cmucam3-hardware (#1) - accessing arrays (#48) - Message List

accessing arrays

We have purchased the cmuCam3 as part of an honours project and are trying to program functions to enable different functions for the tracking alogorithm. As I have not had alot of experience with C programming I am having problems putting information into arrays and manipulating the data.

I am trying to place the frame data of a virtual window into an array to be fed into an algorithm which sorts values of interest (median, deviation, etc). Alternatively is there a way to directly access the information in the buffer

engr_ee
09/06/07 03:35:58
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  • Message #115

    In the hello-world project we show a few different ways to access data from the frame buffer. Keep in mind that you don't have enough RAM to hold a full sized frame in the ARM's memory. If you downsample the image or use a single channel, then you may be able to fit a small frame entirely in memory. Most of the image processing in the CMUcam is done using a scanline based approach. You can always rewind the FIFO or load a set of rows (this is what jpeg does).

    -Anthony

    agr
    09/06/07 11:45:34
    • Message #507

      I edit hello-world project and printf every pixel and read line by line for red channel. Somehow, if i put the cover infront of camera lense, it give a range of value not a fixed number. (i.e. black should give value of 16, therefore all pixels should be 16).

      Is it the nature of this cmos camera ? or because of image enchancement setting on this camera resulted this behaviour.

      Thanks in advance..

      wikki
      05/03/08 03:17:34
      • Message #508

        Yes. If you have auto gain and/or white balance turned on, the camera will increase the pixel gain levels to try and get the image to be gray on average. Try turning them off and doing the same thing. You might not get all 16, but it should be much closer.

        agr
        05/03/08 11:04:10
        • Message #509

          Thanks.. that would solve the puzzle.. and by the way.. if i printf the raw value... would it really be upside down image... somehow i learn in physics that any image will be upside down when it go thro a camera lense.

          Some cmos camera does improves this features and give correct orientation. Does this camera support this features or it is really basic camera which display upside down images when i access pixel starting from top left?

          wikki
          05/04/08 03:17:01
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