publications

2024

1. Color constancy mechanisms in virtual reality environments

   Raquel Gil Rodríguez, Laysa Hedjar, Matteo Toscani, and 3 more authors

   Journal of Vision, May 2024

   Abs DOI PDF

   Prior research has demonstrated high levels of color constancy in real-world scenarios featuring single light sources, extensive fields of view, and prolonged adaptation periods. However, exploring the specific cues humans rely on becomes challenging, if not unfeasible, with actual objects and lighting conditions. To circumvent these obstacles, we employed virtual reality technology to craft immersive, realistic settings that can be manipulated in real time. We designed forest and office scenes illuminated by five colors. Participants selected a test object most resembling a previously shown achromatic reference. To study color constancy mechanisms, we modified scenes to neutralize three contributors: local surround (placing a uniform-colored leaf under test objects), maximum flux (keeping the brightest object constant), and spatial mean (maintaining a neutral average light reflectance), employing two methods for the latter: changing object reflectances or introducing new elements. We found that color constancy was high in conditions with all cues present, aligning with past research. However, removing individual cues led to varied impacts on constancy. Local surrounds significantly reduced performance, especially under green illumination, showing strong interaction between greenish light and rose-colored contexts. In contrast, the maximum flux mechanism barely affected performance, challenging assumptions used in white balancing algorithms. The spatial mean experiment showed disparate effects: Adding objects slightly impacted performance, while changing reflectances nearly eliminated constancy, suggesting human color constancy relies more on scene interpretation than pixel-based calculations.

2. Color matching in the wild

   Raquel Gil Rodriguez, Javier Vazquez-Corral, Marcelo Bertalmío, and 1 more author

   Pattern Recognition, 2024

   Abs DOI

   We present a method that, given two different views of the same scene taken by two cameras with unknown settings and internal parameters, corrects the colors of one of the images making it look as if it was captured under the other camera settings. Our method is able to deal with any standard non-linear encoded images (gamma-corrected, logarithmic-encoded, or any other) without requiring any previous knowledge of the encoding. To this end, our method makes use of two important observations. First, the camera imaging pipeline from RAW to sRGB can be well approximated by considering just a per-pixel shading and a color transformation matrix, and second, for correcting the images we only need to estimate a single matrix –that will contain information from both of the original images– and an approximation of the shading term (that emulates the non-linearity). Our proposed method is fast and the results have no spurious artifacts. The method outperforms the state-of-the-art when compared with other methods that do not require knowledge of the encoding used. It is also able to compete with –and even surpass in some cases– methods that consider information about image encoding.

3. High-fidelity color characterization in virtual reality across head mounted displays, game engines, and materials

   Francisco Díaz-Barrancas, Raquel Gil Rodriguez, Florian S. Bayer, and 2 more authors

   Opt. Express, Jun 2024

   DOI

2023

1. Color calibration in virtual reality for Unity and Unreal

   Francisco Díaz–Barrancas, Raquel Gil Rodriguez, Avi Aizenman, and 2 more authors

   In 2023 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops, 2023

   DOI

2022

1. 

   Colour calibration of a head mounted display for colour vision research using virtual reality

   Raquel Gil Rodrı́guez, Florian Bayer, Matteo Toscani, and 3 more authors

   SN Computer Science, 2022

   DOI PDF

2021

1. Color Conversion in Deep Autoencoders

   Arash Akbarinia and Raquel Gil Rodriguez

   Color and Imaging Conference, 2021

   DOI

2020

1. Color constancy in a Virtual Reality environment

   Raquel Gil Rodriguez, Matteo Toscani, Dar’ya Guarnera, and 3 more authors

   Journal of Vision, 2020

   DOI
2. Pedestrians Egocentric Vision: Individual and Collective Analysis

   Matteo Valsecchi, Arash Akbarinia, Raquel Gil-Rodriguez, and 1 more author

   In ACM Symposium on Eye Tracking Research and Applications, Stuttgart, Germany, 2020

   Abs DOI

   Egocentric videos offer an ecological approach to study human gaze behaviour. We were interested in understanding what people look at while performing the natural task of navigating in urban environments. Is there a collective pattern among all participants or are there substantial individual differences? To this end, we recorded egocentric video and gaze data from forty-three pedestrians. Here, we present this dataset designed to benchmark future research. The content of these videos was examined with respect to the depth and category of attended objects. We observe noticeable individual differences in both factors. Following these criteria, individual gaze patterns form a number of clusters. The unique signature of each set remains to be explored, whether it is based on low-level visual features or high-level cognitive characteristics.

3. Color Matching Images With Unknown Non-Linear Encodings

   Raquel Gil Rodríguez, Javier Vazquez-Corral, and Marcelo Bertalmío

   IEEE Transactions on Image Processing, 2020

   DOI
4. Deciphering image contrast in object classification deep networks

   Arash Akbarinia and Raquel Gil Rodriguez

   Vision Research, 2020

   DOI

2019

1. Assessment of OLED Head Mounted Display for Vision Research with Virtual Reality

   Matteo Toscani, Raquel Gil Rodriguez, Dar’ya Guarnera, and 3 more authors

   In 2019 15th International Conference on Signal-Image Technology & Internet-Based Systems, 2019

   DOI
2. Issues with Common Assumptions about the Camera Pipeline and Their Impact in HDR Imaging from Multiple Exposures

   R. Gil Rodrı́guez, J. Vazquez-Corral, and M. Bertalmı́o

   SIAM Journal on Imaging Sciences, 2019

   DOI

2016

1. High quality video in high dynamic range scenes from interlaced dual-ISO footage

   Raquel Gil Rodríguez and Marcelo Bertalmío

   Electronic Imaging, 2016

   DOI