Steve on Image Processing

December 9th, 2008

Online resources: psychophysics, colour engineering

Here are two sources of useful MATLAB functions that readers might be interested in.

First, an acquaintance at Apple Computer recently told me about the Psychtoolbox. He thought that any researcher using MATLAB to do experiments involving human visual perception might find it useful. I surfed around the web site and was impressed with the content and activity evident there.

Here's a brief description from the home page: "Psychophysics Toolbox Version 3 (PTB-3) is a free set of Matlab functions for vision research. It makes it easy to synthesize and show accurately controlled visual stimuli and interact with the observer."

Second, I saw a link today for the "Colour Engineering Toolbox," a set of MATLAB functions written by Phil Green and associated with the book Colour Engineering, which was co-edited by Green and Prof. Lindsay MacDonald. Both are with the Colour Imaging Group in the London College of Communication. Dr. Green's functions include colour space conversions for a few device-independent spaces, white-point utility functions, mathematical utilities useful for colour computations, colour difference and CIECAM02 computations, and a few psychophysics functions related to experiment design and associated statistics.

There's lots of good MATLAB stuff out there, so don't think you have to implement everything yourself. In addition to Internet search engines, be sure to check out the MATLAB Central File Exchange.

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Steve Eddins manages the Image & Geospatial development team at The MathWorks and coauthored Digital Image Processing Using MATLAB. He writes here about image processing concepts, algorithm implementations, and MATLAB.

  • Steve: Kezia—Try imrotate.
  • kezia: steve, how to perform rotation of structuring element by 15 degrees. kindly answer my question. thank u kezia...
  • Steve: Tasha—I only accept comments that are relevant to the particular blog post or are questions or comments...
  • Tasha: Steve,I send you a comment here but still didn’t get any reply yet.I did not see my comment posted here...
  • Steve: Carsten—Thanks for your input.
  • Carsten: Another vote for either imtranslate.m, or at least a blurb in the imtransform help why pure translation...
  • Loren Shure: If you look towards the end of the fftfilt program, you will see that there’s a check to see if...
  • Steve: Sonja—My imwritesize submission on the MATLAB Central File Exchange might be helpful. It was posted...
  • Steve: Grant—Sorry, but it won’t be for R2010a. That development deadline has already passed.
  • Sonja: My publisher is wanting images for a new book to be 300 dpi. Only 5 of the 19 images are 300, the rest are...

These postings are the author's and don't necessarily represent the opinions of The MathWorks.