??? I do not understand at all. Within the new extended border, I need the pixels from the neighbor tiles.
Normally, if I have a big image, I create the pyramids and finally create the tiles for all levels. If I create the the tiles first and the pyramids for each tile individually, it is possible that the tiles are different. What I mean is that tiling and pyramid building is not commutative, there is no guarantee that the result is identical. Where is my false assumption ? Quoting Simone Giannecchini <[email protected]>: > Ciao Christian, > andrea is right, the trick is to use a border extender of appropriate > size which simply > copies the border pixels over and over within the limits of the > appropriate size of course > which depends on the padding required by the interpolation, 1, 2 ,4 > etc. etc. (see the interpolation class). > > Simone. > ------------------------------------------------------- > Ing. Simone Giannecchini > GeoSolutions S.A.S. > Founder > > Via Poggio alle Viti 1187 > 55054 Massarosa (LU) > Italy > > phone: +39 0584962313 > fax: +39 0584962313 > mob: +39 333 8128928 > > > http://www.geo-solutions.it > http://geo-solutions.blogspot.com/ > http://www.linkedin.com/in/simonegiannecchini > http://twitter.com/simogeo > > ------------------------------------------------------- > > > > On Wed, Feb 2, 2011 at 4:52 PM, <[email protected]> wrote: >> Quoting Andrea Aime <[email protected]>: >> >>> On Wed, Feb 2, 2011 at 3:16 PM, <[email protected]> wrote: >>>> and look at the pictures explaining bicubic and bilinear >>>> interpolation. You cannot interpolate correctly pixels at your tile >>>> borders (expect the tile border is also the border of the big image). >>>> >>>> Nearest neighbor interpolation uses the closet pixel, no calculations. >>>> I assume your images are interpolated with this algorithm and that is >>>> the reason why you are lucky. >>>> >>>> If a user runs in this problem with your architecture, we will have NO >>>> solution. Personally I would add a big warning in the documentation. >>> >>> Normally in JAI chains that is solved by using a border extender of type >>> "copy". Can't this be applied here too? >>> >>> Cheers >>> Andrea >> >> I think not because the border is filled with the pixels from the >> tile, but we need the pixels from the neighbor tiles here. >> >> Example. >> Given a tile 10x10 and bicubic interpolation. This means 16 pixels are >> the input for the calculation of one result pixel. Building a pyramid >> means reduction of the tile to 5x5 which implies reducing 4 pixels to >> one. >> Lets start in the ULC. Pixels (0,0), (1,0), (1,0) and (1,1) will be >> replaced by a new pixel. >> The bicubic interpolation needs all pixels in the range x = -1..2, y = >> -1..2, giving a total of 16 pixels. >> The -1 coordinates are the problem, so you have to load 3 neighbor >> tiles, the upper one, the left one and a third one for (-1,-1), the >> tile touching at the ULC. >> >> Doing a bilinear interpolation calculating one pixel from 4 pixels >> should be now problem as long as your width and height are even. >> >> I think most pyramids are nearest neighbor or bilinar, working without >> problems. Bicubic or even Spline interpolation may cause headache. >> >> Christian >> >>> >>> >>> -- >>> Ing. Andrea Aime >>> Technical Lead >>> >>> GeoSolutions S.A.S. >>> Via Poggio alle Viti 1187 >>> 55054 Massarosa (LU) >>> Italy >>> >>> phone: +39 0584962313 >>> fax: +39 0584962313 >>> >>> http://www.geo-solutions.it >>> http://geo-solutions.blogspot.com/ >>> http://www.linkedin.com/in/andreaaime >>> http://twitter.com/geowolf >>> >>> ----------------------------------------------------- >>> >> >> >> >> ---------------------------------------------------------------- >> This message was sent using IMP, the Internet Messaging Program. >> >> >> >> ------------------------------------------------------------------------------ >> Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! >> Finally, a world-class log management solution at an even better price-free! >> Download using promo code Free_Logger_4_Dev2Dev. Offer expires >> February 28th, so secure your free ArcSight Logger TODAY! >> http://p.sf.net/sfu/arcsight-sfd2d >> _______________________________________________ >> Geotools-devel mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/geotools-devel >> > ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. ------------------------------------------------------------------------------ Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
