Image Processing Toolbox for Matlab

596 Pages·2013·18.64 MB·English

Image Processing Toolbox™
User’s Guide
R2013b
How to Contact MathWorks
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ImageProcessingToolbox™User’sGuide
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Revision History
August1993 Firstprinting Version1
May1997 Secondprinting Version2
April2001 Thirdprinting RevisedforVersion3.0
June2001 Onlineonly RevisedforVersion3.1(Release12.1)
July2002 Onlineonly RevisedforVersion3.2(Release13)
May2003 Fourthprinting RevisedforVersion4.0(Release13.0.1)
September2003 Onlineonly RevisedforVersion4.1(Release13.SP1)
June2004 Onlineonly RevisedforVersion4.2(Release14)
August2004 Onlineonly RevisedforVersion5.0(Release14+)
October2004 Fifthprinting RevisedforVersion5.0.1(Release14SP1)
March2005 Onlineonly RevisedforVersion5.0.2(Release14SP2)
September2005 Onlineonly RevisedforVersion5.1(Release14SP3)
March2006 Onlineonly RevisedforVersion5.2(Release2006a)
September2006 Onlineonly RevisedforVersion5.3(Release2006b)
March2007 Onlineonly RevisedforVersion5.4(Release2007a)
September2007 Onlineonly RevisedforVersion6.0(Release2007b)
March2008 Onlineonly RevisedforVersion6.1(Release2008a)
October2008 Onlineonly RevisedforVersion6.2(Release2008b)
March2009 Onlineonly RevisedforVersion6.3(Release2009a)
September2009 Onlineonly RevisedforVersion6.4(Release2009b)
March2010 Onlineonly RevisedforVersion7.0(Release2010a)
September2010 Onlineonly RevisedforVersion7.1(Release2010b)
April2011 Onlineonly RevisedforVersion7.2(Release2011a)
September2011 Onlineonly RevisedforVersion7.3(Release2011b)
March2012 Onlineonly RevisedforVersion8.0(Release2012a)
September2012 Onlineonly RevisedforVersion8.1(Release2012b)
March2013 Onlineonly RevisedforVersion8.2(Release2013a)
September2013 Onlineonly RevisedforVersion8.3(Release2013b)

Contents
Getting Started
1
ImageProcessingToolboxProductDescription ...... 1-2
KeyFeatures ..................................... 1-2
ConfigurationNotes ............................... 1-3
RelatedProducts .................................. 1-4
Compilability ..................................... 1-5
ImageImportandExport .......................... 1-6
Introduction ...................................... 1-6
Step1: ReadandDisplayanImage ................... 1-6
Step2: CheckHowtheImageAppearsintheWorkspace .. 1-7
Step3: ImproveImageContrast ..................... 1-8
Step4: WritetheImagetoaDiskFile ................ 1-10
Step5: ChecktheContentsoftheNewlyWrittenFile .... 1-10
ImageEnhancementandAnalysis ................... 1-12
Introduction ...................................... 1-13
Step1: ReadImage ................................ 1-13
Step 2: Use Morphological Opening to Estimate the
Background .................................... 1-13
Step 3: View the Background Approximation as a
Surface ........................................ 1-14
Step4: SubtracttheBackground Imagefrom the Original
Image ......................................... 1-15
Step5: IncreasetheImageContrast .................. 1-16
Step6: ThresholdtheImage ........................ 1-17
Step7: IdentifyObjectsintheImage ................. 1-17
Step8: ExamineOneObject ......................... 1-18
Step9: ViewAllObjects ............................ 1-19
Step10: ComputeAreaofEachObject ................ 1-20
Step11: ComputeArea-basedStatistics ............... 1-21
v
Step12: CreateHistogramoftheArea ................ 1-22
GettingHelp ...................................... 1-23
ProductDocumentation ............................ 1-23
ImageProcessingExamples ......................... 1-23
MATLABNewsgroup .............................. 1-24
Acknowledgments ................................. 1-25
Introduction
2
ImagesinMATLAB ................................ 2-2
ExpressingImageLocations ........................ 2-3
PixelIndices ..................................... 2-3
SpatialCoordinates ................................ 2-4
ImageTypesintheToolbox ........................ 2-10
OverviewofImageTypes ........................... 2-10
BinaryImages .................................... 2-11
IndexedImages ................................... 2-12
GrayscaleImages ................................. 2-14
TruecolorImages .................................. 2-15
ConvertingBetweenImageTypes ................... 2-19
ConvertingBetweenImageClasses ................. 2-21
OverviewofImageClassConversions ................. 2-21
LosingInformationinConversions ................... 2-21
ConvertingIndexedImages ......................... 2-21
WorkingwithImageSequences ..................... 2-23
Overview of Toolbox Functions That Work with Image
Sequences ..................................... 2-23
ProcessImageSequences ........................... 2-26
ProcessMulti-FrameImageArrays ................... 2-27
vi Contents
ImageArithmetic .................................. 2-29
OverviewofImageArithmeticFunctions .............. 2-29
ImageArithmeticSaturationRules ................... 2-30
NestingCallstoImageArithmeticFunctions ........... 2-30
Reading and Writing Image Data
3
GettingInformationAboutaGraphicsFile .......... 3-2
ReadingImageData ............................... 3-3
WritingImageDatatoaFile ........................ 3-5
Overview ........................................ 3-5
SpecifyingFormat-SpecificParameters ................ 3-6
ReadingandWritingBinaryImagesin1-BitFormat .... 3-6
DeterminingtheStorageClassoftheOutputFile ....... 3-7
ConvertingBetweenGraphicsFileFormats .......... 3-8
WorkingwithDICOMFiles ......................... 3-9
OverviewofDICOMSupport ........................ 3-9
ReadingMetadatafromaDICOMFile ................ 3-10
ReadingImageDatafromaDICOMFile .............. 3-12
WritingImageDataorMetadatatoaDICOMFile ...... 3-13
WorkingwithMayoAnalyze7.5Files ................ 3-19
WorkingwithInterfileFiles ........................ 3-20
WorkingwithHighDynamicRangeImages .......... 3-21
UnderstandingDynamicRange ...................... 3-21
ReadingaHighDynamicRangeImage ................ 3-21
CreatingaHighDynamicRangeImage ............... 3-22
ViewingaHighDynamicRangeImage ................ 3-22
WritingaHighDynamicRangeImagetoaFile ......... 3-23
vii
Displaying and Exploring Images
4
ImageDisplayandExplorationOverview ............ 4-2
DisplayingImagesUsingtheimshowFunction ....... 4-4
Overview ........................................ 4-4
SpecifyingtheInitialImageMagnification ............. 4-6
ControllingtheAppearanceoftheFigure .............. 4-6
DisplayingEachImageinaSeparateFigure ........... 4-7
DisplayingMultipleImagesintheSameFigure ........ 4-8
UsingtheImageViewerApptoExploreImages ...... 4-11
ImageViewerAppOverview ........................ 4-11
OpeningtheImageViewer .......................... 4-13
SpecifyingtheInitialImageMagnification ............. 4-14
SpecifyingtheColormap ............................ 4-15
ImportingImageDatafromtheWorkspace ............ 4-17
ExportingImageDatatotheWorkspace ............... 4-18
SavingtheImageDataDisplayedintheImageViewer ... 4-18
ClosingtheImageViewer ........................... 4-20
PrintingtheImageintheImageViewer ............... 4-20
ExploringVeryLargeImages ....................... 4-21
Overview ........................................ 4-21
CreatinganR-SetFile ............................. 4-21
OpeninganR-SetFile .............................. 4-22
UsingImageViewerAppNavigationAids ............ 4-23
NavigatinganImageUsingtheOverviewTool ......... 4-23
PanningtheImageDisplayedintheImageViewer ...... 4-26
Zooming In and Out on an Image in the Image Viewer
App ........................................... 4-27
SpecifyingtheMagnificationoftheImage ............. 4-27
GettingInformationaboutthePixelsinanImage .... 4-30
DeterminingtheValueofIndividualPixels ............ 4-30
DeterminingtheValuesofaGroupofPixels ........... 4-32
DeterminingtheDisplayRangeofanImage ........... 4-35
viii Contents
MeasuringtheDistanceBetweenTwoPixels ......... 4-37
UsingtheDistanceTool ............................ 4-37
ExportingEndpointandDistanceData ................ 4-38
CustomizingtheAppearanceoftheDistanceTool ....... 4-39
Getting Information About an Image Using the Image
InformationTool ................................ 4-40
Adjusting Image Contrast Using the Adjust Contrast
Tool ............................................ 4-42
UnderstandingContrastAdjustment ................. 4-42
StartingtheAdjustContrastTool .................... 4-43
UsingtheHistogramWindowtoAdjustImageContrast .. 4-46
UsingtheWindow/LevelTooltoAdjustImageContrast .. 4-47
ModifyingImageData ............................. 4-50
CropanImageUsingtheImageViewerApp ......... 4-52
ViewingImageSequences .......................... 4-55
ImageSequences .................................. 4-55
ViewImageSequencesintheVideoViewerApp ........ 4-55
ViewingImageSequencesasaMontage ............... 4-64
ConvertingaMultiframeImagetoaMovie ............ 4-66
DisplayingDifferentImageTypes ................... 4-67
DisplayingIndexedImages ......................... 4-67
DisplayingGrayscaleImages ........................ 4-68
DisplayingBinaryImages .......................... 4-69
DisplayingTruecolorImages ........................ 4-71
AddingaColorbartoaDisplayedImage ............. 4-73
PrintingImages ................................... 4-75
PrintingandHandleGraphicsObjectProperties ........ 4-75
SettingToolboxPreferences ........................ 4-77
ViewingandChangingPreferencesUsingthePreferences
DialogBox ..................................... 4-77
Retrieving the Values of Toolbox Preferences
Programmatically ............................... 4-77
ix
Setting the Values of Toolbox Preferences
Programmatically ............................... 4-78
Building GUIs with Modular Tools
5
ModularInteractiveTools .......................... 5-2
DisplayingtheTargetImage ........................ 5-10
CreatingtheModularTools ........................ 5-11
Overview ........................................ 5-11
AssociatingModularToolswithaParticularImage ...... 5-12
GettingtheHandleoftheTargetImage ............... 5-14
SpecifyingtheParentofaModularTool ............... 5-15
PositioningtheModularToolsinaGUI ............... 5-18
BuildaPixelInformationGUI ....................... 5-19
AddingNavigationAidstoaGUI .................... 5-22
CustomizingModularToolInteractivity ............. 5-28
Overview ........................................ 5-28
BuildImageComparisonTool ....................... 5-29
CreatingYourOwnModularTools .................. 5-33
Overview ........................................ 5-33
CreateAngleMeasurementTool ..................... 5-35
Geometric Transformations
6
ResizeanImage ................................... 6-2
Overview ........................................ 6-2
SpecifyingtheInterpolationMethod .................. 6-3
PreventingAliasingbyUsingFilters .................. 6-4
x Contents