scripts/builtin/img_cutout.dml

#-------------------------------------------------------------
#
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# to you under the Apache License, Version 2.0 (the
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#
#   http://www.apache.org/licenses/LICENSE-2.0
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# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
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#-------------------------------------------------------------

# Image Cutout function replaces a rectangular section of an image with a constant value.
#
#
# .. code-block:: python
#
#   >>> import numpy as np
#   >>> from systemds.context import SystemDSContext
#   >>> from systemds.operator.algorithm import img_cutout
#   >>> 
#   >>> with SystemDSContext() as sds:
#   ...     img = sds.from_numpy(
#   ...         np.array([[ 50., 100., 150.],
#   ...                   [150., 200., 250.],
#   ...                   [250., 200., 200.]], dtype=np.float32)
#   ...     )
#   ...     result_img = img_cutout(img, 2, 2, 1, 1, 49.).compute()
#   ...     print(result_img)
#   [[ 50. 100. 150.]
#    [150.  49. 250.]
#    [250. 200. 200.]]
#
#
# INPUT:
# ---------------------------------------------------------------------------------------------
# img_in      Input image as 2D matrix with top left corner at [1, 1]
# x           Column index of the top left corner of the rectangle (starting at 1)
# y           Row index of the top left corner of the rectangle (starting at 1)
# width       Width of the rectangle (must be positive)
# height      Height of the rectangle (must be positive)
# fill_value  The value to set for the rectangle
# ---------------------------------------------------------------------------------------------
#
# OUTPUT:
# ------------------------------------------------------------------------------------------
# img_out  Output image as 2D matrix with top left corner at [1, 1]
# ------------------------------------------------------------------------------------------

m_img_cutout = function(Matrix[Double] img_in, Integer x, Integer y, Integer width, Integer height, Double fill_value) return (Matrix[Double] img_out) {
  rows = nrow(img_in)
  cols = ncol(img_in)

  if (width < 1 | height < 1) {
    print("Invalid width or height. Returning input")
    img_out = img_in
  } else {
    end_x = x + width - 1
    end_y = y + height - 1

    start_x = max(1, x)
    start_y = max(1, y)
    end_x = min(cols, end_x)
    end_y = min(rows, end_y)

    img_out = matrix(img_in, rows=rows, cols=cols)
    img_out[start_y:end_y, start_x:end_x] = matrix(fill_value, rows=(end_y-start_y+1), cols=(end_x-start_x+1))
  }
}