Luminance Ratio Research Articles

SeACPFusion: An Adaptive Fusion Network for Infrared and Visible Images based on brightness perception

Generating a single fused image that highlights important targets and preserves textural details is the aim of fusing visible and infrared images. The majority of deep learning-based fusion algorithms now in use can produce decent fusion outcomes; however, the modeling process still lacks consideration of the different amounts of information in different scenes or regions. Thus, we propose in this research SeACPFusion, a luminance-aware adaptive fusion network for infrared and visible images, which adaptively preserves the intensity information of the noticeable targets of the source images with the texture information of the background in an optimal ratio. Specifically, we design pixel-level luminance loss (PBL) to direct the fusion model’s training in real-time, and PBL retains the optimal intensity information according to the pixel luminance ratio of different source images. In addition, we designed the Channel Transformer (CTF) to consider the relationship between different attributes from the point of view of the feature channel and to focus on the key information by using the self-focusing mechanism to achieve the goal of adaptive fusion. Our extensive tests on the MSRS, RoadScene, and TNO datasets demonstrate that SeACPFusion surpasses nine representative deep learning methods on six objective metrics and achieves the best visual results in scenes such as overexposure or underexposure. In addition, the relatively efficient operation and fewer model parameters make our algorithm promising as a preprocessing module for downstream complicated vision tasks.

Effect of luminance of head-up displays on recognition of visual objects on roads

ObjectiveThe purpose of this study is to investigate the effect of visual obstruction when a head-up display (HUD) is presented in front of a driver's field of view. BackgroundThe use of HUDs is expected to increase due to advances in augmented reality (AR) technology. A conventional HUD is displayed at a relatively low position in relation to the driver's viewpoint and has little effect on their front view. However, while an HUD, such as the AR-HUD, is presented in front of the driver's field of vision and helps them in presenting ADAS information, there is a concern that this display may obscure visual objects on the road from the driver's field of vision. MethodAn experiment using a mockup consisting of a HUD and a driver's seat was conducted with 28 participants. A passenger car, motorcycle, and crossing pedestrian were presented as visual objects on a 65-in monitor behind the image of the HUD. Participants were asked questions under different conditions with changes in the HUD luminance and asked to correctly answer questions regarding changes in the inter-vehicle distance and the existence of visual objects on the road. The number of correct answers provided by the participants was recorded. ResultsThe experimental results revealed that the HUD had an effect under the twilight condition wherein the background luminance was low. Furthermore, analyzing the number of correct answers for each visual target revealed that the HUD had an effect under conditions wherein the size of the visual object was small. ConclusionIt was experimentally derived that the luminance ratio Rluminance = 1.1 was the threshold value that affected the recognition of the visual object in the background when the HUD was presented in front of the driver's field of view. ImplicationThe threshold value of the luminance ratio Rluminance obtained in this study can be considered when deciding how to properly display the HUD in front of the driver's field of view.

Exogenous testosterone therapy on choroid in androgen deficiency.

To investigate the effects of exogenous testosterone treatment on the choroidal parameters in patients with androgen deficiency. Right eyes of 24 patients with androgen deficiency and 31 healthy volunteers were included in the study. The eyes were scanned for subfoveal choroidal thickness (SFCT), choroidal vascularity index (CVI), choroid-stromal area (C-SA), choroid-luminal area (C-LA), choroid-stromal to luminal area ratio (CSLR), and the choroidal parameters within central 1500 µm of the macula (CVI1500, C-LA1500, C-SA1500, and CSLR1500) by enhanced-depth imaging optical coherence tomography (EDI-OCT) at baseline, 6th and 18th weeks of the exogenous testosterone treatment. The mean SFCT values of the androgen deficient groups and healthy controls were 307.7±27.0 and 303.2±37.2 µm (P=0.8). However, CVI, C-SA, CSLR, CVI1500, C-LA1500, and CSLR1500 were significantly different between the groups (all P<0.01). At the 6th week visit after exogenous testosterone treatment, SFCT, CVI, C-LA, and C-SA were significantly decreased, and these parameters returned to baseline levels at the 18th-week visit (all P>0.05). However, CVI1500 and LA1500 significantly increased at the end of the follow-up period (P<0.001). CVI is lower in androgen-deficient patients than in healthy subjects. The alterations in the choroid during the testosterone peak are transient in the treatment of patients with androgen deficiency. However, the increase in CVI within the central 1500 µm of the macula persists even after 4mo.

Ultrasonographic measurement of the prostatic dimension-to-aortic luminal diameter in healthy intact male dogs and dogs with benign prostatic hyperplasia.

To establish ultrasonographic measurements of the prostatic dimension-to-aortic luminal diameter ratios including the prostatic volume-to-aortic luminal diameter ratio in healthy, intact male dogs and compare these ratios between healthy dogs and dogs affected by benign prostatic hyperplasia. Healthy dogs (n = 75) and dogs affected by benign prostatic hyperplasia (n=104) were included in the study. Prostate length, width, average height and aortic luminal diameter were measured from ultrasonographic images. In addition, prostatic volume was calculated, and prostatic volume-to-aortic luminal diameter were also compared. In healthy dogs, aortic luminal diameter was significantly associated with bodyweight and the prostatic width while body condition scores, prostate length and prostatic average height were not associated. Prostatic dimension-to-aortic luminal diameter ratios and prostatic volume-to-aortic luminal diameter ratio was not significantly different among dogs with different body condition scores either in healthy dogs or dogs affected by benign prostatic hyperplasia, except prostatic volume-to-aortic luminal diameter ratio in benign prostatic hyperplasia. Prostatic dimension-to-aortic luminal diameter ratios were significantly higher in benign prostatic hyperplasia while prostatic volume-to-aortic luminal diameter ratio significantly higher in healthy dogs. Prostatic dimension-to-aortic luminal diameter ratios demonstrated medium to high sensitivity and specificity when distinguishing between healthy dogs and dogs affected by benign prostatic hyperplasia. Prostatomegaly, should be considered when the prostatic dimension-to-aortic luminal diameter ratios increase. The calculated cut-off values were 3.68, 4.46 and 3.06 for prostate length-to-aortic luminal diameter, prostatic width- to-aortic luminal diameter and prostatic average height-to-aortic luminal diameter, respectively. The prostatic dimension-to-aortic luminal diameter ratios could be useful to evaluate the size of the prostate in dogs, as it is unaffected by the body condition scores.

Investigation of the sensitization effect of Yb3+ in Yb, Er co-doped Sr5(PO4)3F transparent ceramics: From single-band red upconversion to temperature sensing behavior

Lanthanide-ion-doped red upconversion (UC) fluorescent materials with excellent signal-to-noise ratio, stability, and red-green luminous intensity ratio have proven of tremendous research importance for biomedical, three-dimensional (3D) displays, sensors, and other sectors. In this study, xYb, 1Er: Sr5(PO4)3F (S-FAP) (x=0–5 at%) transparent ceramics with outstanding optical quality were fabricated by hot pressing the co-precipitation powder with high sintering activity. The energy dispersive X-ray (EDX) results showed that the trivalent lanthanide ions were evenly doped into the S-FAP ceramic lattice. Increased Yb3+ doping considerably restricted the growth of ceramic grain size, which should be attributable to a decrease in sintering activity under high Yb doping conditions. The co-doping of Yb3+ successfully resulted in a significant improvement in up/down conversion efficiency via effective energy transfer mechanisms and the optimization of the electron population at the energy level of red-green emission. Furthermore, single-band red upconversion luminescence with the greatest red-green upconversion luminescence integral intensity ratio of 125.74 was discovered under 980 nm laser pumping at room temperature. The energy transition process involved in the phenomenon of the up-conversion luminescence intensity shift of red-green emission has been thoroughly examined. Finally, the noncontact optical thermometric ability based on fluorescence intensity ratio (FIR) technology showed that the maximum absolute sensitivity (Sa) of the 5Yb1Er sample in the temperature range of 320–556 K is 1.1×10−3 K−1, implying the possible use of Yb/Er-doped S-FAP transparent ceramics in the field of optical thermometers.

Lightness Peaks during the Menstrual Phase: A Retrospective Challenge to a Visual Arousal Theory of Estrogen

(1) Background: The influence of estrogen on cognitive and perceptual functions is debated. Some research suggests that estrogen increases arousal, improving cognitive function, while others propose that increased arousal might reduce performance in certain tasks. This study investigates the effects of menstrual cycle phase and estrogen levels on lightness perception in cycling women and hormonal contraceptive (HC) users. (2) Methods: Sixteen women (nine with natural cycles and seven HC users) completed three sessions aligned with different menstrual cycle phases. During these sessions, participants adjusted the luminance of five test stimuli (representing blue, green, green-yellow, yellow, and red) until they matched a flickering reference white stimulus. Lightness was calculated as the ratio of the reference stimulus luminance (5 cd/m2) divided by the test luminance required to match. Estrogen levels were also determined for each participant from saliva samples collected on the morning of each session. The effects of wavelength and menstrual cycle phase on lightness perception were analyzed, followed by post hoc comparisons and correlations between lightness perception and estrogen levels for both cycling women and HC users. (3) Results: Lightness varied by menstrual phase (MCP) in cycling women and was slightly higher during the low estrogen menstrual phase compared to peri-ovulation or luteal phases. In HC users, lightness measures were equivalent across phases. For cycling women, lightness was negatively correlated with estrogen for the green and green-yellow stimuli. There were no such associations among HC users. (4) Conclusions: This report challenges the concept that high estrogen phases of the menstrual cycle always positively influence perception. Conversely, these results revealed that—at least in cycling, non-hormonal contraceptive users—lightness perception was both at a maximum during the low estrogen menstrual phase and negatively associated with estrogen levels across all tested wavelengths.

Dual-mode luminescence light intensity modulation characteristics and optical radiation dependence of stannate photochromic ceramics

Alkaline earth stannate is characterized by good physicochemical stability. It has been applied in the field of optical information storage by coupling photoluminescence intensity modulation and photochromic performance, which has attracted the attention of researchers. The development of alkaline earth stannate ceramics with high light intensity modulation properties and non-destructive reading of optical information is of great research value. In this study, Er3+-doped Ca2SnO4 photochromic ceramics were prepared by high-temperature solid-phase reaction method. Alternating UV light irradiation and thermal stimulation, the ceramics achieve a reversible transition between light and dark gray. Er3+ doping gives the ceramics dual-mode luminescence light intensity modulation performance. When the doping amount of Er3+ is 0.01 mol, there is a maximum down-conversion luminous intensity modulation ratio of 93%, which is higher than most of the same type of photochromic materials. The photochromic behavior is explained using the capture-release model of traps for carriers, and the dual-mode luminescence light-intensity modulation behavior is analyzed through the energy transfer mechanism. The optical radiation response properties were investigated and the optimum light response wavelength is found to be 290 nm, which is related to the optical band gap Eg. And the selection of the optimal light response wavelength can effectively improve the performance of photochromic and light intensity modulation. This study provides a promising strategy for performance enhancement of photochromic materials.

Effects of binocular disparity on binocular luminance combination.

This study aimed to examine the effects of binocular disparity on binocular combination of brightness information coming from luminance increments and decrements. The point of subjective equality was determined by asking the observers to judge which stimulus appeared brighter-a bar stimulus with variable disparity or another stimulus with zero disparity. For the bar stimulus, the interocular luminance ratio was varied to trace an equal brightness curve. Binocular disparity had no effect on luminance increments presented on a gray or black background. In contrast, when luminance decrements were presented on a gray background, non-zero disparities elevated points of subjective equality for stimuli with interocular luminance differences. This means that the binocular brightness combination of the two monocular signals shifted from winner-take-all summation toward linear averaging. It has been argued that this effect may be caused by non-zero binocular disparities attenuating interocular suppression, which is deemed to operate normally with zero disparity.

Effectiveness and visual performance assessment of anti-peeping films

Some private information inevitably becomes more visible when using wide-angle electronic devices in public places. Thus, some people use anti-peeping films to achieve privacy protection. To examine the effectiveness and its influence on the visual performance of the anti-peeping film, we investigated the color gamut, luminance, contrast ratio, Bhattacharyya coefficient and structural similarity characteristics of a smartphone without-film screen and with two-sided (left and right) of 25°, 30°, and 45° anti-peeping films, respectively, and four-sided (up, down, left, and right) anti-peeping films. The results show that the film reduces the screen luminance and contrast ratio except for the color gamut. At 0° viewing angle, the luminance decreases by 24.8%, 25.2%, 18.6%, and 53.8%, respectively. For the 25°, 30°, 45°, and 360° anti-peeping films, the luminance and contrast ratio decrease to 50% at 24°, 25°, 19°, and 20° horizontal viewing angles. The effectiveness of four-sided anti-peeping film is the best, followed by the two-sided ones, and the smaller the viewing angle, the better the effect. The Bhattacharyya coefficients of the white images’ pixel micrographs are 0.887, 0.896, 0.898, and 0.878, respectively, of which the smallest four-sided anti-peeping film has the greatest influence on screen clarity. Under the 0-40° viewing angle, the structural similarity continuously decreases, and the screen becomes blurred due to the anti-peeping film. This work investigates the optical characteristics of anti-peeping film and examines its influence on visual performance, and provides strategy for manufacturers and use guidance for users.

Assessing perceptual chromatic equiluminance using a reflexive pupillary response

Equiluminant stimuli help assess the integrity of colour perception and the relationship of colour to other visual features. As a result of individual variation, it is necessary to calibrate experimental visual stimuli to suit each individual’s unique equiluminant ratio. Most traditional methods rely on training observers to report their subjective equiluminance point. Such paradigms cannot easily be implemented on pre-verbal or non-verbal observers. Here, we present a novel Pupil Frequency-Tagging Method (PFTM) for detecting a participant’s unique equiluminance point without verbal instruction and with minimal training. PFTM analyses reflexive pupil oscillations induced by slow (< 2 Hz) temporal alternations between coloured stimuli. Two equiluminant stimuli will induce a similar pupil dilation response regardless of colour; therefore, an observer’s equiluminant point can be identified as the luminance ratio between two colours for which the oscillatory amplitude of the pupil at the tagged frequency is minimal. We compared pupillometry-based equiluminance ratios to those obtained with two established techniques in humans: minimum flicker and minimum motion. In addition, we estimated the equiluminance point in non-human primates, demonstrating that this new technique can be successfully employed in non-verbal subjects.

Enhancing NIR-II Upconversion Monochromatic Emission for Temperature Sensing.

The upconversion luminescence (UCL) in the second near-infrared window (NIR-II) is highly attractive due to its excellent performance in high-resolution bioimaging, anticounterfeiting, and temperature sensing. However, upconvertion nanoparticles (UCNPs) are normally emitted in visible light, potentially impacting the imaging quality. Here, a monochromatic Er3+-rich (NaErF4:x%Yb@NaYF4) nanoparticles with excitation at 1532nm and emission at 978nm is proposed, both situated in the NIR-II region. The proper proportion of Yb3+ ions doping has a positive effect on the NIR-II emission, by enhancing the cross relaxation efficiency and accelerating the energy transfer rate. Owing to the interaction between the Er3+ and Yb3+ is inhibited at low temperatures, the UCL emission intensities at visible and NIR-II regions show opposite trend with temperature changing, which establishes a fitting formula to derive temperature from the luminous intensity ratio, promoting the potential application of UCL in NIR-II regions for the temperature sensing.

Energy transfer mechanism and luminescence properties of green phosphors Sr2YF7: Dy3+, Tb3+

In this study, color-adjustable Sr2YF7: xDy3+, and yTb3+ light-emitting phosphors were synthesized through the hydrothermal method. Systematic experiments were performed to determine the optimal doping concentration for Sr2YF7: xDy3+ phosphor with x = 0.03, resulting in a distinctive light blue emission band attributed to the 4F9/2 → 6H15/2 transition. The energy transfer within the double-doped system of Sr2YF7: Dy3+, yTb3+ (y = 0, 0.06–0.1) was examined by analyzing spectral overlap and reductions in emission lifetimes. Moreover, the mechanism governing this energy transfer phenomenon was investigated. The concentration proportion of Dy3+/Tb3+ in Sr2YF7 phosphors was modulated to achieve color modulation, transitioning from light blue to vibrant green emissions in Sr2YF7: Dy3+, Tb3+ samples. The intensity of green emission increased with increasing Tb3+ ion concentrations because of the dynamics of energy migration from Dy3+ to Tb3+ levels (4F9/2 + 7F6 → 6H15/2 + 5D4). Based on calculations using steady-state rate equations, Tb3+ ion doping effectively reduced ionic spacing and consequently amplified the green emission. Furthermore, the results indicated that the luminous intensity ratio of Sr2YF7: 0.03Dy3+, 0.07 Tb3+ phosphors at 423/303K was notably high at 93.59 %, indicating high thermal stability. Thus, Sr2YF7 phosphors co-doped with Dy3+ and Tb3+ emerge as potential candidates for application in advanced illumination technologies.

Realization of a Healthy Spectrum with High Color Rendering Index and Low Blue Light Hazard Based on Longitudinal Regulation of Luminous Intensity Ratio

Realization of a Healthy Spectrum with High Color Rendering Index and Low Blue Light Hazard Based on Longitudinal Regulation of Luminous Intensity Ratio

Low complexity local dimming algorithm for high quality head up displays in automotive vehicles

We present a high image quality head up display (HUD) based on the local dimming liquid crystal display (LCD). The proposed HUD provides high white luminance to improve day-time visibility and low black luminance to cope with the postcard effect during the night by the local dimming technique. To reduce the computational complexity, the pixel-based boosting values for the pixel compensation are computed by simple bi-linear interpolation, complex power functions are implemented by look-up tables, some multiplications are replaced with the sums of shifted values, and the numbers of look-up tables and multipliers are reduced by sequential process. The simulation results of the proposed local dimming algorithm for 640×1280 LCD panel and 10×22 LED backlight ensure higher peak signal-to-noise ratio than 40 dB and larger power reduction performance than 73% over 7 HUD images. In addition, the postcard effect improvement is verified over images on LCD panel as well as windshield. Maximum luminance and contrast ratio on the windshield of the prototype HUD system are measured as 16,088 cd/m 2 and 342 × 10 6 :1.

Studies on the Effectiveness of High-luminance Monitors in Mammography Softcopy Interpretation

Recently, monitors with maximum luminance exceeding 2000 cd/m2 (high-luminance monitor) have been used for diagnostic mammography. In this study, we examined the visibility of high-luminance monitors by converting luminance meter measurements into the just noticeable difference (JND) Index. The ambient light was also examined at the same time. The high-luminance monitor is a 21.3-inch IPS monochrome monitor with a maximum luminance of 3000 cd/m2. Experiments were conducted with a minimum luminance of 0.6 cd/m2 and a maximum luminance of 500, 850, and 1200 cd/m2. The luminance ratio was set to 1 : 2000 and the maximum luminance was changed to 500, 1000, and 2000 cd/m2. The ambient light was varied to 8.7, 36.1, 61.3, and 129.6 lx. The Japan Radiological Society recommended luminance values for each stage of phantom and Grayscale Standard Display Function curves were measured. The JND increased as the maximum luminance was increased for both the case with the same minimum luminance and the case with the same luminance ratio, and visibility was improved. In both the case of the same minimum luminance and the case of the same luminance ratio, the JND was found to increase as the maximum luminance was increased. The results suggest that high-luminance monitors may improve visibility and allow for higher ambient light settings. Furthermore, the degree of eye fatigue needs to be verified.

Technical Performance Assessment and Quality Control of Ultrasound Device Monitors.

The purpose of this study was to investigate and evaluate the current technical performance of ultrasound imaging device displays. Altogether 53 ultrasound device displays were evaluated in two hospital districts of Finland. The performance of the displays was evaluated with tests and test patterns developed by American Association of Physicists in Medicine (AAPM). Minimum, maximum and ambient luminances (Lmin,Lmax,Lamb) were measured. Ambient ratio (AR), luminance ratio (LR), [Formula: see text] and [Formula: see text] were calculated, and luminance uniformity, defined as deviation from the median (MLD), was evaluated. The results indicate that none of the measured displays fulfill the AAPM Task Group (TG) 270 maximum luminance recommendation for diagnostic displays. A majority (32/53, 60%) of the displays fail the AAPM TG270 acceptable level for secondary displays as well. Only 3 of 53 (6%) displays were at the acceptable level for diagnostic displays. Also, for most of the displays (41/53, 77%), [Formula: see text] was under the diagnostic acceptable level. Ambient ratios exceeded the acceptable limit in 31 of 53 (58%) displays. Luminance ratios, on the other hand, were within acceptable levels for the majority of displays (38/53, 72%). All devices passed the AAPM requirement for luminance uniformity (MLD). The results indicate that the maximum luminance and minimum luminance of most displays are not sufficient. AAPM, the Society for Imaging Informatics in Medicine and the American College of Radiology introduced the updated luminance [Formula: see text] and [Formula: see text] criteria in 2012. All ultrasound displays should at least fulfill the AAPM TG18 secondary display minimum criteria. Even so, 6 of 53 (11%) fail. The newest displays should be expected to fulfill the revised AAPM TG270 criteria as well. Display technology has developed, and therefore, monitor testing needs to be updated.

Paper] Reduction of Crosstalk in Time-Division Multiplexing Parallax Barrier with Low Power Consumption

This paper proposes a method to reduce stereoscopic crosstalk in time-division multiplexing parallax barrier system with reduced power consumption, where a fine slit pattern is generated by projecting LED striped light bars through a lenticular lens. When LEDs and a lenticular lens are used to generate a slit pattern, crosstalk level becomes higher than that of the system using a pair of LCD panels because the LED backlight does not fully synchronize with the update of image in the LCD panel. To overcome this problem, the lighting time of LED light bars is shortened, which enables reduction of crosstalk without lowering the ratio of luminance to power consumption.

Relationship between the gaze point movement and spatial brightness

This study aims to verify the relationship between the spatial brightness evaluation and average luminance on a moving gaze point tracking by targeting offices with different luminance distributions. Subjects wearing eye-tracking devices evaluate the spatial brightness of the various light environments displayed on a large screen display. In the results, the tendency for gazing at the window is found to be high as compared to the other parts. The average luminance is calculated by integrating the time on the path of the moving gaze point. Furthermore, we analyse the relationship between the average luminance of each part of the light environment on the display and the brightness evaluation value. The average luminance considering the movement of the gaze point at the time of brightness evaluation has higher explanatory power,0.305, for the spatial brightness than the average luminance,0.259, in the entire visual field area. In contrast, the explanatory power of brightness evaluation was not improved drastically, even considering the gazing time and luminance. In future, the relationship between the evaluation of the spatial brightness and the gaze point/gaze time can be analysed by considering the absolute value of the luminance of the window surface and the luminance ratio with the surroundings.

Estimating Sheet Flow Velocities Using Quinine as a Fluorescent Tracer: Bare, Mulched, Vegetated and Paved Surfaces

When direct flow velocity measurements are not feasible, the use of tracers can be a valuable tool. In the present study, both laboratory and field experiments were conducted to evaluate the applicability of quinine as a fluorescent tracer for estimating mean sheet flow velocities in different ambient light and surface morphology conditions. Quinine excels in low-light conditions when exposed to UVA light. This tracer was compared with dye and thermal tracers, all in liquid form. In these tracing techniques the tracers were injected into the flow, after which surface velocity was estimated by tracking the leading edge of the tracer plumes and applying a correction factor to calculate the mean velocity (in a water column). The visibility of the tracers was evaluated by measuring the relative luminance and contrast ratio of the quinine and dye tracer plumes. Results show that the quinine tracer can be used to estimate sheet flow velocities over a wide variety of soil and urban surfaces; it has better visibility in comparison to the dye tracer but, in some conditions, lower visibility than the thermal tracer. Although quinine is invisible under bright ambient light conditions, this tracer technique requires low-cost experimental setup and is useful in low-light conditions (e.g., night; twilight; shielded environments).

Sporters' visual comfort assessment in gymnasium based on subjective evaluation & objective physiological response

Visual comfort is affected by the light environment of interior spaces. However, relatively few studies have combined subjective and objective indicators of visual comfort in the assessment of indoor sport facilities. Thus, the purpose of this was to determine the factors influencing visual comfort and establish corresponding thresholds by combining subjective evaluation, objective physiological indicators, and photometric light environment assessment. The experiment was conducted at a university gymnasium in Harbin, located in the northeast of China, during summer, autumn, and winter. The visual comfort of the participants was assessed via subjective evaluation via questionnaires, and objective physiological indicators were recorded using biosensors. Additionally, high-dynamic-range images were used to assess the light environment. Subjective evaluation revealed that visual comfort was affected by the glare intensity, target clarity, and emotional state. Objective physiological indicators showed that emotional arousal and alertness were higher in autumn and winter than in summer. Furthermore, the physiological indicators and subjective evaluation of visual comfort were highly consistent with each other. In summer, acceptable ranges of the luminance ratio of the window area to the field of view were less than 5 and greater than 10, and comfortable ranges were less than 3 and greater than 12. In winter, the upper acceptable and comfortable thresholds were 42 and 13, respectively. This study provides a reference point for optimizing gymnasium light environment design.