A psychophysical model to control the brightness and key-to-fill ratio in CG cartoon character lighting

Wisessing, Pisut; Zibrek, Katja; Cunningham, Douglas W.; McDonnell, Rachel

doi:10.1145/3343036.3343127

Cited by 3 publications

(7 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The latter one is equivalent to the conventional unit of stop, commonly used in cinematography and photography (a stop up is doubling and a stop down is halving a light quantity.) Wisessing et al [2019] confirmed the doubling and halving to be the natural perceived interval where the human visual system can discriminate brightness and shadows. Wisessing et al [2020] later adopted the-power-of-two interval to create their constant stimuli.…”

Section: Digital Lighting Toolsmentioning

confidence: 58%

“…Previous studies have investigated only a subset at a time, such as render style [McDonnell et al 2012;Volante et al 2016], geometry and material [Zell et al 2015], stylization level [Wallraven et al 2007], geometric detail [MacDorman et al 2009, body shape [Fleming et al 2016], etc. More specifically, recent work has investigated the role of lighting on character appeal with respect to key-light brightness, key-to-fill ratio and lighting direction [Wisessing et al 2016[Wisessing et al , 2020[Wisessing et al , 2019. They chose to focus their studies on the perceived brightness and shadow amount in the three-point lighting design which has become ubiquitous in portraiture from the painting in the Renaissance to the everyday news broadcasting.…”

Section: Related Workmentioning

confidence: 99%

“…Investigating a large range of parameters also extends the length of experiments exponentially. As a result, Wisessing et al 's studies only selected a manageable subset of 9 to 16 data points that evenly represent the entire two-dimensional perceptual space of character lighting described in [Wisessing et al 2019], which are considerably too sparse for practical applications despite their conclusive findings.…”

Section: Related Workmentioning

confidence: 99%

“…Wisessing et al [2020] later adopted the-power-of-two interval to create their constant stimuli. Moreover, Tool B was designed specifically to test if limiting the selections to a small subset of data points evenly sampled from the perceived lighting space [Wisessing et al 2019] can further speed-up the experiment process.…”

Section: Digital Lighting Toolsmentioning

confidence: 99%

“…The sliders of Tool B could only select a finite combinations of 4 levels of overall brightness (100%, 50%, 25% and 12.5% and 4 levels of KTFR (1:1, 2:1, 4:1 and 8:1). For each pair of brightness and KTFR, the intensity of key and fill light in the scene were adjusted automatically according to an approximation of the parametric model described by Wisessing et al [2019]. Note that the model maintains consistent iso-brightness level for different KTFRs, and hence the individual light intensity can vary from 12% to 110%.…”

Section: Digital Lighting Toolsmentioning

confidence: 99%

See 4 more Smart Citations

Evalu-light: A practical approach for evaluating character lighting in real-time

Wisessing

McDonnell

2020

ACM Symposium on Applied Perception 2020

Self Cite

View full text Add to dashboard Cite

The demand for cartoon animation content is on the rise, driven largely by social media, video conferencing and virtual reality. New content creation tools and the availability of open-source game engines allow characters to be animated by even novice creators (e.g., Loomie and Pinscreen for creating characters, Hyprface and Mo-tionX for facial motion capture, etc,). However, lighting of animated characters is a skilled art-form, and there is a lack of guidelines for lighting characters expressing emotion in an appealing manner. Recent perceptual research has attempted to provide user guidelines through rigorous and labor-intensive rating-scale experiments exploring many parameters of light [Wisessing et al. 2016, 2020]. We propose an alternative approach based on the method of adjustment, similar to common lighting tools in 3D content creation software, but with the power of modern real-time graphics. Our framework allows users to interactively adjust lighting parameters and instantly assess the results on the animated characters, instead of having to wait for the render to complete.

show abstract

Section: Digital Lighting Toolsmentioning

confidence: 58%

Section: Related Workmentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

Section: Digital Lighting Toolsmentioning

confidence: 99%

Section: Digital Lighting Toolsmentioning

confidence: 99%

See 3 more Smart Citations

Evalu-light: A practical approach for evaluating character lighting in real-time

Wisessing

McDonnell

2020

ACM Symposium on Applied Perception 2020

Self Cite

View full text Add to dashboard Cite

show abstract

3D computational modeling and perceptual analysis of kinetic depth effects

Cui

Wang

et al. 2020

Comp. Visual Media

View full text Add to dashboard Cite

Humans have the ability to perceive kinetic depth effects, i.e., to perceived 3D shapes from 2D projections of rotating 3D objects. This process is based on a variety of visual cues such as lighting and shading effects. However, when such cues are weak or missing, perception can become faulty, as demonstrated by the famous silhouette illusion example of the spinning dancer. Inspired by this, we establish objective and subjective evaluation models of rotated 3D objects by taking their projected 2D images as input. We investigate five different cues: ambient luminance, shading, rotation speed, perspective, and color difference between the objects and background. In the objective evaluation model, we first apply 3D reconstruction algorithms to obtain an objective reconstruction quality metric, and then use quadratic stepwise regression analysis to determine weights of depth cues to represent the reconstruction quality. In the subjective evaluation model, we use a comprehensive user study to reveal correlations with reaction time and accuracy, rotation speed, and perspective. The two evaluation models are generally consistent, and potentially of benefit to inter-disciplinary research into visual perception and 3D reconstruction.

show abstract

Enlighten Me

et al. 2020

View full text Add to dashboard Cite

Lighting has been used to enhance emotion and appeal of characters for centuries, from paintings in the Renaissance to the modern-day digital arts. In VFX and animation studios, lighting is considered as important as modelling, shading, or rigging. Most existing work focuses on either empirical best-practice created by artists of the centuries or on lighting perception with basic shapes. In contrast, our work focuses on the effect of lighting on emotional characters. Our study presents an extensive set of novel perceptual experiments designed to investigate the effects of brightness levels (key light brightness) and the proportion of light intensity illuminating the two sides of a character’s face (key-to-fill ratio). We are particularly interested in the effect of lighting on the recognition of emotion, emotion intensity, and the overall appeal, as these are crucial factors for audience engagement. Our results have implications for artists and developers wishing to increase the appeal and emotional expression of their characters, ranging from cartoon to realistic styles. Our key finding is that lighting can be used to effectively alter the intensity of emotion of a character and that brighter conditions increased appeal across all of our experiments.

show abstract

A psychophysical model to control the brightness and key-to-fill ratio in CG cartoon character lighting

Cited by 3 publications

References 28 publications

Evalu-light: A practical approach for evaluating character lighting in real-time

Evalu-light: A practical approach for evaluating character lighting in real-time

3D computational modeling and perceptual analysis of kinetic depth effects

Enlighten Me

Contact Info

Product

Resources

About