Light Distribution Model Research Articles

Light Distribution Models for Tree Growth Simulation

AbstractThe simulation and modelling of tree growth is a complex subject with a long history and an important area of research in both computer graphics and botany. For more than 50 years, new approaches to this topic have been presented frequently, including several aspects to increase realism. To further improve these achievements, we present a compact and robust functional‐structural plant model (FSPM) that is consistent with botanical rules. While we show several extensions to typical approaches, we focus mainly on the distribution of light as a resource in three‐dimensional space. We therefore present four different light distribution models based on ray tracing, space colonization, voxel‐based approaches and bounding volumes. By simulating individual light sources, we were able to create a more specified scene setup for plant simulation than it has been presented in the past. By taking into account such a more accurate distribution of light in the environment, this technique is capable of modelling realistic and diverse tree models.

Tubular photobioreactor design based on mixing intensity

A novel design methodology for tubular photobioreactors (TPBRs) for the mass culture of microalgae that can account for mixing intensity is presented. To date, TPBRs have been mainly designed and operated under the assumption of perfect mixing with regard to photosynthesis performance (light integration regime). In this work we show that this simplification has been leads to significant errors in the prediction of the optimal dilution rate and biomass productivity. To this end, computational fluid dynamics and light distribution model have been employed to calculate the trajectories and light histories I(t) of a microalgal cell population represented by 50 particles of 5 μm diameter. The density of the microalgal cells was set at 1000 kg m−3 and the tube diameters (D) were 14, 24, 44, 64 and 84 mm, with the circulation velocities (v) ranging from 0.4 to 1 m s-1. This has been coupled to a dynamic photosynthesis model in order to calculate the average photosynthetic response and hence the integration factors in TPBRs. It has been demonstrated that for a generic microalgal strain, the use of the light integration simplification (Γ = 1) would result in the prediction of an optimal dilution rate of 0.0315 h−1 (for D = 14 mm and v = 0.4 m/s as an example), which would lead to an actual biomass productivity of 182.5 g biomass m−3h−1 if the predicted integration factor (Γ = 0.578) is used whereas the newly proposed method predicts an optimal dilution rate of 0.0125 h−1 and a biomass productivity of 362.3 g biomass m−3h−1. This demonstrates that simplifying the light integration regime is inadequate for TPBRs design and operation, resulting in significant inaccuracies. The estimation charts and regressions proposed in this work to estimate actual integration factors will enable the development of an optimization method for TPBRs based on mixing intensity.

Application of smart grid and non-dominated sorting genetic algorithm in adaptive energy-saving control of building lighting

Introduction: In the wave of urbanization, the increase of public lighting equipment in buildings has brought about more prominent problems of energy saving and consumption reduction.Methods: In order to solve the above problems, this paper designs a set of intelligent lighting solutions for digital buildings by combining the smart grid and non-dominant sorting genetic algorithms. Firstly, an intelligent lighting monitoring solution is constructed through ZigBee ad hoc network and sensor technology to monitor the relevant environment and lighting control of the laboratory building. Secondly, this paper uses the DIALux software network to build a public lighting light distributiona public lighting light distribution model in the building, and deeply studies the dimming control strategy of the system under the principle of making full use of sunlight and natural light.Results: The purpose ofself-adaptive intelligent control of desktop illuminance, finally using this scheme to achieve the optimal balance of desktop lighting.Discussion: The simulation experiment counts the power data of the intelligent lighting system under different weather conditions. The experimental results verify that the intelligent lighting control scheme can effectively reduce the output luminous flux of the lamps, thereby reducing power consumption.

Modeling and ex vivo experimental validation of liver tissue carbonization with laser ablation

ObjectiveThe purpose of this study was to model the process of liver tissue carbonization with laser ablation (LA). MethodsA dynamic heat source model was proposed and combined with the light distribution model as well as bioheat transfer model to predict the development of tissue carbonization with laser ablation (LA) using an ex vivo porcine liver tissue model. An ex vivo laser ablation experiment with porcine liver tissues using a custom-made 1064 nm bare fiber was then used to verify the simulation results at 3, 5, and 7 W laser administrations for 5 min. The spatiotemporal temperature distribution was monitored by measuring the temperature changes at three points close the fiber during LA. Both the experiment and simulation of the temperature, tissue carbonization zone, and ablation zone were then compared. ResultsFour stages were recognized in the development of liver tissue carbonization during LA. The growth of the carbonization zone along the fiber axial and radial directions were different in the four stages. The carbonization zone along the fiber axial direction (L2) grew in the four stages with a sharp increase in the initial period and a minor increase in Stage 4. However, the change in the carbonization zone along the fiber radial direction (D2) increased dramatically (Stage 1) to a long-time plateau (Stages 2 and 3) followed by a slow growth in Stage 4. An acceptable agreement between the computer simulation and ex vivo experiment in the temperature changes at the three points was found at all three testing laser administrations. A similar result was also obtained for the dimensions of coagulation zone and ablation zone between the computer simulation and ex vivo experiment (carbonization zone: 2.99± 0.10 vs. 2.78 mm2, 67.39± 0.09 vs. 63.53 mm2, and 90.53± 0.11 vs. 85.15 mm2; ablation zone: 68.95± 0.28 vs. 65.29 mm2, 182.11± 0.24 vs. 213.81 mm2, and 244.80± 0.06 vs. 251.79 mm2 at 3, 5, and 7 W, respectively). ConclusionThis study demonstrates that the proposed dynamic heat source model combined with the light distribution model as well as bioheat transfer model can predict the development of liver tissue carbonization with an acceptable accuracy. This study contributes to an improved understanding of the LA process in the treatment of liver tumors.

Application of Forced Modulation Function Mathematical Model in the Characteristic Research of Reflective Intensity Fibre Sensors

Abstract In order to discuss the application and mode of the forced modulation function in a sensor, the optical fibre emphasis function was established by referring to the geometric method, the tilt factor and the shape factor of the reflecting surface. These were introduced for the first time, and the corresponding mathematical model was established. The method of numerical simulation is systematically studied and multimode optical fibre parameters (including optical fibre of axial spacing, optical fibre core diameter and numerical aperture) are adopted. The reflective surface inclination and shape factors on the RIM–FOS intensity modulation characteristics are studied according to the obtained light quasi-Gaussian distribution model, establishing a general three-intensity modulation function of fibre optic sensor. The results show that the intensity modulation characteristic of specular reflection is obviously better than that of the diffuse reflection surface, and the peak value of the modulation function is five times that of diffuse reflection. The intensity modulation characteristic decreases with increase in the roughness of the reflection surface. The system can not only complete the RIM–FOS characteristic simulation and characteristic testing functions, but can also start-up the test and not be affected by the ambient light interference and power fluctuation of the light source. The test stability is good with high repeatability.

Assessment of light distribution model for marine red microalga Porphyridium purpureum for sustainable production in photobioreactor

Microalgae can accumulate large amounts of nutrients from sustainable elements cycling and wastewater reuse. Light is a key factor determining productivity of algal biomass when recycling. However, light is unevenly distributed in photobioreactors due to light absorption and scatter by algal cells. Understanding the laws of light distribution is needed for optimizing the culture process. In this study, a light distribution model for red alga Porphyridium purpureum was used to optimize the cultivation process and improve culture performance by controlling light intensity. Compared to the Lambert-Beer model, the Hyperbolic law is more flexible and is applicable in a larger range of cell densities. In addition, the content of intracellular phycobiliprotein has a great influence on light distribution inside the photobioreactor while a higher biomass concentration reduces its impact. A maximum biomass concentration of 24.7 g/L along with 1.2 g/L/d cell growth rate was achieved by increasing incident light intensity in a stepwise fashion. The overall light conditions inside the photobioreactor during the culture process was also analyzed and discussed based on light distribution models. A volume-averaged light intensity regulated at ~50 μmol/m2/s along with an incident light intensity of less than 540 μmol/m2/s is an appropriate light condition for Porphyridium purpureum culture. The outcomes of light distribution model assessment and stepwise fashion regulation strategy can be applied to red microalgae in general, especially for high cell density cultivation. These findings provide an essential base for culture optimization, which can be used in future industrial applications of P. purpureum for water clean and sustainability of human nourishment production.

Comparison of actual and simulated tumoricidal effects induced by photodynamic therapy.

Numerous studies employ mathematical methods, such as Monte Carlo simulation, to predict the tumor killing effects of photodynamic therapy (PDT) by simulating optical propagation, photosensitizer distribution, and oxygen distribution. Whether these models faithfully reflect tumor killing is unknown, and model validation using tumor cross sections in these studies is usually insufficient to answer this question. To fill this gap in our knowledge, we employed a mouse model of breast cancer to determine the spatiotemporal effects of PDT using direct histopathological and biochemical analyses of whole tumors. We prepared approximately 700 5-μm-thick serial sections of breast tumors of syngeneic mice treated with PDT employing the photosensitizer photocarcinorin (PsD-007, a second-generation photosensitizer developed in China). Three adjoining sections were subjected to hematoxylin and eosin staining to assess necrosis, the TUNEL assay to evaluate apoptosis, and CD31 staining to detect angiogenesis, respectively. We then generated a three-dimensional (3D) reconstruction of the tumor to evaluate these processes. We simultaneously used the Monte Carlo method to develop a model of light distribution throughout the tumor to evaluate the actual and simulated tumor killing effects induced by PDT. Tumor necrosis decreased exponentially as a function of distance from the source of illumination, while the distributions of apoptosis and neovascularization were independent of light distribution. Most apoptosis occurred in the lower layers (3000-4000 μm) of the tumor where the light intensity was too low to excite the photosensitizer. Neovascularization occurred at depths ranging from 2500 to 3500 μm. These analyses provided a 3D view of how a tumor is destroyed using PDT. Although the optical distribution model predicted tumor necrosis caused by PDT, it was ineffective in predicting the sites of apoptosis and vascular destruction. Mathematical modeling is limited in its capabilities required to gain a comprehensive understanding of the spatiotemporal events associated with PDT. The mouse model developed here will serve as a platform for detailed direct histopathological, biochemical, and molecular genetic analyses of the effects of PDT, which will facilitate the development of optimized treatment strategies.

Analysis and research on the processing threshold of femtosecond laser

In this work, the intensity distribution formula of the focused femtosecond (fs) laser beam is derived. MATLAB was used to establish the light intensity distribution model of the focused fs laser under the processing condition, and the light intensity of focused fs laser under different laser power was simulated. Then the fs laser processing platform was built. The glass was etched by fs laser, and the SU-8 photoresist was processed by fs laser two-photon polymerization (2PP). By adjusting the change of laser power, the etching and polymerization lines of different sizes are obtained. Based on the simulation results and experimental results, the estimated etching threshold of the glass using the fs laser is 5.096 6×1016 W/m2, and the estimated processing threshold of SU-8 photoresist by 2PP using the fs laser is 1.194 2×1014 W/m2. This work is helpful to further analyze the applications of fs laser processing. It provides guidance and reference for different kinds of fs laser processing methods.

Numerical and experimental analysis of optimized conical flask photobioreactor structures to improve liquid–gas two-phase distribution and microalgae carbon sequestration

In this paper, light intensity and gas–liquid distribution of microalgae in the original conical flask photobioreactor with central inlet tube bubbling ventilation are studied by applying both numerical simulation and experimental analysis. The different optimized structures of conical flask photobioreactors are proposed to improve light distribution and microalgae carbon fixation. The advanced effects of light intensity and gas–liquid distribution in advanced conical flask reactors are validation by 5 important parameters. First, the Eulerian gas–liquid two-phase model and DO (Discrete Ordinate) light distribution model of the conical flask reactor are developed. Gas distribution and light distribution are analyzed with different conditions of gas inlet velocity. Second, the optimal gas inlet velocity is evaluated with five vital parameters (average velocity, turbulent kinetic energy, gas holdup rate, average light intensity and velocity of the vertical wall). Then, the optimal CO2 gas inlet concentration is determined by a series of controlled experiment test groups. Finally, based on the numerical simulation and experiment result, three different optimized structures of conical flasks are proposed to prove the effectiveness of optimization, which is named lean-insertion bottle, baffle bottle and cross-nozzle bottle. The results showed that 0.5 m·s−1 gas inlet velocity is the optimal value for the gas–liquid distribution in the 500 ml conical flask reactor. With the increase of CO2 concentration, the growth rate of microalgae biomass concentration increased first and then decreased after the concentration arrives at 4%. At 4% CO2 gas inlet concentration, the highest biomass concentration is increased by 57.4% compared with the lowest ones. The gas distribution and light distribution in the three optimized reactors are significantly improved, and among the three optimizations, the PBR with baffle at 0 mm of the gas inlet pipe is the best one. In conclusion, the cultivation condition of microalgae and the structure of algae photobioreactors are both optimized providing a novel beneficial reference to improve the liquid–gas distribution and carbon sequestration rate of microalgae growth in the laboratory.

Morphology and surface photometry of a sample of isolated early-type galaxies from deep imaging

Context. Isolated early-type galaxies are evolving in unusually poor environments for this morphological family, which is typical of cluster inhabitants. We investigate the mechanisms driving the evolution of these galaxies. Aims. Several studies indicate that interactions, accretions, and merging episodes leave their signature on the galaxy structure, from the nucleus down to the faint outskirts. We focus on revealing such signatures, if any, in a sample of isolated early-type galaxies, and we quantitatively revise their galaxy classification. Methods. We observed 20 (out of 104) isolated early-type galaxies, selected from the AMIGA catalog, with the 4KCCD camera at the Vatican Advanced Technology Telescope in the Sloan Digital Sky Survey g and r bands. These are the deepest observations of a sample of isolated early-type galaxies so far: on average, the light profiles reach μg ≈ 28.11 ± 0.70 mag arcsec−2 and μr ≈ 27.36 ± 0.68 mag arcsec−2. The analysis was performed using the AIDA package, providing point spread function-corrected 2D surface photometry up to the galaxy outskirts. The package provides a model of the 2D galaxy light distribution, which after model subtraction enhances the fine and peculiar structures in the residual image of the galaxies. Results. Our re-classification suggests that the sample is composed of bona fide early-type galaxies spanning from ellipticals to late-S0s galaxies. Most of the surface brightness profiles are best fitted with a bulge plus disc model, suggesting the presence of an underlying disc structure. The residuals obtained after the model subtraction show the nearly ubiquitous presence of fine structures, such as shells, stellar fans, rings, and tails. Shell systems are revealed in about 60% of these galaxies. Conclusions. Because interaction, accretion, and merging events are widely interpreted as the origin of the fans, ripples, shells and tails in galaxies, we suggest that most of these isolated early-type galaxies have experienced such events. Because they are isolated (after 2–3 Gyr), these galaxies are the cleanest environment in which to study phenomena connected with events like these.

On the Development of a Light Dosimetry Planning Tool for Photodynamic Therapy in Arbitrary Shaped Cavities: Initial Results.

Previous dosimetric studies during photodynamic therapy (PDT) of superficial lesions within a cavity such as the nasopharynx, demonstrated significant intra- and interpatient variations in fluence rate build-up as a result of tissue surface re-emitted and reflected photons, which depends on the optical properties. This scattering effect affects the response to PDT. Recently, a meta-tetra(hydroxyphenyl)chlorin-mediated PDT study of malignancies in the paranasal sinuses after salvage surgery was initiated. These geometries are complex in shape, with spatially varying optical properties. Therefore, preplanning and in vivo dosimetry is required to ensure an effective fluence delivered to the tumor. For this purpose, two 3D light distribution models were developed: first, a simple empirical model that directly calculates the fluence rate at the cavity surface using a simple linear function that includes the scatter contribution as function of the light source to surface distance. And second, an analytical model based on Lambert's cosine law assuming a global diffuse reflectance constant. The models were evaluated by means of three 3D printed optical phantoms and one porcine tissue phantom. Predictive fluence rate distributions of both models are within±20% accurate and have the potential to determine the optimal source location and light source output power settings.

Simulation of shading and algal growth in experimental raceways

Many algae research groups use elevated experimental raceways to characterize algal biomass productivity. Side walls and a relatively large paddlewheel shade the culture and lower productivity, particularly in winter and with low culture depth. This paper presents a four-step method to calculate shading for a given raceway shape: (1) develop a computational mesh of the inner surface geometry of the raceway; (2) offset the mesh horizontally in the x and y directions on the water surface as a function of wall height, solar zenith angle, and solar azimuth angle; (3) calculate the shaded area for each projected mesh with the shoelace algorithm; (4) use regression to develop a response surface for shaded area as a function of horizontal x and y offset. For each time step, the shaded area is calculated with the regression equation based on the x and y offset at that time step. The shading model was added to the Huesemann Algae Biomass Growth (HABG) model. In the model, productivity was sensitive to the assumed light distribution below the water surface. Shading and light distribution models were evaluated with biomass concentrations from three Regional Algal Feedstock Testbed (RAFT) experiments with three different species of algae. Averaging light in each layer resulted in higher calculated growth rate than calculating growth separately in shaded and unshaded areas. The Local Photon Flux Density Variable Light (LPFD_V) shading algorithm reduced the HABG estimate of productivity and improved the agreement with observed productivities. The LPFD_V RMSD values ranged between 0.01 and 0.07 g L−1 and the bias factors ranged between 0.9 and 1.1. Shaded area was sensitive to raceway orientation, water depth, and time of year. A north-south raceway orientation had less average shading in winter but more average shading in summer than an east-west orientation.

γ-Ray position reconstruction in large monolithic LaCl3(Ce) crystals with SiPM readout

We report on the spatial response characterization of large LaCl$_{3}$(Ce) monolithic crystals optically coupled to 8$\times$8 pixel silicon photomultiplier (SiPM) sensors. A systematic study has been carried out for 511 keV $\gamma$-rays using three different crystal thicknesses of 10 mm, 20 mm and 30 mm, all of them with planar geometry and a base size of 50$\times$50 mm$^2$. In this work we investigate and compare two different approaches for the determination of the main $\gamma$-ray hit location. On one hand, methods based on the fit of an analytical model for the scintillation light distribution provide the best results in terms of linearity and field of view, with spatial resolutions close to $\sim$1 mm FWHM. On the other hand, position reconstruction techniques based on neural networks provide similar linearity and field-of-view, becoming the attainable spatial resolution $\sim$3 mm FWHM. For the third space coordinate $z$ or depth-of-interaction we have implemented an inverse linear calibration approach based on the cross-section of the measured scintillation-light distribution at a certain height. The detectors characterized in this work are intended for the development of so-called Total Energy Detectors with Compton imaging capability (i-TED), aimed at enhanced sensitivity and selectivity measurements of neutron capture cross sections via the time-of-flight (TOF) technique.

Optimal greenhouse lighting scheduling using canopy light distribution model: A simulation study on tomatoes

Light is considered the most important environmental factor for greenhouse crops, and lack of lighting limits the productivity of greenhouses. Many studies have focused on improving the energy efficiency of lighting in agriculture. In this study, LED lights were mounted in the top, middle and bottom of the plant canopy to provide additional photosynthetically active radiation. Assuming that 100% of the predicted outdoor radiation is available, the canopy light distribution model was used to determine the relationship between the light energy consumption and the optimal yield. Decision-making on lighting scheduling may be considered as a constrained optimisation, and the status of the LEDs in a period acts as the decision variable. Besides, there are two objective functions: one is the energy consumed by the LED device; the other is the expected yield calculated by the crop model of tomatoes. The optimal solution of the multi-objective optimisation is not unique but corresponds to an infinite number of yield/energy combinations. Farmers can select these combinations according to additional restrictions such as energy efficiency ratio or photoperiod. The yield of our strategy was increased by 12.3% under the constraint of equal energy consumption compared to the greenhouse threshold control strategy. Given the same output as the constraint, the energy consumption was reduced by 30.1%.

Development and Optimization of an Immobilized Photocatalytic System within a Stacked Frame Photoreactor (SFPR) Using Light Distribution and Fluid Mixing Simulation Coupled with Experimental Validation

Recently, photocatalytic reactors have been designed with a view toward overcoming mass transfer limitations especially in systems with immobilized catalysts. This paper reports the design of a titanium “bladed” propeller with TiO2 immobilized on the blades. To evaluate the propeller efficiency, modeling using COMSOL Multiphysics was validated experimentally using coumarin as a probe molecule allowing for OH radical quantification. Modeling of light distribution and catalyst irradiance at varying irradiation distance was performed using ray optics, which, alongside experimental work, showed that irradiation at 4 and 5 cm from the propeller yielded the highest irradiance (29.3 and 22.1 mW/cm2) and OH radical concentrations (5.38 and 5.56 μM, respectively). Propeller rotation was modeled and compared against experimental data to assess mass transfer limitations at varying rotation speeds. This showed that 300 rpm provided the highest rate of coumarin degradation (0.32 μM/min) despite the model showing higher fluid velocities at 400 rpm.

Accurate and Robust Synchronous Extraction Algorithm for Star Centroid and Nearby Celestial Body Edge

Celestial body features are important navigation information in deep space exploration. This study provides a synchronous high-precision extraction algorithm for star centroid and nearby celestial body edges for a miniaturized independent optical navigation sensor, which combines the functions of a star tracker and a navigation camera. The image is filtered by a ring filter template to eliminate the interference information of background and improve the contrast between the target and the background. The second-order directional derivative and specific area characteristic method aim to roughly extract and distinguish the features (star centroid and the nearby celestial body edge). In local area template where feature points are located, the 1D energy deviation effect is proposed to extract the features of the two different light intensity distribution models. The accuracy and robustness of our algorithm are verified by simulation and ground-based experiments. The algorithm has certain reference significance for other types of dim target and edge detections, such as infrared detection, medical image, target measurement, and machine vision.

Led Light Computer Simulation and Design on Solar Battery

The article considered the features of architectural lighting and lighting devices. They analyzed the requirements for architectural luminaires and their features, solar elements, their operation principle and design. They described the developed luminaire, its design and light sources and the device electronic elements. The modeling of lamp light distribution and illumination is car-ried out.

Investigation on models for light distribution of Haematococcus pluvialis during astaxanthin accumulation stage with an application case

Light is an important stress factor for astaxanthin accumulation in H. pluvialis. Hence, the light distribution in the H. pluvialis suspension was investigated with biomass concentration from 0.218 g/L to 2.5 g/L during the astaxanthin accumulation stage. Lambert-Beer model and Cornet model were employed to predict the light attenuation. The result showed that Cornet model could slightly better describe and predict the light distribution in H. pluvialis suspension. Besides, Ea (absorption coefficient) and Es (scattering coefficient) were determined as 0.0126 ± 0.0036 m2/g and 0.223 ± 0.023 m2/g, respectively. Es increased with respect to astaxanthin content, whereas Ea declined with the increase of astaxanthin content. The astaxanthin content was the dominant factor at a relatively low mass concentration of H. pluvialis suspension. Furthermore, experiments were carried out in a 3 L-bubble-column PBR (photobioreactor) and a 12 L-bubble-column PBR. Higher volume-averaged light intensity and lower shear stress in 3 L PBR led to 66.67% higher astaxanthin content and 34.48% higher mass concentration than those of 12 L PBR during the outdoor experiment, respectively.

Optogenetic Modulation of a Minor Fraction of Parvalbumin-Positive Interneurons Specifically Affects Spatiotemporal Dynamics of Spontaneous and Sensory-Evoked Activity in Mouse Somatosensory Cortex in Vivo.

Parvalbumin (PV) positive interneurons exert strong effects on the neocortical excitatory network, but it remains unclear how they impact the spatiotemporal dynamics of sensory processing in the somatosensory cortex. Here, we characterized the effects of optogenetic inhibition and activation of PV interneurons on spontaneous and sensory-evoked activity in mouse barrel cortex in vivo. Inhibiting PV interneurons led to a broad-spectrum power increase both in spontaneous and sensory-evoked activity. Whisker-evoked responses were significantly increased within 20 ms after stimulus onset during inhibition of PV interneurons, demonstrating high temporal precision of PV-shaped inhibition. Multiunit activity was strongly enhanced in neighboring cortical columns, but not at the site of transduction, supporting a central and highly specific role of PV interneurons in lateral inhibition. Inversely, activating PV interneurons drastically decreased spontaneous and whisker-evoked activity in the principal column and exerted strong lateral inhibition. Histological assessment of transduced cells combined with quantitative modeling of light distribution and spike sorting revealed that only a minor fraction (~10%) of the local PV population comprising no more than a few hundred neurons is optogenetically modulated, mediating the observed prominent and widespread effects on neocortical processing.

Rapid optimization method of the strong stray light elimination for extremely weak light signal detection.

The strong stray light has huge interference on the detection of weak and small optical signals, and is difficult to suppress. In this paper, a miniaturized baffle with angled vanes was proposed and a rapid optimization model of strong light elimination was built, which has better suppression of the stray lights than the conventional vanes and can optimize the positions of the vanes efficiently and accurately. Furthermore, the light energy distribution model was built based on the light projection at a specific angle, and the light propagation models of the vanes and sidewalls were built based on the Lambert scattering, both of which act as the bias of a calculation method of stray light. Moreover, the Monte-Carlo method was employed to realize the Point Source Transmittance (PST) simulation, and the simulation result indicated that it was consistent with the calculation result based on our models, and the PST could be improved by 2-3 times at the small incident angles for the baffle designed by the new method. Meanwhile, the simulation result was verified by laboratory tests, and the new model with derived analytical expressions which can reduce the simulation time significantly.