Structure Display
Sean's pick this week is Structure Display by Thomas Deneux.
Contents
Structures in MATLAB
A structure in MATLAB is a container for heterogenous data that you reference by a name. Let's take a look at a simple structure: we will reference two fields of S named A and B (I don't win too many awards for creativity!).
S.A = 'Hello World';
S.B = pi;
disp(S)
A: 'Hello World' B: 3.1416
This level of display is sufficient for a simple structure. But what about a more complex structure with possibly nested structures inside of it?
S.C = S; % insert S into one field of S, structure inception?
disp(S)
A: 'Hello World' B: 3.1416 C: [1x1 struct]
The built in display of the structure shows the high-level summary of the fields it contains, not the detailed version which could be complex. Sometimes this additional information is useful, especially for debugging.
Here's the display with fn_structdisp
fn_structdisp(S);
S: A: 'Hello World' B: 3.1416 C: [1x1 struct] S.B: 3.1416 S.C: A: 'Hello World' B: 3.1416 S.C.B: 3.1416
Metadata
One of the places this type of display is really useful is when looking at metadata for files where the meta data can be logically grouped in an array of nested structures.
I have the images from a CT scan of my left ankle that I had taken after a wakeboarding accident a couple of summers ago. We'll read the metadata into MATLAB using dicominfo. Even though I likely trust any human reading this blog, I'm still going to anonymize the file to hide my personal information like name, birthdate etc:
% Anonymize fn = 'CT000000'; anonfn = [fn '_anon']; dicomanon(fn,anonfn); % Read in info: info = dicominfo(anonfn);
Now let's look at the simple display and the complex display using Thomas' fn_structdisp. You'll be able to see how fn_structdisp unrolls the nested structures to reveal their contents.
Regular Display
disp(info)
Filename: 'C:\Documents\MATLAB\potw\StructDisp\C...' FileModDate: '08-Apr-2015 22:35:13' FileSize: 559084 Format: 'DICOM' FormatVersion: 3 Width: 512 Height: 512 BitDepth: 16 ColorType: 'grayscale' FileMetaInformationGroupLength: 222 FileMetaInformationVersion: [2x1 uint8] MediaStorageSOPClassUID: '1.2.840.10008.5.1.4.1.1.2' MediaStorageSOPInstanceUID: '1.3.6.1.4.1.9590.100.1.2.515513049128...' TransferSyntaxUID: '1.2.840.10008.1.2.1' ImplementationClassUID: '1.3.6.1.4.1.9590.100.1.3.100.7.1' ImplementationVersionName: 'MATLAB IPT 7.1' SourceApplicationEntityTitle: 'DCF' SpecificCharacterSet: 'ISO_IR 100' ImageType: 'DERIVED\SECONDARY\OTHER\CSA MPR THICK...' SOPClassUID: '1.2.840.10008.5.1.4.1.1.2' SOPInstanceUID: '1.3.6.1.4.1.9590.100.1.2.515513049128...' StudyDate: '20131007' SeriesDate: '20131007' AcquisitionDate: '20131007' ContentDate: '20131007' StudyTime: '184618.640000' SeriesTime: '184046.156000' AcquisitionTime: '184905.956783' ContentTime: '184046.171000' AccessionNumber: '' Modality: 'CT' Manufacturer: 'SIEMENS' InstitutionName: '' ReferringPhysicianName: [1x1 struct] ManufacturerModelName: 'Sensation 64' ReferencedImageSequence: [1x1 struct] PatientName: [1x1 struct] PatientID: '' PatientBirthDate: '' PatientSex: '' PatientIdentityRemoved: 'YES' DeidentificationMethod: 'DICOMANON (rev R2010a) - PS 3.15-2008...' BodyPartExamined: 'EXTREMITY' SliceThickness: 2 KVP: 120 SoftwareVersion: 'syngo CT 2009E' DistanceSourceToDetector: 1040 DistanceSourceToPatient: 570 GantryDetectorTilt: 0 TableHeight: 179 RotationDirection: 'CW' FilterType: '0' GeneratorPower: 10 FocalSpot: 1.2000 DateOfLastCalibration: '20131007' TimeOfLastCalibration: '061322.000000' ConvolutionKernel: 'B60s' PatientPosition: 'FFS' StudyInstanceUID: '1.3.6.1.4.1.9590.100.1.2.328077616812...' SeriesInstanceUID: '1.3.6.1.4.1.9590.100.1.2.237595359611...' StudyID: '' SeriesNumber: 505 AcquisitionNumber: 3 InstanceNumber: 1 ImagePositionPatient: [3x1 double] ImageOrientationPatient: [6x1 double] FrameOfReferenceUID: '1.3.6.1.4.1.9590.100.1.2.396775851196...' PositionReferenceIndicator: '' SamplesPerPixel: 1 PhotometricInterpretation: 'MONOCHROME2' Rows: 512 Columns: 512 PixelSpacing: [2x1 double] BitsAllocated: 16 BitsStored: 16 HighBit: 15 PixelRepresentation: 0 SmallestImagePixelValue: 0 LargestImagePixelValue: 2802 WindowCenter: 240 WindowWidth: 1200 RescaleIntercept: -1024 RescaleSlope: 1 WindowCenterWidthExplanation: 'WINDOW1\WINDOW2' LossyImageCompression: '00' RequestingPhysician: [1x1 struct] RequestedProcedureDescription: 'CT LOWER EXTREMITY C-' OverlayRows_0: 512 OverlayColumns_0: 512 NumberOfFramesInOverlay_0: 1 OverlayDescription_0: 'Siemens MedCom Object Graphics' OverlayType_0: 'G' OverlayOrigin_0: [2x1 int16] ImageFrameOrigin_0: 1 OverlayBitsAllocated_0: 1 OverlayBitPosition_0: 0 OverlayData_0: [512x512 logical]
fn_structdisp Display
fn_structdisp(info);
info: Filename: 'C:\Documents\MATLAB\potw\StructDisp\C...' FileModDate: '08-Apr-2015 22:35:13' FileSize: 559084 Format: 'DICOM' FormatVersion: 3 Width: 512 Height: 512 BitDepth: 16 ColorType: 'grayscale' FileMetaInformationGroupLength: 222 FileMetaInformationVersion: [2x1 uint8] MediaStorageSOPClassUID: '1.2.840.10008.5.1.4.1.1.2' MediaStorageSOPInstanceUID: '1.3.6.1.4.1.9590.100.1.2.515513049128...' TransferSyntaxUID: '1.2.840.10008.1.2.1' ImplementationClassUID: '1.3.6.1.4.1.9590.100.1.3.100.7.1' ImplementationVersionName: 'MATLAB IPT 7.1' SourceApplicationEntityTitle: 'DCF' SpecificCharacterSet: 'ISO_IR 100' ImageType: 'DERIVED\SECONDARY\OTHER\CSA MPR THICK...' SOPClassUID: '1.2.840.10008.5.1.4.1.1.2' SOPInstanceUID: '1.3.6.1.4.1.9590.100.1.2.515513049128...' StudyDate: '20131007' SeriesDate: '20131007' AcquisitionDate: '20131007' ContentDate: '20131007' StudyTime: '184618.640000' SeriesTime: '184046.156000' AcquisitionTime: '184905.956783' ContentTime: '184046.171000' AccessionNumber: '' Modality: 'CT' Manufacturer: 'SIEMENS' InstitutionName: '' ReferringPhysicianName: [1x1 struct] ManufacturerModelName: 'Sensation 64' ReferencedImageSequence: [1x1 struct] PatientName: [1x1 struct] PatientID: '' PatientBirthDate: '' PatientSex: '' PatientIdentityRemoved: 'YES' DeidentificationMethod: 'DICOMANON (rev R2010a) - PS 3.15-2008...' BodyPartExamined: 'EXTREMITY' SliceThickness: 2 KVP: 120 SoftwareVersion: 'syngo CT 2009E' DistanceSourceToDetector: 1040 DistanceSourceToPatient: 570 GantryDetectorTilt: 0 TableHeight: 179 RotationDirection: 'CW' FilterType: '0' GeneratorPower: 10 FocalSpot: 1.2000 DateOfLastCalibration: '20131007' TimeOfLastCalibration: '061322.000000' ConvolutionKernel: 'B60s' PatientPosition: 'FFS' StudyInstanceUID: '1.3.6.1.4.1.9590.100.1.2.328077616812...' SeriesInstanceUID: '1.3.6.1.4.1.9590.100.1.2.237595359611...' StudyID: '' SeriesNumber: 505 AcquisitionNumber: 3 InstanceNumber: 1 ImagePositionPatient: [3x1 double] ImageOrientationPatient: [6x1 double] FrameOfReferenceUID: '1.3.6.1.4.1.9590.100.1.2.396775851196...' PositionReferenceIndicator: '' SamplesPerPixel: 1 PhotometricInterpretation: 'MONOCHROME2' Rows: 512 Columns: 512 PixelSpacing: [2x1 double] BitsAllocated: 16 BitsStored: 16 HighBit: 15 PixelRepresentation: 0 SmallestImagePixelValue: 0 LargestImagePixelValue: 2802 WindowCenter: 240 WindowWidth: 1200 RescaleIntercept: -1024 RescaleSlope: 1 WindowCenterWidthExplanation: 'WINDOW1\WINDOW2' LossyImageCompression: '00' RequestingPhysician: [1x1 struct] RequestedProcedureDescription: 'CT LOWER EXTREMITY C-' OverlayRows_0: 512 OverlayColumns_0: 512 NumberOfFramesInOverlay_0: 1 OverlayDescription_0: 'Siemens MedCom Object Graphics' OverlayType_0: 'G' OverlayOrigin_0: [2x1 int16] ImageFrameOrigin_0: 1 OverlayBitsAllocated_0: 1 OverlayBitPosition_0: 0 OverlayData_0: [512x512 logical] info.FileSize: 559084 info.Format: DICOM info.FormatVersion: 3 info.Width: 512 info.Height: 512 info.BitDepth: 16 info.ColorType: grayscale info.FileMetaInformationGroupLength: 222 info.FileMetaInformationVersion: 0 1 info.SourceApplicationEntityTitle: DCF info.SpecificCharacterSet: ISO_IR 100 info.StudyDate: 20131007 info.SeriesDate: 20131007 info.AcquisitionDate: 20131007 info.ContentDate: 20131007 info.AccessionNumber: info.Modality: CT info.Manufacturer: SIEMENS info.InstitutionName: info.ReferringPhysicianName: FamilyName: '' GivenName: '' MiddleName: '' NamePrefix: '' NameSuffix: '' info.ReferringPhysicianName.FamilyName: info.ReferringPhysicianName.GivenName: info.ReferringPhysicianName.MiddleName: info.ReferringPhysicianName.NamePrefix: info.ReferringPhysicianName.NameSuffix: info.ReferencedImageSequence: Item_1: [1x1 struct] info.ReferencedImageSequence.Item_1: ReferencedSOPClassUID: '1.2.840.10008.5.1.4.1.1.2' ReferencedSOPInstanceUID: '1.3.12.2.1107.5.99.2.9567.30000013100710203...' info.PatientName: FamilyName: '' GivenName: '' MiddleName: '' NamePrefix: '' NameSuffix: '' info.PatientName.FamilyName: info.PatientName.GivenName: info.PatientName.MiddleName: info.PatientName.NamePrefix: info.PatientName.NameSuffix: info.PatientID: info.PatientBirthDate: info.PatientSex: info.PatientIdentityRemoved: YES info.BodyPartExamined: EXTREMITY info.SliceThickness: 2 info.KVP: 120 info.DistanceSourceToDetector: 1040 info.DistanceSourceToPatient: 570 info.GantryDetectorTilt: 0 info.TableHeight: 179 info.RotationDirection: CW info.FilterType: 0 info.GeneratorPower: 10 info.FocalSpot: 1.2000 info.DateOfLastCalibration: 20131007 info.ConvolutionKernel: B60s info.PatientPosition: FFS info.StudyID: info.SeriesNumber: 505 info.AcquisitionNumber: 3 info.InstanceNumber: 1 info.ImagePositionPatient: -2.3311 -228.0754 222.8133 info.ImageOrientationPatient: 1.0000 -0.0000 0.0000 0.0000 0.0572 -0.9984 info.PositionReferenceIndicator: info.SamplesPerPixel: 1 info.Rows: 512 info.Columns: 512 info.PixelSpacing: 0.3379 0.3379 info.BitsAllocated: 16 info.BitsStored: 16 info.HighBit: 15 info.PixelRepresentation: 0 info.SmallestImagePixelValue: 0 info.LargestImagePixelValue: 2802 info.WindowCenter: 240 info.WindowWidth: 1200 info.RescaleIntercept: -1024 info.RescaleSlope: 1 info.LossyImageCompression: 00 info.RequestingPhysician: FamilyName: 'TARQUINIO' GivenName: 'THOM A.' info.RequestingPhysician.FamilyName: TARQUINIO info.RequestingPhysician.GivenName: THOM A. info.OverlayRows_0: 512 info.OverlayColumns_0: 512 info.NumberOfFramesInOverlay_0: 1 info.OverlayType_0: G info.OverlayOrigin_0: 1 1 info.ImageFrameOrigin_0: 1 info.OverlayBitsAllocated_0: 1 info.OverlayBitPosition_0: 0
And if you're curious what a CT scan of a really bad looking ankle looks like, here's a downsized animated gif created from the full DICOM stack.
Comments
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