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

Patti wrote:In earlier discussions you argued that a system or a field was related to 1 ridge and the groove on each side.

Have you now decided it is more than 1 ridge?

Patti, for sure... I still cherish that argument!

Maybe you missed in my post preceeding your above mentioned comment, that I have been talking about:

"'parallel ridge fields" = several individual ridge fields that are positioned side-by-side.

And 1 ridge field = one ridge + the two surrounding grooves.


Does this now make sense for you?

Martijn (admin) wrote:

Lynn wrote:

Martijn (admin) wrote:

Lynn wrote:thanks for patient explanation Martijn. Where did you get all these different defnitions from?

So, while the scientific approach used to discriminate:

1 - a 'splitting', as a (asymmetric) divergence of one ridge into 2 ridges that follow same direction (no angle);
2 - a 'fork'/'Y-shape', as a (symmetric) divergence of one ridge into 2 ridges that follow the same direction (no angle);
3 - a 'bifurcation', as a divergence of one ridge into 2 ridges in different directions (angle smaller than 90 degrees);
4 - and a 'triradius' as a divergence of one ridge into 2 ridges in different directions (angle larger than 90 degrees up to 120 degrees).

... that is just a specified summary of elements that are mentioned in Schaumann & Alter's book. Penrose also described the requirement for a triradius to have angles that are all larger than 90 degrees.

(Only the aspect of 'symmetry' vs. 'asymmetry' is not mentioned in Schaumann & Alter, not sure about Penrose's work - sorry, I can not specify for that aspect where I have seen it... but that detail is not important regarding the point I tried to make in that post).

Are these Schaumann & Alter's words, or are they your interpretation / summary Martijn? I ask because formally the words bifurcation, fork and Y shape have the same meaning in the dictionary. I have not read anywhere that a 'triradius' as a divergence of one ridge into 2 ridges in different directions

You know what Lynn?

I am going to make my former list a little bit longer, but this time I will only present definitions that are found in the books:

1 - 'Closure' (Schaumann & Alter 1976), visually defined as: a bifurcating ridge with multiple ridges inside;

Martijn (admin) wrote:

Patti wrote:In earlier discussions you argued that a system or a field was related to 1 ridge and the groove on each side.

Have you now decided it is more than 1 ridge?

Patti, for sure... I still cherish that argument!

Maybe you missed in my post preceeding your above mentioned comment, that I have been talking about:

"'parallel ridge fields" = several individual ridge fields that are positioned side-by-side.

And 1 ridge field = one ridge + the two surrounding grooves.


Does this now make sense for you?

Patti wrote:Martijn, just a quick thumb through the FBI manual shows that you are mistaken in thinking that they are presenting as a primary focus for a delta/triradial point, a *bifurcation*.

It appears that they use a *dot* or a *short ridge* just as frequently as a V shaped ridge formation in their samples.

Patti wrote:

Martijn (admin) wrote:

Patti wrote:In earlier discussions you argued that a system or a field was related to 1 ridge and the groove on each side.

Have you now decided it is more than 1 ridge?

Patti, for sure... I still cherish that argument!

Maybe you missed in my post preceeding your above mentioned comment, that I have been talking about:

"'parallel ridge fields" = several individual ridge fields that are positioned side-by-side.

And 1 ridge field = one ridge + the two surrounding grooves.


Does this now make sense for you?

Cool! That means that if we are talking about 3 different and separate ridge systems converging, we can say we are looking at 3 ridges. 1 ridge from each different system.

Cool???

Not all, because we're not in agreement at all about what you just described regarding the 'triradius'... ... no way!!!


Patti, will you please re-read my post preceeding your question?
And please check the 4 definitions for the 'triradius' that I presented in reply to Lynn's question!


Because... ONE MORE TIME:

Loesch is talking about:
'three fields of parallel lines'.

Schaumann & Alter are talking about:
'the confluence of three ridge systems'.

And Cummins & Midlo:
'meeting point of three opposing ridge systems'.


See the similarities???
And just like Loesch, Penrose is talking as well about 'parallel ridges'.


Patti, the word 'parallel' is an essential element where it is mentioned: because that word describes EXPLICITELY that all these definitions relate to multiple ridges in each of the three 'pattern areas'.

(Cummins & Midlo did not yet use the word 'parallel', but Penrose did.... and Schaumann & Alter instead used the word 'confluencing'; but Loesch continued with the word 'parallel'.)


And as a consequence, these definitions do not talk about "1 ridge from each different system" - like you described above.


These 'ridge systems' ARE not the triradius, only the BORDERS of those ridge systems form the triradius!

This is also explicitely described by Cummins & Midlos first sentence in their triradius definition:

"A triradius is located at the meeting point of three opposing ridge systems"

But one should not 'read' this like if they are saying that the three opposing ridge systems are the triradius, because only the 3 'border ridges' BETWEEN the 3 topographic areas can form a true tridadius!

(And of course: if these 3 'borders' manifest as ridges that are connecting in the 'triradial point'... then these 'borders' form the 'radiants' of a triradius)

Patti wrote:I absolutely disagree that the FBI gives preference to the bifurcation. In my book on page 11 figs. 21 - 24 appear before they illustrate the bifurcation in fig. 25.

There is no order to this list. First or last they are all equal locations for the FBI's focal point, the delta.

There are rules for when more than one possible location such as a bifurcation and a dot, or more than one bifurcation, but typically there isn't more than one good choice present. Particularly if you have followed the innermost ridges in, innermostly.

Sorry Patti, what are you saying here?

The ''bifurcation' is already DEFINED and ILLUSTRATED at page 8... ... and in my book page 8 is before page 11. How about yours? ( )


I am wondering... why did you start talking about figure 21-24 on page 11, and use that as an argument, while the 'bifurcation' is already present before that page?

Patti wrote:

Martijn (admin) wrote:

Lynn wrote:

Martijn (admin) wrote:

Lynn wrote:thanks for patient explanation Martijn. Where did you get all these different defnitions from?

So, while the scientific approach used to discriminate:

1 - a 'splitting', as a (asymmetric) divergence of one ridge into 2 ridges that follow same direction (no angle);
2 - a 'fork'/'Y-shape', as a (symmetric) divergence of one ridge into 2 ridges that follow the same direction (no angle);
3 - a 'bifurcation', as a divergence of one ridge into 2 ridges in different directions (angle smaller than 90 degrees);
4 - and a 'triradius' as a divergence of one ridge into 2 ridges in different directions (angle larger than 90 degrees up to 120 degrees).

... that is just a specified summary of elements that are mentioned in Schaumann & Alter's book. Penrose also described the requirement for a triradius to have angles that are all larger than 90 degrees.

(Only the aspect of 'symmetry' vs. 'asymmetry' is not mentioned in Schaumann & Alter, not sure about Penrose's work - sorry, I can not specify for that aspect where I have seen it... but that detail is not important regarding the point I tried to make in that post).

Are these Schaumann & Alter's words, or are they your interpretation / summary Martijn? I ask because formally the words bifurcation, fork and Y shape have the same meaning in the dictionary. I have not read anywhere that a 'triradius' as a divergence of one ridge into 2 ridges in different directions

You know what Lynn?

I am going to make my former list a little bit longer, but this time I will only present definitions that are found in the books:

1 - 'Closure' (Schaumann & Alter 1976), visually defined as: a bifurcating ridge with multiple ridges inside;

Martijn!!!

I had to go look as I earlier said a bifurcating ridge shouldn't be wide enough for more than one ridge. Now you go and describe a "closure" with several ridges inside!

Taking a look at your source Schaumann & Alter (page 38) A *closure* is a formation that forms in the ridges on the middle and proximal phalanges!!!!!

See also page 83 "Finger Prints Palms & Soles" they also point out the hook and closure formations are on the middle and proximal phalanges.

Alrighty!! I will delete the 'closure' from my earlier list.

Lynn wrote:thanks for your time researching Martijn, tho I hope you understand I have never disagreed with
"A bifurcation is the forking or dividing of one line into two or more branches."

Lynn, of course I understand that!

But I am not discussing the validity of this F.B.I. definition... I am only describing how this multi-concept definition can serve as well as a synonym for the 'triradius' in the scientific approach - remember, earlier today I presented the example 139 as an illustrative example for this point: because we see a clear 'triradius' ... and the F.B.I. calls is a 'bifurcation'!

(And in that perspective, our discussion about the 'bifurcation'... directly relates to the topic of this discussion: the definition of the triradius.)


I hope that this now all makes sense for you?

And if so, then it is time to present my earlier question once again to you:

"Lynn, if you can not agree with this short 'summary' [/i][see also my new list of the definitions for the various elements][i]... will you specify where you perceive the problem?"

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!

Patti wrote:

Lynn wrote:Sorry I notice that 3 other posts have been made while I was writing,,,, not read them yet, just wanted to say while I thought about it....

Do either of you have access to any papers by Harris H Wilder? I've got a print-out of something called "IX Palm and Sole Studies", page 393 - 405. But I can't get my scanner to work! In all his illustrations of triradii, the triradius consists of a roughly 'triangular shaped plot' coloured in black, that looks remarkably like Patti's central picture on her illustration....


It also takes me back to my original teachings about triradius being the vaguely triangular shaped area where the 3 ridge fields converge (which we are now talking about as being the 'triradial area').

If you look at fig 18 on P 202 of this pdf, this gives you an idea of how he colours the triradius in black. (he refers to this black area as 'triradius' in the paper I have quoted above).
http://www.biolbull.org/cgi/reprint/49/3/182.pdf

Thank you for this link to the paper by Wilder! I did not have it!

It does look like he was seeing the same shape(s) as I do!

Triradius
Area on the friction ridges where three ridge systems meet.
Quantitative-Qualitative Friction Ridge Analysis, David R. Ashbaugh 1999 CRC Press

This term was introduced by one of the authors of the book "Personal
Identification". It suggests a 3 point star and includes both the delta
and the 3 radiating lines where ridges deviate in different directions.
Personal Identification, Wentworth and Wilder 1918 pg. 117.

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!

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: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.

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.)

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:

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:
The circled bifurcation is a common location for a bifurcation in most patterns. It is where one ridge is part of the distal system and one ridge is part of the pattern area. Sometimes they appear as a bifurcation, sometimes diverging parallel ridges, or abutting ridges.

That's the reason I think you gravitate to choosing a bifurcation as the main location.

You can see in fig. 20 that it is clearly a mistaken location, yet you don't see how that is the location you have chosen in Kiwi's print.

Martijn (admin) wrote:

Patti wrote:
The circled bifurcation is a common location for a bifurcation in most patterns. It is where one ridge is part of the distal system and one ridge is part of the pattern area. Sometimes they appear as a bifurcation, sometimes diverging parallel ridges, or abutting ridges.

That's the reason I think you gravitate to choosing a bifurcation as the main location.

You can see in fig. 20 that it is clearly a mistaken location, yet you don't see how that is the location you have chosen in Kiwi's print.

Patti, we can continue to talk about Kiwihands fingerprint in her discussion.


But I don't understand that you come up with this figure 20 example... by suggesting that I should have placed the 'delta' in the location which you encircled.

Because in your suggestion... you are ignoring the delta sub-rules for situations when there are multiple bifurcations.

And I think we agreed that we should never accept when any rule is violated, so it's quite a mystery for me why you are making this suggestion regarding figure 20.