4 Replies Latest reply on Sep 10, 2008 11:34 PM by Mylenium

    PATTERNS OF DISTORTION

    Level 1
      Hello there,

      I am working with some footage of buildings and have found that the details are not translating well when shrunken down in scale. I get odd patterns and artifacts. Is there a way to deal with this, short of putting a directional blur on the footage? I don't want to blur the image, but want the patterns to go away... I wonder if applying a median filter very very subtly...?

      Thanks very much for your thoughts!

      - Fredo
        • 1. Re: PATTERNS OF DISTORTION
          Level 1
          This is common with images that contain lots of fine detail. A herring bone suit or a striped neck tie is a good example. When I started in this business I worked for a TV station in the news department and our weather man kept wearing this neck tie that would dance around like crazy on camera. The only solution was to zoom out or in a bit to remove the moray pattern or run him just a little out of focus.
          • 2. Re: PATTERNS OF DISTORTION
            Level 1
            Thanks, Rick. Yes, I knew about the problem with clothing patterns. Just never would have imagined it would happen with the brick from a building. One thing I did was remove the sharpening I applied, which definitely accentuated the problem. I can remember hearing that when you are dealing with single pixels a vertical directional blur helped solve the problem. Maybe I will try that out. I'll let you know how it works. Thanks again!
            • 3. Re: PATTERNS OF DISTORTION
              Level 1
              A pattern is a pattern. Interlaced video makes the problem worse. Progressive video makes strobing with movement worse. Making movies, just like life, is nothing more than a series of compromises that eventually tells a story.

              If these are stills you might try Photoshop's dust and scratches filter. I use it all the time to smooth out stills for video.
              • 4. Re: PATTERNS OF DISTORTION
                Mylenium Most Valuable Participant
                Indeed. High frequency detail interference is common even at HD resolutions. Simple physical/ technical thing (if the spatial/ temporal frequency[resolution] is lower than..., then it follows that...). A little blur is almost inevitable, whether you intentionally introduce it with an effect or it comes by transforming the pixels. You can try to also use a tiny bit of rotation to improve the sampling pattern, but that's pretty much it. If you want to use effects, I recommend you use adapative blurs such as RevisionFX' Smoothkit package. Base on e.g. the luminance of the image, it will blur some areas more, others not at all, which ultimately is what you would want. It's also a great toolset for dealing with other things like DV and MPEG artifacts, so it might be even more worth an investment.

                Mylenium