJ&printsec=frontcover&dq=%22personal+identification%22+wilder&source=bl&ots=Ojbcx1uJdJ&sig=JVO3ra-98-AtD1Swt9T9e51t5ro&hl=en&ei=Hpu3TYXnOYm4tweBtsTeBA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBoQ6AEwAA#v=onepage&q&f=false

Here at the origins, the *delta* is the triangular shape formed by 3 fields meeting.
The *star* is the triradius.

(which is what Cummins & Midlo referred to about the delta being a triangular plot and a triradius was more than a triangular plot)

Patti wrote:
Then you agree with where the FBI would place the 'fbi delta' in fig. 20?

Patti wrote:
But that is only relating to when you have a bifurcation. It's in a sub category of rules. They didn't need sub category of rules for a dot. (they even have extra rules here too) They did however explain a short ridge with more than one rule, but that doesn't make the short ridge special.

Martijn (admin) wrote:

Patti wrote:

Based on your bifurcation theory the triradial point would be as circled, which the FBI does not suggest as a location for the delta, if the dot were missing.

Patti... ... of course not:

1 - Why don't you simply apply the delta-rules? Because regarding your encircled point in that example: there is actually another likewise 'bifurction' (see the 'bifurcation' at line Y-Y), so there are mulitiple 'bifurcations' in that example (actually, there are 4)... but none of them is 'open to the core'!!!!

2 - And in that example, none of these 4 'bifurcations' shows any sign that could relate to an 'abutting ridge' either.


Therefore is it not a surprize at all that the bifurcation in that example is found at another point - as described by the other rules in the F.B.I. book.

Patti wrote:

Martijn (admin) wrote:

Patti wrote:

Based on your bifurcation theory the triradial point would be as circled, which the FBI does not suggest as a location for the delta, if the dot were missing.

Patti... ... of course not:

1 - Why don't you simply apply the delta-rules? Because regarding your encircled point in that example: there is actually another likewise 'bifurction' (see the 'bifurcation' at line Y-Y), so there are mulitiple 'bifurcations' in that example (actually, there are 4)... but none of them is 'open to the core'!!!!

2 - And in that example, none of these 4 'bifurcations' shows any sign that could relate to an 'abutting ridge' either.


Therefore is it not a surprize at all that the bifurcation in that example is found at another point - as described by the other rules in the F.B.I. book.

The bifurcations at A & Z are also not chosen because they are not out in front of the diverging ridges. See dotted line E.

So, you do agree that if the dot were missing the delta would be on ridge B and not on the circled bifurcation?

... Of course!


(Again, I don't understand why you continue here about figure 20? - I can only understand this in the perspective of Kiwihands' fingerprint ... but if that is what you have in mind, then you better continue on figure 20 in the topic about her fingerprint!)

Martijn (admin) wrote:
After the word 'triradius' became introduced in the field of fingerprints at the beginning of the 20th century, it had already become an old-fashioned concept in the 80's - illustrated by the fact that the F.B.I. no longer used it in their Classic work of fingerprint assessment: 'The Science of Fingeprints' (1985, republished in 1989).

The major reason for this step made by the F.B.I. in the field of fingerprint assessment was probably resulting from the fact that only the 'delta' (point) - or the so-called 'triradial point' - is a necessary element to be identified (next to the indentification of the so-called 'core').

While the word 'triradius' is usually no longer used in the perspective of fingerprints (the F.B.I. only speaks of 'bifurcations'), it is still a common name used in the perspective of 'palmar dermatoglyphics' - especially the 'axial triradius' is still a very significant name (in the scientific literature this name was only rarely replaced by the words: 'axial delta').

Below follows a quick introduction to the concept of the 'triradius' + it's associated vocabulary.


How is a 'triradius' created?

In the following pictures one can see how 'triradii' result from the order of development for individual ridges in the various topographic areas of the fingerprints:



These pictures are taken from an article presented by Babler:
http://www.forensicitc.com/critical_stage_of_friction_ridge.htm
+ the pictures in this article are available here:
http://www.clpex.com/animation.htm


The scientific definition of a triradius

Schaumann & Alter defined the 'triradius' as follows (Dermatoglyphics in Medical Disorders, 1976, page 34):

"A triradius is formed by the confluence of three ridge systems... The geometric center of the triradius is designated as the triradial point. Ideally, the triradial point is the meeting point of three ridges that form angles of approximately 120 degrees with another."


(Edit:) Cummins & Midlo defined the 'triradius' as follows (Finger prints, palms & soles, 1943, page 57):

"TRIRADII. A triradius is located at the meeting point of three opposing ridge systems. In a typical whorl or loop such a meeting occurs that the conjunction of the three topographic zones - the pattern area, the distal transverse system and the proximal transverse system."


And Lionel Penrose (who invented the word 'dermatoglyphics') wrote about the triradius:

"From the central point of a triradius, which may be an island, a ridge junction, a ridge end or even a triangular enclosure, three radiant ridges lying roughly at angles of 120 degrees with one another can be theoretically traced. If the angle between two of these radiants is less than 90 degrees no triradius is deemed to exist."


NOTICE: During the 20 century the 'fingerprint vocabulary' has developed, and sometimes the vocabulary-choices of the researchers became quite confusing (resulting in that the words 'type lines' became defined differently in the F.B.I. system compared to how 'type lines' are defined in the earlier scientific vocabulary; and after Sir Francis Galton had introduced the word 'delta' as a typical SHAPE in a fingerprint, it became later re-defined as a POINT in the F.B.I. system)


Now... what does this all mean?


A SIMPLE, ADVANCED & VISUAL definition for the triradius!


1 - A SIMPLE DEFINITION FOR THE 'TRIRADIUS' IN A FINGERPRINT:

The 'triradius' is recognized by the presence of a meeting of 3 individual 'ridge fields', where the 3 'radiants' (starting from the 'triradial' point) should make angles that are close to 120 degrees - specified: all angles are required to be higher than 90 degrees [NOTICE: ridges manifest in a fingerprint as 'black lines'].

Therefore a 'triradius' can simply be recognized by the presence of the following shape (which represents: a meeting of 3 ridges, or the three 'radiants'):



(Additionally, if one of the angles between the radiants is smaller than 90 degrees, then one can speak of a radiating 'bifurcation', instead of a 'triradius')


2 - AN ADVANCED DEFINITION FOR THE 'TRIRADIUS' IN A FINGERPRINT:

A 'triradus' can be recognized by the presence of the following three elements:
- (a) a meeting of 3 individual 'ridge fields'; the meeting-point of the 3 ridges is the 'triradial point', and the 3 'radiants' starting from this point should make angles close to 120 degrees - and all angles should be higher than 90 degrees. [NOTICE: ridges manifest in a fingerprint as 'black lines'].
- (b) the confluence of 3 parallel 'ridge systems' [NOTICE: 'ridge system' = one ridge + the surrounding grooves];
- (c) it's location borders the 'three topographic zones' of the fingerprint [NOTICE: topographic areas include: (I) proximal area + (II) distal area + (III) pattern area].


3 - A VISUAL DEFINITION FOR THE 'TRIRADIUS' IN A FINGERPRINT:

NOTICE: In the picture below you can see how in the topographic areas (I, II and III) the three 'confluencing ridge systems' (RED ARROW I, RED ARROW 2, RED ARROW 3) are found, and how the three 'radiants' (1, 2 and 3)... can be recognized as (imaginary)borders between the topographic areas!!!

Patti wrote:
I bring up figure 20 because in your suggested, updated to this century, definition of a triradius, you suggest in your third paragraph a triradius, according to the FBI, is a bifurcation.

A beginner would read this post and not realize they could also expect to find a bifurcation lacking completely, or a bifurcation that is not in the proper location.

Okay Patti, I think I understand what you are trying to say here (but I am not sure yet):

Are you saying that a 'delta' can manifest in various shapes (the six items listed at page 9)... and not only a 'bifurcation'?


By the way, the title of this topic is basically focussed on the 'triradius'... and not solely on the 'triradial point' (though I have mentioned that element as well in the definition); but the other 5 items in the list can not serve as a synonym for a 'triradius'... because these can only serve as a manifestation shape for a 'triradial point' = the F.B.I.'s delta.

But maybe it is a good idea to add the F.B.I. list of 6 items to the definition... next to Loesch's definition for the Triradius.


Patti, do you think that adding those elements to my first post of this topic could become helpful?

(If so, then I will do that!)

Martijn (admin) wrote:

Patti wrote:
I bring up figure 20 because in your suggested, updated to this century, definition of a triradius, you suggest in your third paragraph a triradius, according to the FBI, is a bifurcation.

A beginner would read this post and not realize they could also expect to find a bifurcation lacking completely, or a bifurcation that is not in the proper location.

Okay Patti, I think I understand what you are trying to say here (but I am not sure yet):

Are you saying that a 'delta' can manifest in various shapes (the six items listed at page 9)... and not only a 'bifurcation'?


By the way, the title of this topic is basically focussed on the 'triradius'... and not solely on the 'triradial point' (though I have mentioned that element as well in the definition); but the other 5 items in the list can not serve as a synonym for a 'triradius'... because these can only serve as a manifestation shape for a 'triradial point' = the F.B.I.'s delta.

But maybe it is a good idea to add the F.B.I. list of 6 items to the definition... next to Loesch's definition for the Triradius.


Patti, do you think that adding those elements to my first post of this topic could become helpful?

(If so, then I will do that!)

Patti wrote:

Martijn (admin) wrote:

Patti wrote:
I bring up figure 20 because in your suggested, updated to this century, definition of a triradius, you suggest in your third paragraph a triradius, according to the FBI, is a bifurcation.

A beginner would read this post and not realize they could also expect to find a bifurcation lacking completely, or a bifurcation that is not in the proper location.

Okay Patti, I think I understand what you are trying to say here (but I am not sure yet):

Are you saying that a 'delta' can manifest in various shapes (the six items listed at page 9)... and not only a 'bifurcation'?


By the way, the title of this topic is basically focussed on the 'triradius'... and not solely on the 'triradial point' (though I have mentioned that element as well in the definition); but the other 5 items in the list can not serve as a synonym for a 'triradius'... because these can only serve as a manifestation shape for a 'triradial point' = the F.B.I.'s delta.

But maybe it is a good idea to add the F.B.I. list of 6 items to the definition... next to Loesch's definition for the Triradius.


Patti, do you think that adding those elements to my first post of this topic could become helpful?

(If so, then I will do that!)

Since the fbi delta is a focal point, I visualize it as a 'spot' or location, not a shape. FBI has placed this location on a ridge.

Patti wrote:Here's a description of the delta from Wilder. Page 193.



Note how fig. a is like a "Y" shape, but fig. c and d are not.

The 'delta' is described as a 3 pointed star or a triangle

The delta is also the first location to find on a fingerprint. Therefore, this confirms an order to properly proceed in identifying and classifying a fingerprint.

Also note how in the text describing fig. e, they tell us about the *idea* of a triangle. Just as Penrose suggested to trace the radiants theoretically, Wilder tells you to have an idea of a triangle in mind.

This confirms to me Martijn, that all those times you accused me of "phantasy" and imagination, I was imagining what the authors wanted us to imagine.

....

Sorry Patti, but I don't understand why you associate the Wilder's use of the word 'idea' with your "phantasies":

Because here Wilder only talks about the 'triangle' when there is actually a complete ridge-triangle visible: his comment directly relates to example e.

So I don't see how there is any 'phantasy' involved in Wilder's comment here: because he only talks about 'the idea of a trirangle' because in that triangle is 'bending' of the ridges involved (see the right side of the triangle)... which could suggest that formally one can not speak of a triangle: because in a true triangle the 'sides' are straight!

I hope this now makes sense for your as well.

Patti wrote:

By the way...

Patti, this comment of Wilder includes a very important statement:

Because Wilder quotes Henry's perception on how a delta (triradius) typically manifests:

"Henry describes the usual formation as made 'either by the forking of a single ridge or by the wide seperation of two ridges that up to this point had run side by side'... "


Patti, this QUOTE from Henry's work ... clearly shows that even Henry had recognized that a delta (triradius) typically manifests as a 'forking' - which directly relates to how a the 'bifurcation' is defined in the F.B.I. book:

"A bifurcation is the forking or dividing of one line into two or more branches."


This actually is the 'proof' for my point about the crucial-role of the bifurcation in the F.B.I. system:

Because Wilder's words (+ the quote from Henry's work) illustrate that the F.B.I.'s choice to describe in their approach the 'bifurcation' as THE major variant of how a 'delta' can manifest... was very sensible choice, and should be directly associated with basic concept of a 'triradius'!

Wilder describes the typical form of a triradius as a 'three pointed star', Henry speaks for the usual formation about a 'forking'... and in the F.B.I.'s approach only the 'bifurcation' can serve as an alternative synonym for the concept of a true triradius.


So this clearly shows how the F.B.I.'s 'bifurcation'... was preceeded by (1) Henry's 'forking', (2) Wilder's 'three pointed star', and (3) the 'triradius' of the other researchers:

Welcome in the land of 'bifurcations' - which was already discovered by sir Edward Henry (1850 – 1931)...!!!

Martijn (admin) wrote:

Patti wrote:

By the way...

Patti, this comment of Wilder includes a very important statement:

Because Wilder quotes Henry's perception on how a delta (triradius) typically manifests:

"Henry describes the usual formation as made 'either by the forking of a single ridge or by the wide seperation of two ridges that up to this point had run side by side'... "


Patti, this QUOTE from Henry's work ... clearly shows that even Henry had recognized that a delta (triradius) typically manifests as a 'forking' - which directly relates to how a the 'bifurcation' is defined in the F.B.I. book:

"A bifurcation is the forking or dividing of one line into two or more branches."


This actually is the 'proof' for my point about the crucial-role of the bifurcation in the F.B.I. system:

Because Wilder's words (+ the quote from Henry's work) illustrate that the F.B.I.'s choice to describe in their approach the 'bifurcation' as THE major variant of how a 'delta' can manifest... was very sensible choice, and should be directly associated with basic concept of a 'triradius'!

Wilder describes the typical form of a triradius as a 'three pointed star', Henry speaks for the usual formation about a 'forking'... and in the F.B.I.'s approach only the 'bifurcation' can serve as an alternative synonym for the concept of a true triradius.


So this clearly shows how the F.B.I.'s 'bifurcation'... was preceeded by (1) Henry's 'forking', (2) Wilder's 'three pointed star', and (3) the 'triradius' of the other researchers:

Welcome in the land of 'bifurcations' - which was already discovered by sir Edward Henry (1850 – 1931)...!!!

Martijn (admin) wrote:
Patti, this comment of Wilder includes a very important statement:

Because Wilder quotes Henry's perception on how a delta (triradius) typically manifests:

"Henry describes the usual formation as made 'either by the forking of a single ridge or by the wide seperation of two ridges that up to this point had run side by side'... "


Patti, this QUOTE from Henry's work ... clearly shows that even Henry had recognized that a delta (triradius) typically manifests as a 'forking' - which directly relates to how a the 'bifurcation' is defined in the F.B.I. book:

"A bifurcation is the forking or dividing of one line into two or more branches."

This actually is the 'proof' for my point about the crucial-role of the bifurcation in the F.B.I. system:

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(edit-) Yes I see that Henry says bifurcation as opposed to others who see the Y shape (or star shape triradius) as 3 abutting ridges, or 3 ridges radiating from a common point.

btw....Martijn, you said something about some of C&M work was outdated because it was older than the other sources,,,, but Henry's is even older than C&M ! and you embrace it ...because it agrees with what you were saying

Patti wrote:


A three pointed star or a triangle. Yes. Both from the start.

...

Patti, I am not sure that you understood what I described:


It would be helpful to know, can you now as well confirm the following develeopments as 'historical facts'?

1 - First Henry described that the most common shape where the delta is found is: a 'forking';
2 - Then Wilder described it as a 'three pointed star' (he also used ocasionally the word 'triradius');
3 - Later the scientific researchers (Cummins & Midlo, Penrose, Schaummen & Alter, Loesch) adopted the word 'triradius';
4 - And finally the F.B.I. presented their combi-definition: the word: 'bifurcation'.


(NOTICE: Patti, the first two points are described in your copy from Wilder's work...!)

Lynn wrote:

Martijn (admin) wrote:
Patti, this comment of Wilder includes a very important statement:

Because Wilder quotes Henry's perception on how a delta (triradius) typically manifests:

"Henry describes the usual formation as made 'either by the forking of a single ridge or by the wide seperation of two ridges that up to this point had run side by side'... "


Patti, this QUOTE from Henry's work ... clearly shows that even Henry had recognized that a delta (triradius) typically manifests as a 'forking' - which directly relates to how a the 'bifurcation' is defined in the F.B.I. book:

"A bifurcation is the forking or dividing of one line into two or more branches."

This actually is the 'proof' for my point about the crucial-role of the bifurcation in the F.B.I. system:

[/color]

More interesting to me is the other option that Henry mentions, which you didn't comment on Martijn.
"Henry describes the usual formation as made 'either by the forking of a single ridge or by the wide seperation of two ridges that up to this point had run side by side... "
This option sounds more like the 'triradius' that I had been taught about (or at least two of the 3 triradial ridges).

Martijn (admin) wrote:
It would be helpful to know, can you now as well confirm the following develeopments as 'historical facts'?

1 - First Henry described that the most common shape where the delta is found is: a 'forking';

Patti wrote:I think this is the FBI's innermost diverging parallel ridges. The FBI describes 1 set and Schaumann & Alter mention 3 sets of diverging ridges. 3 sets may contain the Y or Star shape and 3 sets may appear as a triangular plot as per Cummins & Midlo.

Lynn wrote:

Martijn (admin) wrote:
Patti, this comment of Wilder includes a very important statement:

Because Wilder quotes Henry's perception on how a delta (triradius) typically manifests:

"Henry describes the usual formation as made 'either by the forking of a single ridge or by the wide seperation of two ridges that up to this point had run side by side'... "


Patti, this QUOTE from Henry's work ... clearly shows that even Henry had recognized that a delta (triradius) typically manifests as a 'forking' - which directly relates to how a the 'bifurcation' is defined in the F.B.I. book:

"A bifurcation is the forking or dividing of one line into two or more branches."

This actually is the 'proof' for my point about the crucial-role of the bifurcation in the F.B.I. system:

[/color]

More interesting to me is the other option that Henry mentions, which you didn't comment on Martijn.
"Henry describes the usual formation as made 'either by the forking of a single ridge or by the wide seperation of two ridges that up to this point had run side by side... "
This option sounds more like the 'triradius' that I had been taught about (or at least two of the 3 triradial ridges).

Lynn wrote:

Martijn (admin) wrote:
It would be helpful to know, can you now as well confirm the following develeopments as 'historical facts'?

1 - First Henry described that the most common shape where the delta is found is: a 'forking';

Henry gives two options for the 'usual formation', not just a bifurcation... "Henry describes the usual formation as made 'either by the forking of a single ridge or by the wide seperation of two ridges that up to this point had run side by side'... "