Dr. Christopher W. Tyler Profile

Dr. Christopher W. Tyler

Associate Director

SPIE Involvement:

Author

Publications (30)

Proceedings Article | 12 March 2014 Paper

3D space perception as embodied cognition in the history of art images

Christopher Tyler

Proceedings Volume 9014, 901416 (2014) https://doi.org/10.1117/12.2045415

KEYWORDS: Cognition, Brain, 3D image processing, Mirrors, Space mirrors, Neuroimaging, Image processing, Limbic system, Venus, Head

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Proceedings Article | 10 March 2014 Paper

Perceiving, measuring, and modeling materials

Christopher Tyler

Proceedings Volume 9018, 901802 (2014) https://doi.org/10.1117/12.2046104

KEYWORDS: Reflectivity, Visual system, Spatial frequencies, Visualization, Shape analysis, Image compression, Distortion, Transparency, Diffuse reflectance spectroscopy, CRTs

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Proceedings Article | 14 March 2013 Paper

Binocular eye movements in health and disease

Christopher Tyler

Proceedings Volume 8651, 86510Y (2013) https://doi.org/10.1117/12.2012253

KEYWORDS: Eye, Traumatic brain injury, Brain, Visualization, Basal ganglia, Head, Error analysis, Motion analysis, Eye models, Calibration

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Proceedings Article | 21 February 2012 Paper

In search of Leonardo: computer-based facial image analysis of Renaissance artworks for identifying Leonardo as subject

Christopher Tyler, William Smith, David Stork

Proceedings Volume 8291, 82911D (2012) https://doi.org/10.1117/12.904749

KEYWORDS: 3D modeling, Cameras, Statistical analysis, Data modeling, Image analysis, Error analysis, Electronic imaging, 3D image reconstruction, Statistical modeling, Expectation maximization algorithms

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Proceedings Article | 18 February 2012 Paper

3D discomfort from vertical and torsional disparities in natural images

Christopher Tyler, Lora Likova, Kalin Atanassov, Vikas Ramachandra, Sergio Goma

Proceedings Volume 8291, 82910Q (2012) https://doi.org/10.1117/12.915466

KEYWORDS: 3D displays, 3D image processing, 3D modeling, Cameras, Visualization, Data modeling, 3D vision, Stereoscopic cameras, Eye models, Eye

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Proceedings Article | 22 February 2010 Paper

Darkness and depth in early Renaissance painting

Christopher Tyler

Proceedings Volume 7527, 75270V (2010) https://doi.org/10.1117/12.846851

KEYWORDS: Electronic imaging, Image quality, Human vision and color perception, Current controlled current source

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Proceedings Article | 18 February 2010 Paper

How did Leonardo perceive himself? Metric iconography of da Vinci's self-portraits

Christopher Tyler

Proceedings Volume 7527, 75271D (2010) https://doi.org/10.1117/12.846850

KEYWORDS: Nose, Mouth, Eye, Head, Quantitative analysis, Visualization, Laser induced plasma spectroscopy, 3D modeling, Electronic imaging, Skull

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Proceedings Article | 14 March 2007 Paper

Instantaneous stimulus paradigm: cortical network and dynamics of figure-ground organization

Lora Likova, Christopher Tyler

Proceedings Volume 6492, 64921E (2007) https://doi.org/10.1117/12.707556

KEYWORDS: Functional magnetic resonance imaging, Brain, Modulation, Visualization, Hemodynamics, Eye, Cerebral cortex, Data modeling, Object recognition, Integration

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Proceedings Article | 18 March 2005 Paper

A horopter for two-point perspective

Christopher Tyler

Proceedings Volume 5666, (2005) https://doi.org/10.1117/12.602237

KEYWORDS: Eye, Lanthanum, Visualization, Solids, Retina, Electronic imaging, Visual system, Brain, Human vision and color perception, Head

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Proceedings Article | 18 March 2005 Paper

Transient-based image segmentation: top-down surround suppression in human V1

Lora Likova, Christopher Tyler

Proceedings Volume 5666, (2005) https://doi.org/10.1117/12.610865

KEYWORDS: Image segmentation, Visualization, Functional magnetic resonance imaging, Brain, Signal processing, Modulation, Neurons, Cortical activation, Feedback loops, Visual cortex

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Proceedings Article | 18 March 2005 Paper

The riches of the cyclopean paradigm

Christopher Tyler

Proceedings Volume 5666, (2005) https://doi.org/10.1117/12.602896

KEYWORDS: Brain, Eye, Visual system, Neurons, Retina, Stereo holograms, Visualization, Spatial frequencies, Lutetium, Sensory processes

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Proceedings Article | 7 June 2004 Paper

Local channel structure of sustained peripheral vision

Leonid Kontsevich, Christopher Tyler

Proceedings Volume 5292, (2004) https://doi.org/10.1117/12.548290

KEYWORDS: Spatial frequencies, Data modeling, Target detection, Modulation transfer functions, Retina, Visualization, Contrast sensitivity, Phase shift keying, Electronic imaging, Modulation

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Proceedings Article | 7 June 2004 Paper

Is the hMT+/V5 complex in the human brain involved in stereomotion perception? an fMRI study

Lora Likova, Christopher Tyler

Proceedings Volume 5292, (2004) https://doi.org/10.1117/12.568026

KEYWORDS: Functional magnetic resonance imaging, Brain, Modulation, Signal processing, Visual cortex, Visualization, Electronic imaging, Neural networks, Lutetium, Neuroimaging

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Proceedings Article | 17 June 2003 Paper

Failure of stereomotion capture in an object disappearance paradigm

Lora Likova, Christopher Tyler

Proceedings Volume 5007, (2003) https://doi.org/10.1117/12.485517

KEYWORDS: Visualization, Visual system, Switches, Brain, 3D acquisition, Switching, Classification systems, Failure analysis, Electronic imaging, Scene classification

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Proceedings Article | 30 May 2002 Paper

Extending the modelfest image/threshold database into the spatio-temporal domain

Thom Carney, Stanley Klein, Brent Beutter, Anthony Norcia, Chien-Chung Chen, Christopher Tyler, Walter Makous, Andrew Watson, Simon Cropper, Ariella Popple, Ken Robertson, Velitchko Manahilov, Bill Simpson, Klara Wenzel

Proceedings Volume 4662, (2002) https://doi.org/10.1117/12.469510

KEYWORDS: Data modeling, Visual process modeling, Motion models, Performance modeling, Binary data, Video, Databases, Visual system, Visualization, Image compression

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Proceedings Article | 8 June 2001 Paper

Concept of space in 20th century art

Christopher Tyler, Amy Ione

Proceedings Volume 4299, (2001) https://doi.org/10.1117/12.429529

KEYWORDS: Visualization, Eye, Photography, Visual optics, Solids, Modulation, Distortion, Astronomical imaging, Reflection, Bridges

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Proceedings Article | 28 June 2000 Paper

Spatial long-range modulation of contrast discrimination

Chien-Chung Chen, Christopher Tyler

Proceedings Volume 4080, (2000) https://doi.org/10.1117/12.389432

KEYWORDS: Linear filtering, Data modeling, Target detection, Image quality, Modulation, Image filtering, Visualization, Modulation transfer functions, Visual process modeling, Chlorine

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Proceedings Article | 2 June 2000 Paper

Spatial summation of face information

Christopher Tyler, Chien-Chung Chen

Proceedings Volume 3959, (2000) https://doi.org/10.1117/12.387183

KEYWORDS: Facial recognition systems, Nose, Image filtering, Image processing, Data modeling, Electronic filtering, Psychophysics, Bridges, Data processing, Spatial frequencies

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Proceedings Article | 2 June 2000 Paper

Modelfest: principal component analysis reveals underlying channel structure

Chien-Chung Chen, Christopher Tyler

Proceedings Volume 3959, (2000) https://doi.org/10.1117/12.387151

KEYWORDS: Spatial frequencies, Data modeling, Principal component analysis, Visual process modeling, Visual system, Sensors, Factor analysis, Independent component analysis, Visual analytics, Visualization

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Proceedings Article | 2 June 2000 Paper

Perspective as a geometric tool that launched the Renaissance

Christopher Tyler

Proceedings Volume 3959, (2000) https://doi.org/10.1117/12.387209

KEYWORDS: Visualization, Eye, Floods, Human vision and color perception, Electronic imaging, Computer aided design, Inspection, Distortion, Projection systems, Etching

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Proceedings Article | 2 June 2000 Paper

Modelfest: year one results and plans for future years

Thom Carney, Christopher Tyler, Andrew Watson, Walter Makous, Brent Beutter, Chien-Chung Chen, Anthony Norcia, Stanley Klein

Proceedings Volume 3959, (2000) https://doi.org/10.1117/12.387150

KEYWORDS: Data modeling, Visual process modeling, Spatial frequencies, Human vision and color perception, Databases, Video compression, Composites, Visualization, Performance modeling, Image compression

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Proceedings Article | 19 May 1999 Paper

Development of an image/threshold database for designing and testing human vision models

Thom Carney, Stanley Klein, Christopher Tyler, Amnon Silverstein, Brent Beutter, Dennis Levi, Andrew Watson, Adam Reeves, Anthony Norcia, Chien-Chung Chen, Walter Makous, Miguel Eckstein

Proceedings Volume 3644, (1999) https://doi.org/10.1117/12.348473

KEYWORDS: Visual process modeling, Data modeling, Spatial frequencies, Databases, Visualization, Image quality, Image compression, Human vision and color perception, Performance modeling, Linear filtering

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Proceedings Article | 17 July 1998 Paper

Eye placement principles in portraits and figure studies over the past two millennia

Christopher Tyler

Proceedings Volume 3299, (1998) https://doi.org/10.1117/12.320133

KEYWORDS: Eye, Head, Mouth, Statistical analysis, Human vision and color perception, Electronic imaging, Reflectivity, Laser engraving, Californium

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Proceedings Article | 3 June 1997 Paper

Seven models of masking

Stanley Klein, Thom Carney, Lauren Barghout-Stein, Christopher Tyler

Proceedings Volume 3016, (1997) https://doi.org/10.1117/12.274510

KEYWORDS: Transducers, Visual process modeling, Data modeling, Spatial frequencies, Visualization, Image compression, Visibility, Samarium, Medical imaging, Eye

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Proceedings Article | 3 June 1997 Paper

Partitioning mechanisms of masking: contrast transducer versus divisive inhibition

Lauren Barghout-Stein, Christopher Tyler, Stanley Klein

Proceedings Volume 3016, (1997) https://doi.org/10.1117/12.274550

KEYWORDS: Transducers, Interference (communication), Spatial frequencies, Systems modeling, Visualization, Psychophysics, Signal to noise ratio, Visual system, Target detection, Signal detection

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The properties of spatial vision mechanisms are often explored psychophysically with simultaneous masking paradigms. A variety of hypotheses have been proposed to explain how the mask pattern utilized in these paradigms increases threshold. Numerous studies have investigated the properties of a particular origin of masking hypothesis but few have attempted to compare the properties of masking at several points in the process. Our study isolates masking due to lateral divisive inhibition at a point where mechanism responses are combined, and compares it with masking of the same target due to a nonlinearity either intrinsic to a mechanism or directly operating on the response of a single mechanism. We also measure the slopes of psychometric functions to examine the relationship between uncertainty and mask contrast. Studies of simultaneous masking utilizing a pedestal mask (an identical test and mask pattern) have measured facilitation for low contrast masks. This decrease in threshold from the solo target threshold is commonly referred to as the 'dipper' effect and has been explained as an increase in signal-to- noise ratio from the high unmasked level occurring as the visual system becomes more certain of target location. The level of uncertainty is indicated by the slope of sensitivity to the target as a function of target contrast in the threshold region. In these studies, high contrast masks have evoked an increase in target threshold. There have been many theories explaining this threshold increase. Some suggest that masking is the result of an intrinsic nonlinearity within a mechanism or of a contrast nonlinearity that operates directly on the output of a single mechanism. Others put the source of masking at a gain control operation which occurs when a surrounding set of mechanisms divide the response of a single mechanism by their summed response. Still others attribute the masking to noise that is multiplicative relative to the neural response signal, or noise that intrudes on the detecting mechanism from neighboring mechanisms. A detailed review of this debate is provided by the paper by Klein et al., 3016-02 in this Proceedings. Threshold elevation functions that show the relationship between mask spatial frequency and masking magnitude cannot illuminate this debate, as we demonstrated at ARVO (1994). For that study, we generated threshold elevation functions (the ratio of unmasked versus masked target threshold) for multi-channel systems using computational models that invoked either divisive inhibition, a set of transducer nonlinearities or multiplicative noise. Threshold elevation functions were indistinguishable when each masking process was assumed to have similar strength. These results led us to design the experiment presented here, which attempts to compare the effects of two of these masking processes, lateral divisive inhibition and nonlinear transducer compression.

Proceedings Article | 3 June 1997 Paper

Diffuse illumination as a default assumption for shape-from-shading in the absence of shadows

Christopher Tyler

Proceedings Volume 3016, (1997) https://doi.org/10.1117/12.274530

KEYWORDS: Reflectivity, Visual system, Distortion, Diffuse reflectance spectroscopy, Image compression, Surface properties, Reflection, Light sources, Computer vision technology, Modulation

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Proceedings Article | 17 March 1994 Paper

Computational reconstruction of the mechanisms of human stereopsis

Christopher Tyler, Lauren Barghout, Leonid Kontsevich

Proceedings Volume 2054, (1994) https://doi.org/10.1117/12.171143

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The properties of human stereoscopic mechanisms may be derived from dichoptic interaction and masking effects on stereoscopic detection thresholds in any relevant stimulus domain (spatial frequency, temporal frequency, disparity, orientation, etc.). The present study focuses on the spatial properties of mechanisms underlying stereoscopic depth detection. The computational approach is based on the full exploration of plausible model structures to characterize their idiosyncrasies, which often allows exclusion of proposed mechanisms by comparison with data obtained under conditions in which the idiosyncrasies should be expressed. For example, we conducted a detailed analysis of threshold elevation functions (TEFs) under plausible channel shapes, combination rules and masking behavior derived from previous studies. The analysis reveals that TEFs may be much narrower than and differ in shape from the underlying mechanisms. For example, only two discrete channels are required to produce TEFs peaking close to each fixed test frequency, with no relation to channel peaks. We apply this analysis to the stereospatial masking functions collected by Yang and Blake (1991) to determine the likely channel structure underlying the empirical masking performance. The analysis generally supports the two-mechanism model that they propose but shows that the assumptions underlying their estimates of the unmasked sensitivity function are incorrect. The analysis excludes stereospatial channels tuned below 2.5 c/deg, a region in which Schor, Wood, and Ogawa (1984) obtained evidence for many narrowly tuned channels by measuring disparity thresholds for targets with different peak tunings in the two eyes. Our computational model for the latter data is consistent with the lowest tuned channel being at 2.5 c/deg, this channel being narrowly tuned to dichoptic contrast differences, as described by Legge and Gu (1989) and Halpern and Blake (1988). Thus, all such stereo tuning data can be explained in a model in which all stereoscopic channels are tuned above 2.5 c/deg.

Proceedings Article | 27 August 1992 Paper

Bit stealing: how to get 1786 or more gray levels from an 8-bit color monitor

Christopher Tyler, Hoover Chan, Lei Liu, Brennan McBride, Leonid Kontsevich

Proceedings Volume 1666, (1992) https://doi.org/10.1117/12.135981

KEYWORDS: RGB color model, Human vision and color perception, Visualization, Optical filters, Calibration, Image resolution, Binary data, LCDs, Computing systems, Video

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Proceedings Article | 30 June 1992 Paper

Spatiotemporal limitations on vernier and stereoscopic alignment acuity

Christopher Tyler, Clifton Schor, Nancy Coletta

Proceedings Volume 1669, (1992) https://doi.org/10.1117/12.60420

KEYWORDS: Spatial frequencies, Stereoscopic displays, Eye, Visualization, Modulation, Target detection, Data processing, Image fusion, Chlorine, CRTs

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Proceedings Article | 1 September 1990 Paper

Autostereogram

Christopher Tyler, Maureen Clarke

Proceedings Volume 1256, (1990) https://doi.org/10.1117/12.19904

KEYWORDS: Stereo holograms, Stereoscopic displays, Eye, Stars, Chlorine, Image processing, 3D image processing, Modulation, Image fusion, Image segmentation

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