Grooper Help - Version 25.0
25.0.0017 2,127
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Box Detection

IP Command Grooper.IP

Detects check boxes in an image and reads their check state.

Remarks

The Box Detection command is used to locate, analyze, and classify check boxes (OMR marks) within document images. It is a foundational component for optical mark recognition (OMR) workflows in Grooper, providing the Layout Data required by OMR extractors such as Labeled OMR, Ordered OMR, Zonal OMR, and OMR Reader.

How Box Detection Works

  1. The command preprocesses the input image, typically binarizing and optionally filtering it to reduce noise.
  2. Connected components (blobs) are analyzed to identify rectangular regions that match the configured size and aspect ratio criteria for check boxes.
  3. Each detected box is further analyzed to determine its check state (checked or unchecked) based on the fill ratio of its interior.
  4. The results are stored as Layout Data, including the position, size, and check state of each box.

Supported Pixel Formats

All common pixel formats are supported, including Pixel8bppGrayscale, Pixel24bppBgr, and Pixel1bppIndexed. Images are automatically converted as needed for box detection.

Diagnostics

When run in diagnostic mode, Box Detection generates additional output to assist with configuration and troubleshooting:

  • Diagnostic images showing the binarized and filtered input.
  • Diagnostic images with detected boxes annotated (color-coded by check state).
  • Log messages summarizing the number of boxes detected, their check states, and any boxes welded to line structures.
  • Text files listing detailed information about each detected box.

These diagnostics help you tune detection parameters and verify that only the intended boxes are being detected and classified.

Layout Data

Box Detection captures detailed Layout Data for each detected check box, including its bounding rectangle, check state, and whether it is welded to a line. This Layout Data is required by OMR extractors and is used for downstream classification and extraction validation activities.

Configuration and Usage

To use Box Detection, add it to an IP Profile or configure it as a property of a Grooper object. Adjust the size range, aspect ratio, and border thickness properties to match the expected characteristics of check boxes in your documents. Use the 'Binarization Settings' and 'Filtering' properties to optimize preprocessing for your image quality and document type. Review diagnostic output to ensure accurate detection and classification of check boxes.

Properties

NameTypeDescription
General
Image Preprocessing
Command Info

Derived Types

There are 1 implementations of Box Detection.

Box Removal Removes checkboxes from an image and generates Layout Data for OMR extraction.

See Also

Used By

Notification