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  1. #1
    Registered User
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    May 2008
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    2

    Video camera exposure and zoom

    Hi all,

    I was playing with acquiring images of different exposures from video stream, due to too large still image latency. My code currently receives one frame and sets exposure to another supported value.

    When taking such images, although zoom factor is still the same (0), image taken on EExposureNight is somewhat "zoomed out" compared to other images. Development is done on Nokia N95.

    So,

    1) is there any technical reason, aka sensory hardware, to be so, or is it my fault?
    2) would Partnering Api Request solve our problem when taking multiple images of different exposure, shortest possible time between images and same *visualy perceived* zoom factor on each image?

    We really need this to implement some image deconvolution and superresolution algorithms.

    Thanks for reply,
    rp
    Last edited by romanpauk; 2008-09-29 at 13:04.

  2. #2
    Registered User
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    Dec 2006
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    2,280

    Re: Video camera exposure and zoom

    I think this is a question for the resident Forum Nokia Expert, janza, if he is around.

    It sounds like it might be simply trying to use more pixels in the sensor and then downscaling the image in order to capture more light. It might just be a bug though.

    Have you experimented to see if you can find a zoom factor reverses the change?

    Sorcery

    P.S. The process for API partnering is to submit a technical support request with details of your use case and requirements and they will then tell you if API partnering will help. Nokia can't give details of private APIs you might be able to partner on the public discussion boards.

  3. #3
    Nokia Developer Expert
    Join Date
    Dec 2003
    Posts
    148

    Re: Video camera exposure and zoom

    hi romanpauk,

    Seems that you have found a feature that I have not been aware of! I tried this with my N95 8BG and it really seems that the field of view is bigger in night mode. Partnering API request will not solve this issue. There is no way to control this from Symbian OS SW, it seems to be very low level camera HW feature. The only solution I could think of is the one suggested by Sorcery-ltd: apply some digital zoom in night mode to compensate the changed field of view. Of course this will make your application specific to N95, since there is no guarantee that the behavior is the same in devices with different camera HW.
    janza

  4. #4
    Registered User
    Join Date
    May 2008
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    2

    Re: Video camera exposure and zoom

    Thanks you both for your help.

    Zoom factor 6 makes the images look almost the same. We will try how fast the computation will be running first, images we have now seem to suffice for it.

    Have a nice day

  5. #5
    Registered User
    Join Date
    Oct 2007
    Location
    Israel
    Posts
    77

    Re: Video camera exposure and zoom

    Hi ,

    I need to change the exposion time (exposion method by SetExposureL has not been relevant).
    Dow you know how I can to access to camera (N95) on low level? Is it open interface? Where is it described ?

    Thanks Alex

  6. #6
    Nokia Developer Expert
    Join Date
    Dec 2003
    Posts
    148

    Re: Video camera exposure and zoom

    Sorry Alex, exposure time API is not available.
    janza

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