Video Image Centering

Discussion in 'General Electronics Chat' started by jpanhalt, Oct 17, 2014.

  1. jpanhalt

    Thread Starter AAC Fanatic!

    Jan 18, 2008
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    I have been working with installing a rear view camera on a skid steer. I am trying to go cheap. My monitor is a Pyle PLHRQD9B. That is a 9" TFT LCD monitor. It allows both NTSC and PAL inputs and the aspect ratio is switchable between 16:9 and 4:3. It is described as having a resolution of 640 horizontal and 234 vertical. I am not quite sure what those metrics mean. There are no adjustments for centering such as exist on my PC monitor.

    The problem I am having is the field of view (FOV) is not centered on the optical axis of the camera. The camera is a an inexpensive "typical" CCD from China. The FOV is supposed to be 130°. I suspect the width of the scan from the camera is different than the monitor width and the image is getting clipped on one side. That makes it difficult to back into the center between open doors. The clipping is camera right side, monitor left side because of the mirroring.

    Is there a box made that can adjust the clipping to give a centered image? What is the box called?

    All searches I have done for image centering have returned either loads of stuff on HTML image centering or video games.

    Regards,

    John
     
  2. DNA Robotics

    Member

    Jun 13, 2014
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    Does it work right with a different monitor? Maybe the camera is bad???
     
  3. jpanhalt

    Thread Starter AAC Fanatic!

    Jan 18, 2008
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    I don't have a different monitor of that type that I can test. I have ordered another cheap camera and a wide field (170°) lens. Those items are all in China Post, which may take awhile.

    After another couple of hours on Google, I found some recent patents for doing it, which of course are of no help to me now, and references to Inline, which used to make boxes that addressed the issue somewhat(IN2100). All of the Inline products are describe as "Analog Video Interface" and are discontinued. Further searches for that term didn't yield anything in my price range. The available products seem to be more appropriate for studios.

    Worse comes to worse, I have ordered a 170° camera, will mount it relatively forward on the machine, and cover the right side of the monitor with duct tape to give equal field of views. :D Basically, all I need to see is the back of the machine relative to what I am about to hit. Just seeing open space without the machine reference points doesn't give me a degree of confidence with which I am comfortable.

    John
     
  4. jpanhalt

    Thread Starter AAC Fanatic!

    Jan 18, 2008
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    PROBLEM SOLVED

    I tore into the camera and noted that the lens mount is screwed to the PCB on which the image sensor is mounted. Loosened the two screws and slid the lens a little in the other direction. Image is now centered, warranty (ha, ha) is voided.

    John
     
  5. MrChips

    Moderator

    Oct 2, 2009
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    Ha, ha. Sometimes the obvious solution is the simplest one.:)

    I just finished salvaging a very expensive looking LCD projector. Presumably it was being thrown out because they couldn't focus it. It turns out that the lens was mounted on a cylindrical tube that was pushed in too far. Loosing a simple set screw and repositioning the tube was all it took to fix the problem.
     
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