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Charles J. C. Lloyd

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Publication statistics

Pub. period:1988-1994
Pub. count:4
Number of co-authors:6

Co-authors

Number of publications with 3 favourite co-authors:

Jennie J. Decker:2
William F. Reinhart:2
Craig Dye:1

Productive colleagues

Charles J. C. Lloyd's 3 most productive colleagues in number of publications:

Harry L. Snyder:8
Ko Kurokawa:4
Jennie J. Decker:3

Calendar

May 22

Knowing (by) Designing 2013

May 27

13th Intl. Conf. on New Interfaces for Musical Expression

May 28

Graphics Interface 2013

May 21

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Charles J. C. Lloyd

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Publications by Charles J. C. Lloyd (bibliography)

1994

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Reinhart, William F. and Lloyd, Charles J. C. (1994): A Human Factors Simulation Tool for Stereoscopic Displays. In: Proceedings of the Human Factors and Ergonomics Society 38th Annual Meeting 1994. pp. 1290-1294.

“The increasing complexity of advanced display systems places increased importance on simulation tools. Display simulation tools allow the development of displays with the desired balance of image quality and end cost while reducing the time and cost otherwise associated with iterative testing of physical prototypes. In addition, simulation offers the advantage of permitting demonstration of display systems to targeted users and decision makers early in the display design cycle, allowing for more feedback in the design process. A new display simulation tool is described in this paper with the capability of simulating advanced electronic stereoscopic displays. To illustrate the use of this tool, an evaluation of a simulated stereoscopic head-mounted display is reported. Surgeons viewed stereoscopic laparoscopic imagery and rated the acceptability of display gray scale, resolution, and field of view. Clear preferences were seen for levels of each of these parameters. Simulations such as the one described in this report play an invaluable role in defining acceptable design parameters prior to commitment to display production.”

1993

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Lloyd, Charles J. C. and Reinhart, William F. (1993): Requirements for HUD Raster Image Modulation in Daylight. In: Proceedings of the Human Factors and Ergonomics Society 37th Annual Meeting 1993. pp. 1335-1339.

“Head-up displays (HUDs) represent the leading candidate display technology for inclusion in an enhanced or synthetic vision system (EVS or SVS) for commercial transport aircraft. One common EVS concept assumes the raster display of raw or processed sensor (radar or IR) data. However, experience with the use of raster rather than stroke display modes has been largely limited to the presentation of images captured by IR sensitive and image-intensified cameras during night flying conditions when the luminance of the forward scene over which the image will be superimposed is much lower than in daytime. The objective of this work is to generate a specification for minimum HUD raster image modulation assuming real-world luminance values typically found in low-visibility, daylight flight. Six Honeywell pilots rated the image quality and utility of flight video as presented through a military-style HUD in a transport cockpit mockup. Flight video came from daylight FLIR and daylight CCD cameras. The luminance of the forward scene against which the HUD image was superimposed was varied among nine levels ranging from 5 fL to 10,000 fL. The results indicate that HUD raster luminance must be approximately 50% external scene luminance to promote good pilot awareness of general terrain. To maintain good utility and visibility of standard, high-contrast runway markings, runway center line, and runway edges, HUD raster luminance must be approximately 15% of the forward scene luminance.”

1990

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Snyder, Harry L., Decker, Jennie J., Lloyd, Charles J. C. and Dye, Craig (1990): Effect of Image Polarity on VDT Task Performance. In: D., Woods, and E., Roth, (eds.) Proceedings of the Human Factors Society 34th Annual Meeting 1990, Santa Monica, USA. pp. 1447-1451.

“Three experiments were conducted in which positive and negative contrast on visual display terminals were directly compared. Operator tasks included visual search and reading, with accuracy and timeliness of response measured. In all cases where significant differences exist, better performance was obtained with negative contrast (dark characters or symbols on a lighter background). The increases in performance range from a low of 2.0 percent to a high of 31.6 percent. Based on the above results, we believe that there are significant advantages in visual task performance obtained from the selection of negative contrast displays. Current standards that require negative contrast appear to be justified, while future revisions of ANSI/HFS 100-1988 and other standards should seriously consider incorporating negative contrast as a recommendation or requirement.”

1988

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Decker, Jennie J., Dye, Craig J., Kurokawa, Ko and Lloyd, Charles J. C. (1988): Effects of Display Failures and Symbol Rotation on Visual Search Using Dot-Matrix Symbols. In: Proceedings of the Human Factors Society 32nd Annual Meeting 1988. pp. 1386-1390.

“This study was conducted tin investigate the effects of display failures and rotation of dot-matrix symbols on visual search performance. The type of display failure (cell, horizontal line, vertical line), failure mode (ON, failures matched the symbols; OFF, failures matched the background), percentage of failures (0, 1, 2, 3, 4%), and rotation angle (0, 70, 105 degrees) were the variables examined. Results showed that displays which exhibit ON cell failures greater than 1% significantly affect search time performance. Cell failures degrade performance more than line failures. Search time and accuracy were best when symbols were oriented upright. The effects of display failures and rotation angle were found to be independent. Implications for display design and suggestions for quantifying the distortion due to rotation are discussed.”

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