Java and Image Manipulation

							Java and Image Manipulation




            February 18, 2008
    Outline



     1   JAI



     2   Image Manipulation



     3   Questions?




2               Monday, January 21, 2008
Java Image Processing

Old and Busted:

     • Java AWT
     • Java2D

New Hotness:

     • JAI




3              Monday, January 21, 2008
What is JAI?


• Java Advanced Imaging



• Image IO



• Advanced Image Processing API



4             Monday, January 21, 2008
First JAI program


public class HelloJAI {
        public static void main(String args[]) {

            ParameterBlock pb = new ParameterBlock();
            pb.add(args[0]);
            PlanarImage img = JAI.create(“fileload”, pb, null);

            // ta da
        }
}
    5                   Monday, January 21, 2008
First JAI program


ParameterBlock

     • Groups arguments

     • Appends to the end

     • ParameterBlockJAI




6                Monday, January 21, 2008
First JAI program

JAI.create(String, ParameterBlock, ?)‫‏‬

     • “A convenience class for instantiating operations.”

     • Basically how JAI operations are executed.

     • Our example performed the “fileload” operation.




 7               Monday, January 21, 2008
First JAI program


RenderingHints

     • Just what it sounds like: Hints for rendering
            »   Layout
            »   Border
            »   Interpolation
            »   Rendering Quality
            »   others...




8                  Monday, January 21, 2008
Second JAI Program
public class HelloAgainJAI {
     public static void main(String args[]) {
       PlanarImage img = ....;

         ParameterBlock pb = new ParameterBlock();
         pb.addSource(img)‫‏‬
           .add(10.0f)‫‏‬
           .add(0.75f);
         PlanarImage scaledImg = JAI.create(“scale”, pb);

         // ta da again
     }
}9                   Monday, January 21, 2008
Gotchas


• RenderingHints

• “fileload” vs “stream”

• Lazy Evaluation




 10             Monday, January 21, 2008
     2   Image Manipulation




11              Monday, January 21, 2008
Morphology

               Dilation




              Erosion
12       Monday, January 21, 2008
Morphology


• Opening




13          Monday, January 21, 2008
Morphology


• Closing




14          Monday, January 21, 2008
Morphology


• Thinning




15           Monday, January 21, 2008
Morphology




      How do we do all this?




16         Monday, January 21, 2008
Morphology


• Structuring element

      • Can be any be any shape

      • Defines what pixels of an image to keep

      • “Slid” around an image




 17              Monday, January 21, 2008
Morphology
• Assume a 3x3 square element
• Performing an erosion




18            Monday, January 21, 2008
Morphology




     You supply the structuring element,
       JAI provides the computation.




19              Monday, January 21, 2008
     Morphology

float[] elem = {1, 1, 1, 1, 1, 1, 1, 1, 1};
KernelJAI kernel = new KernelJAI(3, 3, 1, 1, elem);

ParameterBlock pb = new ParameterBlock();
pb.addSource(img).add(kernel);

RenderingHints rh = new RenderingHints(
  JAI.KEY_BORDER_EXTENDER,
  BorderExtender.createInstance(BorderExtender.BORDER_REFLECT));


PlanarImage erodeImg = JAI.create(“erode”, pb,
  rh);
      20                Monday, January 21, 2008
Feature Detection


• Edge Detection
     • Canny
     • Sobel
     • Roberts Cross




21              Monday, January 21, 2008
Digital Filters

• Filters and Smoothing
      • Mean Filtering
      • Median Filtering
      • Gaussian Blurring




 22              Monday, January 21, 2008
Feature Detection / Digital Filters




      Again, how do we do this?




23          Monday, January 21, 2008
Feature Detection / Digital Filters


• Convolution

     • Structuring element not just 1/0

     • “Slid” across the image as well

     • Sum of products




24               Monday, January 21, 2008
Feature Extraction / Digital Filters




25          Monday, January 21, 2008
    Feature Extraction / Digital Filters


            Once again, the JAI abides.




PlanarImage img = JAI.create(“convolve”, pb, rh);




     26             Monday, January 21, 2008
     3   Questions?




27              Monday, January 21, 2008
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