×

Discussion Board

Results 1 to 8 of 8
  1. #1
    Regular Contributor
    Join Date
    Apr 2004
    Posts
    96

    N95 camera distortion ?

    I’m making full screen version of my AR Tower Defense game, and stumble at some strange problem. It seems to me the camera distortion is absent if I’m getting scaled down viewfinder image 240x180. If I’m getting full viewfinder image 320x240 it looks like some camera distortion creep in - seems markers getting distorted. I may have to calibrate camera, and that would create portability problem. The game will work only for N95 camera…

  2. #2
    Registered User
    Join Date
    Dec 2006
    Posts
    2,280

    Re: N95 camera distortion ?

    Hi,

    What sort of distortion? With still images or only motion?

    To be honest I wouldn't be too surprised if there was a little distortion around the edges - the optics are squeezed down so small in these thing...

    Is it so bad that you can't "just" make the marker detection robust to a bit of noise/variation?

    Sorcery

  3. #3
    Regular Contributor
    Join Date
    Apr 2004
    Posts
    96

    Re: N95 camera distortion ?

    That's geometric distortion near edges. Single marker is not a problem, but with several markers geometry become inconsistent.
    What I'm trying to understand how distortion depend on the resolution. If lower resolution viewfined just cropped out of the bigger camera frame somehow, that would explain why it has less distortion.

  4. #4
    Registered User
    Join Date
    Dec 2006
    Posts
    2,280

    Re: N95 camera distortion ?

    Yes, I think small frames are generally cropped from the sensor rather than scaled down from the full resolution.

    I'm not 100% certain on that but if it's consistent with what you're seeing that makes it a very likely explanation.

    Sorcery

  5. #5
    Regular Contributor
    Join Date
    Apr 2004
    Posts
    96

    Re: N95 camera distortion ?

    Actually I could have been wrong. Distortion could have been on the order of magnitude less then I previously thought. The problem with geometry inconsistency I'm having with bigger viewfinder frame could be caused some other reason. Actually what caused my presumed mistake was tis research on Nokia N95 camera calibration
    http://scien.stanford.edu/class/psyc...kia/index.html
    They got huge distortion estimation - like 3% of the screen width. I don't detect anything like this in 320x240 viewfinder. My upper bound is like .7% (though I didn't do complete calibration, just did some shots of rectangles).

  6. #6
    Registered User
    Join Date
    Dec 2006
    Posts
    2,280

    Re: N95 camera distortion ?

    Hi,

    Well, if the image is much smaller than the full resolution (whether cropped from the centre or scaled down) then you wouldn't expect to see as much distortion...

    .7% distortion sounds quite impressively small to me given the scale of the optics and the necessary size of sensor.

    Personally though, I'd prefer it if they stuck with say 3MPix so that the physical pixels were larger and I didn't get so much noise in low light shots (which are most of the pictures I take).

    Sorcery

  7. #7
    Nokia Developer Expert
    Join Date
    Dec 2003
    Posts
    148

    Re: N95 camera distortion ?

    I am not exactly sure on what sort of distortion you are talking about...

    What I can say is that all view finder sizes should have the same field-of-view i.e. smaller images are not cropped any more than bigger images are.
    Last edited by janza; 2008-12-02 at 13:18.
    janza

  8. #8
    Regular Contributor
    Join Date
    Apr 2004
    Posts
    96

    Re: N95 camera distortion ?

    Quote Originally Posted by janza View Post
    I am not exactly sure on what sort of distortion you are talking about...
    Check this link
    http://scien.stanford.edu/class/psyc...istortion_eval
    and this
    http://scien.stanford.edu/class/psyc...ortion_results

Similar Threads

  1. Nokia N-Series Complete Model Line-Up
    By Dopod in forum General Development Questions
    Replies: 6
    Last Post: 2008-07-22, 20:16
  2. jsr234 camera getSnapShot() on Nokia N95
    By garyjamessilva in forum Mobile Java Media (Graphics & Sounds)
    Replies: 21
    Last Post: 2008-07-02, 15:14
  3. N95 camera selection
    By pflammertsma in forum Streaming and Video
    Replies: 1
    Last Post: 2008-05-02, 19:17
  4. N95 Camera issue
    By sandy_zeng in forum Symbian
    Replies: 13
    Last Post: 2007-09-08, 15:16
  5. jsr135 highest supported camera resolutions for getSnapShot() on N95
    By garyjamessilva in forum Mobile Java Media (Graphics & Sounds)
    Replies: 3
    Last Post: 2007-05-30, 21:14

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
×