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finger tip extraction

kao.lite
Hi,

I have the contour of an hand (cvfindcontour). I wants to extract the fingertips position in the contour. Is there any quick way to do that?

kao


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Re: finger tip extraction

Walter Lucetti
cvFindConvexityDefect

Kao ha scritto:

>  
>
> Hi,
>
> I have the contour of an hand (cvfindcontour). I wants to extract the
> fingertips position in the contour. Is there any quick way to do that?
>
> kao
>
>


[Non-text portions of this message have been removed]

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Re: finger tip extraction

kao.lite
thanks a lot ... If I understand correctly, CvConvexityDefect will return the fingertip position but also the minima between two finger ? How can I find if it's a fingertip or a minima ?

--- In [hidden email], Walter Alex Lucetti <w.lucetti@...> wrote:

>
> cvFindConvexityDefect
>
> Kao ha scritto:
> >  
> >
> > Hi,
> >
> > I have the contour of an hand (cvfindcontour). I wants to extract the
> > fingertips position in the contour. Is there any quick way to do that?
> >
> > kao
> >
> >
>
>
> [Non-text portions of this message have been removed]
>


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Re: finger tip extraction

Golan Levin
In reply to this post by kao.lite
Fingertips are points of high curvature.
Resample and smooth the contour, then find points of high curvature.
g

On Thu, Oct 22, 2009 at 3:01 AM, Kao <[hidden email]> wrote:

>
>
> Hi,
>
> I have the contour of an hand (cvfindcontour). I wants to extract the
> fingertips position in the contour. Is there any quick way to do that?
>
> kao
>
>  
>


[Non-text portions of this message have been removed]

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Re: Re: finger tip extraction

Golan Levin
In reply to this post by kao.lite
positive curvature versus negative curvature.

On Thu, Oct 22, 2009 at 4:45 AM, Kao <[hidden email]> wrote:

>
>
> thanks a lot ... If I understand correctly, CvConvexityDefect will return
> the fingertip position but also the minima between two finger ? How can I
> find if it's a fingertip or a minima ?
>
>
> --- In [hidden email] <OpenCV%40yahoogroups.com>, Walter Alex
> Lucetti <w.lucetti@...> wrote:
> >
> > cvFindConvexityDefect
> >
> > Kao ha scritto:
> > >
> > >
> > > Hi,
> > >
> > > I have the contour of an hand (cvfindcontour). I wants to extract the
> > > fingertips position in the contour. Is there any quick way to do that?
> > >
> > > kao
> > >
> > >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>  
>


[Non-text portions of this message have been removed]

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Re: finger tip extraction

lizkizvn
In reply to this post by kao.lite
Let's try with Curvature or Ridge detection.

TL

--- In [hidden email], "Kao" <kao.lite@...> wrote:
>
> Hi,
>
> I have the contour of an hand (cvfindcontour). I wants to extract the fingertips position in the contour. Is there any quick way to do that?
>
> kao
>


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Re: finger tip extraction

kao.lite
In reply to this post by Golan Levin
Is there any ready to use function in opencv to smooth the contour and find minima and extrema or do I need to do it myself ? Can I use cvFindDominantPoints ?


kao

--- In [hidden email], Golan Levin <golan@...> wrote:

>
> positive curvature versus negative curvature.
>
> On Thu, Oct 22, 2009 at 4:45 AM, Kao <kao.lite@...> wrote:
>
> >
> >
> > thanks a lot ... If I understand correctly, CvConvexityDefect will return
> > the fingertip position but also the minima between two finger ? How can I
> > find if it's a fingertip or a minima ?
> >
> >
> > --- In [hidden email] <OpenCV%40yahoogroups.com>, Walter Alex
> > Lucetti <w.lucetti@> wrote:
> > >
> > > cvFindConvexityDefect
> > >
> > > Kao ha scritto:
> > > >
> > > >
> > > > Hi,
> > > >
> > > > I have the contour of an hand (cvfindcontour). I wants to extract the
> > > > fingertips position in the contour. Is there any quick way to do that?
> > > >
> > > > kao
> > > >
> > > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> >
> >  
> >
>
>
> [Non-text portions of this message have been removed]
>


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Re: Re: finger tip extraction

Walter Lucetti
In reply to this post by kao.lite
It return a CvConvexityDefect structure:
typedef struct CvConvexityDefect
{
CvPoint* start; /* point of the contour where the defect begins */
CvPoint* end; /* point of the contour where the defect ends */
CvPoint* depth_point; /* the farthest from the convex hull point within
the defect */
float depth; /* distance between the farthest point and the convex hull */
} CvConvexityDefect;

it says all... start and end points are fingertips ^_^

Kao ha scritto:

>  
>
> thanks a lot ... If I understand correctly, CvConvexityDefect will
> return the fingertip position but also the minima between two finger ?
> How can I find if it's a fingertip or a minima ?
>
> --- In [hidden email] <mailto:OpenCV%40yahoogroups.com>,
> Walter Alex Lucetti <w.lucetti@...> wrote:
> >
> > cvFindConvexityDefect
> >
> > Kao ha scritto:
> > >
> > >
> > > Hi,
> > >
> > > I have the contour of an hand (cvfindcontour). I wants to extract the
> > > fingertips position in the contour. Is there any quick way to do that?
> > >
> > > kao
> > >
> > >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>


[Non-text portions of this message have been removed]

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Re: finger tip extraction

kao.lite
Hi,

thanks a lot ... cvConvexityDefect does the job !!! but it seems that I need to smooth the contour before because I have a lot of false detection. Does anyone know how to do that ? is there a magic opencv function :) I have tryed with cvApproxPoly(contour,sizeof(CvContour),storage,CV_POLY_APPROX_DP,3,1);
but it's not working the detecting fingertip are strobbing ... cvapproxPoly is too simplist ..



--- In [hidden email], Walter Alex Lucetti <w.lucetti@...> wrote:

>
> It return a CvConvexityDefect structure:
> typedef struct CvConvexityDefect
> {
> CvPoint* start; /* point of the contour where the defect begins */
> CvPoint* end; /* point of the contour where the defect ends */
> CvPoint* depth_point; /* the farthest from the convex hull point within
> the defect */
> float depth; /* distance between the farthest point and the convex hull */
> } CvConvexityDefect;
>
> it says all... start and end points are fingertips ^_^
>
> Kao ha scritto:
> >  
> >
> > thanks a lot ... If I understand correctly, CvConvexityDefect will
> > return the fingertip position but also the minima between two finger ?
> > How can I find if it's a fingertip or a minima ?
> >
> > --- In [hidden email] <mailto:OpenCV%40yahoogroups.com>,
> > Walter Alex Lucetti <w.lucetti@> wrote:
> > >
> > > cvFindConvexityDefect
> > >
> > > Kao ha scritto:
> > > >
> > > >
> > > > Hi,
> > > >
> > > > I have the contour of an hand (cvfindcontour). I wants to extract the
> > > > fingertips position in the contour. Is there any quick way to do that?
> > > >
> > > > kao
> > > >
> > > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> >
> >
>
>
> [Non-text portions of this message have been removed]
>


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