Jan Hergesel

I am a PhD student and researcher at the Technical University of Liberec, Faculty of Mechatronics, Informatics, and Interdisciplinary Studies. I obtained my Ing. degree in 2024 and my Bc. degree in 2022 from the same faculty. My research focuses on flicker perception and measurement.

RESEARCH, TEACHING, or OTHER INTERESTS

Electrical and Electronic Engineering

Scopus Publications

Flicker Visibility With Different Spectra of White Light
Leoš Kukačka, Jan Hergesel, Jakub Nečásek, Petr Bílek, Michal Vik, Robert Stiegler, Morteza Pourarab, Jan Meyer, and Jiří Drápela
Institute of Electrical and Electronics Engineers (IEEE)



Critical Flicker Frequency and Auditory Stimuli - Procedure Settings
Leoš Kukačka, Michaela Chmelařová, Jan Hergesel, Pascal Dupuis, and Georges Zissis
Institute of Electrical and Electronics Engineers (IEEE)
The standing standardized measure for the assessment of flicker severity, the light flickermeter (IEC TR 61547-1:2020), evaluates the flicker irritability level in reference conditions as a necessary simplification. This misestimates the actual level in the presence of other factors known to influence flicker visibility. One such factor is noise, which interacts with the visual system under specific circumstances. However, direct effect of noise or any auditory stimuli on the flicker visibility threshold is not yet understood. This article is concerned with the design of experiments aimed at determining whether the critical flicker frequency (CFF) is subject to change when the observer is exposed to pulsating sounds. The article describes the work done in designing the experiments and also reveals data from a preliminary campaign. Data collected so far are insufficient to establish a direct link between pulsating sound and CFF, but are used to adjust the conditions of a wider campaign. Mathematical tools are developed to evaluate the experiment results using a probabilistic framework.


Flicker Visibility with Different Spectra of White Light
Leoš Kukačka, Jan Hergesel, Jakub Nečásek, Petr Bílek, Michal Vik, Jan Meyer, Robert Stiegler, Morteza Pourarab, and Jiří Drápela
IEEE
The standard flickermeter algorithm commonly used for the evaluation of flicker severity in current electromagnetic compatibility standards originates from the 1980s. It was developed with an incandescent lamp as a reference light source and optimized to voltage fluctuations caused by arc furnaces. However, the algorithm is questionable as the situation in the grid changed since the 1980s; many modern devices are being connected to the grid, creating voltage distortion patterns which are not properly recognized by the flickermeter. Moreover, incandescent lamps have been largely replaced by LEDs and discharge lamps. Transitioning the algorithm from incandescent lamp light to LED light requires detailed revision of every part of the algorithm, This paper is concerned with verifying the frequency weighting function which is a basis of Block 3 of voltage flickermeter and Block B of light flickermeter. Flicker sensitivity of over 30 human observers is measured with two different light sources (warm and neutral white) and compared with the frequency weighting function used in the current standards.


Comparison of Procedures for Measuring the Temporal Contrast Sensitivity Function
Leoš Kukačka, Jan Hergesel, Jakub Nečásek Petr Bílek, Michal Vik, Jan Meyer, Robert Stiegler, and Jiří Drápela
IEEE
The IEC voltage flickermeter and light flickermeter are algorithms used to estimate the severity of flicker produced by artificial lighting systems. The algorithm was developed around incandescent lamps. In an effort to revise and update the algorithm to be compatible also with LED lamps, the flicker sensitivity curve needs to be verified with white light produced by LEDs, which have a distinct spectrum.This paper is concerned with comparing two distinct approaches to measure the flicker sensitivity of human observers. Traditionally, the flicker sensitivity (Temporal Contrast Sensitivity Function – TCSF) is measured by the Method of Adjustments, where the observer adjusts the stimulus intensity until they are satisfied with finding the flicker visibility threshold. In this paper, the method is compared to Two Alternative Forced Choice tests driven by a dynamic QUEST algorithm in terms of accuracy, speed, friendliness towards the observer, and the information yield in general.


Critical Flicker Frequency and Auditory Stimuli-Procedure Settings
Leos Kukacka, Michaela Chmelarova, Jan Hergesel, Pascal Dupuis, and Georges Zissis
IEEE
This paper concerns with the design of experiments aimed at determining whether the critical flicker frequency (CFF) is subject to change when the observer is exposed to pulsating sounds. The paper describes the work done in designing the experiments and also reveals data from a preliminary campaign. Data do not form a basis to prove a direct link between pulsating sound and CFF, but can be used to better adjust the conditions before the full campaign.

RECENT SCHOLAR PUBLICATIONS

Flicker visibility with different spectra of white light
L Kukačka, J Hergesel, J Nečsek, P Blek, M Vik, R Stiegler, M Pourarab, ...
IEEE Transactions on Industry Applications 2025



Critical Flicker Frequency and Auditory Stimuli–Procedure Settings
L Kukačka, M Chmelařov, J Hergesel, P Dupuis, G Zissis
IEEE Transactions on Industry Applications 60 (1), 1938-1945 2023



Comparison of Procedures for Measuring the Temporal Contrast Sensitivity Function
L Kukačka, J Hergesel, JNP Blek, M Vik, J Meyer, R Stiegler, J Drpela
2023 IEEE Sustainable Smart Lighting World Conference & Expo (LS18), 1-6 2023



Pascal DUPUIS a Georges ZISSIS
L KUKAČKA, M CHMELŘOV, J HERGESEL
Critical Flicker Frequency and Auditory Stimuli–Procedure Settings [online 2022



Řdic program pro experiment na měřen prahu viditelnosti f likru na klasickch žrovkch
IA CH, S TUL




Realizace Experimentů pro měřen vjemu flikru u žrovek
J Hergesel, J Nečsek, P Blek, L Kukačka

MOST CITED SCHOLAR PUBLICATIONS

Flicker visibility with different spectra of white light
L Kukačka, J Hergesel, J Nečsek, P Blek, M Vik, R Stiegler, M Pourarab, ...
IEEE Transactions on Industry Applications 2025
Citations: 2



Comparison of Procedures for Measuring the Temporal Contrast Sensitivity Function
L Kukačka, J Hergesel, JNP Blek, M Vik, J Meyer, R Stiegler, J Drpela
2023 IEEE Sustainable Smart Lighting World Conference & Expo (LS18), 1-6 2023
Citations: 2



Pascal DUPUIS a Georges ZISSIS
L KUKAČKA, M CHMELŘOV, J HERGESEL
Critical Flicker Frequency and Auditory Stimuli–Procedure Settings [online 2022
Citations: 2



Critical Flicker Frequency and Auditory Stimuli–Procedure Settings
L Kukačka, M Chmelařov, J Hergesel, P Dupuis, G Zissis
IEEE Transactions on Industry Applications 60 (1), 1938-1945 2023
Citations: 1