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| SPECTRAVIEW II - USER'S GUIDE
Information window - DICOM Conformance tab
The DICOM Conformance tab shows graphically and numerically how well the calibrated display conforms to
the ideal DICOM (Digital Imaging and Communications in Medicine) response when a DICOM Target curve of
is used.
The aim of the DICOM response is to have a perceptually linear luminance response. Each step along the
display's grayscale should have an equally perceptive increase in luminance. The actual shape of the DICOM
response curve is based on the display's measured Black Level and Intensity, since the DICOM response
considers the human eye's non-linear response to light.
In DICOM terminology, the grayscale level is called the Digital Driving Level and represents the digital output
video level, from 0 to 255. Each step in Digital Driving Level, should result in an equal step in perceived
luminance. In DICOM terminology, a change in luminance that is just perceptible, is considered to be 1 JND
(Just Noticeable Difference). So, ideally, each step in Digital Driving Level should result in an equal change in
Just Noticeable Difference value. The JND values are calculated using a complex formula from two measured
luminance values.
The display calibration results can be viewed in two different types of graphs, JND per DDL, and Contrast
Response, by selecting the corresponding graph type.
JND per DDL (Just Noticeable Difference per Digital Driving Level)
Average - shows the average JND per DDL value. The actual value will depend on the Black Level and
Intensity of the display.
Std Dev - shows the standard deviation of all of the calculated JND per DDL values.
Show Average - shows the average JND per DDL value as a horizontal line on the graph.
Show Linear Fit - shows the best fit line between all the calculated JND per DDL values as a line on the
graph. Ideally this line should be horizontal, indicating equal steps in JDN per DDL along the display's
grayscale.
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