Chapter 5: Blob analysis

This chapter describes the basic steps to extract connected regions of pixels (blobs) within an image.

• Blob analysis overview
• • MIL and blob analysis
• Steps to performing blob analysis
• Identifying blobs
• • Segmenting the blob image
  • Preprocessing
• Adjusting blob analysis processing controls
• • Controlling the image lattice
  • The pixel aspect ratio
  • Setting the blob identification mode
  • • Calculations on blobs
  • Returning partial results
• Selecting blobs
• Making feature extractions
• The area and perimeter
• Dimensions
• Determining the shape
• Finding the blob location and its bounding box
• • Points of the bounding box aligned with the pixel coordinate system
  • • Minimum-area and minimum-perimeter bounding box points
    • Points with respect to the relative world coordinate system
  • Chained pixels
• Moments
• Location, length and number of runs
• Blob reconstruction
• Merging results
• • A simple merge
  • Border blobs
  • Inclusion state
  • Other remarks
• Blob analysis example