BIG logo
Imaging Web Demonstration
Contents Teaching Research Students Contents

Comparison of interpolators - Rotation
  roundleft Introduction roundright   Example        
bullet Description

This demonstration compares the standard interpolation functions with the ones developped by the Biomedical Imaging Group [1] when a rotation is successively applied to an image. The rotation is implemented in a separable fashion using the digital filtering algorithm described in [2].

bullet List of the interpolators

Standard methods:

  • Constant: Nearest-Neighbor
  • Linear: B-Spline
  • Quadratic: Dodgson
  • Cubic: Keys
  • Cubic: Schaum

BIG methods:

  • Constant: B-spline
  • Linear: B-spline
  • Quadratic: B-spline
  • Quadratic: Omoms
  • Cubic: B-spline
  • Cubic: Omoms
  • High Quality: B-spline 11
bullet References

[1] P. Thévenaz, T. Blu, M. Unser, "Image Interpolation and Resampling," Handbook of Medical Imaging, Processing and Analysis, I.N. Bankman, Ed., Academic Press, San Diego Ca, USA, pp. 393-420, 2000.

[2] M. Unser, P. Thévenaz, L.P. Yaroslavsky, "Convolution-Based Interpolation for Fast, High-Quality Rotation of Images," IEEE Transactions on Image Processing, vol. 4, no. 10, pp. 1371-1381, October 1995

Be patient to load the applet!
Some versions of Netscape on Macintosh do not refresh the screen correctly.
Instruction to use the applet
  1. Choose an input image in the list.
  2. Choose the number of rotations (iterations).
  3. Choose methods of interpolation.
  4. Press ">" to run one step or ">>" to run all the steps. Press "<" to run one step in counter-clockwise and "<<" to run all steps.

Toolbar in the image display
Get the coordinates and value of a pixel.
Get the maximum, minimum and the value of the image.
Open a new window containing the image.
Zoom out by a factor 2.
Zoom in by a factor 2.
Move the zoomed part of the image.

EPFL Swiss Federal Institute of Technology Lausanne
BIG Biomedical Imaging Group
Address: DMT/IOA, BM-Ecublens, CH-1015 Lausanne, Switzerland
Imaging Web Demonstration
Contact: Webmaster
14 June 2000