8 results about "Optical absorption coefficient" patented technology

The invention belongs to the technical field of laser processing numerical simulation, and discloses a random forest model laser absorption coefficient efficient prediction method based on factor analysis, and a laser absorption coefficient data set comprises four parameters of laser power density, a forming coefficient, conductivity and thermal diffusivity. According to the method, multiple factors influencing the laser absorption coefficient in laser processing are comprehensively considered, the dimensionality of a data set is reduced, the feature correlation between data is low, and a high-quality training set is provided for subsequent training of a random forest model. Multiple Gaussian distribution linear mixing probability distributions are generated through a Gaussian mixture model to describe original data, new samples are generated through random sampling to form an incremental data set, the training effect of the random forest model is improved, and the over-fitting condition is avoided; through factor analysis, features with strong correlation are divided into one group, generation of a weak decision tree is avoided, the accuracy and convergence speed of the model are improved, and an efficient model training mode is realized.

The invention relates to the technical field of atmospheric remote sensing monitoring, discloses a hyperspectral atmospheric methane concentration inversion method and system for a high-aerosol scene, and solves the problems of low inversion precision and poor adaptability of a hyperspectral imager in a high-aerosol heterogeneous earth surface in an existing method. The method comprises the following steps: acquiring and processing atmospheric parameters and multiband surface albedo data, and constructing a radiation transmission model to output a forward simulation vector; based on CLARS-GFIT, constructing an optical absorption coefficient lookup table of methane and interference gas containing different temperatures and pressures; correcting the forward simulation model by using GIFT3 to quantify the aerosol influence, and generating a forward simulation spectrum in combination with a spectral response function; and adjusting the state variable to converge through an iterative maximum posteriori algorithm to obtain the methane concentration. The method improves the inversion precision of a high aerosol scene, adapts to heterogeneous earth surfaces such as a coal mine area, matches AHSI characteristics, gives consideration to efficiency, and can provide support for methane point source monitoring.

The invention belongs to the field of biomedical photonics, photoacoustic imaging and deep learning, and provides an optical absorption coefficient resolving system and method based on photoacoustic imaging and a non-training network, and the method comprises the steps: taking physically-driven Monte Carlo simulation as an optical forward model, and embedding the optical forward model into a neural network frame which does not need to be trained in advance, direct and high-precision inversion from a single initial sound pressure distribution image to optical absorption coefficient distribution is realized through a self-constraint resolving process.

Provided is an optical absorption coefficient calculation technique capable of calculating an optical absorption coefficient of any part of an object at high speed. An optical absorption coefficient calculation device A includes a global coordinate transform operator determination unit 3 that determines a global coordinate transform operator for transforming a specific coordinate in a specific region into a global coordinate value, a rotational transform operator determination unit 4 that determines a rotational transform operator for transforming the global coordinate value into a coordinate after relative rotation, a detector coordinate value determination unit 5 that determines a detector coordinate value based on a coordinate acquired by applying the global coordinate transform operator and the rotational transform operator to the specific coordinate, a convolution operation unit 6 that performs convolution operation with a filter function on transmission projection data, and an integration unit 7 that calculates the optical absorption coefficient of the specific coordinate by acquiring a calculated value of the convolution operation calculated based on the transmission projection data of the detector coordinate value for each rotation angle and accumulating the calculated value.

The present application belongs to the technical field of deep learning, and particularly relates to a two-stage blind image defogging method based on priori guiding diffusion, aiming at solving the distortion problem of traditional defogging methods in complex scenes. The method comprises constructing a two-stage blind image defogging model, which comprises a first stage and a second stage. The first stage is based on an improved atmospheric scattering model for physical modeling, and the improved atmospheric scattering model is an enhanced atmospheric scattering model with the introduction of an optical absorption coefficient. The first stage outputs a transmission map, a haze-free reference image and an atmospheric light parameter. The second stage is based on a diffusion model for generation optimization. The transmission map, the haze-free reference image and the atmospheric light parameter output by the first stage are used as physical priors to be integrated into the generation process of the diffusion model for image defogging. In the second stage, an adaptive difference fusion convolution is set, a fog domain multi-source fusion attention mechanism is set, and a pixel-level and wavelet domain dual-effect color correction strategy is adopted.

The invention particularly relates to a tissue multi-chromophore in-vivo quantitative imaging method based on a probability generation model. The tissue multi-chromophore in-vivo quantitative imaging method comprises the following steps: acquiring a multi-wavelength photoacoustic initial sound pressure reconstruction diagram of a target biological tissue area; blind unmixing processing is carried out on the multi-wavelength photoacoustic initial sound pressure reconstruction diagram, and spectral characteristics and concentration distribution of all chromophores in the target biological tissue are initialized; converting the multi-wavelength photoacoustic initial sound pressure reconstruction diagram into a logarithmic multi-wavelength photoacoustic initial sound pressure reconstruction diagram through an LOG logarithmic decoupling method; constructing a probability generation model based on a variational auto-encoder, inputting the logarithmic multi-wavelength photoacoustic initial sound pressure reconstruction diagram and the initialized spectral characteristics and concentration distribution into the probability generation model based on the variational auto-encoder, solving a new light absorption coefficient matrix, reconstructing a logarithmic multi-wavelength photoacoustic initial sound pressure reconstruction diagram by the light absorption coefficient matrix, and obtaining a logarithmic multi-wavelength photoacoustic initial sound pressure reconstruction diagram. And thus, the chromophore in-vivo spectrum and concentration image output by the model are constrained. And the precision and robustness of structure distinguishing in the complex biological tissue are improved.

The embodiments of the present invention disclose a method, system, device and electronic apparatus for measuring concentration of water and lipids components. The method includes acquiring an optical absorption coefficient of a sample to be measured irradiated by a light source of at least two wavelengths, wherein a wavelength of the light source of at least two wavelengths is not greater than 1000 nm; and acquiring an extinction coefficient of water irradiated by the light source of at least two wavelengths and an extinction coefficient of lipids irradiated by the light source of at least two wavelengths; determining a concentration of water in the sample to be measured and a concentration of lipids in the sample to be measured, respectively, based on the optical absorption coefficient of the sample to be measured irradiated by the light source of at least two wavelengths, the extinction coefficient of water irradiated by the light source of at least two wavelengths, and the extinction coefficient of lipids irradiated by the light source of at least two wavelengths.

A system for in-situ monitoring of optical element health in a laser apparatus comprises direct measurement of optical element temperature and recording a history of variations of the optical element temperature during successive periods of irradiation and non-irradiation. The direct measurement may be achieved by a thermocouple inserted into the laser system and pace di contact with the optical element. The history of temperature variations may be used to calculate as trajectory of the change in optical absorption coefficient, which may be used to predict the remaining lifetime of the optical element and schedule service event.