Multispectral Simulation Research Articles

The Necessity for Multi-Spectral Simulations of the Indoor Non-Visual Luminous Environment: A Simplified Annual Approach

The difference between the functioning of the human non-visual and photopic systems has elicited the need for complex in situ measurements or time-consuming multi-spectral simulations to accurately predict the non-visual luminous content of the indoor environment. As such methodologies are time-consuming, the aim of the present study was to determine whether such complex methodologies are needed. The issue was studied through simulations of four cardinally oriented identical offices located in Ljubljana, Slovenia. Each was studied using orange, grey and blue walls. Diurnal luminous conditions were studied under clear, hazy and overcast skies on December, March and June 21st. The non-visual content was evaluated using novel metrics, the Autonomy of Circadian Potential and Circadian Autonomy, which assess temporal circadian luminous content. Diurnal results were used to construct climate-based spectral months to evaluate the monthly non-visual potential of the studied offices. Furthermore, simulations addressed the question of whether the requirements of the non-visual system might contradict the visual comfort of indoor environments. The results show that compliance with non-visual requirements for indoor spaces with spectrally neutral surfaces or those in shades of blue could be assessed using photopic methodologies. However, this is not true for spaces characterised by orange and red materials.

Modeling and simulation of multispectral imaging through anisoplanatic atmospheric optical turbulence

We explore the modeling and simulation of multispectral imaging through anisoplanatic atmospheric optical turbulence. We analyze the impact of wavelength on a number of key atmospheric optical turbulence statistics. This includes the impact of wavelength on tilt and tilt variance. The modeling analysis also includes the impact of wavelength on the atmospheric optical transfer function. Here, we investigate the balance between diffraction and turbulence degradation as a function of wavelength. We also present a method for simulating atmospheric degradation for multispectral imagery using numerical wave propagation. Our approach uses a phase screen resampling method to allow for modeling the same atmospheric realization but with sampling parameters tailored to each wavelength. A number of multispectral simulation results, along with a validation study that compares the empirical statistics from the simulation to their theoretical counterparts, are presented. Real image data are also studied to validate theoretical multispectral tilt statistics.

Neural Network Generalization: The Impact of Camera Parameters

We quantify the generalization of a convolutional neural network (CNN) trained to identify cars. First, we perform a series of experiments to train the network using one image dataset - either synthetic or from a camera - and then test on a different image dataset. We show that generalization between images obtained with different cameras is roughly the same as generalization between images from a camera and ray-traced multispectral synthetic images. Second, we use ISETAuto, a soft prototyping tool that creates ray-traced multispectral simulations of camera images, to simulate sensor images with a range of pixel sizes, color filters, acquisition and post-acquisition processing. These experiments reveal how variations in specific camera parameters and image processing operations impact CNN generalization. We find that (a) pixel size impacts generalization, (b) demosaicking substantially impacts performance and generalization for shallow (8-bit) bit-depths but not deeper ones (10-bit), and (c) the network performs well using raw (not demosaicked) sensor data for 10-bit pixels.

Interaction Between Fulvic Acid and Pepsin Investigated by Multispectral and Molecular Docking Simulation

Interaction Between Fulvic Acid and Pepsin Investigated by Multispectral and Molecular Docking Simulation

Study on the binding characteristics of hydroxylated polybrominated diphenyl ethers and thyroid transporters using the multispectral technique and computational simulation

Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) are a class of toxic environmental pollutants that are persistent, bioaccumulative, and difficult to degrade. Their structure is very similar to the thyroid hormone (T4) and uses the body’s thyroid transporter (TTR) binding to interfere with the endocrine balance, disrupting the body’s normal physiological activity. According to Fourier transform infrared spectroscopy and dynamics simulation of do_dssp module analysis, there are three kinds of OH-PBDEs that can induce TTR secondary structural changes. Fluorescence spectra and UV–Vis spectra show that for the three kinds of OH-PBDEs for TTR, the main methods of quenching are static quenching and non-radiative energy transfer. According to thermodynamic analysis, ΔG < 0, ΔH > 0, and ΔS > 0 combine to show that the hydrophobic interaction is the main driving force of the combination. From the molecular docking analysis, it was found that 4′-hydroxy-2,2′,4,5′- tetrabromodiphenyl ether (4′-OH-BDE49) and 4 hydroxy-2,2′,3,4′,5,6,6′- heptabromodiphenyl ether (4-OH-BDE188) had a cationic–π interaction with TTR, whereas 4 hydroxy-2,2′,3,4,5,5′,6- heptabromodiphenyl ether (4-OH-BDE187) was bonded to TTR by hydrogen bonds to form stable complexes. In this paper, we highlight the consistency of spectroscopic experiments and computer simulations so as to provide a reliable analytical method for the toxicological properties of small molecule contaminants.

Method of multispectral simulation of the radiation of point objects

This paper discusses a method of simulating the spectral composition of the optical radiation of a point source, which is used when optoelectronic devices that operate with the radiation of remote objects undergo energy testing in the laboratory. The layout and the characteristics of the point-source radiation simulator are presented.