Pr. J.-P. Antoine*, L. Jacques*,+, Dr. J.-F. Hochedez**

12 May 2000






* Institut de Physique Théorique, FYMA, UCL, Louvain-la-Neuve.
+ Doctorant F.R.I.A.
** Department of Solar Physics, Royal Observatory of Belgium.






1. Example of multiscale ridges and edges detection

Here is an academic example of edges and ridges detection with multiscale selection.


Figure 1: Academic example: an angular
gaussian (128x128x8bits)



Figure 1a: Ridges(*)

Figure 1b: Edges(*)





(*) The scales range from 0.2 to 180, that is from 1 to 80 pixels (filter width)





2. Multiscale ridges and edges in the four different wavelengths of solar corona pictures



Original Images
Multiscale ridges
Multiscale edges





3. Conjugated multiscale ridges detection



Here is a color visualisation of a cumulated multiscale ridges detection in the four following wavelengths:




171 Å

195 Å

284 Å

304 Å

Original Images





Figure 2: Each color represents the wavelength
of the ridges. There is a thresholding
of 0.5% in the ridge measure.






4. Questions









5. References



  1. J.-P. Antoine, P. Carette, R. Murenzi and B. Piette, Image analysis with two-dimensional continuous wavelet transform, Signal Proc. 31 (1993), 241-272.

  2. J. Canny. A computational approach to edge detection. IEEE-PAMI, 8(6):679-698,1986.

  3. T. Lindeberg. Edge detection and ridge detection with automatic scale selection. In Proceeding IEEE Comp. Soc. Conf. on Computer Vision and Pattern Recognition, 1996, pages 465-470, San Francisco, California, June 1996. IEEE Computer Society Press.