EVALUATING IMAGING EVALUATING IMAGING QUALITY QUALITY

Federal Agencies Digitization Initiative – Still Image Working GroupFederal Agencies Digitization Initiative – Still Image Working Group

Presented byPresented byMichael StelmachMichael Stelmach

Library of Congress, Office of Strategic InitiativesLibrary of Congress, Office of Strategic InitiativesMarch, 2009March, 2009

The ChallengeThe Challenge

o Define Content CategoriesDefine Content Categorieso Define Imaging ObjectivesDefine Imaging Objectiveso Decide on Measures of QualityDecide on Measures of Qualityo Identify Standard Methods to Derive Identify Standard Methods to Derive

MeasuresMeasureso Design Tools to Evaluate Image Design Tools to Evaluate Image

Performance and QualityPerformance and Qualityo Create Standard Methods of EvaluationCreate Standard Methods of Evaluation

ProgressProgress

o Detailed definitions established for content Detailed definitions established for content categories and imaging objectivescategories and imaging objectives

o Performance measures to be captured Performance measures to be captured and defined (current)and defined (current)

o Performance measurement standards Performance measurement standards identifiedidentified

o Tools developed to validate required Tools developed to validate required image performance measures to actual image performance measures to actual values values

Roadmap to Image Requirements – Content and ObjectivesRoadmap to Image Requirements – Content and Objectives

Combined with…

Roadmap to Image Requirements – Performance MeasuresRoadmap to Image Requirements – Performance Measures

Advances Image Specs FromAdvances Image Specs From

Color vs. MonochromaticColor vs. Monochromatic

Bit DepthBit Depth

Pixel DensityPixel Density

To….To….ToneTone ResolutionResolution Color Color UniformityUniformity NoiseNoise

GammaGamma

WhiteWhite BalanceBalance

SpatialSpatial FrequencyFrequency Response (SFR) Response (SFR)

ResolutionResolution

SamplingSampling EfficiencyEfficiency

SamplingSampling FrequencyFrequency

LuminanceLuminance

Delta EDelta E20002000

Delta E(a*b*)Delta E(a*b*)20002000

ChannelChannel Mis-registrationMis-registration

% Lighting % Lighting Non-uniformityNon-uniformity

Total rmsTotal rms deviationdeviation

Specific to content and objectives…

Example of Concept Requirements Matrix

Image Performance Measure – Image Performance Measure – ToolsTools

Digital Image Conformance Evaluation Digital Image Conformance Evaluation (DICE) System(DICE) SystemTargets providing known referencesTargets providing known referencesDevice Target – Imaging Device Device Target – Imaging Device PerformancePerformanceObject Target – Actual Image QualityObject Target – Actual Image QualityEvaluation/Validation Software – Evaluation/Validation Software – LabVIEW-basedLabVIEW-basedData export for use in SQC/SPC Data export for use in SQC/SPC

Device and Object TargetsDevice and Object Targets

Object Target in UseObject Target in Use

DICE Software – Main PanelDICE Software – Main Panel

DICE – QC Summary PanelDICE – QC Summary Panel

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More to Come…More to Come…

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http://digitizationguidelines.gov/http://digitizationguidelines.gov/