Visual Characteristics of Afterimage under Dark Surround Conditions
Round 1
Reviewer 1 Report
This is a very interesting paper concerning visual perception and confort in dark spaces. Even, if the subject is somehow marginal with MDPI Energies themes, it can be considered for publication.
Globally the paper is well written and the results are sound. However, before accepting the paper for publication authors should take into account some simple recommendations and respond to some questions:
1. Don’t use acronyms in the abstract. Please explicit RMSE and MAE
2. Usually break lights are red, thus I can’t understand why in line 30 authors speak about ‘injuries of eyes’. Do-you have any evidence about injuries caused by break-lights ? In not, just delete this part of the sentence.
3.The paper concerns mainly car driver vision, why do you speak about pilots and night flights, this in another field with different requirements. For instance, pilots wear sun glasses event during night flight to avoid glare for unexpected light sources (including laser beams).
4. Why your panel is limited to young people ? Are male of female ? Have any visual impairment or not ? What is the number of people used ?
5. As all you subjects are young, it will be opportune to discuss in extenso what is expected to be the influence of age to your results This is a compulsory demand before accepting your paper.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
# Visual characteristics... The authors have carried out three experiments to characterize afterimages produced by LED in the mesopic range under dark surroundings. They have shown that duration of after-images (DT), visibility (V) and color difference (CT) can be modeled with a 2 parameters in linearized functions with the variable Y being the product of the luminance ratio (Ls/Lb) with the exposure time te. General remarks: 1. On average the text is clear and understandable but as more as I read it, I found small inconsistencies. 2. The text is too long. Reading 15 pages need too long. For some part of the text, I had the impression to read a textbook and not a scientific article. 3. The introduction is too long and thus the relationship between the presented study and the previous work is diluted and as a reader I felt lost. 4. The explanation of the coefficient of variation is in the context of an article not useful (lines 179-189). 5. Also the text is too long, there is no discussion about the result. I would personally be interested to know why relationship between Y and DT is linear whereas between V and Y or between CD and Y the log(Y) I used. Line 79 with ref 21 seems to give an explanation, that would be nice to discuss it. 6. The difference between the presented study and previous studies is not clear. (Lines 109-116: What is the relationship with ref 31 ?) 7. In the experimental procedure after the description of the device, the procedure to acquire the three parameters DT, CT and V should be clearly separated. 8. Regression analysis belongs to the results (line 257). 9. The parameter Y contains the inverse of Lb. But the background is dark, which means that Lb is very small. What is the error made on the luminance ratio ? Line 121 does not gives any values of the background level. Specific remarks 1. Line 16: The "three indices" are not obvious. 2. Line 17: Abbreviation RME and MAE should not be in the abstract. However LED is very broadly used in common language and is accepted. 3. Line 53: reference number is missing. 4. Lines 72-73: I do not understand why the exposure duration should be less than a second to induce significant vision impairment: Does a long exposure time induce less vision impairment ? 5. Lines 103-104: Is this the goal of the article ? 6. Figure 4 could be integrated in Fig 4. 7. Line 136: Why not to use more recent chromaticity diagram (2006) ? 8. Line 148: Mean age and SD of the subjects are missing. 9. Fig 5 and Fig 6 should be in one Fig with a) and b). 10. Fig 7, 8b and 9: Why a line between the cases. There is no sequential link between Red, Green, .. or Pattern 1, 2, ... 11. Fig 7: Vertical scales are different and no visual comparison are not possible. All three graphs could be placed on one. 12. Table 6, 7 and 8 could be in one Table only. 13. Fig 8a: Caption needs more explanation. 14. Equations 3, 4 and 5: the "x" should be replaced by a dot. 15. Table 9, 10 and 11: the r factor is already in the text could be dropped in the tables. 16. Fig 10, 11 and 12: Visual comparison is impossible. Each figure should be into one graph (and not three) so that comparison between the values for black, gray and white background would be easier. 17. Line 307ss could be better placed into a discussion. 18. Line 124: "penetration" should be replaced by "transmission". However, a half-silvered micro has some absorption which are higher than a few percent! 19. Experiment was done mostly in the mesopic range, which corresponds to indoor illumination (as given in table 2). Could the authors explain more about the range of illumination ? 19. How did the author measured the luminance ? 20. Table 2: "Illuminated intensity" has no meaning. It must be either luminance [cd/m2=lm/m2/sr] or luminous intensity [cd=lm/sr]. 21. Table 2: I did not found where level 1 and level 2 are used later on. 22. Line 164-165: What is level 9 when subject have to estimate gray level between 1 and 8. 23. Line 214: Is "intensity 2" the same as the "level 2" of table 2 ?Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Congratulation for well-designed scientific research. The results are clearly show that the exposure time, intensity level, and background luminance are the significant factors influencing the afterimage characteristics. The great idea was to introduce into this reasarch the machine learning approach. This kind of aproche is showing great possiblity for using it at other related to that applications, which gives for this paper posiblity for high citation index in the future.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Authors respected my initial recommendations and enhanced the paper accordingly. I understood the fact that experiments with older people will be the next step of the work. The paper can be published. Just two suggestions: (1) give the number of observers and, if possible, the proportion of male/female; (2) Please state in the conclusions that the next step of the study will deal with elderly and that for this population the results can be different.
Reviewer 2 Report
All raised questions were answered. Also for some answers, I am not fully convinced. Captions of figures (8, 9, 11 and so on) which should be more extensive.
Personally, I still find that the article is long and close to a textbook, but this also means that the writing is clear and understandable.
However, I would like to come back to the fact that the scale of the graphs in figures 10, 11 and 12 does not allow any visual comparison. As an example, I took the date from figure 11 and plot them on a unified scale to show clearly what I mean.
Comments for author File: Comments.pdf
