19 results about "Line Spread Function" patented technology

The invention discloses an SAR (Synthetic Aperture Radar) image MTF (Modulation Transfer Function) quality evaluation method and system based on a natural scene edge, and the method comprises the steps: building a selection standard system for automatic edge screening of a natural scene SAR image, and determining a high-contrast linear edge according to the standard system; automatically detecting a high-contrast linear edge in the natural scene, and intercepting a region of interest for subsequent calculation based on the position of the linear edge; gray level distribution is extracted in the normal direction of the linear edge, and an edge spread function is constructed and used for describing gray level transition response of the imaging system in the edge area; carrying out normalization and smoothing processing on the edge spread function, and carrying out spatial domain first-order differential calculation to obtain a line spread function; and performing fast Fourier transform on the line spread function to obtain a modulation degree transfer function curve, and representing the detail transfer capability of the system under different spatial frequencies. According to the method, the imaging quality of the SAR image of the natural scene can be automatically, accurately and quantitatively evaluated under the condition that manual field arrangement is not needed.

The invention relates to a geometric parameter calculation and performance evaluation algorithm based on an integrated motif, which is applied to the integrated motif comprising a geometric parameter calculation module, a spatial resolution module, a contrast module, a uniformity module and a spatial accuracy module. Comprising the following steps: calculating geometric parameters of a CBCT system by using position information of a metal ball in a geometric parameter calculation module and known information; acquiring a line spread function of the metal wire by using position information and known information of the metal wire in the spatial resolution module, and then calculating the spatial resolution; sampling by using position information and known information of an annular insertion block in the contrast module; automatically selecting a center area and a peripheral area of a uniformity module to carry out gray value average value calculation to obtain uniformity information of the image; and the distance and the included angle between the positioning small holes are calculated by using the position information of the positioning small holes in the space accuracy module and known information. According to the invention, high-frequency, high-precision and low-cost performance evaluation requirements in the research and development process can be met.

The invention relates to the technical field of interference spectrum data simulation, in particular to an interference spectrum data simulation generation method based on a DFDI system, and the method comprises the steps: extracting an absorption line characteristic parameter from a standard fixed star spectrum database, combining an interferometer fixed optical path difference parameter, and generating interference fringe distribution by using an equal thickness interference principle; carrying out convolution modulation by adopting a spectrograph line spread function to obtain a continuous interference spectrum image, and carrying out discretization sampling to generate a digital data matrix; generating a diversified data set through parameterization adjustment, and adding Poisson distribution noise to simulate a real observation environment; and formatting the noise data into a dual-channel image, and finally realizing the inversion of the radial velocity through the training of the convolutional neural network. According to the method, the problem of insufficient training samples caused by scarcity of real DFDI data is solved, and the phase feature extraction precision of the interference fringes and the inversion reliability of the radial velocity are improved.

The present invention provides a method for calculating an optical modulation transfer function based on a knife-edge image, comprising the following steps: using an optical modulation function measurement device to collect a knife-edge image and converting the knife-edge image into a grayscale image; calculating the knife-edge rising edge width of the grayscale image; performing a convolution operation on the grayscale image using a differential template matrix to obtain an LSF image; identifying the edge coordinates of the LSF image, and then rotating the LSF image using an affine transformation; and then performing a discrete Fourier transform to obtain an optical modulation transfer function curve. The optical modulation transfer function calculation method provided by the present invention calculates the average value of the rising edge pixel width of each row to obtain a corresponding adaptive differential convolution template, then convolves the knife-edge image to obtain a line spread function (LSF) image, and finally obtains an optical transfer function curve through a discrete Fourier transform. Because the differential method of this method relies on an adaptive differential template to perform convolution, it effectively removes noise.

This invention discloses a method and system for restoring defocused images based on estimating the point spread function from a spot image. The method includes: 1) reading the original spot image and the defocused blurred image; 2) cropping the area where the spot is located; 3) projecting the cropped spot image into grayscale along the vertical axis to obtain the original line spread function curve; 4) performing Gaussian fitting on the original line spread function curve to obtain a smooth line spread function curve; and then calculating the standard deviation of the Gaussian function; 5) calculating the blur coefficient of the Gaussian defocus model using the standard deviation; 6) substituting the blur coefficient into the Gaussian defocus model to obtain the point spread function; 7) performing Wiener filtering on the defocused blurred image in the frequency domain to obtain the initial restored image in the frequency domain; 8) performing a second Wiener filtering on the initial restored image to obtain the final restored image in the frequency domain; and 9) performing an inverse Fourier transform to obtain the restored image. This invention effectively reduces the blurriness of defocused images and solves the problem of computational complexity.

To provide a simple focal spot size measuring method satisfying requirements of the fifth edition of IEC 60336 by using a two-dimensional digital X-ray sensor and reducing the number of data used for noise reduction.SOLUTION: An X-ray tube focal spot size measuring device comprises a power supply unit for driving an X-ray tube, the X-ray tube, the source of X-rays, a slit camera with a continuously uniform slit width, and a two-dimensional digital X-ray sensor. An X-ray tube focal spot size measuring method measures a focal spot size of the X-ray tube by the steps of: averaging signals having a line spread function corresponding to intensities of X-rays of a plurality of lines different in the longitudinal direction of the slit by using the X-ray tube focal spot size measuring device to calculate an averaged signal; and calculating the focal spot size on the basis of the width of two points having a prescribed ratio to a maximum value of an averaged signal having the line spread function.SELECTED DRAWING: Figure 17

The invention discloses a software test method and system for a contrast transfer function of a low-light image intensifier. The system comprises a parameter configuration module, an illumination adjustment module, an automatic focusing module, a region extraction module and a function generation module. The method comprises the steps of parameter adaptation, illumination calibration, step-by-step focusing, region determination and feature conversion. In parameter adaptation, parameters are automatically configured and corrected according to the image intensifier and the target type; the step length of a diaphragm is dynamically adjusted by combining multi-stage adjustment with a filtering model in illumination calibration; the focus is locked through coarse adjustment and fine adjustment in step-by-step focusing; the area determination supports manual delimiting or automatic identification; according to feature conversion, an edge spread function, a line spread function and a modulation transfer function are obtained through image processing, and a contrast transfer function curve is generated and stored. According to the invention, the automatic test precision is improved, and necessary technical support is provided for quality monitoring of the image intensifier.

This application provides a dynamic star point localization method, apparatus, and device based on an effective line spread function, relating to the field of optical imaging measurement technology. The method includes: estimating the trailing parameters of a star point image based on the coarsely estimated coordinate position changes of the star point image on adjacent frames of starscape images; the coarsely estimated coordinate position characterizing the center position coordinates of the star point image obtained by calculating the centroid of the star point image using the threshold centroid method; establishing an effective line spread function under the current motion conditions based on an effective point spread function pre-established under static imaging conditions, and combining the trailing parameters; the effective line spread function characterizing the energy distribution pattern of the trailing star point image obtained by integrating the effective point spread function along the trailing trajectory; and using the effective line spread function to perform localization calculations on the imaging data of the trailing star point image to obtain a finely estimated coordinate of the star point image.

The invention discloses a method for high-precision measurement of a modulation transfer function (MTF) of an optical system, and relates to the field of optical measurement. The method comprises the following steps of: acquiring a digital image of a slit target, and obtaining an accurate centroid position of a slit in each pixel row through a centroid positioning algorithm of an iterative adaptive window function for each pixel row intersected with the slit in the image. The method comprises the following steps: carrying out linear fitting on an accurate mass center position, calculating an accurate inclination angle of a slit relative to an image sensor pixel array, determining a super-sampling interval by using a geometrical relationship, constructing a super-sampling line spread function (SSLSF), and finally carrying out correction by using a joint correction model through Fourier transform to obtain an accurate MTF (Modulation Transform Function). According to the method, the problem of inaccurate MTF measurement caused by image noise and detector sampling frequency limitation in the prior art is solved, and the MTF measurement precision and the anti-noise capability are remarkably improved.

A method for calibrating a spectrometer device in a batch of spectrometer devices is disclosed in the abstract of a method for calibrating a spectrometer device in a batch of spectrometer devices. The present invention relates to a spectrograph arrangement comprising at least one detector arrangement comprising at least one optical element configured to separate incident light into a spectrum having constituent wavelength components and further comprising a plurality of light sensitive elements, each photosensitive element is configured for receiving at least a portion of one of the constituent wavelength components and for generating a respective detector signal as a function of an illumination of the respective photosensitive element by at least a portion of the respective constituent wavelength component, the method comprising the following steps: a) at least one system characterization step, the at least one system characterization step comprises determining a line spread function at a corresponding wavelength by comparing at least one spectrum measured by using the spectrometer device with at least one reference spectrum; 15b) at least one resolution homogenization step comprising converting, for each wavelength, the resolution of the line spread function to a predefined target resolution for the corresponding wavelength, where the target resolution for each wavelength is a predefined target batch resolution value for the corresponding wavelength. 20 (Fig. 1A).

To provide a simple focal spot size measuring method satisfying requirements of the fifth edition of IEC 60336 by using a two-dimensional digital X-ray sensor and reducing the number of data used for noise reduction.SOLUTION: An X-ray tube focal spot size measuring device comprises a power supply unit for driving an X-ray tube, the X-ray tube, the source of X-rays, a slit camera with a continuously uniform slit width, and a two-dimensional digital X-ray sensor. An X-ray tube focal spot size measuring method measures a focal spot size of the X-ray tube by the steps of: averaging signals having a line spread function corresponding to intensities of X-rays of a plurality of lines different in the longitudinal direction of the slit by using the X-ray tube focal spot size measuring device to calculate an averaged signal; and calculating the focal spot size on the basis of the width of two points having a prescribed ratio to a maximum value of an averaged signal having the line spread function.SELECTED DRAWING: Figure 17

The embodiment of the application provides an MTF testing method and device for an AR projection light machine, comprising: acquiring a projection test target, wherein the projection test target is a cross slit bright line; collecting a test projection image corresponding to the projection test target; based on the test projection image, scanning along the direction perpendicular to the extension direction of each bright line in the cross slit bright line respectively, and determining the brightness data of each corresponding scanning position; performing brightness feature extraction on the brightness data of each corresponding scanning position to obtain an effective brightness data sequence; based on the effective brightness data sequence, constructing a line spread function; and based on the line spread function, determining a test result. Through the cross slit bright line test target combined with directional scanning, brightness feature extraction and line spread function construction, the imaging quality of the AR projection light machine is accurately tested, and the reliability and applicability of the test result are improved.

This invention discloses a method and system for improving the stability of a coherent dispersive spectrometer based on cross-cancellation, belonging to the field of spectral imaging technology. It includes acquiring two interference spectra with a phase difference of π in an asymmetric coherent dispersive system; separating the local spectrum and interference spectrum through addition and subtraction; performing Fourier transform on both to obtain the local spectrum and interference spectrum in the frequency domain; determining the optical path difference based on the grating line spread function and signal-to-noise ratio condition; and dividing the interference spectrum into a first component region and a second component region; determining the weights using a phase residual optimization method within the frequency range from zero to the optical path difference; and performing a weighted summation of the spectral components of the local spectrum and the first component region to obtain the mixed spectrum after cross-cancellation. This invention further improves spectral resolution through high-frequency stitching and suppresses ringing effects through equalization processing. This invention significantly improves system stability and spectral resolution without increasing system size and complexity.

The present application relates to a kind of image restoration methods of fitting PSF, including S1, extract actual image LSF, actual image LSF is converted into the linear combination of Gaussian second derivative;S2, according to the linear combination of Gaussian second derivative, actual line spread function is fitted and corrected;S3, using actual line spread function after fitting and correction, generate restoration image.The method of the present application extracts actual image line spread function, and it is modeled into the form of linear combination of a series of Gaussian second derivative;Then, based on the Gaussian second derivative model established, the LSF extracted from blurred image is fitted and corrected;Finally, blurred image is restored using PSF after fitting and correction, and finally clear image is obtained.Compared with the prior art image restoration method, the method of the present application can produce clearer restoration image when facing high blur degree original image.

The invention discloses a semi-automatic ground resolution distance measurement method for an in-orbit medium-resolution remote sensing image. The method comprises the following steps: S1, selecting natural targets and constructing a target library; s2, extracting target sub-pixels and generating a profile coordinate set; s3, extracting a gray value sequence of a normalized image from the obtained coordinate set of the section, constructing a section matrix and averaging according to rows to obtain an average edge spread function, performing first-order difference operation on the edge spread function to obtain a line spread function, and further performing normalization processing on the line spread function; s4, extracting a peak value of the normalized line spread function curve and a corresponding half peak value position, determining a distance between half peak points on the left side and the right side through linear interpolation, taking the distance as a width metric value, and multiplying the width metric value by a ground sampling distance of the satellite image to obtain a ground resolution distance value; and S5, summarizing and outputting results. The method is applied to the technical field of remote sensing image measurement or surveying and mapping geographic information services.

The invention relates to the field of magnetic resonance imaging, in particular to a magnetic resonance image spatial resolution detection method and device and electronic equipment. The method comprises the following steps: acquiring a rectangular magnetic resonance image comprising a target line segment; and performing edge detection to obtain an edge point set and fitting the edge point set into an edge line. Determining the directed distance from each pixel to the edge line in the rectangular magnetic resonance image, and fitting the relation between the pixel value of each pixel and the directed distance to obtain an edge spread function; determining the change rate of the pixel value of each pixel in the edge spread function along with the change of the position to obtain a change rate function, extracting features from the change rate function and normalizing the features to obtain a line spread function, and converting the line spread function to a frequency domain and normalizing the line spread function to obtain a modulation transfer function; and determining a corresponding spatial frequency when the modulation transfer function value is a threshold value as a spatial resolution score of the rectangular magnetic resonance image. The method is used for improving the accuracy of spatial resolution evaluation of the magnetic resonance image and widening the evaluation range of the magnetic resonance spatial resolution.

The invention belongs to the technical field of image quality online detection, and particularly relates to a camera modulation transfer function estimation method and system based on a pulse neural network, and the method comprises the steps: obtaining a test image collected by a camera, and selecting a region of interest from the test image; performing gray scale differential coding on the ROI image in the continuous time window to generate a sparse pulse sequence; the pulse sequence is input into a pulse neural network, and the pulse neural network is constructed based on a leakage integration distribution model and is used for carrying out feature extraction and dynamic contrast reconstruction on the pulse sequence and outputting a corresponding pulse response; gaussian smoothing and deconvolution are carried out on the impulse response, and a high-precision line spread function is reconstructed; carrying out fast Fourier transform on the modulation transfer function curve to obtain a complete modulation transfer function curve; by using an event-driven mechanism and sparse calculation characteristics of the spiking neural network, ultralow-power-consumption and ultralow-delay MTF estimation at the embedded front end is realized, and the requirement of online full inspection of a high-speed production line is met.

Provided are an apparatus, method, and computer program for measuring spatial resolution of electro-optical system, by which the influence of edge spread function (ESF) by micro-vibrations is mitigated by using deep learning techniques. The method of measuring spatial resolution of electro-optical system includes obtaining raw ESF data from an edge image obtained by using the electro-optical system, obtaining a corrected ESF curve by inputting the raw ESF data to a deep learning model, obtaining a line spread function (LSF) curve by differentiating the corrected ESF curve, obtaining a modulation transfer function (MTF) curve by Fourier-transforming the LSF curve; and obtaining a MTF value from the MTF curve.

The application discloses a kind of semi-automatic ground resolution distance measurement methods of on-orbit medium resolution remote sensing image.The present application includes the following steps: step S1.natural target selection and target database construction;Step S2.target subpixel extraction and profile coordinate set generation;Step S3.the coordinate set of obtained profile extracts the gray value sequence of normalized image, constructs profile matrix and averages by row, obtains average edge spread function, carries out first-order difference operation to edge spread function, obtains line spread function, further carries out normalization processing to line spread function;Step S4.extract the peak value of normalized line spread function curve and its corresponding half-peak position, determine the distance between left and right half-peak points by linear interpolation, as the measure of width, multiply the measure of width with the ground sampling distance of satellite image, obtain ground resolution distance value;Step S5: result summary output.The present application is applied to the technical field of remote sensing image measurement or surveying and mapping geographic information service.