Mapping P-Values to Input of Characteristic Curve (DDL’s)
300
250
200
DDL
150
100
50
0 0 50 100 150 200 250 300
P-Values
Slide Provided by David Clunie, Quintiles Intelligent Imaging
Basic Print Meta SOP Class consist of four SOP Classes (Film Session, Film Box, Image Box, and Printer)
N-Create (create film sheet, format printer) N-Set (place images on film sheet) N-Action (request to print the film sheet) N-Event-Report (status of the printer)
Characteristic curve
– Mapping digital input to luminance/density – Shape – Linearity

Ambient light or illumination
Causes of Inconsistency
•Display devices vary in the maximum luminance they can produce •Display CRT vs. film on a light box is an extreme example
To Achieve Consistent Presentation of Images, the DICOM Standard Defines:
Basic Print Management with Presentation Look Up Table, for controlling the consistent appearance of preformatted images on printed output Grayscale Softcopy Presentation State, for controlling the consistent appearance of images on softcopy display
Basic Print Management Meta SOP Class
Association Negotiation - “Contract Agreement”
Agreed set of SOP Classes and Transfer Syntaxes ( Basic Print Meta SOP Class) Print (SCP) Print (SCU)
Monitor Characteristic Curve
Monitor Characteristic Curve
100
10
0.1
Ambient Light
0.01 0 50 100 150 Digital Driving Level 200 250 300
Slide Provided by David Clunie, Quintiles Intelligent Imaging
Slide Provided by Jerry Gaskill, Image Smiths Inc.
Perceptual Linearization
Grayscale Standard Display Function
1000
Despite different change in absolute luminance
Suspected area
Example Continued: Referring Physician Views the Original Image…
Radiologist: Referring Physician:
Suspected area
Radiologist Should Store the Viewing Parameters Using GSPS!
100
10
1 0 200 400 600 800 1000
.1
.01 JND Index
Same number of Just Noticeable Difference == Same perceived contrast
Slide Provided by David Clunie, Quintiles Intelligent Imaging
Laser Printer
Slide Provided by David Clunie, Quintiles Intelligent Imaging
Causes of Inconsistency

Gamut of device
– Minimum/maximum luminance/density

Standard Display Function
Grayscale Standard Display Function
1000
Maximum Luminance + Ambient Light
100
Monitor’s Capability
10
1
Minimum Luminance + Ambient Light
– Input: Just Noticeable Differences (JNDs) – Output: absolute luminance
Printer Calibration Tools (Densitometer)
Display Calibration Tools (Photometer)
The Grayscale Consistency Problem:




Optimal image viewing parameters (e.g. window/ level) selected on one device appear different when displayed on a different device Device capabilities/ characteristics vary - the same number of gray levels cannot be rendered or perceived on different devices Displayed images look different from printed images …other
100
Standard
10
1 0 50 100 150 200 250
0.1
Characteristic Curve
DDL or P-Values
Slide Provided by David Clunie, Quintiles Intelligent Imaging
Standardizing a Display
.1
0
200
400
600
8001000源自Jmax == P-Value of 2n-1 Jmin == P-Value of 0
JND Index
.01
Slide Provided by David Clunie, Quintiles Intelligent Imaging
Standardizing a Display
Slide Provided by David Clunie, Quintiles Intelligent Imaging
Problems of Inconsistency
0.5 1.0 •Not all display levels are perceivable on all devices
1.5
1.0
.66
Slide Provided by David Clunie, Quintiles Intelligent Imaging
Towards a Standard Display
Can’t use absolute luminance since display capabilities different Can’t use relative luminance since shape of characteristic curves vary Solution: exploit known characteristics of the contrast sensitivity of human visual system - contrast perception is different at different levels of luminance
Problems of Inconsistency
•VOI chosen on one display device •Rendered on another with different display •Mass expected to be seen is no longer seen mass visible mass invisible
3.0
Slide Provided by David Clunie, Quintiles Intelligent Imaging
Problems of Inconsistency
0.5 1.0 •Not all display levels are perceivable on all devices
Grayscale Softcopy Presentation State: