block some part of an image for image process

    Hi Friends,


    I am a APPLET beginner and have to learn a lot. Thanks for help in advance.


    One question: how to block some part of an image for image process?

    I want to do the real time image process for the captured video. However, only is the central part useful image and surrounding area is useless. How can I filter out the surrounding area?

    Solution is appreciated.


    Thanks,

    Baoxi

    Dear Baoxi,


    You can use the build-in ImageBuffer Width/Height + X/Y Offset to apply a region of interest to the image.
    There are more operators that can do a region of interest, like: DynamicROI or ImageBufferMultiROI(dyn) ...


    If the region of interest is not rectangular, please let us know.


    Best regards,

    Dear Baoxi,


    thank you for your answer. As the region of interest is a circle I have some additional questions:

    1. Do you know the coordinates x and y, where there is useful or useless information without further image processing?

    2. Is it suitable for you to do a filtering by setting the useless pixel to zero value?


    If yes, you can think of a processing like sketched in the following:

    pasted-from-clipboard.png


    With this processing you can set all pixels outside a specified region to a zero value. You also can combine this processing with a previous selection of a rectangular region of interest for example using operators SelectROI, DynamicROI,....

    Dear CarmenZ,


    1. Yes, I know the coordinates x and y.

    2. Yes, setting the useless pixel to zero value is expected.


    Thank you very much for the suggested processing. I will try it.

    <3


    Thanks again and best regards,

    Baoxi

    Dear Baoxi,

    please find attached a ViausalApplets design example, for the definition of a round central region. The idea of the design is to go in a coordinate system reletive to the image center, and calculate the distance of the current position relative to the center of the image. Then we can set all pixels outside a specific radius to value zero.