Sobel Function. BoundaryConditions

[arturoar3nas]

Hello,

I'm trying to perform a Sobel filter with the below code:

  Func Sobel_filter_h(Buffer<uint8_t>& src)
  {
    Var x("x"), y("y"), c("c");
    Func clamped = BoundaryConditions::constant_exterior(src, 0);

    Func input_16("input_int16");
    input_16(x, y, c) = cast<int16_t>(clamped(x, y, c));

    Func output("output");
    output(x, y, c) = -input_16(x - 1, y - 1, c) + input_16(x + 1, y - 1, c)
    - 2 * input_16(x - 1, y, c) + 2 * input_16(x + 1, y, c)
    - input_16(x - 1, y + 1, c) + input_16(x + 1, y + 1, c);

    return output;
  }

And I compare the result against Opencv Sobel

Sobel( img, grad_x, ddepth, 1, 0, ksize, scale, delta, BORDER_DEFAULT );

But they are not equal results. I'm comparing with this function:

std::equal(grad_x.begin<int16_t>(), grad_x.end<int16_t>(), grad_x_halide.begin<int16_t>());

It could be that I'm using the edges wrong?

[arturoar3nas]

Sorry,

I fix this using mirror_interior