Talk:Image moment

message: Can anyone check: I think the second central moments are wrong and M10 or M01 in the equation should not be squared.  — Preceding unsigned comment added by 192.44.38.255 (talk) 07:21, 6 December 2017 (UTC)
thread_title:  Mistake 

message: This article needs a more general introductory section to give better context to the layman.--Hooperbloob 05:11, 12 August 2005 (UTC)
thread_title:  Suggestions 

message: I just read the first paragraph, word-for-word, of the Raw Moments section out of the popular book "Digital Image Processing, Second Edition" by Rafael C. Gonzalez - pg 672-673. I'm not sure on the legalities but should this not at least be referenced? Yani 03:05, 20 November 2006 (UTC)
replies: text: Word for word?  That would indeed be an astonishing coincidence, as I made some small tweaks to the first paragraph a couple of months ago, without ever having read Gonzalez, making the changes for readability, accuracy, and logical flow.  But I've heard great minds think alike [smile].  That said, if you think that book is a good reference for this page, by all means add it.  I don't have access to it now, but I you think there are fair use issues, why don't you quote the relevant parts here on the talk page and we can deal with what to do next. Baccyak4H (talk) 03:28, 20 November 2006 (UTC)
replies: text: I'm not going to quote the relevant parts simply because I'd be retyping the whole section! I agree this is astonishing ...but it is unbelievable that such a large correspondence is a coincidence. The only other explanations are that either the book copied Wikipedia, or both have been copied some third party source. Yani 14:38, 12 December 2006 (UTC)
thread_title:  Raw Moments - unreferenced/plagiarism/fair use? 

message: I reorganized the article to make its style more consistent throughout, and showed more explicitly its outliine structure both in sectioning and language.  I kept pretty much all the previous material, just moved it around a bit and reworded / elaborated slightly.  And I added a little more explanatory material in the intro per Hooperbloob's good request.
I am considering writing an article on moment invariants which would apply to moments in general (e.g., physics) and cover the translation, scale, and rotation types, as well as (possibly) invariance to certain well-defined types of "blurring" (useful for image processing obviously).  It would also describe analogs in 3D and perhaps 1D, and it would hopefully update 2D rotation invariant moments to sets which are superior to Hu's in some ways.  If I did this, I may move some of this material to that article.  Any comments? Baccyak4H 03:38, 19 August 2006 (UTC)
thread_title:  Streamlining and background info 

message: Could someone please check the formula for the orientation angle, obtained from the covariance matrix ? I implemented this formula and it yielded partially incoherent results. I instead used the formula on this page (3rd slide), worked fine. But I don't want to change the original page if it's correct.Mr Bam (talk) 10:21, 16 January 2008 (UTC)
replies: text: Well, anyone who uses a single-argument arctan gets what they deserve, eh? 70.234.244.77 (talk) 05:40, 6 July 2010 (UTC)
thread_title:  Orientation angle formula 

message: Maybe it is useful to note that there is a difference between scale invariance and size invariance. What the article talks about, is scale invariance, which means the features are the same if the size of the object changes, but not the size of the embedding space (or the digital image). When however we have a digital image, and the size of this image changes (but not the size of the object relative to the image), we need another invariance measure. I'd call it size invariance because we're dealing with image size. Think of it as calculating the moments of an image, and of the same image, resized. When you want to obtain the same features from both images, these are the invariants I found:
:\eta'_{ij} = \frac{\mu_{ij}} 
                        {width^{i+1}\, height^{j+1}}\!
where i + j ≥ 2.
The +1's are there because the features, besides dividing by the respective amounts of width and height, should also be divided by the area of the image.
Similarly, we can obtain size invariance for the important raw moments M_{00}\!, \bar{x}\! and \bar{y}\!:
\frac{M_{00}}{width\, height}, \frac{\bar{x}}{width}, \frac{\bar{y}}{height}
--Zom-B (talk) 14:09, 20 November 2009 (UTC)
thread_title:  Scale invariance vs Size invariance 

message: This relatively new book just came on my radar:
: 
 
Baccyak4H (Yak!) 19:02, 10 June 2010 (UTC)
thread_title:  New source 

message: I am new to this and cannot provide definitive proof for this, but it appears that the scale invariant moments η are just approximately invariant to scale.
Please see:
http://math.stackexchange.com/questions/1218329/scale-invariant-image-moments-not-scale-variant
for an example.
This should maybe be pointed out in the article.
Max Krichenbauer (talk) 23:26, 3 April 2015 (UTC)
thread_title:  Scale invariance possibly only approximate