Image Processing In IDL
ImageProcessingIDL Version 7.1May 2009 EditionCopyright ITT Visual Information SolutionsAll Rights Reserved0509IDL71IP
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ContentsChapter 1Introduction to Image Processing in IDL . 9Overview of Image Processing .Digital Images and Image Processing .Understanding Image Definitions in IDL .Representing Image Data in IDL .Accessing Images .Querying Images .References .10101213151516Chapter 2Transforming Image Geometry . 17Overview of Geometric Transformations .Cropping Images .Padding Images .Resizing Images .Image Processing in IDL182023263
4Shifting Images . 28Reversing Images . 30Transposing Images . 32Rotating Images . 34Rotating an Image by 90 Degree Increments . 34Using the ROT Function for Arbitrary Rotations . 36Planar Slicing of Volumetric Data . 38Displaying a Series of Planar Slices . 38Extracting a Slice of Volumetric Data . 40Interactive Planar Slicing of Volumetric Data . 42Displaying Volumetric Data Using SLICER3 . 43Manipulating Volumetric Data Using SLICER3 . 43Chapter 3Mapping an Image onto Geometry . 47Mapping Images onto Surfaces Overview . 48Mapping an Image onto Elevation Data . 50Opening Image and Geometry Files . 50Initializing the IDL Display Objects . 52Displaying the Image and Geometric Surface Objects . 53Mapping an Image onto a Sphere . 57Mapping an Image onto a Sphere Using Direct Graphics . 57Chapter 4Working with Masks and Image Statistics . 61Overview of Masks and Image Statistics . 62Masking Images . 64Clipping Images . 69Locating Pixel Values in an Image . 73Calculating Image Statistics . 77Chapter 5Warping Images . 81Overview of Warping Images . 82Tips for Selecting Control Points . 83Creating Transparent Image Overlays . 84Displaying Image Transparencies Using Direct Graphics . 84ContentsImage Processing in IDL
5Displaying Image Transparencies Using Object Graphics . 84Warping Images Using Direct Graphics . 85Chapter 6Working with Regions of Interest (ROIs) . 95Overview of Working with ROIs . 96Contrasting an ROI’s Geometric Area and Mask Area . 97Defining Regions of Interest . 99Displaying ROI Objects in a Direct Graphics Window . 101Programmatically Defining ROIs . 105Growing a Region . 109Creating and Displaying an ROI Mask . 114Testing an ROI for Point Containment . 118Creating a Surface Mesh of an ROI Group . 121Chapter 7Transforming Between Domains . 125Overview of Transforming Between Image Domains .Transforming Between Domains with FFT .Transforming to the Frequency Domain .Displaying Images in the Frequency Domain .Transforming from the Frequency Domain .Removing Noise with the FFT .Transforming Between Domains with Wavelets .Transforming to the Time-Frequency Domain .Displaying Images in the Time-Frequency Domain .Transforming from the Time-Frequency Domain .Removing Noise with the Wavelet Transform .Transforming to and from the Hough and Radon Domains .Transforming to the Hough and Radon Domains (Projecting) .Transforming from the Hough and Radon Domains (Backprojecting) .Finding Straight Lines with the Hough Transform .Color Density Contrasting with the Radon Transform hapter 8Contrasting and Filtering . 177Overview of Contrasting and Filtering . 178Image Processing in IDLContents
6Byte-Scaling . 181Working with Histograms . 184Equalizing with Histograms . 185Adaptive Equalizing with Histograms . 188Filtering an Image . 193Low Pass Filtering . 194High Pass Filtering . 197Directional Filtering . 201Laplacian Filtering . 204Smoothing an Image . 209Smoothing with Average Values . 209Smoothing with Median Values . 213Sharpening an Image . 218Detecting Edges . 222Removing Noise . 225Windowing to Remove Noise . 225Lee Filtering to Remove Noise . 229Chapter 9Extracting and Analyzing Shapes . 233Overview of Extracting and Analyzing Image Shapes . 234Applying a Morphological Structuring Element to an Image . 234Determining Structuring Element Shapes and Sizes . 237Determining Intensity Values for Threshold and Stretch . 240Thresholding an Image . 241Stretching an Image . 242Eroding and Dilating Image Objects . 243Characteristics of Erosion . 243Characteristics of Dilation . 243Applying Erosion and Dilation . 243Smoothing with MORPH OPEN . 248Smoothing with MORPH CLOSE . 251Detecting Peaks of Brightness . 254Creating Image Object Boundaries . 257Selecting Specific Image Objects . 261Detecting Edges of Image Objects . 266ContentsImage Processing in IDL
7Creating Distance Maps .Thinning Image Objects .Combining Morphological Operations .Analyzing Image Shapes .Using LABEL REGION to Extract Image Object Information .Using CONTOUR to Extract Image Object Information .269272277282282286Index . 291Image Processing in IDLContents
8ContentsImage Processing in IDL
Chapter 1Introduction to ImageProcessing in IDLThis chapter describes the following topics:Overview of Image Processing . . . . . . . . . . 10Understanding Image Definitions in IDL . . 12Representing Image Data in IDL . . . . . . . . . 13Image Processing in IDLAccessing Images . . . . . . . . . . . . . . . . . . . . 15References . . . . . . . . . . . . . . . . . . . . . . . . . 169
10Chapter 1: Introduction to Image Processing in IDLOverview of Image ProcessingToday, the medical industry, astronomy, physics, chemistry, forensics, remotesensing, manufacturing, and defense are just some of the many fields that rely uponimages to store, display, and provide information about the world around us. Thechallenge to scientists, engineers and business people is to quickly extract valuableinformation from raw image data. This is the primary purpose of image processing –converting images to information.This book explains how to process images using IDL (Interactive Data Language).IDL is a high-level programming language that contains an extensive library of imageprocessing and analysis routines. With IDL, you can quickly access image data andbegin investigating the best way to extract useful information.Each chapter introduces image processing topics and includes information regardingwhen one method may be preferred over another to enhance specific image features.Numerous step-by-step examples illustrate IDL’s image processing and analysisroutines, allowing you to quickly understand how to get the desired results whenworking with your own image data. This book is not intended to be a complete sourcefor image processing knowledge, an advanced image processing manual or an imageprocessing reference guide. This book is designed to teach people how to use IDL toperform basic image processing, and does not assume that they are already experts inthe field of image processing.Digital Images and Image ProcessingA digital image is composed of a grid of pixels and stored as an array. A single pixelrepresents a value of either light intensity or color. Images are processed to obtaininformation b
10 Chapter 1: Introduction to Image Processing in IDL Overview of Image Processing Image Processing in IDL Overview of Image Processing Today, the medical industry, astronomy, physics, chemistry, forensics, remote sensing, manufacturing, and defense are just some of the many fields that rely upon
IDL Recreation Sign Manual. 5. After the trail designation process, IDL should consider removing, rerouting, or blocking access to undesignated trails. 6. Quarterly, IDL area staff must provide a list of inventoried and designated trails to IDL '
fit irregularly-sampled data to a regular grid. This regularly-gridded data can then be sent to IDL’s plotting routines. Animation in IDL -Use IDL for Animation tasks to visualize your data dynamically and to create an array of images and play them back as an animated sequence. Creat
† ENVI — ENVI is used to visualize, analyze, and present all types of digital imagery. † ENVI IDL — The flexibility and power of ENVI are maximized by adding the IDL development environment. ENVI IDL provides complete access to all IDL functions, therefore allowing you to customize ENVI. You can create
The input for image processing is an image, such as a photograph or frame of video. The output can be an image or a set of characteristics or parameters related to the image. Most of the image processing techniques treat the image as a two-dimensional signal and applies the standard signal processing techniques to it. Image processing usually .
IDL Lab: Interpolation and Displaying of Lidar Data The purpose of this lab is to introduce you to some IDL functions for interpolation and visualization. Lidar is becoming an important tool for getting high quality digital terrain (or elevation)
9 27 November 2013 1 Installing IMD . 1.1 System Requirements IMD is written in the IDL scientific programming language, and will run on any platform supported by IDL. Little or no IDL expertise is required to use IMD. There are two ways to run IMD: (1) using a
Chapter 1: Importing and Writing Data into Variables 9 Using IDL Accessing Files Using Dialogs Accessing Files Using Dialogs DIALOG_PICKFILE and DIALOG_READ_IMAGE are the two primary file access dialogs in IDL. Use DIALOG_PICKFILE to select any type of file. You can select multiple files, define the directory or define file filters using .
work and language games. - reading texts extending the main story-line. - translation exercises. - some songs and poems for learners. At the end of the book you will find the texts of the listening exercises, a summary of the grammar covered in the course, a pronunciation guide and Russian to English and English to Russian dictionaries.
