Function close

pub fn close(image: &GrayImage, norm: Norm, k: u8) -> GrayImage

Dilation followed by erosion.

See the erode and dilate documentation for definitions of dilation and erosion.

Examples

use imageproc::morphology::close;
use imageproc::distance_transform::Norm;

// Small holes are closed - hence the name.
let small_hole = gray_image!(
    255, 255, 255, 255;
    255,   0,   0, 255;
    255,   0,   0, 255;
    255, 255, 255, 255
);

let closed_small_hole = gray_image!(
    255, 255, 255, 255;
    255, 255, 255, 255;
    255, 255, 255, 255;
    255, 255, 255, 255
);

assert_pixels_eq!(
    close(&small_hole, Norm::LInf, 1),
    closed_small_hole
);

// Large holes survive unchanged.
let large_hole = gray_image!(
    255, 255, 255, 255, 255;
    255,   0,   0,   0, 255;
    255,   0,   0,   0, 255;
    255,   0,   0,   0, 255;
    255, 255, 255, 255, 255
);

assert_pixels_eq!(
    close(&large_hole, Norm::LInf, 1),
    large_hole
);

// A dot gains a layer of foreground pixels
// when dilated and loses them again when eroded,
// resulting in no change.
let dot = gray_image!(
      0,   0,   0,   0,   0;
      0,   0,   0,   0,   0;
      0,   0, 255,   0,   0;
      0,   0,   0,   0,   0;
      0,   0,   0,   0,   0
);

assert_pixels_eq!(
    close(&dot, Norm::LInf, 1),
    dot
);

// A dot near the boundary gains pixels in the top-left
// of the image which are not within distance 1 of any
// background pixels, so are not removed by erosion.
let dot_near_boundary = gray_image!(
      0,   0,   0,   0,   0;
      0, 255,   0,   0,   0;
      0,   0,   0,   0,   0;
      0,   0,   0,   0,   0;
      0,   0,   0,   0,   0
);

let closed_dot_near_boundary = gray_image!(
    255, 255,   0,   0,   0;
    255, 255,   0,   0,   0;
      0,   0,   0,   0,   0;
      0,   0,   0,   0,   0;
      0,   0,   0,   0,   0
);

assert_pixels_eq!(
    close(&dot_near_boundary, Norm::LInf, 1),
    closed_dot_near_boundary
);