09/12/2021
Marie Skłodowska-Curie Actions

MSCA-COFUND-CLEAR-Doc - PhD Position #CD21-55 : Assessment of the quality of urban lighting by photography. Development and validation of a diagnostic tool

This job offer has expired


  • ORGANISATION/COMPANY
    Université Gustave Eiffel
  • RESEARCH FIELD
    Engineering
  • RESEARCHER PROFILE
    First Stage Researcher (R1)
  • APPLICATION DEADLINE
    21/03/2022 17:00 - Europe/Brussels
  • LOCATION
    France › Marne-La-Vallée
  • TYPE OF CONTRACT
    Temporary
  • JOB STATUS
    Full-time
  • HOURS PER WEEK
    35
  • OFFER STARTING DATE
    01/10/2022
  • EU RESEARCH FRAMEWORK PROGRAMME
    H2020 / Marie Skłodowska-Curie Actions COFUND
  • MARIE CURIE GRANT AGREEMENT NUMBER
    101034248

OFFER DESCRIPTION

Public policies promote active mobility for environmental and public health reasons. In particular, they encourage pedestrian mobility in the city, day and night, where public lighting has a major role in making the urban space accessible and safe for everyone (Alfonzo, 2005). In the context of ecological and energy transitions, lighting design should ensure feeling safe and walking safely, by making objects and other people visible, while limiting glare and energy consumption. Current standards recommend illumination levels and uniformity, easy to measure on site with a luxmeter, but inappropriate in view of the challenges (CIE-236, 2019). Indeed, the notions of visibility and glare mainly depend on the reflection of light across the urban space (roadway, buildings, etc.), quantifiable by a luminance distribution.

Existing models computing the Visibility Levels and glare indexes are not used by practitioners because they need semantic information (e.g. size and position of sources and objects of interest), and are difficult to implement in the field (Brémond, 2021; Girard et al., 2021). The recent development of ILMDs (Imaging Luminance Measurement Device) and HDR (High Dynamic Range) images, and the increasing improvement of cameras on smartphones, allow new approaches for the design and the diagnosis of lighting installation based on luminance. New image processing algorithms, based on human vision models, are an interesting alternative: Joulan et al. (2011) compute a map of visible contours from calibrated images, taking the contrast sensitivity of the human eye into account. Still, an additional step is required to extract indexes, from these visibility maps, that could be used in urban lighting. There are also avenues for estimating the two aspects of glare, disability (loss of visibility) and discomfort (psychological feeling), by image processing techniques. Disability glare can be modelled by a Point Spread Function (Spencer et al., 1995), while image processing models linking visual discomfort to the vision of contrast have been proposed (Penacchio and Wilkins , 2008; Scheir, 2016); however, these models cannot predict yet the absolute level of discomfort.

In this context, the objective of the thesis is to develop visibility and visual discomfort indexes of the urban lighting quality, from in situ photographs. ILMD (videophotometer and smartphones) will allow the acquisition of urban scenes, and a set of calculation modules will estimate the quality or nuisance indexes associated with lighting. These indexes may be tuned, for example according to the age or a pathology (e.g. cataract) of the road user.

The main scientific challenges are as follows:

To develop a method to extract a visibility index from a visible contours map, and assess the quality of urban lighting in terms of visibility in images;

To propose a descriptor of visual discomfort based on characteristics extracted from urban night images, and assess the quality of urban lighting in terms of visual discomfort.

The first PhD year will be devoted to reading the literature, to implementing existing image processing models, and to building a reference database of nocturnal urban images, associated with judgments of visibility and discomfort. Calibrated images will be taken in different urban sites, and psycho-visual laboratory experiments will provide judgments of a panel of participants on the lighting quality in these images. This database will be used in the second year to improve the image processing algorithms in order to get the best possible prediction of the visibility and discomfort from the images. In the third year, an experiment will be carried out on an urban site to validate the diagnostic tool in the field.

The thesis will propose new indexes of the quality of urban lighting based on calibrated images. This innovative approach and the developed image processing models will constitute a significant contribution for the scientific and technical community, providing an innovative diagnostic tool for the quality of urban lighting. The methodology can also be transposed to other aspects of the lighting quality, such as facial recognition. The development of this tool may serve as a basis for urban diagnostic from easily obtainable images (smartphones) allowing planners and lighting engineers to improve pedestrian mobility at night in the city, with smart lighting (remote management). It may also be adapted for citizens (crowd-sourced science), who could send, from photographs taken with their smartphones, lighting quality indexes from all around the city. This diagnostic tool could be in the future a software brick allowing various innovations: in artificial vision for the automotive industry (automotive lighting, ADAS), and in the digital city simulation, allowing a diagnosis of lighting in the urban planning phase.

References

Alfonzo (2005). To walk or not to walk? The hierarchy of walking needs. Environment and behavior 37(6):808-836.

Brémond (2021). Visual Performance Models in Road Lighting: A Historical Perspective. Leukos 17(3), 212-241.

CIE-236. (2019). Lighting for pedestrians: a summary of empirical data. Technical report 236, CIE, Vienna.

Girard et al. (2021). Discomfort Glare from Several Sources: A Formula for Outdoor Lighting. Leukos 17(2), 108-124.

Joulan et al.(2011). A Unified CSF-based Framework for Edge Detection and Edge Visibility. CVPR Workshop on biologically-consistent vision. Colorado Springs, CO.

Penacchio & Wilkins (2015). Visual discomfort and the spatial distribution of Fourier energy. Vision Research 108, 1-7.

Scheir et al. (2018). A psychophysical model for visual discomfort based on receptive fields. Lighting research & Technology 50(2), 205-217.

Spencer et al. (1995). Physically-based glare effects for digital images. In Proc. 22th conference on Computer Graphics and Interactive Techniques, pp. 325-334."

International Mobility:

To be discussed with the PhD thesis supervisor.

 

More Information

Benefits

  • High-quality doctoral training rewarded by a PhD degree, delivered by Université Gustave Eiffel
  • Access to cutting-edge infrastructures for research & innovation.
  • Appointment for a period of 36 months based on a salary of 2 700 € (gross salary per month).
  • Job contract under the French labour legislation in force, respecting health and safety, and social security: 35 hours per week contract, 25 days of annual leave per year.
  • International mobility will be mandatory
  • An international environment supported by the adherence to the European Charter & Code.
  • Access to dedicated CLEAR-Doc trainings with a strong interdisciplinary focus, together with a Career development Plan.

 

Eligibility criteria

  • At the time of the deadline, applicants must be in possession or finalizing their Master’s degree or equivalent/postgraduate degree. At the time of recruitment, applicants must be in possession of their Master’s degree or equivalent/postgraduate degree which would formally entitle to embark on a doctorate.
  • At the time of the deadline, applicants must be in the first four years (full-time equivalent research experience) of their research career (career breaks excluded) and not yet been awarded a doctoral degree. Career breaks refer to periods of time where the candidate was not active in research, regardless of his/her employment status (sick leave, maternity leave etc). Short stays such as holidays and/or compulsory national service are not taken into account.
  • At the time of the deadline, applicants must not have resided or carried out their main activity (work, studies, etc.) in France for more than 12 months in the 3 years immediately prior to the call deadline.
  • Applicants must be available to start the programme on schedule (around 1st October 2022).

Selection process

Additional comments

  • The First step before applying is contacting the PhD supervisor. You will not be able to apply without an acceptation letter from the PhD supervisor.
  • Please contact the PhD supervisor for any additional detail on job offer.
  • There are no restrictions concerning the age, gender or nationality of the candidates. Applicants with career breaks or variations in the chronological sequence of their career, with mobility experience or with interdisciplinary background or private sector experience are welcome to apply.
  • Support service is available during every step of the application process by email: clear-doc@univ-eiffel.fr

Web site for additional job details

Offer Requirements

  • REQUIRED LANGUAGES
    ENGLISH: Good
    FRENCH: Basic

Skills/Qualifications

  • At the time of the deadline, applicants must be in possession or finalizing their Master’s degree or equivalent/postgraduate degree.
  • At the time of recruitment, applicants must be in possession of their Master’s degree or equivalent/postgraduate degree which would formally entitle to embark on a doctorate.

 

Work location(s)
1 position(s) available at
Université Gustave Eiffel
France
Marne-La-Vallée
77454
5, Boulevard Descartes

EURAXESS offer ID: 717425

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