Lorinc Garai

56736750200

Publications - 5

MEASURING AGE-DEPENDENCE OF COLOUR AFTERIMAGE PERCEPTION

Lorinc Garai Andras Horvath

Publication Name: Light and Engineering

Publication Date: 2022-01-01

Volume: 30

Issue: 2

Page Range: 70-81

Description:

Afterimages are common and frequent perceptual phenomena of everyday life. A typical appearance is the negative “ghost” image of a bright light source when we turn away from it. In the case of significant colour contrast, the afterimage can be coloured. The perceived false image’s strength decreases gradually and completely disappears in a (10–100) s timescale. The underlying processes have multiple components: a quick adaptation on the retinal level, and a slower adaptation on the neural level. Several studies discuss these mechanisms, but there are still important questions to be answered. In our research, we apply the top-level, black-box style approach: instead of focusing on the inner details, we ask human test subjects to test and measure the duration and “strength score” of the same light-transitions. Our goal is to find the main features that affect the duration and subjective strength of the colour afterimages. Specifically, we examine whether the age and gender of the test subjects or the colourimetry parameters affect these parameters. Two set of experiments were performed: colour-colour transitions with 41 and colour-grey transitions with 16 test subjects between 19 and 62. We found that gender has no measurable influence, but age makes a difference in high significance. Both experiment types confirmed that over 40 years the average duration of colour afterimages decreases.

Open Access: Yes

DOI: 10.33383/2021-061

Colour afterimages: Computing and measuring virtual colour perception provided by two display types

Lorinc Garai Andras Horvath

Publication Name: 11th IEEE International Conference on Cognitive Infocommunications Coginfocom 2020 Proceedings

Publication Date: 2020-09-23

Volume: Unknown

Issue: Unknown

Page Range: 109-114

Description:

Afterimages are common and frequent perceptual phenomena of everyday life. When looking into a bright light source compared to environment and suddenly turning the eyes away from it, the illusionary image of the light source remains in perception, for a while. A subordinate to afterimages defined in our research is virtual colour perception that, according to our interpretation is an unusual and intense temporary colour perception provoked by quick colour change in the incident light. Modelling virtual colour perception can be useful in the field of visual design, for example in dynamic advertising. A computational kinetic model established for simulating and quantifying virtual colour perception was developed in our previous work and was validated with preliminary tests involving 20 observers. Validation test results were contestable due to the high variance (about 50 RSD%) of duration and intensity of afterimage results at each incident light colour change. Thus, in our current work, validation on one-observer tests was performed to minimize the variance of results. Further, these validation tests were run on two liquid crystal display (LCD) types: a nowadays frequently present In-Plane Switching (IPS) display providing vivid colours, and an older LCD-TN (twisted nematic) display.

Open Access: Yes

DOI: 10.1109/CogInfoCom50765.2020.9237835

Measuring colour afterimage perception

Lorinc Garai Andras Horvath

Publication Name: 11th IEEE International Conference on Cognitive Infocommunications Coginfocom 2020 Proceedings

Publication Date: 2020-09-23

Volume: Unknown

Issue: Unknown

Page Range: 191-196

Description:

Afterimages are common and frequent perceptual phenomena of everyday life. When looking into a high-intensity light source and suddenly turning away from it, a temporary 'ghost' of the light source remains in perception, for a while. A highly saturated, coloured incident light has a different effect on the three types of cone cells. Therefore, the fast change in the colour of incident light triggers different intensity afterimage on the different types of cones, and the observer perceives a colour afterimage disappearing in a between 10- and 100-second timescale. By choosing incident light colours, colour afterimages can be applied in visual design, like in modern, dynamic advertising. Our previous work describes simulation of colour afterimages triggered by given colour combinations. For the validation of simulation, preliminary tests were performed with 20 subjects. Test results suggested the possibility of age dependence of intensity and duration of colour afterimages. In this work, we present the experimental results of 28 observers with different ages and gender. The disappearing time and perceived initial 'intensity' of the colour afterimages were measured in nine fast colour transition cases.

Open Access: Yes

DOI: 10.1109/CogInfoCom50765.2020.9237851

Modelling of human color perception depending on quick color shifts on screen

Lorinc Garai Andras Horvath

Publication Name: 9th IEEE International Conference on Cognitive Infocommunications Coginfocom 2018 Proceedings

Publication Date: 2018-07-02

Volume: Unknown

Issue: Unknown

Page Range: 223-226

Description:

The eye is considered as the most important human sensory organ. Its important part is the retina, which converts light to neural impulses by several millions of sensor cells: rods and cones. To understand this process, modelling by computer simulation is required. The well-known phenomenon of afterimages is examined in this paper. When a fast color change on screen is performed, a color after image appears temporarily. This afterimage may result in a more intensive color perception. A model was established to characterize the color perception intensity and duration depending on color changes.

Open Access: Yes

DOI: 10.1109/CogInfoCom.2018.8639909

Improving HPLC Analysis of Vitamin A and E: Use of Statistical Experimental Design

Lorinc Garai

Publication Name: Procedia Computer Science

Publication Date: 2017-01-01

Volume: 108

Issue: Unknown

Page Range: 1500-1511

Description:

Analyses of vitamin supplements A and E in food samples are performed mostly with high performance liquid chromatography (HPLC). In majority of cases, sample preparation preceding HPLC implies saponification, a step critical to heat sensitivity of analytes. The method of saponification is clearly defined by ISO standards, however, two important factors, temperature and time of saponification are only given in value ranges instead of exact settings. Resolving this deficiency with the promise of eliminating time and cost consuming experimental probes, statistical experimental design (SED) is introduced to find optimum settings of temperature and time for the best recovery of vitamin supplements in food samples. Finding the optimum settings in SED was supported with Statsoft Statistica 13 For illustrating SED, margarine samples supplemented with vitamin A and E were applied.

Open Access: Yes

DOI: 10.1016/j.procs.2017.05.177