Steve on Image Processing with MATLAB

Image processing concepts, algorithms, and MATLAB


Steve on Image Processing with MATLAB has been archived and will not be updated.


The MathWorks updates its product line twice per year on a regular schedule. Early last month we shipped our second release of the year, R2008b.

My fellow bloggers have already been busy posting about the new release. In particular, Ken and Mike (with some help from Lori and James) have already written several posts about some great new features in the MATLAB Desktop. You should click over and read their October posts.

In MATLAB, the main thing that caught my eye specific to image processing is the enhancements to imread. We've added JPEG 2000 and netCDF support.

The Image Processing Toolbox has several enhancements. We've made several operations faster, including:

  • binary erosion and dilation (imdilate)
  • binary hit-miss (bwhitmiss)
  • range filtering (rangefilt)
  • gray-level co-occurrence matrix (graycomatrix)

We added a new corner detection function, cornermetric. It offers two choices for the metric: Harris, and Shi / Tomasi.

Also, the ROI functions such as imrect, imellipse, impoly, etc., offer a new createMask method for converting the ROI to binary image mask form.

Here's a timing of imdilate on a 1k-by-1k image using a 3-by-3 structuring element.

bw = repmat(imread('text.png'), 4, 4);
se = strel(ones(3,3));
timeit(@() imdilate(bw, se))
ans =


That result is about 3 times faster than R2008a on my computer.

You might also be interested in updates to the Image Acquisition Toolbox and the Video and Image Processing Blockset. Key new features in the Image Acquisition Toolbox include:

  • Support for display of high bit-depth cameras in the Video Preview window
  • Enhancements to Image Acquisition Tool
  • Support for additional DALSA® hardware

Video and Image Processing Blockset enhancements include:

  • Fixed-point and integer word size limit extended from 32 to 128 bits for Embedded MATLAB code, accelerated simulation modes, and automatic code generation
  • New Apply Geometric Transformation block
  • New Bar Code Recognition demo
  • Enhanced Lane Departure Warning System demo

For more details about these or any other product updates in R2008b, see the product release notes.

Published with MATLAB® 7.7

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