DICOM%20Imaging%20Pipeline%20Model

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DICOMImaging Pipeline Model

• Cor loef
• Philips Medical Systems

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Presentation Overview

• Scope
• Image Processing and Viewing
• DICOM Pixel Processing model
• Processing Functions
• Single Pixel
• Pixel Set
• Geometric transformations
• Color representation
• Annotations and view area

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Scope

• Pixel processing operations supported by DICOM
  concepts
• Contrast and Spatial Resolution
• Single image view, with annotations
• Monitor display and Film printing

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Image Processing and Viewing
Annotations
Image Object
Viewing device
Columns
Pixel Value
Gray Level
Rows
Processing
Pixel Size
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Image Processing and Viewing

• Image Object
• Spatial Resolution
• Rows, Columns
• Pixel Size
• Contrast Resolution
• Pixel Value Range
• Number of Images
• Annotations

• Viewing Device
• Spatial resolution
• Rows, Columns
• Pixel Size
• Contrast Resolution
• Pixel Luminance/Density Range
• Number of Images
• Annotations

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DICOM Pixel Processing model
Normalize Physical Value
Acquisition specific Image improvements
Application dependent subrange selection
Normalize Perception
(Non-DICOM) Acquisition processing
Modality LUT or Linear Transformation
VOI LUT or Linear Transformation
Presentation LUT or Linear Transformation
Original Acquired Image
Meaningful for Modality, manufacturer independent
Gray Levels
Stored Pixel Value
P-Values
Photometric Intepretation Monochrome 1 min
value -gt White Monochrome 2 min value -gt
Black Polarity Opposite of whats
specified with Photometric Interpretation (Print)
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Processing Functions(1)
Single Pixel, Single Image

• Viewing Device
• Spatial resolution
• Rows, Columns
• Pixel Size
• Contrast Resolution
• Pixel Luminance/Density Range
• 1 Image

• Image Object
• Spatial Resolution
• Rows, Columns
• Pixel Size
• Contrast Resolution -gt
• Pixel Value Range -gt
• 1 Image

Processing
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Processing Functions(1)
Single Pixel, Single Image
Linear operation Add, Subtract, Divide and
Multiply by Constant Value
DICOM
OutputRSxPixel RI
Max Rescale Type Range
Ya.Xb
Output Y Range
Rescale Slope
a
Max Stored Pixel Value Range
Rescale Intercept
Input X Range
b
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Processing Functions(1)
Non-Linear operation OutputF(Input)
DICOM Modality LUT, VOI LUT
YnFStart Value n-1
Output Y Range
Output Y Range 0..2B-1
YF(X)
Input X Range
N Number of Entries
Start Value
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Processing Functions(1)
Histogram operations Contrast Stretching,
Contrast Compression Histogram is pixel
intensity distribution
Frequency
Pixel value ( intensity )
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Processing Functions(1)
Histogram, Contrast Stretching Applied to an
Image to stretch (part of) a histogram to fill
the full dynamic range of the display device.
DICOM VOI Window Width/Window Center
No values
Max Output Range (Dynamic Range Display Device)
No values
WC
Max Input range
WW
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Processing Functions(1)
Histogram, Contrast Compression Applied to an
Image to suppress a part of the dynamic range of
the display device.
DICOM VOI Window Width/Window Center
Max Output Range (Dynamic Range Display Device)
WC
No values
Max Input range
WW
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Processing Functions(2)
Set Pixels, Single Image or Multiple Frames

• Image Object
• Spatial Resolution
• Rows, Columns
• Pixel Size
• Contrast Resolution -gt
• Pixel Value Range -gt
• gt1 Images -gt

• Viewing Device
• Spatial resolution
• Rows, Columns
• Pixel Size
• Contrast Resolution
• Pixel Luminance/Density Range
• 1 Image

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Processing Functions(2)
Convolution
Image Out
Image In
P1 P2 P3 P4 P5 P6 P7 P8 P9
X
Kernel
C1 C2 C3 C4 C5 C6 C7 C8 C9
DICOM Convolution operations not supported.
Could become part of the Advanced Presentation
State SOP Class. Example of Industry use Edge
Enhancement OutputInput Gain(Input-Convolu
ted_Region)
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Processing Functions(2)
Add,Subtract and Average operations on multiple
Images, Frames Operations on 1 pixel in multiple
frames, and generation of output pixel based on
two (processed) input pixel values.
Images/Frames
Sum N
_
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Processing Functions(2)
DICOM XA Multi-frame supports subtraction
Mask Frames
Sum N
_
Applicable Contrast Frames
Sum N
Pixel Intensity Relationship is LOG
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Processing Functions(3)
Geometry operations Scaling, Rotate/Flip/Displaye
d Area Single Image

• Image Object
• Spatial Resolution -gt
• Rows, Columns -gt
• Pixel Size -gt
• Contrast Resolution -gt
• Pixel Value Range -gt
• 1 Image

• Viewing Device
• Spatial resolution
• Rows, Columns
• Pixel Size
• Contrast Resolution
• Pixel Luminance/Density Range
• 1 Image

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Processing Functions(3)
Scaling, Zoom-in, Zoom-out No more 1-to-1
mapping of pixels gt holes and overlaps in
pixel view area Need for interpolation.
Interpolation types Replicate, Bilinear,
Cubic DICOM Print has Magnification Type with
the mentioned interpolation options. Requested
Image Size, Rows/Columns and Pixel Aspect Ratio.
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Processing Functions(3)
Replicate Bilinear Cubic
X
Pi
Pi1
X
Pi
Pi1
Pi-1
Pi2
Pi
Pi1
X
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Processing Functions(3)
Rotate/Flip
Rotate may result in rescaling operation
Horizontal Flip
Rotate
DICOM Presentation State has Rotate ( 90,180,
270) and Horizontal Flip
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Processing Functions(3)
Pixel size Different pixel size may result in the
need to interpolate DICOM CT/MR has Pixel
Spacing, absolute Row Height/Column Width X-Ray
has Pixel Aspect Ratio, relative Row
Height/Column Width and Imager Pixel Spacing (
absolute, on detector plate ) Print has
Requested Image Size , x-dimension in mm of image
in Image Box, and Image Display Format. Printer
Pixel Spacing retrieved with new SOP Class
Printer Configuration
Processing
Pixel Aspect Ratio 2/1
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Color representation
DICOM Photometric Interpretation - Palette
Color, 1 sample value with 3 Palette Color LUTs
that define R,G,B - RGB, 3 sample values for
R,G,B
Red-Palette Color LUT
Sample pixel value
Green-Palette Color LUT
Blue-Palette Color LUT
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Annotations and view area
Text and Vector graphics, added to the Image
pixels Currently in DICOM only Overlay and
Curve. In Presentation State directly text and
vector graphics, both in Image space and Display
Device coordinate space.
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Annotations
Vector Graphics
Bounding Box
Text
Polyline (Filled)
(Anchor)
X
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DICOM Overlays and Curves ( in Image space )
Overlay ROI or Graphic - 1 bit, on-off -
Origin, Rows, Columns - Type Graphics or ROI -
Max 16 planes - May be multi-frame Curve Type
ROI or POLY - List of (x,y) coordinates
Image
Overlay
Origin
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Annotations and view area
Shutter, geometric mask applied on the image
during display to neutralize the display of any
pixels located outside the shutter shape. DICOM
has the following shutter shapes Rectangular, Cir
cular, Polygonal