Digitization and metric conversion for image quality test targets: Part II

William C. Kress

doi:10.1117/12.530068

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18 December 2003 Digitization and metric conversion for image quality test targets: Part II

William C. Kress

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Proceedings Volume 5294, Image Quality and System Performance; (2003) https://doi.org/10.1117/12.530068
Event: Electronic Imaging 2004, 2004, San Jose, California, United States

Abstract

A common need of the INCITS W1.1 Macro Uniformity, Color Rendition and Micro Uniformity ad hoc efforts is to digitize image quality test targets and derive parameters that correlate with image quality assessments. The digitized data should be in a colorimetric color space such as CIELAB and the process of digitizing will introduce no spatial artifacts that reduce the accuracy of image quality parameters. Input digitizers come in many forms including inexpensive scanners used in the home, a range of sophisticated scanners used for graphic arts and scanners used for scientific and industrial measurements (e.g., microdensitometers). Some of these are capable of digitizing hard copy output for image quality objective metrices, and this report focuses on assessment of high quality flatbed scanners for that role. Digitization using flatbed scanners is attractive because they are relatively inexpensive, easy to use, and most are available with document feeders permitting analysis of a stack of documents with little user interaction. Other authors have addressed using scanners for image quality measurements. This paper focuses (1) on color transformations from RGB to CIELAB and (2) sampling issues and demonstrates that flatbed scanners can have a high level of accuracy for generating accurate, stable images in the CIELAB metric. Previous discussion and experimental results focusing on color conversions had been presented at PICS 2003. This paper reviews the past discussion with some refinement based on recent experiments and extends the analysis into color accuracy verification and sampling issues.

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William C. Kress "Digitization and metric conversion for image quality test targets: Part II", Proc. SPIE 5294, Image Quality and System Performance, (18 December 2003); https://doi.org/10.1117/12.530068

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