Low quality of zoomeable images

  • Anonymous - 2013-05-03

    We are in the process of switching from Zoomify (with pre-processed images) to IIPImage. We use JPEG2000 as the image format. Everything is working fine but the quality of the tiles generated by IIPImage for zoomeable images is low, making the image appear blurry. The full-resolution image rendered by IIPImage from the same source image looks good. Here some examples:

    IIPZoom with image rendered by IIPImage

    Zoomify with image rendered by IIPImage

    Full-resolution JPEG rendered by IIPImage (looks nice and sharp)

    Zoomify with pre-tiled jpegs (looks nice and sharp)

    Could this be a problem with IIPImage not using all quality layers? Here the command we use to compress the images:

    kdu_compress -i $source -o $destination -rate 3,0.01 Clayers=8 Clevels=8 Cprecincts={256,256},{256,256},{256,256},{128,128},{128,128},{64,64},{64,64} Cblk={64,64} Corder=RPCL ORGgen_plt=yes ORGtparts=R

    and the settings for IIPImage are:

    FcgidInitialEnv JPEG_QUALITY "75"
    FcgidInitialEnv MAX_CVT "8000"
    FcgidInitialEnv MAX_LAYERS "-1"

    We are using the latest version of kakadu and IIPImage.



  • Ruven

    Ruven - 2013-05-03

    Are you using the latest code from github? Or the latest stable release?
    Because there were quality layer decoding issues with JPEG2000 in the stable which (should) now be fixed in the latest development code.

    You could also try changing MAX_LAYERS=8 in the server conf and adding LYR=8 to the image path you give to iipzoom to force the loading of all layers.

  • Anonymous - 2013-05-04

    We are using version 0.9.9 (Ubuntu 64bit) from the oldmapsonline website. Doing some more testing it looks like for all zoom tiles only layer 4 is being used. Unfortunately we don't have a Kakadu license to compile the development code. Is there any chance you could send me a compiled version? When will the new version be released? Thanks a lot.



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