Image Processing Applications

Documentation external to the source code is provided for the following applications:

• Removing dark lines from a light pencil drawing
• Dewarping Text Pages
  • What distortions do you expect with camera images?
  • How do you dewarp a camera image based on text lines?
  • Example showing images and disparity fields
• Measuring the Skew of Document Images
  • For further reading . . .
• Color Quantization
  • How did the need for color quantization arise?
  • What are the basic problems in color quantization?
  • Why is error diffusion dithering important?
  • What methods have been proposed for color quantization?
  • Modified median cut implementation
  • Octree implementation
    • What is the octree data structure used in Leptonica?
    • How is the octree formed?
    • What color is associated with each octcube in the color table?
    • How are color indices assigned to the image pixels?
    • How is the error diffusion dithering applied?
    • How fast is the implementation?
  • For further reading on color quantization . . .
• Color Segmentation
  • What is color segmentation and why do it?
  • How does color segmentation differ from color quantization?
  • How do we generate the color segmented images?
  • How does a color segmented image look?
• Border Representations of Connected Components
  • Overview of connected component borders
  • Generating chain codes for connected components
  • Serializing the data for a compressed file format
  • Forming a single border for each connected component
  • Rendering the outline as a filled raster
  • Putting it together
• Document Image Analysis
• Jbig2 Classifier
  • What is the origin of the Jbig2 application?
  • What is jbig2?
  • What is provided in Leptonica?
  • What is the definition of the hausdorff distance, and how is it implemented efficiently?
  • How are the images aligned for comparison?
  • What’s special about the Leptonica implementation?
  • Open source implementation of jbig2
  • What is Mixed Raster format?