[Bug 678485] opencv templatematch element improvements

Mon Jul 28 12:00:00 PDT 2014

https://bugzilla.gnome.org/show_bug.cgi?id=678485
  GStreamer | gst-plugins-bad | 0.10.x

Thiago Sousa Santos <thiagossantos> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |thiagossantos at gmail.com
         Resolution|                            |FIXED
   Target Milestone|HEAD                        |1.5.1
         OS/Version|Linux                       |All

--- Comment #6 from Thiago Sousa Santos <thiagossantos at gmail.com> 2014-07-28 18:59:53 UTC ---
Never too late, right? :)
Updated the patches for 1.0 API and implemented a better test than the one that
used the script. Thanks for the patches and sorry it took so long.

commit 06243b7eeee9ab09515e7367c189ef99bf5b652f
Author: Thiago Santos <ts.santos at osg.sisa.samsung.com>
Date:   Mon Jul 28 15:45:09 2014 -0300

    tests: templatematch: add test to check that we use the correct rgb format

    templatematch should use the same RGB format that opencv uses (BGR), make
sure
    we keep it that way with this test.

    https://bugzilla.gnome.org/show_bug.cgi?id=678485

commit f5992a6cdd13c5460a9dd2bef17c7502a0816237
Author: David Rothlisberger <david.rothlisberger at youview.com>
Date:   Fri Jun 15 13:19:06 2012 +0100

    opencv templatematch: Set caps to BGR order

    templatematch operates on BGR data. In fact, OpenCV's IplImage always
    stores color image data in BGR order -- this isn't documented at all in
    the OpenCV source code, but there are hints around the web (see for
    example

http://www.cs.iit.edu/~agam/cs512/lect-notes/opencv-intro/opencv-intro.html#SECTION00041000000000000000
    and http://www.comp.leeds.ac.uk/vision/opencv/iplimage.html ).

    gst_templatematch_load_template loads the template (the image to find)
    from disk using OpenCV's cvLoadImage, so it is stored in an IplImage in
    BGR order. But in gst_templatematch_chain, no OpenCV conversion
    functions are used: the imageData pointer of the IplImage for the video
    frame (the image to search in) is just set to point to the raw buffer
    data. Without this fix, that raw data is in RGB order, so the call to
    cvMatchTemplate ends up comparing the template's Blue channel against
    the frame's Red channel, producing very poor results.

commit aa5e25820b0a721580b5d4054477345f66352bb8
Author: Thiago Santos <ts.santos at osg.sisa.samsung.com>
Date:   Mon Jul 28 13:10:35 2014 -0300

    templatematch: mark pads as proxy caps

    Allows negotiation to happen properly

commit 1b5483eef98928d000acea579d4e68a5374557f1
Author: William Manley <william.manley at youview.com>
Date:   Mon Jun 25 20:37:01 2012 +0100

    templatematch: Produce a warning message if we can't load a template image

commit 88cb33a1dce12ab6ae847dd417effc00d6954688
Author: William Manley <william.manley at youview.com>
Date:   Wed Jun 20 15:22:52 2012 +0100

    templatematch: Match rectangle grows redder with increased match certainty

    This is useful for debugging your matches as it indicates how certain the
    match was in addition to its position.

commit b608767288b738889b4afaf6141fa92c72bb5645
Author: William Manley <william.manley at youview.com>
Date:   Wed Jun 20 15:05:40 2012 +0100

    templatematch: Allow changing template property on the fly

    Previously changing the template property resulted in an exception
    thrown from cvMatchTemplate, because "dist_image" (the intermediate
    match-certainty-distribution) was the wrong size (because the
    template image size had changed).

    Locking has also been added to allow changing the properties (e.g. the
    pattern to match) while the pipeline is playing.

     * gst_element_post_message is moved outside of the lock, because it will
       call into arbitrary user code (otherwise, if that user code calls into
       gst_templatematch_set_property on this same thread it would deadlock).

     * gst_template_match_load_template: If we fail to load the new template
       we still unload the previous template, so this element becomes a no-op
       in the pipeline. The alternative would be to keep the previous template;
       I believe unloading the previous template is a better choice, because it
       is consistent with the state this element would be in if it fails to
       load the very first template at start-up.

    Thanks to Will Manley for the bulk of this work; any errors are probably
    mine.

commit c77808055de487260363adf4969a4b62cc9048a8
Author: David Rothlisberger <david.rothlisberger at youview.com>
Date:   Fri Jun 1 16:07:34 2012 +0100

    templatematch: Pass video through when nothing to match against

    The early return was bypassing the call to gst_pad_push. With no
    filter->template (and thus no filter->cvTemplateImage) the rest of this
    function is essentially a no-op (except for the call to gst_pad_push).

    This (plus the previous commit) allows templatematch to be
    enabled/disabled without removing it entirely from the pipeline, by
    setting/unsetting the template property.

commit 056d652b922c6bf926bbfdcd3e9edbf31944e605
Author: William Manley <william.manley at youview.com>
Date:   Wed Jun 20 15:05:06 2012 +0100

    templatematch: Remove no-op call to gst_templatematch_load_template

    We have just set filter->template to NULL, so
    gst_templatematch_load_template did nothing.

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