opencv_dnn_ch6

Mix.install([
  {:kino, "~> 0.7.0"},
  {:evision, "~> 0.1.19"}
])

setup

alias Evision, as: Ev
base = "/Users/shou/livebook_samples/images/"

to_img = fn mat ->
  Ev.imencode(".png", mat)
  |> Kino.Image.new(:png)
end

ch6/6.3/conv

src_img = Ev.imread(base <> "veggie.png", flags: Ev.cv_IMREAD_GRAYSCALE())

filter_vertical = Nx.tensor([[-1, 0, 1], [-2, 0, 2], [-1, 0, 1]], type: :f32)

dst_img_v =
  Ev.filter2D(src_img, -1, filter_vertical)
  |> Ev.convertScaleAbs()
  |> to_img.()

filter_horizontal = Nx.tensor([[-1, -2, -1], [0, 0, 0], [1, 2, 1]], type: :f32)

dst_img_h =
  Ev.filter2D(src_img, -1, filter_horizontal)
  |> Ev.convertScaleAbs()
  |> to_img.()

Kino.Layout.grid([to_img.(src_img), dst_img_v, dst_img_h], columns: 3)