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2013-05-29 18:21:31 -0500 asked a question imread() declaration / definition / location
  1. In what .h or .hpp file is imread() defined ?
  2. When Cmake builds the lib for same, where does it "normally" end up ?

    Let's say I built it this way (from an [I think unclear] example located here )


Does that generate

/usr/local/opencv/{all the .so files}

or something else ?

Thank you !

  • HP
2013-05-29 16:22:52 -0500 commented question can't open android camera with opencv.

Did your opencv build include the android camera stuff? I think it doesn't come out of the box with that enabled. Good luck with Samsung and their cameras in any case. I've spent weeks getting their dorked-with-android phones to do what other do in minutes. :-((

2013-05-29 16:04:04 -0500 answered a question How to detect crescent shape?

Hi Jean-Francois. You're welcome - well, again this isn't an answser, but my comment wouldn't fit in a comment :-| Curve fitting is a big subject area which you'd need to research a bit more on your own. Here's some ways to head out: almost any 2 dimensional curve can be generated using polynomial equations. Take for example a basic parabola, y = x^2. Each x value generates a y. This process can be reversed. Any set of points, if they are not too chaotic or random, can be used to 'connect the dots' making a curve. If you fit your image data points (you know now the y, but need to figure out the x ), you can figure out :)) what figure it is. So how to get the image points? If, as Sammy suggests, you get the crescent to stand out enough, you can use the black/white transistion pixels, either to make a filled form (meaning you don't care about whats 'inside' the crescent), or, create a shadow line drawing. (There's also a set of opencv routines that do this, but I don't recall their name - maybe someone can chime in here.) It's like a hit or miss, like the mine sweeper game ... your points will be on one or the other side of the "edge" of the crescent, then you use those points to 'regress' and refine the actual location of the edges. Once you have an x,y matrix of points, you can figure out the polynomial equation. If the curve edge of the crescents are smooth and circle like, then you only need the polynomial for a partial circle, used twice - one for the inner (partial) circle, and one for the outer. The only difference is the radii of the two. - H

2013-05-28 20:38:54 -0500 commented question Starting from the beginning - problems w/sample code or install ?

ok, I'm bailing for now on Fedora... attempting on Mac instead ... :-O I'm just not getting this... weird unresolved items buried deep in the include files... all files except a few, e.g. core_c.h doesn't know what seqInsert is in this block: template<typename _Tp> inline void Seq<_Tp>::insert(int idx, const _Tp& elem) { seqInsert(seq, idx, &elem); }

2013-05-28 16:56:02 -0500 commented question Starting from the beginning - problems w/sample code or install ?

Thanks for the prompt reply. Hmmm, sorry, I have only a slight clue what you're asking me to do ... I don't know where the problems originate from - or even IF they originate from somewhere else besides me ... thought I'd clearly said so in my OP. EDIT: all files I see are opencv-2.4.5

2013-05-28 16:51:01 -0500 commented question How to detect crescent shape?

a general observation, not an answer per se. First (and obviously) mask out the noise and "other" shapes as best you can. Assuming the input data is strictly a "crescent" - that is two circles of differing diameter, joined at two common points - you could find the common points of intersection, then treat the two 'edges' as simple 2-d polynomial curves. Do multiple linear regression on each curve until they " fit " ... if your curves are generic enough, a simple data set would be your baseline to compare against. HTH - HP

2013-05-28 16:34:14 -0500 received badge  Editor (source)
2013-05-28 16:31:31 -0500 asked a question Starting from the beginning - problems w/sample code or install ?

Haveing no luck with Using OpenCV with Eclipse (plugin CDT) for several days

Read on forum that "CV_" as a prefix is no longer used... not sure if this is the problem.

The build went correctly (I think) - ./opencv_test_core works. Only one or two misc. tests failed out of its > 100 or so that were OK.

However, I am unable to get one sample to compile... and I bet I'm not the first person to run into this... sooo....

The example originally suggests getting the installed path via:

pkg-config --cflags opencv

However, that yields only:

$ pkg-config --cflags opencv
Package opencv was not found in the pkg-config search path.
Perhaps you should add the directory containing `opencv.pc'
to the PKG_CONFIG_PATH environment variable
No package 'opencv' found

Huh ? If so, how did Cmake work to make the original build that generated the core test executables ?

Clearly, (I think) it's on the CDT side - I am having problems getting the header files in the correct places. I've tried moving them everywhere (!) including copying them into the project itself, setting the property->include path. ... even just dropped to a shell and command-lined the compile lines complete with includes, but still get unresolved errors - like CV_WINDOW_AUTOSIZE unknown, etc.

Is this because of the header files using relative references, e.g.


or because of the dropping of "CV_" and somehow I've gotten mixed up versions ? (I got mine from github, not via the tar ball ... and, why should THAT matter ??)

[EDIT] all files I see are opencv-2.4.5, attempting on Fedora

Thanks much for any assistance !

  • HP
2013-05-28 15:46:52 -0500 commented question Constants not found under Linux

arggg :-| .... ok :))

2013-05-28 15:43:12 -0500 commented question Constants not found under Linux

So does that mean I need to throw out the github version and start all over ???