Dr. Donald R. Williams
Consultant at Image Science Associates
SPIE Involvement:
Author | Instructor
Publications (15)

Proceedings Article | 3 February 2014
Proc. SPIE. 9016, Image Quality and System Performance XI
KEYWORDS: Imaging systems, Spatial frequencies, Cameras, Image resolution, Digital cameras, Distortion, Image quality, Digital imaging, Modulation transfer functions, Standards development

Proceedings Article | 4 February 2013
Proc. SPIE. 8653, Image Quality and System Performance X
KEYWORDS: Human-machine interfaces, Digital image processing, Visualization, Calibration, Image quality, Digital imaging, Light sources and illumination, Image display, Standards development, Image quality standards

Proceedings Article | 25 January 2012
Proc. SPIE. 8293, Image Quality and System Performance IX
KEYWORDS: Image compression, Imaging systems, Cameras, Image processing, Interference (communication), Computer simulations, Image quality, Image sensors, Digital imaging, Modulation transfer functions

Proceedings Article | 19 January 2009
Proc. SPIE. 7242, Image Quality and System Performance VI
KEYWORDS: Signal to noise ratio, Imaging systems, Spatial frequencies, Interference (communication), Distortion, Image quality, Modulation transfer functions, Taxonomy, Standards development, Image quality standards

Proceedings Article | 28 January 2008
Proc. SPIE. 6808, Image Quality and System Performance V
KEYWORDS: Visualization, Calibration, Image processing, Quality measurement, Printing, Image quality, Quantization, Standards development, Inkjet technology, Image quality standards

Proceedings Article | 28 January 2008
Proc. SPIE. 6808, Image Quality and System Performance V
KEYWORDS: Visualization, Spatial frequencies, Cameras, Image resolution, Digital cameras, Image quality, Digital imaging, Modulation transfer functions, Standards development, Image quality standards

Showing 5 of 15 publications
Course Instructor
SC807: Digital Camera and Scanner Performance Evaluation: Standards and Measurement
This is an updated course on imaging performance measurement methods for digital image capture devices and systems. We introduce several ISO measurement protocols for camera resolution, tone-transfer, noise, etc. We focus on the underlying sources of variability in system performance, measurement error, and how to manage this variability in working environments. The propagation of measurement variability will be described for several emerging standard methods for; image texture, distortion, color shading, flare and chromatic aberration. Using actual measurements we demonstrate how standards can be adapted to evaluate capture devices ranging from cell phone cameras to scientific detectors. New this year, we will be discussing the use of raw files to investigate intrinsic signal and noise characteristics of the image-capture path.
SC825: Imaging Performance Evaluation for Digital Cameras, Cell-phone Cameras and Scanners
This is an updated theory-to-practice course on imaging performance measurement methods for digital image capture devices and systems. We focus on science-based standard ISO measurement protocols* for tone-transfer, speed, resolution, noise, dynamic range, and color. Using actual measurements we demonstrate how standard methods can be adapted to measure capture devices and evaluate vendor compliance for various capture systems. Because practical metrology and field application can limit measurement precision and accuracy, we will identify ways to maintain measurement utility in the presence of error sources. ISO-compliant executable software will be provided and demonstrated. In addition, several available alternative methods and analysis software will be explained and compared. *(ISO 12233, 16067-1, 16067-2, 15529, 15739, 21550, and 17321),
SC513: Digital Camera/Scanner Evaluation Workshop: A Critical Look at ISO Standards, Tools and Limitations
This theory-to-practice course on speed, resolution, dynamic range, and noise metrology for digital image capture is based on our previous highly rated courses offered at this Symposium. Improved this year, it takes the form of a workshop. We focus on standardized measurement protocols for resolution (ISO 12233, 16067-1, 16067–2, & 15529), speed (ISO 12232), and image dynamic range/noise (ISO 15739, 21550). We will also describe and compare alternative methods currently under consideration like CIPA DC-003 and polar sine-wave techniques. About half of our day will be spent addressing various challenges to reliable evaluation and system comparison using actual test data and software tools. These examples will expose error sources (rarely addressed in the standards), and reveal ways to maintain measurement utility and workflow.
SC745: Basic Testing and Calibration of Digital Imagers
The course is aimed at providing an understanding of basic performance testing of image acquisition for digital cameras and scanners, in both consumer and technical applications. The assembly of basic elements, optics, detector, supporting electronics and image processing, are described. We then identify several key imaging performance metrics for such systems, and testing methods consistent with ISO standards. How the standard methods are applied to several types of image acquisition systems and field conditions will be explained using results from actual measurements. It is common to apply compensation for practical performance limitations either in the device or supporting driver software. We describe and demonstrate several approaches to this for; spatial distortion, white-point balance, resolution and sharpness, scene uniformity, and detector fixed-pattern noise, and pixel defects. Attendees should then be prepared for other courses on, e.g., Color Management, understanding sources of performance variation.
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