Drop Noise

This layer (drop_noise) removes connected components smaller than the specified size from bitmap annotations. This can be useful to eliminate noise after running neural network.

Settings

• classes (type: array of strings)
• min_area (type: string)
• src_type (type: enum ["image", "bbox"])

Minimum area (min_area) for pixel group to be removed can be provided in pixels (ex. 10px) or in percentage (1%).

If min_area is in percentage, area of pixel group to delete can be calculated based on total resoultion of image (src_type = image) or based on area of bounding box of annotation (src_type = bbox).

Only annotations of classes from array classes would be processed. Those classes should have shape bitmap.

{
  "action": "drop_noise",
  "src": ["$input" ],
  "dst": "$output",
  "settings": {
    "classes": ["noise"],
    "min_area": "2%",
    "src_type": "bbox"
  }
}

Example

In this example we will remove noise from annotations of class shoes (bitmap) less than 20px in size.

Input annotation with noise Output annotation without noise

[
  {
    "dst": "$data",
    "src": [
      "example/*"
    ],
    "action": "data",
    "settings": {
      "classes_mapping": "default"
    }
  },
  {
    "action": "drop_noise",
    "src": ["$data"],
    "dst": "$output",
    "settings": {
      "classes": ["shoes"],
      "min_area": "20px",
      "src_type": "image"
    }
  },
  {
    "dst": "example_drop_noise",
    "src": [
      "$output"
    ],
    "action": "supervisely",
    "settings": {}
  }
]