from http://tech.groups.yahoo.com/group/OpenCV/message/26317
1. Dilation of the white squares by 1 pixel, so that the black squares
don't touch (it might be the oter way, i'm not shure).
2. Thresholding with a value beneath the medium intensity
3. Contour extraction and approximation to a rectangle. This extract
the black (i suppose) squares.
4. selection of the inner corners by rejecting the points which don't
belong to two extracted rectangles.
I noticed that this is not working very well for images taken using a
camera with a flash, due to non uniform illumination.
But i managed to extract the correct corners by running the contour
extraction several times, using several different thresholds, even
adaptive thresholding, different combinations of Dilate/Erode and
rejecting duplicate rectangles prior to step 4.
G�nter
--- In OpenCV@yahoogroups.com, S�kr� OZAN <perdesiz@y...> wrote:
>
>
> I wonder what kind of algorithms does FindChessBoardCorners uses to
> find out the corresponding corners... any ideas?
Re: cvFindChessboardCorners() uses what??
1. Dilation of the white squares by 1 pixel, so that the black squares
don't touch (it might be the oter way, i'm not shure).
2. Thresholding with a value beneath the medium intensity
3. Contour extraction and approximation to a rectangle. This extract
the black (i suppose) squares.
4. selection of the inner corners by rejecting the points which don't
belong to two extracted rectangles.
I noticed that this is not working very well for images taken using a
camera with a flash, due to non uniform illumination.
But i managed to extract the correct corners by running the contour
extraction several times, using several different thresholds, even
adaptive thresholding, different combinations of Dilate/Erode and
rejecting duplicate rectangles prior to step 4.
G�nter
--- In OpenCV@yahoogroups.com, S�kr� OZAN <perdesiz@y...> wrote:
>
>
> I wonder what kind of algorithms does FindChessBoardCorners uses to
> find out the corresponding corners... any ideas?
