Virtual Reconstruction

Filter Applet
Instructions:
  • This applet demonstrates the effect of two-dimensional filters on grayscale or color images.
  • The output image is calculated in a 3-stage process:
    (1) convolution of the input image with the filter kernel,
    (2) multiplication with the scaling factor
    (3) addition of the offset value
  • The panel on the left has the following structure:
  • The 5x5 square represents the filter kernel that is applied to every pixel in the image (image pixels within a 5x5 neighborhood are multiplied by the corresponding kernel values; the resulting 25 values are summed up, then sent as an output to the central image pixel).
  • Use the applet as follows:
    • load an image
    • apply a pre-set filter kernel (the values appear in the kernel panel), or create your own filter by typing values into the respective kernel fields
    • press Filter! to apply the kernel to every pixel of the image and to visualize the result.
    • You may concatenate various filters, or apply one and the same filter again and again.
  • The Normalize button sets the sum of all filter entries to 1.
  • The Scale and Offset fields are used to optionally fit the filter output to a suitable range of values (e.g. to [0...255], the number of gray values that your monitor can display).
    • Scale multiplies the result of the convolution by the indicated amount.
    • Offset adds the indicated amount to the result of the convolution.
  • Each filter is applied to the result of the previous filtering process; this permits application of a sequence of filters to the original image. To return to the original image, press the Reset button
  • Try to detect edges in the image!
  • Try to create a negative image!

Download Java Application (local execution allows you to load your own files)

    • download Filter.jar (e.g. to your desktop)
    • execution:
      • Windows / Mac : double click on icon
      • shell / dos: >>java -jar Filter.jar
    • now you can load your own images (in gif or jpg format)

0. Introduction
1. Virtual Reconstruction
2. Data Representation
Data Format Applet
Color Applet
Links
3. Data Acquisition
Links
4. Image Data Processing
Filter Applet
Links
5. Visualization and Interaction
Transformation Applet
Links
Software Hints
6. Virtual Fossil Reconstruction
Links
Software Hints
7. From VR to RV
Links
8. Morphometric analysis
Links
Figure 8.23 (color)


Available from John Wiley & Sons

Virtual Reconstruction:
A Primer in Computer-Assisted Paleontology and Biomedicine

Virtual Reconstruction: A Primer in Computer-Assisted Paleontology and Biomedicine

Christoph P. Zollikofer,
Marcia Ponce de Leon

ISBN: 0-471-20507-9
Hardcover
333 pages
June 2005

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