D. Rene Rasmussen

ISO 19751 macro-uniformity

The ISO WD 19751 macro-uniformity team works towards the development of a standard for evaluation of perceptual image quality of color printers. The team specifically addresses the types of defects that fall in the category of macrouniformity, such as streaks, bands and mottle. The first phase of the standard will establish a visual quality ruler for macro-uniformity, using images with simulated macro-uniformity defects. A set of distinct, parameterized defects has been defined, as well as a method of combining the defects into a single image. The quality ruler will be a set of prints with increasing magnitude of the defect pattern. The paper will discuss the creation and printing of the simulated images, as well as initial tests of subjective evaluations using the ruler.

Predicting customer preference from objective image quality metrics for monochrome document products

This paper describes a regression model for predicting customer preference from objective image quality metrics for black and white printers, copiers and multifunction systems. In order to quantify customer preference for monochrome images the quantitative preference system was previously developed. Using this system, a preference survey with five different customer-type documents was used to obtain the preference data. Objective image quality metrics were obtained from a scanner-based measurement system. Using this regression model, typically 80% or more of the variation of the overall preference can be explained by six objective image quality metrics: Relative TRC Error; Mottle; Visual Noise; Visual Structure; Streaks and Bands; and Relative Dynamic Range Reduction. The results also provide the relative significance of these attributes for the different kinds of customer images.

The mobile image quality survey game

In this paper we discuss human assessment of the quality of photographic still images, that are degraded in various manners relative to an original, for example due to compression or noise. In particular, we examine and present results from a technique where observers view images on a mobile device, perform pairwise comparisons, identify defects in the images, and interact with the display to indicate the location of the defects. The technique measures the response time and accuracy of the responses. By posing the survey in a form similar to a game, providing performance feedback to the observer, the technique attempts to increase the engagement of the observers, and to avoid exhausting observers, a factor that is often a problem for subjective surveys. The results are compared with the known physical magnitudes of the defects and with results from similar web-based surveys. The strengths and weaknesses of the technique are discussed. Possible extensions of the technique to video quality assessment are also discussed.

INCITS W1.1 development update: appearance-based image quality standards for printers

In September 2000, INCITS W1 (the U.S. representative of ISO/IEC JTC1/SC28, the standardization committee for office equipment) was chartered to develop an appearance-based image quality standard.(1),(2) The resulting W1.1 project is based on a proposal(3) that perceived image quality can be described by a small set of broad-based attributes. There are currently six ad hoc teams, each working towards the development of standards for evaluation of perceptual image quality of color printers for one or more of these image quality attributes. This paper summarizes the work in progress of the teams addressing the attributes of Macro-Uniformity, Colour Rendition, Gloss & Gloss Uniformity, Text & Line Quality and Effective Resolution.

Recent Progress in the Development of INCITS W1.1, Appearance-Based Image Quality Standards for Printers

In September 2000, INCITS W1 (the U.S. representative of ISO/IEC JTC1/SC28, the standardization committee for office equipment) was chartered to develop an appearance-based image quality standard.(1),(2) The resulting W1.1 project is based on a proposal(4) that perceived image quality can be described by a small set of broad-based attributes. There are currently five ad hoc teams, each working towards the development of standards for evaluation of perceptual image quality of color printers for one or more of these image quality attributes. This paper summarizes the work in progress of the teams addressing the attributes of Macro-Uniformity, Color Rendition, Text and Line Quality and Micro-Uniformity.

Tent-pole spatial defect pooling for prediction of subjective quality assessment of streaks and bands in color printing

An algorithm is described for measuring the subjective, visual impact of 1-D defects (streaks and bands) in prints. A general approach to measurements of spatially localized image defects is described, attempting to directly match three stages of processing by the human observer: formation of the perceived image, identifi- cation of individual defects, and pooling of the visual defect magni- tudes into an overall assessment. The emphasis of the discussion is on the method of pooling of multiple streaks and band defects. It is demonstrated that the commonly used Minkowski pooling method does not satisfy the basic criteria necessary for this application, and a tent-pole pooling method is defined and analyzed. A complete algorithm for measuring streaks and bands, which uses tent-pole pooling, is described. The performance of the algorithm is demon- strated by comparison to results from new and independently col- lected subjective ratings.

W1.1 macro-uniformity

The INCITS W1.1 macro-uniformity team works towards the development of a standard for evaluation of perceptual image quality of color printers. The team specifically addresses the types of defects that fall in the category of macrouniformity, such as streaks, bands and mottle. This paper provides a brief summary of the status of this work, and describes recent results regarding the precision of the macro-uniformity quality ruler for assessment of typical printer defects.

INCITS W1.1 macro-uniformity

This paper describes the status of the INCITS W1.1 macro-uniformity ad hoc team, towards development of standards for perceptual image quality for color printers. The team has defined the macro-uniformity attribute, has developed several test patterns to be used for subjective and objective evaluations and has defined test patterns and methods to address color conversions of digitizing devices. A set of print samples, originating from diverse printing systems, has been established, and digitization of these samples is in progress. These activities and next steps are reviewed in this paper.

Update on INCITS W1.1 standard for perceptual evaluation of micro-uniformity

INCITS W1 is the U.S. representative of ISO/IEC JTC1/SC28, the standardization committee for office equipment. In September 2000, INCITS W1 was chartered to develop an appearance-based image quality standard. The resulting W1.1 project is based on a proposal that perceived image quality could be described by a small set of broad-based attributes. There are currently five ad hoc W1.1 teams, each working on one or more of these image quality attributes. This paper summarizes the work of the W1.1 Microuniformity ad hoc team. The agreed-upon process for developing the W1.1 Image Quality of Printers standards is described in a statement located on the INCITS W1.1 web site (ncits.org/tc_home/w11htm/incits_w11.htm), and the process schematic is reproduced here as Figure 1, (in which a final, independent confirmation step has been excluded for brevity).