52 results about "Light field imaging" patented technology

The invention discloses a three-dimensional combustion multi-parameter field inversion method based on two-dimensional infrared imaging and hyperspectral light field imaging, and belongs to the technical field of flame combustion detection. The invention aims to solve the problem of low reconstruction precision caused by limited spontaneous radiation information and poor low-temperature region signal sensitivity in the existing combustion flow field temperature field reconstruction. Comprising the following steps: obtaining a flame two-dimensional infrared temperature distribution image and a flame hyperspectral light field image; a two-dimensional blackbody radiation intensity curve and a three-dimensional blackbody radiation intensity curve are obtained through calibration according to the blackbody radiation law; combining the corresponding image gray values to obtain two-dimensional infrared radiation intensity, three-dimensional visible radiation intensity and three-dimensional infrared radiation intensity; determining a temperature threshold value of the high-temperature area; constructing a multispectral radiation source term matrix equation, and reconstructing a three-dimensional temperature field; obtaining a separated flame hyperspectral light field image, and reconstructing a low-temperature region and a reconstructed temperature field; and combining with a high-temperature region reconstruction temperature field to obtain a whole temperature field. The method is used for three-dimensional combustion multi-parameter field inversion.

The invention discloses a light field microscopic self-supervised denoising system and method fusing a physical process. The system comprises a light field imaging subsystem and a self-supervised denoising subsystem. The light field imaging subsystem is used for capturing multi-view light field original data of a sample; the self-supervised denoising subsystem is used for processing original data of a light field, preprocessing the original data of the light field in a training stage, and decomposing the original data into multi-view sub-images; the method comprises the following steps: constructing original data of a training set through two different self-supervision strategies, and then generating a self-supervision training data pair through RL deconvolution according to a physical optical process; and finally, a denoising model is obtained through 3D neural network training. In the reasoning stage, light field original data to be reconstructed are preprocessed and then subjected to RL deconvolution to generate input data to be denoised, the input data are input into the trained denoising model, and a reconstruction result is output. According to the invention, the problems of noise amplification, data dependence and poor universality of the light field fluorescence microscope are effectively overcome.

The application relates to an improved cage type light field imaging system and a debugging method, and belongs to the technical field of light field imaging. The system comprises a main lens for collecting light spots on an object plane and imaging light emitted by the light spots onto a microlens; the microlens is used for separating the light collected by the main lens into light beams in different directions and imaging the light beams onto a virtual image plane; a relay lens is used for twice imaging the light beams in different directions onto different pixels of a CCD detector of a camera; the relay lens comprises a first lens and a second lens, the focal lengths of the first lens and the second lens are both positive, the focal length of the first lens is smaller than that of the second lens, and the magnification of the relay lens is greater than 1:1. During the debugging process of the system, parallel light beams are arranged in front of the microlens, and the parallel light beams are vertically injected into the microlens to determine the position of the microlens. The system is not affected by the vignetting and distortion generated by the relay lens, and the debugging method improves the positioning accuracy of the microlens.

This application discloses a method and system for synchronous testing of metasurface grating waveguide performance, relating to the field of metasurface grating technology. The method includes polarization state modulation and spatial frequency encoding of multi-wavelength incident beams to obtain a modulated incident light field; coupling this modulated incident light field into the metasurface grating waveguide under test, which then undergoes total internal reflection to form the outgoing light field; acquiring a raw dataset of the entire light field, including Stokes polarization images and spatial spectrum images corresponding to each wavelength of the outgoing beam; calculating the total internal reflection hop count based on the Stokes polarization image; calculating the spatial step size offset based on the spatial spectrum image; and establishing a mapping relationship between the image pixel coordinates of the raw dataset and the internal physical regions of the metasurface grating waveguide under test to obtain local diffraction efficiency distribution data. This application solves the problem that traditional outgoing end intensity testing is difficult to trace to local defects inside the waveguide, achieving synchronous, high-precision quantitative characterization of local diffraction efficiency across multiple wavelengths.

Described are embodiments of a multi-layer giga-pixel plenoptic camera that enable three-dimensional (3D) light-field imaging, high resolution and large field-of-view. In embodiments, the camera includes a radiation conversion array layer, an optics array layer, a complementary metal-oxide-semiconductor (CMOS) image sensor array layer, and a memory layer. Depending on the embodiment, the sequence of the radiation conversion array layer and the optics array layer may be reversed, and / or additional isolation layers may be provided between some of the layers. Applications can span the visible light spectrum, and can include ultraviolet (UV) and infrared (IR) spectra. In an embodiment, applications can span x-ray spectra and gamma ray spectra. Radiation converters in the radiation conversion array layer can be filters or scintillation converters. Optics in the optics array layer can be lenses or pinholes and / or coded apertures.

The light field imaging device of the present invention may comprise: a linear polarizing plate; a first polarization switching element on which light passing through the linear polarizing plate is incident and which is electrically controlled to be turned on / off; a quarter-wave plate on which the light passing through the first polarization switching element is incident; and a first geometric phase lens on which the light passing through the quarter-wave plate is incident.

The invention belongs to the technical field of computer vision and light field imaging, and discloses a large-area highlight detection and repair method and system. The method comprises the following steps: imaging by using a light field camera array to obtain a multi-view-angle light field image, and calculating an initial parallax; the method comprises the following steps: obtaining a multi-view highlight area mask through highlight detection, removing the highlight area mask to obtain a light field image without a highlight area, carrying out light field refocusing to obtain a non-highlight refocusing image stack, applying the highlight area mask obtained through central view angle detection to an initial parallax image, and constructing a reliable parallax set to realize parallax layering; according to parallax layer information of a non-highlight area pixel adjacent to a highlight pixel space in the highlight area, carrying out adaptation on a parallax layer of the highlight pixel; and constructing a hierarchical restoration strategy based on observation conditions of different viewpoints when no-highlight refocusing image of the highlight pixel in the corresponding parallax layer is superposed and averaged at the pixel position, thereby realizing restoration of the highlight area. According to the method, high-quality and large-area highlight repair can be realized.

The invention discloses an optical measurement method and an optical imaging system, and relates to the technical field of optical imagines.The optical measurement method comprises the steps that a first image and a second image are obtained, the first image comprises fluorescence information generated by quantum dots in a standard quantum dot sample, and the second image comprises overlay error information in a wafer to be detected; determining a system aberration based on the fluorescence information; and based on the system aberration, correcting the overlay error information, and obtaining the overlay error information after the influence of the system aberration is removed. According to the invention, super-resolution optical fluctuation imaging can be carried out on the standard quantum dot sample through the optical imaging system to form the first image, wide light field imaging can be carried out on the wafer to be detected through optical imaging to form the second image, the system aberration can be rapidly and accurately determined through fluorescence information in the first image, and the detection accuracy is improved. And overlay error information can be corrected through system aberration, so that more accurate overlay error information can be obtained.

This invention relates to the field of activated carbon raw material screening, providing a method and system for activated carbon raw material screening based on multimodal image feature fusion. The method includes: acquiring original images of edge contours and surface textures, constructing a set of binary edge contour images and a set of grayscale surface texture images; extracting edge chain codes to generate edge curvature sequences, extracting effective cutting feature vectors based on coating damage critical thresholds, and mapping them to generate a physical wear risk index; mapping the texture region of interest to a three-dimensional grayscale topological surface, calculating fractal dimension feature values ​​and the proportion of hygroscopic texture, and coupling them to generate an environmental hygroscopic preemption index; calculating the compatibility score of color-changing beads using an environment-medium dual-constraint weighted algorithm, and performing multi-path diversion decisions based on optimization thresholds, elimination thresholds, and physicochemical test data to generate particle grading control instructions. This invention achieves intelligent screening and resource scheduling of activated carbon particle microstructure through synchronous time-division optical field imaging and multimodal feature coupling.

The three-dimensional imaging system and method provided by the present disclosure comprises a three-dimensional imaging light field to be measured, an imaging unit, a polarized photoelectric detection unit and a processing unit; a diffractive optical element or a superlens with the ability to independently control the imaging distance and the light transmission phase is selected to form the imaging unit, and the diffractive optical element and the superlens each contain at least one coding point spread function related to the imaging distance; the three-dimensional light field to be measured located at the object plane of the imaging unit is imaged to the polarized photoelectric detection unit located at the image plane of the imaging unit, and the images coded along the z direction are located at different positions of the polarized photoelectric detection unit; the polarized photoelectric detection unit is used to detect the light intensity of each linear polarization direction of the three-dimensional light field to be measured after the three-dimensional light field to be measured passes through the imaging unit; and the processing unit decodes the three-dimensional distribution information of the three-dimensional light field to be measured according to the captured polarized light intensity distribution. The present disclosure can realize a small-sized integrated and high-precision single-aperture three-dimensional imaging system.

The present application relates to a diffraction field printing system and an optical output method, comprising a light source, an illumination optical subsystem, an imaging optical subsystem, a reference light subsystem, a mechanical motion subsystem and a control subsystem, the light emitted by the light source is split into a first illumination light field and a second illumination light field; the imaging optical subsystem comprises a diffractive optical device, a spatial light modulator and a Fourier transform lens, the spatial light modulator is located at the input face of the Fourier transform lens, used for modulating data structure, and forming the sub-wavefront information of the diffraction field on the output face of the Fourier transform lens, the first illumination light field forms a limited band dissipation spot and a Gaussian-removed light field on the input face and the output face of the Fourier transform lens; the reference light subsystem comprises a galvanometer and a relay lens group, the second illumination light field forms a reference light field on the output face of the relay lens group, and the light spot formed by the light field coincides with the output face of the Fourier transform lens or the image face of the output face. The formed diffraction field has high signal-to-noise ratio and strong uniformity.

The application discloses a kind of light field imaging parameter control method and device of underwater light field camera, the method includes: S1, the underwater light field camera including light field camera and waterproof spherical shell is built;S2, the physical parameter of light field camera is acquired, and the light propagation model of the waterproof spherical shell is built;S3, according to light propagation analysis, the equivalent object distance of light field camera is acquired;S4, based on the disparity between the microlens array of light field camera and equivalent object distance, the shortest distance between the center of the waterproof spherical shell of underwater light field camera and the lens optical center of light field camera is calibrated;S5, based on equivalent object distance and the shortest distance between the center of the waterproof spherical shell of underwater light field camera and the lens optical center of light field camera, the light field imaging parameter of underwater light field camera is optimized;The application can improve the light field imaging definition of underwater light field camera;Improve the field of view angle of underwater light field camera, visual effect is better, improve the light field imaging quality of underwater light field camera.

Systems and method for light field imaging with mirror arrays in accordance with embodiments of the invention are illustrated. One embodiment includes a light field imaging system, including a mirror array where each mirror in the mirror array is positioned to reflect light from a target object towards a lens such that a different view of the target object is visible in each mirror from the viewpoint of the lens. The system further includes a lens configured to focus the reflected light, a sensor configured to capture an image depicting a plurality of reflections of the target object, a processor, and a memory containing a light field imaging application that directs the processor to obtain the captured image, extract a light field of the target object based on the plurality of reflections of the target object, and construct a three-dimensional model of the target object based on the light field.

The invention discloses an automatic multi-modal image registration method and system. The method comprises the following steps: initializing and preprocessing a registration image; extracting feature points of the registered image, and calculating descriptors; matching descriptors of the registered image pairs; calculating an affine matrix; and performing affine matrix processing on the to-be-registered image to obtain a registered image. According to the method, the registration problem of an endogenous imaging technology, a light field imaging technology, a tissue slicing technology and the like which cannot be solved in the prior art can be solved at the same time, fine adjustment is not needed for different modes, zero sample learning can be achieved, and the method can be suitable for imaging conditions of different scales from mesoscopic imaging to microscopic imaging and the like.

The present application relates to the technical field of light field imaging measurement, and particularly relates to an absolute depth measurement method based on a parallax angle of a polarized microlens light field image. The method comprises the following steps: 1) image pixel level classification based on multi-view sub-aperture depth maps, which provides a benchmark for optimization of a parallax map; 2) constructing a matching cost equation based on pixel classification results, so as to realize global optimization of a relative depth map from coarse to fine; 3) establishing a linear mapping model from the relative depth map to the absolute depth map based on the hardware structure of a microlens light field camera, so as to realize depth calibration; 4) combining the depth calibration with internal parameters of the light field camera, so as to calculate absolute depth physical parameters of an observed target. Thus, physical measurement and characterization of three-dimensional absolute size of a real observed object are realized, and absolute depth information of a target to be measured in a light field image can be obtained, in particular, absolute depth information of a weak texture and a blocked target can be obtained.

This invention relates to a continuous three-dimensional particle field reconstruction method based on single-light-field imaging using EM deconvolution, belonging to the field of optical imaging technology. This method employs a light field camera to capture light field images of a discretized three-dimensional flow field, acquiring the light intensity information of scattered light emitted by particles on each pixel of a CCD detector. Based on the light intensity information, a weight matrix for each voxel is calculated, and the entire weight matrix is ​​loaded only once. The nth frame of the light field image is loaded, and the non-zero pixels in the nth frame are identified. The non-zero pixel sequence formed by the scattered light from tracer particles is extracted. An EM deconvolution algorithm is used to iteratively calculate the non-zero pixel sequence, updating the intensity of each voxel, thereby reconstructing the three-dimensional particle field of a single frame. The above steps are repeated to complete the reconstruction of the three-dimensional particle field from multiple frames of high temporal resolution light field images, resulting in higher reconstruction accuracy and consistency, and less time consumption.

This invention discloses a modular light field microscope system based on a Lytro light field camera and its debugging method, belonging to the field of optical imaging and microscopy technology. The system includes a microscope objective, a first lens, a second lens, and a Lytro light field camera arranged sequentially along the optical path. The focal length of the first lens is shorter than that of the second lens, forming a relay optical path. The system also includes a modular mechanical support assembly composed of a cage rod and a cage plate, and each optical component can be slidably adjusted along the axial direction of the cage rod. This invention also discloses a step-by-step debugging method for the system. This invention utilizes the advantages of the commercial Lytro light field camera—small size and low cost—and overcomes the technical bottleneck of Lytro cameras being unsuitable for microscopic observation through a focal length gradient dual-lens relay optical path design. The system is compact, portable, and easy to debug, enabling high-quality four-dimensional light field imaging of microscopic samples. It is suitable for scenarios such as three-dimensional velocimetry of fluid particles, biological fluorescence microscopy, and in-situ microscale detection.

The invention discloses a dual-optical-path polarization-Fourier light field microscopic imaging system, which comprises a microscope, a polarization imaging module, a second semitransparent reflective mirror and a Fourier light field imaging module, and is characterized in that the microscope comprises an objective lens, a first semitransparent reflective mirror, an imaging lens and a first camera which are arranged along an imaging optical path; the polarization imaging module comprises a rotatable polaroid; the second semi-transparent reflective mirror is positioned between the imaging lens and the rotatable polarizing film; and the Fourier light field imaging module comprises a Fourier lens, a micro lens array and a second camera which are sequentially arranged along the light field branch. Through the double-optical-path design, the polarization branch provides sample surface polarization characteristics to achieve normal estimation and microstructure concave-convex characteristic judgment, the Fourier light field branch provides absolute depth information, and the reconstruction precision of the microstructure is greatly improved after two kinds of modal data are fused.

This invention discloses a four-channel polarization imaging system, comprising a housing containing four acquisition channels. These channels are respectively equipped with a near-infrared multispectral imaging camera, a near-infrared light field imaging camera, a visible light imaging camera, and an infrared imaging camera for multi-dimensional imaging and detection of objects. The near-infrared multispectral imaging camera has an adjustable filter that transmits light of different wavelengths. The near-infrared light field imaging camera has a polarization device that polarizes the light before imaging. The visible light imaging camera acquires and images light within the visible wavelength range. The infrared imaging camera acquires and images light within the infrared wavelength range. This invention can acquire light of different wavelengths, intensities, and polarization states, and image light with different properties, thereby enabling multi-dimensional imaging and detection of objects.

The invention relates to a credible integrated imaging method capable of realizing light field tampering detection and information self-recovery, which can realize clear multi-view light field display and consider tampering detection and recovery at the same time. Firstly, depth and angle information in a monocular scene is extracted by combining light field mapping of deep learning; then, a neural network is built, and a region of interest (ROI) and a region of interest (non-ROI) of the 3D light field are further extracted; and then, embedding recovery information constructed based on multiple view angles into the extracted ROI. And after the receiver receives the light field data, tampering detection is firstly carried out on the light field data. And when the recorded light field is tampered, the system can position a tampered area by using the random relationship among the recovery sub-blocks, and realizes recovery. And finally, the recovered micro-image array passes through a self-made 3D light field display device, so that credible 3D light field imaging is realized.

The application discloses an underwater crack defect detection method based on a polarized light field imaging, first, a polarized light field collection device is built, aiming at the underwater crack defect data problem, a small-scale underwater crack defect dataset is established and an unsupervised network is used for detection; the collected polarized light field image is processed to obtain a visible light intensity, a polarization degree and a depth image, a selection attention module is designed to fuse deep features of the three images, a multi-scale network structure is used to take into account crack defects of different sizes, and the detection accuracy is improved. The application can improve the detection precision, and achieve the purpose of quickly and accurately identifying and detecting underwater facility crack defects.

The invention discloses an orthodontic tooth arrangement three-dimensional reconstruction method and system based on light field imaging. The orthodontic tooth arrangement three-dimensional reconstruction method comprises the following steps: acquiring light field data of a tooth area; reconstructing a light path according to the light field data to obtain tooth surface light field distribution; extracting tooth geometric features according to the light field distribution, and performing depth estimation on the tooth geometric features to obtain a three-dimensional geometric model; matching the three-dimensional geometric model with the optical data to obtain a tooth optical model; carrying out reality sense verification on the tooth optical model, and judging a digital model passing verification by comparing a rendering result under simulated illumination with an actual tooth appearance; generating a virtual tooth arrangement scene according to the digital model, and dynamically adjusting the virtual tooth arrangement scene to obtain a treatment design scheme; and according to a treatment design scheme, performing simulation evaluation on patient experience parameters, and generating visual feedback by integrating the three-dimensional geometric model and the light field data to obtain a digital orthodontic model. According to the invention, the precision and reality sense of the orthodontic model are improved.

The invention discloses a Fourier light field depth-fused polarization microscopic three-dimensional reconstruction algorithm, which comprises the following steps of: acquiring an image sequence on a polarization imaging branch, and calculating a normal zenith angle and a polarization normal azimuth angle of each pixel point; fourier light field three-dimensional reconstruction is carried out based on an image collected by the Fourier light field imaging branch, and a reconstructed depth map is obtained; performing spatial registration on the visual field of the double branches, and judging and correcting a polarization normal azimuth angle; and constructing a convex optimization objective function to obtain an optimal solution target depth map Z. According to the method, absolute depth information provided by a Fourier light field is utilized to carry out auxiliary correction on an azimuth angle of a normal in a polarization three-dimensional reconstruction process, and the problem of reconstruction result local direction uncertainty caused by pi ambiguity is relieved. A joint model fusing the polarization normal and the light field depth is constructed and solved, and more accurate and continuous absolute depth reconstruction is realized by introducing global guidance and surface smoothness constraint of the light field depth.

The application discloses a kind of based on diffraction's light field imaging method and system, comprising: set up including having axial chromatic aberration lens, diffraction grating and image sensor's imaging device;Using imaging device to the point light source on optical axis imaging, move point light source adjustment its distance to have axial chromatic aberration lens let the imaging result of point light source have minimum dispersion circle on image sensor plane, capture the focused imaging image of point light source and calibration obtain the distance of diffraction grating to image sensor;According to the distance of diffraction grating to image sensor and the diffraction efficiency of diffraction grating obtained, the optical coding response of each wavelength corresponding focusing plane image is calculated;Using imaging device to the scene meeting the condition under multi-wavelength environment imaging, the data of image sensor and optical coding response are substituted into optimization model calculation reconstruction to obtain all focusing plane images;The application can realize the single exposure acquisition of multiple focusing plane light field, complete dynamic scene light field acquisition.

The present application relates to the technical field of image processing, and more particularly to a cloud and fog sheltered target inversion imaging method and device for image enhancement, wherein the method comprises: obtaining a reflected three-dimensional light field of a cloud and fog sheltered target; constructing an image enhancement filter function, and performing convolution operation on the reflected three-dimensional light field and the image enhancement filter function to obtain an enhanced filtered light field; performing frequency domain filtering on the enhanced filtered light field based on a cloud and fog transmission function; and based on the frequency domain filtered light field, performing target light field inversion imaging through a free space inversion method. The present application can improve the signal-to-noise ratio and contrast of cloud and fog sheltered target inversion imaging, and can meet the high resolution imaging requirement for cloud and fog sheltered targets.

The invention relates to a rapid hyperspectral light field Raman body imaging system and method, and the system employs wide-field imaging, combines a multi-dimensional information coding unit with a CCD detector, carries out the integrated coding of the panoramic depth information of a sample, and employs an adjustable spectrum filtering sub-module to achieve the integrated coding of the panoramic depth information of the sample. And high-quality acquisition of three-dimensional space and Raman hyperspectral information under the wavelength required by the sample can be realized only by single exposure. According to the imaging method, a light field Raman body imaging algorithm is provided, data priori of different stages in the light field imaging process is constructed respectively, and the training processes of light field denoising, a supramolecular network and a three-dimensional reconstruction sub-network are guided in sequence, so that rapid and high-fidelity isotropic resolution three-dimensional reconstruction of a low-signal-to-noise-ratio light field image is realized. According to the method, a multi-dimensional image rapid and high-resolution three-dimensional visualization processing technology system integrating traditional optics, information optics and computational optics is constructed, the imaging efficiency and precision are remarkably improved, and efficient three-dimensional information capture and high-quality reconstruction are achieved.

The present invention provides a full-field imaging camera, including an imaging component and a two-dimensional array detector sequentially arranged to form an image plane intensity information collection system, an imaging component, a Fourier transform lens and a two-dimensional array detector sequentially arranged to form a spatial Fourier spectrum intensity information collection system, and an arithmetic processor communicatively connected to the detector, the imaging component receives illumination light from an object to be measured to form an imaging light, the imaging light is imaged on a detection surface of the detector to form a first image plane, the imaging light is imaged in front of the Fourier transform lens to form a second image plane, and a spatial Fourier spectrum intensity information plane is formed on the detection surface of the detector on the focal plane after the Fourier transform lens. The present invention further provides a corresponding imaging method and a full-field imaging device. The full-field imaging camera of the present invention solves the problems of existing phase imaging technology, such as high sampling rate requirement, need for overlap to obtain redundant information, slow algorithm convergence, etc.

This invention discloses a parameter design method for a long-wave infrared focusing light field camera, belonging to the field of computational imaging technology. The method includes: determining the parameters of the main lens and the pixel size of the detector based on the imaging object distance, while satisfying the long-wave infrared diffraction limit constraint; employing a high-fill-rate microlens array structure; calculating the axial distance between the microlens array, the detector, and the main lens based on pupil matching and multi-view depth recovery requirements; determining the allowable circle of confusion according to the long-wave infrared diffraction limit, and designing a multi-focal-length microlens array to achieve continuous depth-of-field coverage; finally, optimizing the microlens aperture using a depth resolution model to balance depth resolution and depth-of-field range. This invention, through the collaborative design and overall optimization of the parameters of the main lens, microlens array, and detector, achieves long-distance, large depth-of-field, and high depth-resolution light field imaging in the long-wave infrared band, providing effective design guidance for infrared three-dimensional sensing systems.

The invention provides a flame light field imaging measurement uncertainty quantitative evaluation method, which comprises the following steps of: acquiring a light field original white image of a light field camera under an actual error condition and an ideal condition, and determining a central pixel block of each micro-lens sub-image area, the method comprises the following steps: acquiring an original light field image of a light field camera for imaging a target scene under an actual error condition, dividing a reference image and a to-be-measured image into corresponding sub-image pairs, sequentially calculating a local mean square error and a local structural similarity of each sub-image pair, sequentially calculating an overall mean square error and a structural similarity of a sub-aperture image under each view angle, and obtaining a sub-aperture image; according to the method, a quality evaluation system of a local sub-image and a multi-view sub-aperture image is established for a flame light field image from the angles of image intensity and structural distortion; therefore, the quantitative evaluation of the response uncertainty of the flame light field imaging measurement system under the given error input is realized.

The present application relates to the technical field of image processing, and discloses a kind of polarization filtering and light field imaging's underwater alum flower identification method and system, solve the problem that prior art cannot realize the high-fidelity acquisition and accurate quantification of alum flower morphological characteristics under high turbidity, dynamic water quality working condition.The present application is through the collaborative optical design of polarization filtering and light field imaging, suppresses water backscattering and Mie scattering interference at the collection source, provides high-fidelity image basis for subsequent morphological quantification;Introduce double-domain Gaussian window spectrum shaping and truncated sinc interpolation kernel, improve the refocusing position accuracy without hardware modification, eliminate the ringing artifact and phase distortion caused by traditional linear interpolation;Multi-scale Retinex enhancement model accurately adapts to the low contrast and multi-scale texture characteristics of alum flower, retains the texture information required for fractal dimension calculation completely under the premise of avoiding noise amplification, and linear fitting is combined with box counting method, so that the fractal dimension estimation error is reduced.