Talk:Ridge detection

message: Would it be possible to include a discussion on the difference/similarities between ridges and edges.  Maybe an example which demonstrates the conceptual differences?  --KYN 21:01, 24 September 2006 (UTC)
thread_title:  Edges and Ridges 

message: I'm concerned about the language of the introduction.  When I read it, I understand how someone could easily miss that the ridge of a function is different from the ridge of a "scale-space" function.  I have revised the language to reflect the differences.  I have also added references to relative critical sets (RCS) because I think the set of RCS give important geometric information about the function, and this is something that people could find useful.  (Example:  RCS intersect exactly at critical points of the function; they end/transition at point where operative principle curvatures of the function are equal.)  I think the two different approaches to ridges in the first paragraph are owed to my approaching the question from a purely mathematical direction and TPL's approach as a computer scientists.  No?  It's great to have both perspectives represented in the article.
I would like to see references to the scientific literature for the statement, " In typical applications, ridge and valley descriptors are often used for detecting roads in aerial images and for detecting blood vessels in retinal images or three-dimensional magnetic resonance images."  Can somebody supply some? Millerj870 14:07, 24 February 2007 (UTC)
thread_title:  On ridge definitions and their applications in computer vision 

message: In a 2-D function, a ridge is a connected set of points that are maximal in at least one dimension.  In 2D, "maximal in at least one dimension" would include singular point maximas are ridges.  Is this correct?  When extended to N dimensions, a ridge is a connected sequence of points that are maximal in N-1 dimensions.   In both sentences the word "maximal" is used, but I would guess that "minimal" may also be applicable?  Or is the concept of ridges restricted to bright structures on dark background?   --KYN 07:54, 27 September 2006 (UTC)
thread_title:  The first paragraph 

message: In the scale space of an image, ridges provide an invariant description of elongated structures invariant relative to what? , and thus provide a complement to natural interest points (local extremal points)  I take it that local extremal points are an example of what here is called natural interest points.  There are other natural interest points in the form of corners or crossings.  Are ridges complements also of these interest points? . In image scale space, a ridge is a connected set of points that are maximal in one of the spatial dimensions as well as in the scale dimension.   1) Is this an alternative definition relative to the one provided in the first paragraph, or a more precise formulation?  2) This definition is interesting since it suggests that a ridge can be a curve in the 3D scale space of a 2D image.  Is this correct?  Is the resulting ridge then the projection of this curve onto the 2D image?   Ridges occur along the center of elongated structures  since "elongated structures" is a rather vaguely defined concept maybe "in general occur along..." is better since it promises less? , and thus provide a form of scale invariant skeleton for organizing spatial constraints on local appearance.  These three concepts need to be explained, perhaps in terms of examples: 1) Scale invariant skeleton 2) spatial constraints (which constraints?) 3) Local appearance   --KYN 18:33, 30 September 2006 (UTC)
thread_title:  Second paragraph 

message: After the restructuring of this article by user Millerj870, I made a second restructuring trying to accomplish a better compromise between the best aspects of the previous  outline and the new suggestion. For an encyclopedia article, I think that it is better to start with a verbal description of the most important information rather than starting with a set of formulae. Therefore I reinsrted a general overview introduction which aims at accomplishing this. Since the two-dimensional case is much easier to handle in terms of closed-form expressions for the formulae, I also developed the two-dimensional theory for the cases of fixed scale ridge detection and variable scale ridge detection. My view is that this material could be presented before proceeding to the more general N-dimensional case, which may be harder to grasp for unfamiliar readers. I have also added a number of more references concerning main topics of the theory as well as applications. I have, however, tried as much as possible not to touch the material that Miller870 seems to indicate that he may work further upon. My only suggestion in this respect is to merge the generalization of the concept of local maxima to ridges in arbitrary dimension to a section that describes N-dimensional ridge definitions in more detail. In the new outline of the article, there is a specific section about the N-dimensional case. Tpl 16:39, 19 January 2007 (UTC)
thread_title:  Second restructuring of the article 

message: This is a fast algorithm that has been used to acquire cell outlines and by surface profile 3-D laser scanners.  It has also been called the Center of Mass Algorithm since the calculation for one point is the same.  I think it would be good to include a short description of it on this page, along with references.   The reason I haven't just dived in and started doing it is because the page is so well written and so cohesive I first want to discuss what would be the best way to make this change.  Zen-in (talk) 17:08, 12 September 2010 (UTC)
thread_title:  Center of Luminance Ridge Detection 

message: The stub on height ridge appears to (want to) treat the same topic. The main references seem to be the same: Lindeberg, Haralick, Eberly etc. Tijfo098 (talk) 12:46, 2 September 2012 (UTC)
thread_title:  Height ridge 

message: this article jumps right into the technical specifications. it does not provide a basic, generic statement saying what ridge detection actually is.
its way too focussed on maths and does not provide any way for someone to find out what ridge detection is unless they already knew what ridge detection was.  — Preceding unsigned comment added by 111.69.192.23 (talk) 14:19, 2 February 2013 (UTC)
thread_title:  requires more generic summary