Kirk Moffitt

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Kirk Moffitt is a private consultant in the application of human factors to the design of displays and controls—specializing in head-mounted displays, virtual imagery, UX and XR. He has worked on military, medical and entertainment display system projects. He holds a Ph.D. in Engineering Psychology from New Mexico State University, and has 40-plus years of industry experience.
Phone: (760) 409-9860
Address: La Quinta CA

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Papers by Kirk Moffitt

Ocular Response to Monocular and Binocular Imagery

Eye movement and ocular vergence measurements were made for two observers of monocular and binocu... more

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Visibility of color symbology in head-up and head-mounted displays in daylight environments

Abstract. Color-coded symbology has the potential to enhance the performance of people using head... more Abstract. Color-coded symbology has the potential to enhance the performance of people using head-up and head-mounted displays, as well as head-worn, optical see-through, augmented-reality displays. The distinguishing feature of these displays is the optical combiner that presents symbology overlaid upon the forward natural scene. The presence of high-ambient daylight can desaturate the symbol colors, making them difficult to identify. This is especially true for blue symbols that become faint and colorless in even moderate daylight. We defined a set of colors for testing based on color coding conventions, color symbology research, and results from our previous testing. Included in this set was blue-prime, a color that lies between blue and cyan. We then conducted an experiment to test the visibility of color symbols, the naming of symbol colors, and the legibility of color text mixed with daylight. Results were statistically analyzed and modeled using color-difference formulae. Additional experiments were conducted to test the effects of increasing the luminance of blue symbols and shifting primary colors to increase the luminance. Specific attention was given to the symbol color blue, where the alternative color blue-prime was shown to always outperform the color blue while retaining the color name blue.

<title>Color helmet display for the tactical environment: the pilot's chromatic perspective</title>

Proceedings of SPIE, Oct 30, 1992

ABSTRACT The applications of color symbology, graphics, and imagery in helmet-mounted displays ha... more ABSTRACT The applications of color symbology, graphics, and imagery in helmet-mounted displays have the potential to reduce workload and improve piloting performance. Unfortunately, there are three well-recognized paradigms that disallow the use of color in helmet-mounted displays in aviation environments. We provide evidence of three corresponding paradigm shifts that encourage the use of color in these displays. The rationales for these paradigm shifts are based on new methods of training and rehearsing, new lighting environments, and new display technologies.

Sensor-offset HMD perception and performance

Proceedings of SPIE, Apr 27, 2007

The perceptual and performance effects of viewing HMD sensor-offset video were investigated in a ... more The perceptual and performance effects of viewing HMD sensor-offset video were investigated in a series of small studies and demonstrations. A sensor-offset simulator was developed with three sensor positions relative to left-eye viewing: inline and forward, temporal and level, and high and centered. Several manual tasks were used to test the effect of sensor offset: card sorting, blind pointing and open-eye pointing. An obstacle course task was also used, followed by a more careful look at avoiding specific obstacles. Once the arm and hand were within the sensor field of view, the user demonstrated the ability to readily move to the target regardless of the sensor offset. A model of sensor offset was developed to account for these results.

Chromatic aftereffects associated with a night vision goggle simulation

PubMed, Feb 1, 1988

A visual perception experiment was conducted to determine the chromatic aftereffects of viewing a... more A visual perception experiment was conducted to determine the chromatic aftereffects of viewing a yellow-green field that simulated the display of current night vision goggles. Six females and two males served as subjects in a color-naming procedure. Subjects sequentially viewed an adaptation field, which was either yellow-green or white, and small colored targets presented on a CRT display. The time required to name the color of the targets was found to be dependent on the color of the adaptation field, the color of the target, and the interaction of these two variables. It was recommended that the effects of attenuation of the luminance of the night vision goggles be studied, and that color cockpit displays be redundantly coded whenever possible.

Ocular Responses To Monocular And Binocular Helmet-Mounted Display Configurations

Proceedings of SPIE, Sep 5, 1989

ABSTRACT

Stereoscopic Head-mounted Display Incorporated into Microsurgical Procedures: Technical Note

Neurosurgery, Aug 1, 1998

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PROCEEDINGS OF THE HUMAN FACTORS SOCIETY-30th ANNUAL MEETING-1986 Naming Colors on a CRT Display in Simulated Daylight

The use of color CRT displays in daylight conditions is accompanied by problems of visibility and... more The use of color CRT displays in daylight conditions is accompanied by problems of visibility and discriminability. A simulator was constructed, and six experiments were conducted to measure color-naming performance for CRT-displayed symbols. The effects of display and daylight luminance, and symbol chromaticity, size, and shape were studied. A reciprocal relationship was found between display and daylight luminance, and models of visual performance were constructed. In addition, color metrics based on the CIE 1976 L*u*v * space were found to be inconsistent predictors of performance. This finding was attributed to the dependency of these measures on symbol size and chromaticity. Finally, complex interactions involving symbol chromaticity and shape were discovered, suggesting that simplistic analytical models may not be viable substitutes for empirical research.

<title>Ecological approach to partial binocular overlap</title&gt

Proceedings of SPIE, Aug 1, 1991

Mitigating Visual Anomalies for Binocular HMDs Integrated with Faceted Simulators

Many existing flight simulators employ faceted displays, with multiple panels of “out the window”... more Many existing flight simulators employ faceted displays, with multiple panels of “out the window” visual information presented at different angles and with multiple vertices. Using a head-mounted display (HMD) in a faceted simulator can present visual artifacts not seen in the cockpit, including HMD imagery which appears slanted and with a distorted perspective compared to the imagery presented on the faceted simulator displays. Users viewing information presented across the vertices of the simulator display may notice anomalies due to the HMD imagery being “flat” while the vertex represents a “fold” in the displayed simulator imagery. Binocular HMDs present issues with vergence mismatch when integrated with faceted displays, where the vergence distance (the distance at which the user’s eyes converge) to the HMD imagery stays constant while the vergence distance to the simulator imagery varies with head position. These effects could potentially lead to double-imaging (diplopia) and discomfort, and could also diminish the feeling of immersion. In our previous research, adaptive vergence clearly led to improved comfort and utility compared to fixed vergence, and also led to increased performance on a targeting task. However, some users complained about the distorted perspective, and this may have also affected targeting performance. We have expanded upon those earlier results and examined the effects of mitigating these artifacts using a combination of image perspective warping, rotation and bending. We evaluated both adaptive vergence mitigation only, as well as adaptive vergence mitigation with image warping, rotation, and bending. For each experimental condition, we asked the users to report diplopia/comfort and we also measured their timed performance in a simulated targeting task. We conducted this experiment in a simplified two-facet display system with viewing distance ranging from 36 – 45 inches. Our results show that attempting to mitigate slant and vertex effects have no measureable increase in operator comfort and actually decrease operator performance. In addition, many subjects did not like the fact that the symbology bent into the vertex and moved in space to become coplanar with the out the window displays. Given our previous positive results from adaptive vergence alone, we would recommend not implementing slant and vertex mitigation, but instead just using adaptive vergence mitigation.

P-21: Human Factors Guidelines for Binocular Near-Eye Displays

Sid's Digest Of Technical Papers, 2003

A series of experiments was conducted that addressed basic human‐factors challenges for near‐eye ... more A series of experiments was conducted that addressed basic human‐factors challenges for near‐eye displays. Topics included linking the eyebox to viewing comfort, focus and line‐of‐sight preferences, eyewear compatibility, and field‐of‐view and brightness preferences. We present highlights of this research.

Evaluation of the fixation duration in visual search

Attention Perception & Psychophysics, Jul 1, 1980

Vaughan and Graefe (1977) proposed that visual fixation duration measures dunng visual search are... more Vaughan and Graefe (1977) proposed that visual fixation duration measures dunng visual search are confounded by two factors, cognitive processing ti.~e and time required by the oculomotor system to trntiate the next eye movement, the oculomotor latency. It was concluded that, under some conditions, the fixation duration is independent of the visual information available to the eye during the fixation. That is the oculomotor latency exceeds the information p;ocessing time. This independe~~e was~ound. to occur in a relatively simple recogrution task involving one display item per fixation. In a visual search involving relatively high information .display it~ms.' or where several items are included m each fixation, the oculomotor latency would not be expected to determine the fixation duration. This proved to be the case in a study by Mackworth (1976) in which several items were included in each fixation. Subjects searched a strip of several rows of circles for a square target. Display density increased with the number of circles in the strip. By counting the number of eye movements made on each strip, the number of circles per fixation was estimated. Above four circles per fixation, both the fixation duration and the number of circles per fixation tended to increase with display density. Mackworth attributed the increase in fixation duration to the extra cognitive demand added by the need to process more nontarget circles during each fixation. An alternate method of estimating the number of display items per fixation is to construct a display that controls this factor. Mocharnuk (1978) had subjects search a display consisting of clusters of letters. It was likely that each fixation would accommodate one cluster. As expected, fixation duration increased with the number of letters per cluster. A fixation duration effect was also found by Moffitt (Note I), who varied the information content of each display item while controlling the number of items per fixation. Subjects scanned back and forth be~ween two changing display items, located 10 deg of visual angle apart, searching for a member of the memory. set. Given the size of each display item, .22 deg of visual

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Feeling a little blue: problems with the symbol color blue for see-through displays and an alternative color solution

The color blue is problematic for inclusion in a symbology color set for use by operators with he... more The color blue is problematic for inclusion in a symbology color set for use by operators with head-up and helmet-mounted displays (HUDs and HMDs), as well as with augmented reality (AR) displays. The distinguishing feature of these see-through displays is the optical combiner that presents color-coded symbology combined with the forward real-world scene. Unlike head-down displays that can use color fills, see-through displays are limited to lines and text. The presence of high-ambient daylight can desaturate symbol colors and make them difficult to recognize. This is especially true for blue symbols that become faint and colorless in moderate daylight as well as when mixed with green night-vision imagery. We propose the alternative color blue prime (blue')—a mix of 100% blue and 50% green that lies between blue and cyan—as an alternative to blue. The color blue’ is more resistant to daylight than blue, yet still retains the color name “blue.” Blue' lags other colors such as green and white in visibility, and its use needs to be moderated. We present experimental data to support the use of blue’ as a basic color code.

Safety Implications of Repeated Exposure to Near-Infrared Radiation

Proceedings of the Human Factors Society annual meeting, Oct 1, 1980

Eye safety implications of repeatedly exposing human subjects to near-infrared radiation were exp... more Eye safety implications of repeatedly exposing human subjects to near-infrared radiation were explored. Of particular interest was the infrared radiation emitted by the GaAs diode source of an eye tracking device. The reported safety analysis was considered inadequate in that it was based on short exposure durations, one-time accidental exposures, and/or laser sources. Measurements made in our laboratory of the device's output were related to recent retinal damage threshold data obtained from a GaAs diode. A decision was made to attach a stop to the eye tracker's infrared source to limit the radiation output to a value less than 10% of the critical threshold for retinal damage.

Color helmet display for the military cockpit

ABSTRACT The application of color symbology, graphics, and imagery in a helmet-mounted display ca... more ABSTRACT The application of color symbology, graphics, and imagery in a helmet-mounted display can code and organize this complex and dynamic information resulting in a possible reduction of workload and an improvement in performance. Unfortunately, there are three well-recognized paradigms that disallow the use of color in helmet-mounted displays in aviation environments. Evidence of three corresponding paradigm shifts that encourage the use of color in these displays is provided. The authors discuss the rationales for these paradigm shifts in the context of new methods of training and rehearsing, new lighting environments, and new display technologies. The liquid crystal shutter is considered as a color image source

Naming Colors on a CRT Display in Simulated Daylight

Proceedings of the Human Factors Society annual meeting, Sep 1, 1986

The use of color CRT displays in daylight conditions is accompanied by problems of visibility and... more The use of color CRT displays in daylight conditions is accompanied by problems of visibility and discriminability. A simulator was constructed, and six experiments were conducted to measure color-naming performance for CRT-displayed symbols. The effects of display and daylight luminance, and symbol chromaticity, size, and shape were studied. A reciprocal relationship was found between display and daylight luminance, and models of visual performance were constructed. In addition, color metrics based on the CIE 1976 L* u* v* space were found to be inconsistent predictors of performance. This finding was attributed to the dependency of these measures on symbol size and chromaticity. Finally, complex interactions involving symbol chromaticity and shape were discovered, suggesting that simplistic analytical models may not be viable substitutes for empirical research.

Partial Binocular-Overlap In Helmet-Mounted Displays

Proceedings of SPIE, Mar 21, 1989

ABSTRACT

Accommodation and the Acquisition of Distant Targets by Observers with Superior Vision

Proceedings of the Human Factors Society annual meeting, Oct 1, 1983

The visual accommodation ability of young observers with healthy eyeballs has typically been unde... more The visual accommodation ability of young observers with healthy eyeballs has typically been underestimated. A series of experiments and demonstrations was conducted to study how a pilot might use his eyes to optimize target acquisition performance in different visual environments. Observers with uncorrected far acuities of 20/20 or better were selected for participation. Target acquisition tasks were performed while accommodation was simultaneously monitored with an infrared optometer. The target was always small and located at optical infinity. The average dark focus was more distant than is typically reported and tended to shift outwards with experience on the optometer. When observers were provided with distance information, half were apparently able to “look through” near peripheral texture in order to optimize accommodation accuracy and target detection performance. Although most observers were capable of using imagery to shift their accommodation outwards in the dark, this did not predict the ability to “look through” near texture. In a subsequent demonstration, two observers were able to focus and defocus small targets on demand. Implications for military pilots, many of whom have superior vision, are discussed.

Visibility of color symbology in head-up and head-mounted displays in daylight environments

Optical Engineering, Mar 26, 2019

Preliminary experimental results from a dichoptic vision system (DiVS)

Proceedings of SPIE, May 13, 2011

A dichoptic HMD vision system can provide an expansive and highly detailed visual experience by p... more

Ocular Response to Monocular and Binocular Imagery

Eye movement and ocular vergence measurements were made for two observers of monocular and binocu... more

Download

Visibility of color symbology in head-up and head-mounted displays in daylight environments

<title>Color helmet display for the tactical environment: the pilot's chromatic perspective</title>

Proceedings of SPIE, Oct 30, 1992

Sensor-offset HMD perception and performance

Proceedings of SPIE, Apr 27, 2007

Chromatic aftereffects associated with a night vision goggle simulation

PubMed, Feb 1, 1988

Ocular Responses To Monocular And Binocular Helmet-Mounted Display Configurations

Proceedings of SPIE, Sep 5, 1989

ABSTRACT

Stereoscopic Head-mounted Display Incorporated into Microsurgical Procedures: Technical Note

Neurosurgery, Aug 1, 1998

Download

PROCEEDINGS OF THE HUMAN FACTORS SOCIETY-30th ANNUAL MEETING-1986 Naming Colors on a CRT Display in Simulated Daylight

<title>Ecological approach to partial binocular overlap</title&gt

Proceedings of SPIE, Aug 1, 1991

Mitigating Visual Anomalies for Binocular HMDs Integrated with Faceted Simulators

P-21: Human Factors Guidelines for Binocular Near-Eye Displays

Sid's Digest Of Technical Papers, 2003

Evaluation of the fixation duration in visual search

Attention Perception & Psychophysics, Jul 1, 1980

Download

Feeling a little blue: problems with the symbol color blue for see-through displays and an alternative color solution

Safety Implications of Repeated Exposure to Near-Infrared Radiation

Proceedings of the Human Factors Society annual meeting, Oct 1, 1980

Color helmet display for the military cockpit

Naming Colors on a CRT Display in Simulated Daylight

Proceedings of the Human Factors Society annual meeting, Sep 1, 1986

The use of color CRT displays in daylight conditions is accompanied by problems of visibility and... more The use of color CRT displays in daylight conditions is accompanied by problems of visibility and discriminability. A simulator was constructed, and six experiments were conducted to measure color-naming performance for CRT-displayed symbols. The effects of display and daylight luminance, and symbol chromaticity, size, and shape were studied. A reciprocal relationship was found between display and daylight luminance, and models of visual performance were constructed. In addition, color metrics based on the CIE 1976 L* u* v* space were found to be inconsistent predictors of performance. This finding was attributed to the dependency of these measures on symbol size and chromaticity. Finally, complex interactions involving symbol chromaticity and shape were discovered, suggesting that simplistic analytical models may not be viable substitutes for empirical research.

Partial Binocular-Overlap In Helmet-Mounted Displays

Proceedings of SPIE, Mar 21, 1989

ABSTRACT

Accommodation and the Acquisition of Distant Targets by Observers with Superior Vision

Proceedings of the Human Factors Society annual meeting, Oct 1, 1983

Visibility of color symbology in head-up and head-mounted displays in daylight environments

Optical Engineering, Mar 26, 2019

Preliminary experimental results from a dichoptic vision system (DiVS)

Proceedings of SPIE, May 13, 2011

A dichoptic HMD vision system can provide an expansive and highly detailed visual experience by p... more

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