Binary Mask Enclosed Hole Fill

Description

Fill enclosed background components under the chosen connectivity while retaining the original foreground.

A binary grid represents foreground as numeric one and background as zero. A stencil is a set of integer [rowOffset,columnOffset] positions relative to a cell. Connectivity describes allowed neighbor steps: four-neighbor connectivity uses orthogonal steps, while eight-neighbor connectivity also includes diagonals. Finite image borders and asymmetric stencils affect the result.

Fill enclosed background components under the chosen connectivity while retaining the original foreground.

When to use this tool

Use hole filling when enclosed zero regions should become foreground and boundary-connected background should remain.

How to use the tool and how it works

Enter mask, eight using the definitions below.
Run the operation. Resolve input-format errors before interpreting an output.
Read result.mask, using the stated boundary, ordering, sign and absence conventions.

Label background components using the chosen four/eight-neighbor rule. Fill with one exactly those components that have no cell on the outermost row or column, while retaining original foreground.^[1]

Input field	Meaning and units	Accepted input
mask	Rectangular numeric 0/1 rows, up to 64×64; row is the first coordinate and column the second.	Dense numeric rows, each dimension at most 128; the stated shape rules also apply.
eight	True uses all eight adjacent neighbors; false uses only four orthogonal neighbors for the foreground/background component specified above.	Boolean true or false.

Output field	Interpretation
result	Object containing the fields below.
result.mask	Result grid in original frame dimensions, with numeric cell meanings and any signed subtraction convention described above.

json

{
  "input": {
    "mask": [
      [
        1,
        1,
        1
      ],
      [
        1,
        0,
        1
      ],
      [
        1,
        1,
        1
      ]
    ],
    "eight": false
  },
  "output": {
    "result": {
      "mask": [
        [
          1,
          1,
          1
        ],
        [
          1,
          1,
          1
        ],
        [
          1,
          1,
          1
        ]
      ]
    }
  }
}

Limitations and assumptions

Connectivity applies to background here. A diagonal route to the boundary can open a hole under eight-neighbor connectivity while leaving it enclosed under four-neighbor connectivity.
Masks are rectangular dense arrays of numeric 0/1 cells, with at most 64 rows and 64 columns. Empty frames are allowed where no in-bounds seed is required. Stencils are nonempty lists of distinct integer [rowOffset,columnOffset] pairs, each coordinate between -16 and 16. Outside-frame samples are zero at every stage.
Every declared outer field is required and unknown outer fields are rejected. Strings and JSON text have size limits, lists are bounded to 128 entries, and JSON nesting/node counts are bounded. Tighter operation-specific bounds stated above take precedence.
Numeric outputs must remain finite and within safe-integer magnitude. Original record indexes and cell coordinates are zero-based; stated half-open ranges exclude their end.

Alternative or Complementary methods

Choose a component operation for connected regions and an explicit stencil for local shape tests. Fix connectivity and border policy before comparing masks; convert cell counts to physical area separately when pixel spacing is known.

References

Tool behavior and example: Binary Mask Enclosed Hole Fill — tool.io

Similar or alternative tools

Binary Mask Enclosed Hole Area Table
List cell counts for background components that do not touch the finite mask boundary.
Binary Mask Boundary Connected Background Mask
Mark background components connected to the finite mask boundary under the chosen connectivity.