Talk:Fiducial marker

Text moved from disambiguation page

The disambiguation page "fiducial" contained a lot of substantive material that overlapped with this article. As most of the "fiducial" page concerned markers of various types, I moved this text to "fiduciary marker". Nothing of substance was deleted (though a careful reader might note some duplication in the expanded article). Fbarw (talk) 08:46, 19 July 2008 (UTC)

Fiduciary vs. fiducial

In medical imaging only the "fiducial marker" term is used. To illustrate this, just do these two Google searches (IEEE Transactions on Medical Imaging is one of the premier publications in this field): +"fiducial marker" +"transactions on medical imaging" => 4210 hits +"fiduciary marker" +"transactions on medical imaging" => 9 hits The 0.2% occurrence of "fiduciary" is so low that it can be considered to be editor/reviewer oversight.

Google search for "fiduciary marker" and "fiducial marker" shows that "fiducial" is about 10x more commonly used in general.

Would it be possible to rename this entry to "fiducial marker" to be consistent with the current naming conventions? — Preceding unsigned comment added by Alasso (talk • contribs) 02:15, 3 August 2011 (UTC)

• I have never seen the term fiduciary mark in any domain. The term I encountered in physics back in the 1960s (bubble chamber and spark chamber image analysis) was fiducial mark. The term I encountered in electronic voting (analysis of mark-sense ballots) is fiducial mark. A quick Google search tells me that some people do indeed refer to fiduciary marks in some of these contexts, but I believe this usage should be depricated. Douglas W. Jones (talk) 17:03, 15 November 2011 (UTC)

• Agree it should be moved to "Fiducial marker" for the reasons cited. —Ben FrantzDale (talk) 17:25, 15 November 2011 (UTC)

• On the other hand, the only two references in this article call them "Fiduciary Markers" 15:16, 16 March 2012 (UTC)

Is arrow in image correct?

It seems to me the red arrow on the left side of the image is pointing at the wrong spot. The arrow on the right points to a round solid gold circle. There is another such circle on the left side of the image, but the arrow isn't pointing to it. 15.219.169.74 (talk) 20:29, 21 April 2015 (UTC)

Looking at the original picture, the left fiducial is meant for a chip that is mostly cropped away. I'll replace the image in two steps to fix both issues. Peter Buijs (talk) 09:57, 2 June 2017 (UTC)

Coins as markers?

The image text says coins are good fiducials. Coins make up a rough scale, but I disagree that they make up a good fiducial. Coin sizes vary quite a bit, and usually people only know the size of local coins. — Preceding unsigned comment added by 91.152.241.34 (talk) 09:56, 24 February 2016 (UTC)

Printed circuit boards — two vs. three fiducials for pcb location

Regarding the mention of using three fiducials for an SMT machine to determine PCB offset in X, Y, and rotation—this can in fact be achieved with only two fiducials. Granted that using three or more fiducials is preferable especially for large PCBs; however, using two fiducials is the theoretical minimum for X, Y, and rotation unless some SMT machines have different requirements.

I have not had problems using only two fiducials for X, Y, and rotation compensation whether on small or large PCBs with Panasonic, Fuji, Siplace and Universal GSM machines though if three or more fiducials are present on the PCB, I typically use at least three.

Also, with at least three fiducials, any shrink or stretch of the PCB can be calculated and many machines will apply this compensation. However, I very rarely encounter PCBs having significant shrink or stretch variances as this would also negatively impact the screen printing process which cannot compensate for it.

Another reason for the SMT industry to popularize the use of three fiducials is to prevent the SMT machine from placing parts on a board loaded with the wrong orientation. If only two fiducials are used when there are three fiducials on the PCB, it is possible, for example, that the machine will recognize and place parts on a rectangular PCB loaded incorrectly by 180 degrees. Having the third fiducial prevents this.

Crash test dummies - new heading

The 'see also' section links to the article on 'Secchi disk'. The Secchi disk article refers to the black and yellow circles used as fiducial markers on crash test dummies. This would be a good example to include under its own heading in the present article. Canberran (talk) 08:38, 21 February 2024 (UTC)