# Unknown mathematical symbol in context of computer vision

I'm currently reading the paper "A Template Matching Method for Multi-Scale and Rotated Images Using Ring Projection Vector Conversion" and in one formula there is a mathematical symbol I don't know. I tried to search it and looked over several Latex Math-Symbol Sheets to find it, but without luck.

Here's a picture from it: Ring projection vector formula

The unknown symbol is: unknown symbol in formula

What does this symbol mean?

• Could it be a square root sign? – Mark Bennet Jan 11 at 12:45
• Could it just be a $J$? Doesn’t the paper explain its own notation? – Randall Jan 11 at 12:48
• Since this is not a standard symbol, I decalre: either it is defined in the paper, or in a prerequisite paper explicitly mentioned, or else this is a very bad paper. It could be that the author used his own private notation. It could be that typesetting and computerized change of format ended up with the wrong symbol, perhaps because a certain font did not have that special symbol. – GEdgar Jan 11 at 13:17
• Unfortunately there is no further explanation to this symbol. It is an IEEE paper, so there had to be a few people reviewing it before the publication. There has to be an answer. But it appears in the context of scaling: "Then the ring projection vector Pk of the template image after k-time scaled is obtained according to (formula) ..." – tobyblack Jan 11 at 13:35
• Probably a square root – nemo Jan 11 at 15:17