[Octave-bug-tracker] [bug #42437] Image fspecial with type="motion" doesn't work for most other angles than 0

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?42437>

                 Summary: Image fspecial with type="motion" doesn't work for
most other angles than 0
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Tue 27 May 2014 09:01:26 AM UTC
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Petter Moe Kvalvaag
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.8.1
        Operating System: GNU/Linux

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Details:

The function fspecial from the image package doesn't work properly for
constructing motion blur psf. 

Eg. psf = fspecial("motion", 10, 45)

returns a 15x15 matric containing only NA. This goes for all other angles than
0 as far as I can tell. This can be fixed by changing the call to imrotate
within the "motion" case thus

  -f = imrotate (f, angle, "bilinear", "loose")
  +f = imrotate (f, angle, "bilinear", "loose", 0)

so that undefined values outside of the original image which are introduced in
the rotation get extrapolated to zero and not undefined.




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