Preface (Image Processing Toolbox)

Image Processing Toolbox

Image Processing Demos

The Image Processing Toolbox is supported by a full complement of demo applications. These are very useful as templates for your own end-user applications, or for seeing how to use and combine your toolbox functions for powerful image analysis and enhancement. The toolbox demos are located under the subdirectory,

...\TOOLBOX\IMAGES\IMDEMOS

under the top-level directory in which MATLAB is installed.

The table below lists the demos available. Demos whose names begin with "ipss" operate as slide shows.

The easiest way to run an individual demo is to enter its name at the MATLAB command prompt. You can also launch MATLAB demos from the MATLAB demo window. To invoke this window, type demo at the command prompt. To see the list of available image processing demos, double-click on Toolboxes from the list on the left, and then select Image Processing. Select the desired demo and click the Run button.

To view the code in a demo, type

edit demoname

at the MATLAB command prompt.

For information on what is happening in the demo and how to use it, press the Info button, which is located in the lower right corner of each demo window. All demos that are not slide shows offer a selection of images on which to operate and a number of settings for you to experiment with. Most of these demos also have an Apply button, which must be pressed to see the results of your new settings.

Demos for the Image Processing Toolbox

Demo Name
Brief Description

dctdemo
Discrete cosine transform (DCT) image compression: you choose the number of coefficients and it shows you a reconstructed image and an error image.

edgedemo
Edge detection: all supported types with optional manual control over threshold, direction, and sigma, as appropriate to the method used.

firdemo
2-D Finite impulse response (FIR) filters: design your own filter by changing the cut-off frequency and filter order.

imadjdemo
Contrast adjustment and histogram equalization: adjust intensity values using brightness, contrast, and gamma correction, or by using histogram equalization.

ipss001
Connected components labeling slide show: includes double thresholding, feature-based logic, and binary morphology. All operations are performed on one image.

ipss002
Feature-based logic slide show containing two examples: the first example shows object selection using AND operations on the on pixels in two binary images; the second example shows filtering and thresholding on a single image.

ipss003
Correction of nonuniform illumination slide show: creates a coarse approximation of the background, subtracts it from the image, and then adjusts the pixel intensity values to fill the entire range.

landsatdemo

Landsat color composites: choose a scene and assign spectral bands to RGB intensities to create images that reveal topography, vegetation, and moisture; toggle saturation stretching to see its effect on image contrast.

nrfiltdemo
Noise reduction using linear and nonlinear filters: enables you to add different types of noise with variable densities, and choose a filter neighborhood size.

qtdemo
Quadtree decomposition: enables you to select a threshold and see a representation of the sparse matrix, and a reconstruction of the original image.

roidemo
Region of Interest (ROI) selection: enables you to select an ROI and apply operations such as unsharp and fill. It displays the binary mask of the ROI.

**Demos for the Image Processing Toolbox**
Demo Name	Brief Description
`dctdemo`	Discrete cosine transform (DCT) image compression: you choose the number of coefficients and it shows you a reconstructed image and an error image.
`edgedemo`	Edge detection: all supported types with optional manual control over threshold, direction, and sigma, as appropriate to the method used.
`firdemo`	2-D Finite impulse response (FIR) filters: design your own filter by changing the cut-off frequency and filter order.
`imadjdemo`	Contrast adjustment and histogram equalization: adjust intensity values using brightness, contrast, and gamma correction, or by using histogram equalization.
`ipss001`	Connected components labeling slide show: includes double thresholding, feature-based logic, and binary morphology. All operations are performed on one image.
`ipss002`	Feature-based logic slide show containing two examples: the first example shows object selection using `AND` operations on the `on` pixels in two binary images; the second example shows filtering and thresholding on a single image.
`ipss003`	Correction of nonuniform illumination slide show: creates a coarse approximation of the background, subtracts it from the image, and then adjusts the pixel intensity values to fill the entire range.
landsatdemo	Landsat color composites: choose a scene and assign spectral bands to RGB intensities to create images that reveal topography, vegetation, and moisture; toggle saturation stretching to see its effect on image contrast.
`nrfiltdemo`	Noise reduction using linear and nonlinear filters: enables you to add different types of noise with variable densities, and choose a filter neighborhood size.
`qtdemo`	Quadtree decomposition: enables you to select a threshold and see a representation of the sparse matrix, and a reconstruction of the original image.
`roidemo`	Region of Interest (ROI) selection: enables you to select an ROI and apply operations such as unsharp and fill. It displays the binary mask of the ROI.

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