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Drop Lines by Length

Layer drop_lines_by_length - remove too long or to short lines. Also this layer can drop lines with length in range.

Lines with more than two points also supported. For multi-lines total length is calculated as sum of sections.

    "action": "drop_lines_by_length",
    "src": [
    "dst": "$sample9",
    "settings": {
      "lines_class": "A-Line",
      "resolution_compensation": false,
      "invert": false,
      "min_length": 3,
      "max_length": 20


  • lines_class - class name of target lines.

  • resolution_compensation - used for images with different resolution (scales). If false - line length calcalute with pixels. If true - in relative units.

  • min_length - minimal line length.

  • max_length - maximal line length.

  • invert - invert drop results. This mode can be used to remove lines with length in range.

Resolution compensation

Guess that we have images with width 1000px and 2000px. Also guess that we want to remove lines with length less than 10px.

Resolution compenstation based on images width and calculated as:

new_min_length = (image_width / 1000) * min_length

If resolution_compensation is enabled, actual minimal line length will be 10px and 20px respectively.