Grooper Help - Version 25.0
25.0.0017 2,127
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Speck Removal

Binary Dropout Grooper.IP

Removes small specks from an image.

Remarks

The Speck Removal command is designed to automatically detect and remove small specks from document images. Specks are typically small, isolated blobs of pixels that result from scanning artifacts, dust, or print imperfections. Removing these artifacts improves image quality and enhances the accuracy of downstream processes such as OCR and data extraction.

Speck Removal works by analyzing a binarized (black and white) version of the input image. It identifies blobs that meet the criteria defined by the 'Max Speck Size' and 'Max Speck Weight' properties. Optionally, a quiet zone can be enforced around character-sized objects to prevent the removal of punctuation or other small, meaningful marks.

How Speck Removal Works

  1. The input image is binarized using the settings inherited from Binary Dropout.
  2. Connected components (blobs) are detected in the binarized image using the specified 'Connectivity'.
  3. Blobs are classified as specks if they meet the size and/or weight criteria.
  4. If a quiet zone is configured, specks within the quiet zone are preserved unless they are smaller than the 'Quiet Zone Override' threshold.
  5. A mask is generated for the detected specks and applied to the original image, removing the unwanted artifacts.

Configuration and Usage

  • Use 'Max Speck Size' to set the maximum width or height for a blob to be considered a speck.
  • Use 'Max Speck Weight' to set the maximum pixel count for a blob to be considered a speck.
  • At least one of these properties must be specified.
  • Configure 'Quiet Zone Size' to protect punctuation or other small marks near text from being removed.
  • Use 'Quiet Zone Override' to allow very small specks to be removed even within the quiet zone.
  • Set 'Connectivity' to control how pixels are grouped into blobs (4- or 8-connectivity).
  • Review diagnostic images to verify that only unwanted specks are being removed.

Supported Pixel Formats

  • Pixel8bppGrayscale
  • Pixel24bppBgr
  • Pixel1bppIndexed

Images are automatically converted as needed for processing.

Diagnostics

When run in diagnostic mode, Speck Removal generates several diagnostic images and logs:

  • Binarized: Shows the result of the binarization process.
  • Small Specks: Highlights specks that qualify for quiet zone override.
  • Large Specks: Shows larger specks detected for removal.
  • Large Specks (Masked): Displays large specks after quiet zone masking.
  • Quiet Zone Mask: Visualizes the quiet zone boundaries.
  • Character Mask: Shows detected character-sized blobs.
  • Log Messages: Reports the number of blobs detected, specks removed, and timing.

Use these diagnostics to fine-tune detection parameters and ensure that only unwanted specks are removed.

Notes

  • Overly broad settings may remove punctuation or other small, meaningful marks. Always review diagnostic output.
  • At least one of 'Max Speck Size' or 'Max Speck Weight' must be specified for the command to function.
  • Speck Removal does not generate classification features directly, but the results can improve downstream OCR and extraction by eliminating visual noise.

Properties

NameTypeDescription
General
Image Preprocessing
Command Info

See Also

Used By

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