LINX/How to get the subpixel area or subpixel coordinates of edges

  • We consider to get the subpixel area or subpixel edges' coordinates.

    We use 8k line scan camera that is raL8192-80km as Full configuration.

    It is too fast to calcurate subpixel area by using HALCON(CPU).

    We consider FPGA (Marathon-VCL) can do it, however FPGA only cannot get the subpixel areas.

    So, we consider if we get the subpixel coordinates of each edges, we can calcurate the sub pixel area of cirlces.

    Do you have any ideas?

    Hajime Miyata

  • Dear Miyata-san,

    thank you for your question.

    Please find attached a small design example, which is maybe useful for you.

    In this example based on a simple threshold the circles are segmented. The edges are detemined using FIR Kernel operation. A multiplication with Coordinate X and Coordinates Y gives the coordinates of the edges.

  • Dear Carmen-san,

    Thank you for your cooperation.

    I think your sample program is determing Coordinate X and Y of edges with "pixel accuracy," is it right?

    I'm not sure how to calculate sub-pixel accuracy with your sample.

    Do you have any more ideas?

    Best regards,

    Hajime Miyata

  • Dear Miyata-san,

    please find attached the extended design with the idea how you may calculate the subpixel position. As the subpixel position of the edges only depends on the different gray values at the edges you may use a kind of interpolation between the gray values to extract the subpixel coordinates of the edges. Please find some comment boxes in the design. Please let us know. if you have further questions.