9. Geometric Transformations

  1. Donald G. Bailey

Published Online: 2 JUN 2011

DOI: 10.1002/9780470828519.ch9

Design for Embedded Image Processing on FPGAs

Design for Embedded Image Processing on FPGAs

How to Cite

Bailey, D. G. (2011) Geometric Transformations, in Design for Embedded Image Processing on FPGAs, John Wiley & Sons (Asia) Pte Ltd, Singapore. doi: 10.1002/9780470828519.ch9

Author Information

  1. Massey University, New Zealand

Publication History

  1. Published Online: 2 JUN 2011
  2. Published Print: 1 JUN 2011

ISBN Information

Print ISBN: 9780470828496

Online ISBN: 9780470828519

SEARCH

Keywords:

  • field programmable gate array (FPGA);
  • forward mapping;
  • geometric transformations;
  • image registration;
  • perspective transformation;
  • reverse mapping

Summary

Examples of geometric transformations include zooming, rotating and perspective transformation. Such transformations are typically used to correct spatial distortions resulting from the imaging process, or to normalise an image by registering it to a predefined coordinate system. A forward mapping allows data to be streamed from an input. To maintain an accumulator image, with consequent bandwidth issues, the mapping can be separated into two passes. The first pass operates on each row and warps each pixel into the correct column, whereas the second pass operates on each column, getting each pixel into the correct row. The reverse mapping determines for each output pixel where it comes from in the input image. General image registration involves four steps: feature detection, feature matching, transform model estimation and image transformation and resampling. Field programmable gate array (FPGA) implementations of optical flow have been reported by Diaz and Wei.

Controlled Vocabulary Terms

image registration