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Getting Started

    What Is the Image Processing Toolbox?
        Configuration Notes
        Related Products

    Example 1 -- Some Basic Concepts
        1. Read and Display an Image
        2. Check How the Image Appears in the Workspace
        3. Improve Image Contrast
        4. Write the Image to a Disk File
        5. Check the Contents of the Newly Written File

    Example 2 -- Advanced Topics
        1. Read and Display an Image
        2. Estimate the Value of Background Pixels
        3. View the Background Approximation as a Surface
        4. Create an Image with a Uniform Background
        5. Adjust the Contrast in the Processed Image
        6. Create a Binary Version of the Image
        7. Determine the Number of Objects in the Image
        8. Examine the Label Matrix
        9. Display the Label Matrix as a Pseudocolor Indexed Image
        10. Measure Object Properties in the Image
        11. Compute Statistical Properties of Objects in the Image

    Getting Help
        Online Help
        Image Processing Demos
        MATLAB Newsgroup

    Image Credits



    Images in MATLAB and the Image Processing Toolbox
    Image Types in the Toolbox
        Binary Images
        Indexed Images
        Grayscale Images
        Truecolor Images

    Converting Between Image Types
        Color Space Conversions

    Converting Between Image Classes
        Losing Information in Conversions
        Converting Indexed Images

    Multiframe Image Arrays
    Reading and Writing Image Data
        Reading a Graphics Image
        Writing a Graphics Image
        Querying a Graphics File
        Converting Graphics File Formats

    Working with DICOM Files
        Reading Image Data from a DICOM File
        Reading Metadata from a DICOM File
        Writing Image Data or Metadata to a DICOM File
        Example: Creating a New Series

    Image Arithmetic
        Image Arithmetic Saturation Rules
        Nesting Calls to Image Arithmetic Functions

    Coordinate Systems
        Pixel Coordinates
        Spatial Coordinates

Displaying and Exploring Images

        Understanding Handle Graphics Object Property Settings

    Using imshow to Display Images
        Specifying the Initial Image Magnification
        Controlling the Appearance of the Figure

    Using the Image Tool to Explore Images
        Opening the Image Tool
        Specifying the Initial Image Magnification
        Specifying the Colormap
        Importing Image Data from the Workspace
        Exporting the Image to the Workspace
        Closing the Image Tool
        Printing the Image in the Image Tool

    Using Image Tool Navigation Aids
        Overview Navigation
        Panning the Image Displayed in the Image Tool
        Zooming In and Out on an Image
        Specifying the Magnification of the Image

    Getting Information about the Pixels in an Image
        Determining the Value of Individual Pixels
        Getting the Display Range of an Image
        Viewing Pixel Values with the Pixel Region Tool

    Getting Information About an Image
    Adjusting the Contrast and Brightness of an Image
        Understanding Contrast Adjustment
        Adjusting Contrast and Brightness
        Using the Window/Level Tool

    Viewing Multiple Images
        Displaying Each Image in a Separate Figure
        Displaying Multiple Images in the Same Figure

    Displaying Different Image Types
        Displaying Indexed Images
        Displaying Grayscale Images
        Displaying Binary Images
        Displaying Truecolor Images

    Special Display Techniques
        Adding a Colorbar
        Displaying All Frames of a Multiframe Image at Once
        Converting a Multiframe Image to a Movie
        Texture Mapping

    Printing Images
        Printing and Handle Graphics Object Properties

    Setting Toolbox Display Preferences
        Toolbox Preferences
        Retrieving the Values of Toolbox Preferences
        Setting the Values of Toolbox Preferences

Building GUIs with Modular Tools

    Using Modular Tools
        Displaying the Target Image
        Specifying the Target Image
        Specifying the Parent of a Modular Tool
        Positioning the Modular Tools in a GUI
        Example: Building a Pixel Information GUI
        Adding Navigation Aids to a GUI
        Making Connections for Interactivity

    Creating Your Own Modular Tools

Spatial Transformations

        Interpolation Methods
        Interpolation and Image Types

    Resizing an Image
        Specifying the Size of the Output Image
        Specifying the Interpolation Method
        Using Filters to Prevent Aliasing

    Rotating an Image
        Specifying the Size of the Output Image
        Specifying the Interpolation Method

    Cropping an Image
    Performing General 2-D Spatial Transformations
        Example: Performing a Translation
        Defining the Transformation Data
        Creating TFORM Structures
        Performing the Spatial Transformation

    Performing N-Dimensional Spatial Transformations
    Example: Performing Image Registration
        Step 1: Read in Base and Unregistered Images
        Step 2: Display the Unregistered Image
        Step 3: Create a TFORM Structure
        Step 4: Transform the Unregistered Image
        Step 5: Overlay Registered Image Over Base Image
        Step 5: Using XData and YData Input Parameters
        Step 6: Using XData and YData Output Values

Image Registration

    Registering an Image
        Point Mapping
        Example: Registering to a Digital Orthophoto

    Types of Supported Transformations
    Selecting Control Points
        Using the Control Point Selection Tool
        Starting the Control Point Selection Tool
        Viewing the Images
        Specifying Matching Control Point Pairs
        Saving Control Points

    Using Correlation to Improve Control Points

Linear Filtering and Filter Design

    Linear Filtering
        Filtering Using imfilter
        Using Predefined Filter Types

    Filter Design
        FIR Filters
        Frequency Transformation Method
        Frequency Sampling Method
        Windowing Method
        Creating the Desired Frequency Response Matrix
        Computing the Frequency Response of a Filter


    Fourier Transform
        Definition of Fourier Transform
        Discrete Fourier Transform
        Applications of the Fourier Transform

    Discrete Cosine Transform
        The DCT Transform Matrix
        DCT and Image Compression

    Radon Transform
        Plotting the Radon Transform
        Viewing the Radon Transform as an Image
        Using the Radon Transform to Detect Lines
        Inverse Radon Transform
        Example: Reconstructing an Image from Parallel Projection Data

    Fan-Beam Projection Data
        Computing Fan-Beam Projection Data
        Reconstructing an Image from Fan-Beam Projection Data
        Working with Fan-Beam Projection Data

Morphological Operations

    Dilation and Erosion
        Understanding Dilation and Erosion
        Structuring Elements
        Dilating an Image
        Eroding an Image
        Combining Dilation and Erosion
        Dilation- and Erosion-Based Functions

    Morphological Reconstruction
        Marker and Mask
        Pixel Connectivity
        Flood-Fill Operations
        Finding Peaks and Valleys

    Distance Transform
    Objects, Regions, and Feature Measurement
        Connected-Component Labeling
        Selecting Objects in a Binary Image
        Finding the Area of the Foreground of a Binary Image
        Finding the Euler Number of a Binary Image

    Lookup Table Operations

Analyzing and Enhancing Images

    Getting Information about Pixel Values and Statistics
        Getting Information About Image Pixels
        Getting the Intensity Profile of an Image
        Displaying a Contour Plot of Image Data
        Creating an Image Histogram
        Getting Summary Statistics About an Image
        Computing Properties for Image Regions

    Analyzing an Image
        Detecting Edges
        Tracing Boundaries
        Detecting Lines Using the Hough Transform
        Using Quadtree Decomposition

    Analyzing the Texture of an Image
        Using Texture Filter Functions
        Using a Gray-Level Co-Occurrence Matrix (GLCM)

    Intensity Adjustment
        Adjusting Intensity Values to a Specified Range
        Histogram Equalization
        Contrast-Limited Adaptive Histogram Equalization
        Decorrelation Stretching

    Noise Removal
        Using Linear Filtering
        Using Median Filtering
        Using Adaptive Filtering

Region-Based Processing

    Specifying a Region of Interest
        Selecting a Polygon
        Other Selection Methods

    Filtering a Region
        Example: Filtering a Region in an Image
        Specifying the Filtering Operation

    Filling a Region

Image Deblurring

    Understanding Deblurring
        Causes of Blurring
        Deblurring Model

    Using the Deblurring Functions
        Deblurring with the Wiener Filter
        Deblurring with a Regularized Filter
        Deblurring with the Lucy-Richardson Algorithm
        Deblurring with the Blind Deconvolution Algorithm
        Creating Your Own Deblurring Functions

    Avoiding Ringing in Deblurred Images


    Working with Different Screen Bit Depths
        Determining Screen Bit Depth
        Choosing a Screen Bit Depth

    Reducing the Number of Colors in an Image
        Color Approximation
        Reducing Colors in an Indexed Image

    Converting Color Data Between Color Spaces
        Converting Between Device-Independent Color Spaces
        Performing Profile-Based Conversions
        Converting Between Device-Dependent Color Spaces

Neighborhood and Block Operations

    Block Processing Operations
        Types of Block Processing Operations

    Sliding Neighborhood Operations
        Padding Borders
        Linear and Nonlinear Filtering

    Distinct Block Operations

    Column Processing
        Sliding Neighborhoods
        Distinct Blocks

Functions -- Categorical List

    Image Input, Output, and Display
    Modular Interactive Tools
    Spatial Transformation and Registration
    Image Analysis and Statistics
    Image Arithmetic
    Image Enhancement and Restoration
    Linear Filtering and Transforms
    Morphological Operations
    Region-Based, Neighborhood, and Block Processing
    Colormap and Color Space Functions
    Miscellaneous Functions

Functions -- Alphabetical List

Printable Documentation (PDF)

Product Page (Web)