19 results about "Coherent diffraction imaging" patented technology

The invention belongs to the technical field of micro-nano processing, and particularly relates to a Pt-HSQ-based high-resolution X-ray Fresnel zone plate and a preparation method thereof. According to the X-ray Fresnel zone plate, a Pt-HSQ metal-inorganic material system is adopted, a diffraction structure with a large aspect ratio and Pt material quasi-periodic dense stripes specially needed by an X-ray zone plate lens is formed through electron beam lithography and an ALD process, and diffraction focusing from a soft X-ray wave band to a hard X-ray wave band and imaging with an amplification function are achieved. The wave zone plate has excellent mechanical stability, and the irradiation resistance and morphology retentivity of the wave zone plate under high-energy irradiation are remarkably improved. And high-resolution X-ray focusing elements with different energy wavebands and different focal lengths can be prepared according to geometric design and material selection of the wave zone plate. The lens is suitable for microscopic imaging, coherent diffraction imaging, X-ray spectrum, nanometer detection and other scenes of a synchrotron radiation or off-line laboratory X-ray light source, and has wide popularization value and application prospect.

This application belongs to the field of coherent diffraction imaging technology, specifically disclosing an ultra-low dose coherent diffraction imaging method and apparatus. Based on a blind source separation strategy, this application uses principal component analysis to process the acquired diffraction signals, performing noise separation and updating in reciprocal space. This effectively separates mixed noise energy into noise components, thus avoiding crosstalk to the reconstruction process and significantly improving the convergence stability and robustness of coherent diffraction imaging when reconstructing diffraction signals with extremely low signal-to-noise ratios under ultra-low exposure doses. Simultaneously, this application constructs noise components separately for each scanning position and correlates noise components at different positions through low-dimensional spatial projection, achieving non-stationary noise separation. This enables more effective handling of random noise caused by the low quantum efficiency of ultra-short band detectors, thus maintaining extremely high noise robustness and reconstruction accuracy even under ultra-low exposure doses, achieving an effective improvement in resolution.

The invention discloses a double-domain joint evaluation method for imaging quality in wide-spectrum coherent diffraction imaging, which belongs to the related technical field of wide-spectrum coherent diffraction imaging, and comprises the following steps: 1, measuring light source spectrum distribution for wide-spectrum coherent diffraction imaging, and imaging a wide-spectrum diffraction field through an imaging algorithm; 2, obtaining a current reconstructed image and actually measured diffraction light intensity after each iteration of the imaging algorithm, constructing wide spectrum diffraction light intensity by using spectral distribution and reconstructed image values, and using and calculating diffraction field errors; 3, performing no-reference quality evaluation on the reconstructed image after each iteration, and calculating an image error; and 4, using weighting to form a double-domain joint evaluation result. The method can effectively solve the problem that the existing wide-spectrum laminated diffraction imaging lacks a unified and accurate evaluation method, thereby improving the reliability and consistency of reconstruction quality evaluation.

The invention relates to the technical field of optical detection, and discloses a super-resolution optical detection system and method for material surface defects. According to the system and the method, a structured evanescent wave field is formed on the surface of a plasmon evanescent wave chip to serve as a near-field illumination probe, the relative position of the probe and a sample is changed through non-mechanical scanning modes such as angle or wavelength tuning, and a group of far-field polarization resolution diffraction patterns are acquired by a diffraction signal acquisition module. And the central control and data processing unit performs iterative computation by adopting a vector coherence diffraction imaging algorithm based on the diffraction data set, and reconstructs complex amplitude distribution of the probe and a high-resolution Jones matrix image of the sample at the same time. By analyzing the Jones matrix, quantitative detection of the morphology, the size and the anisotropic physical attributes of the surface defects can be completed. According to the invention, vibration caused by mechanical scanning is avoided, and high-stability and high-resolution nondestructive testing is realized.

The application provides a single-pixel diffraction imaging method and device, and belongs to the field of coherent diffraction imaging and computational photography, wherein the method comprises the following steps: (1) in the single-pixel imaging light path, different modulation sequences are used to modulate the illumination light beam of the target scene, and a single-pixel detector is used to record the intensity value of a one-dimensional sequence; (2) the intensity value corresponding to the different modulation sequences is used to replace the amplitude value of the reconstructed diffraction light field on the detector plane, and then alternating iteration calculation is performed until the target scene is reconstructed. The application has the advantages of simple structure, strong operability, wide application range and strong expandability. Through the application, the cost of single-pixel diffraction imaging can be reduced, fast and accurate measurement of the target scene is realized, and convenience is brought to high-quality single-pixel imaging.

The invention discloses a reflective coherent diffraction imaging method and system based on tilt phase correction, and relates to the technical field of extreme ultraviolet optical imaging. The method comprises the following steps: acquiring extreme ultraviolet diffraction signals to obtain an original data matrix; acquiring an initial inclination angle value of the sample; executing a phase recovery iteration process: substituting the current inclination angle parameter into a coordinate mapping relational expression to calculate a corrected frequency domain coordinate, and determining a reflectivity compensation coefficient; performing coordinate resampling and amplitude correction on the original data to generate correction data; calculating a reconstruction error and dynamically updating an inclination angle parameter; and outputting a reconstructed image if the convergence condition is satisfied, otherwise, returning to re-execute. According to the method, the inclination angle is used as a variable optimization variable to be embedded into an iterative closed loop, and the extreme ultraviolet multilayer film reflectivity compensation is combined, so that the problems of geometric distortion and intensity artifacts caused by sample inclination are effectively solved, sub-pixel-level angle correction precision and high-fidelity image reconstruction are realized, and the imaging efficiency and stability are remarkably improved.

The invention discloses a hyperspectral diffraction imaging device, system and method based on blind coding, and relates to the technical field of hyperspectral coherent diffraction imaging.The method comprises the steps that a hyperspectral light beam emitted by a light source is transmitted to a mask plate through a reflector after being subjected to beam expanding, focusing and collimation; controlling the mask plate to move from the first position to the second position, so that the mask plates at different positions before and after movement have overlapped areas along the light path direction, and obtaining a diffraction image of each lamination scanning position; and according to the diffraction image, performing joint reconstruction on the unknown mask plate, the spectrum and the imaging object by using a broadband phase reconstruction algorithm based on multi-parameter constraint to obtain amplitude and phase information of the reconstructed mask plate, the spectrum and the imaging object so as to complete hyperspectral illumination coherent diffraction imaging. According to the method disclosed by the invention, multi-spectrum amplitude-phase-spectrum joint reconstruction of the hyperspectrum under low-time coherent illumination can be realized by utilizing laminated scanning under the condition that codes are unknown.

In one embodiment, there is provided method of imaging a biological sample. The method includes providing, by a polarizing source assembly, a source polarized coherent electromagnetic beam to the biological sample. The method further includes capturing, by a detector assembly, an intermediate electromagnetic beam from the biological sample. The intermediate electromagnetic beam is related to the source polarized coherent electromagnetic beam and to an optical anisotropic property of the biological sample. The method further includes providing, by the detector assembly, an output electrical signal corresponding to an output electromagnetic beam. The output electromagnetic beam is related to the intermediate electromagnetic beam. The method further includes generating, by an imaging circuitry, an image of at least a portion of the biological sample based, at least in part, on the output electrical signal.

The application discloses an X-ray real-time imaging device and method based on an image plane coherent diffraction imaging, and the device comprises an X-ray source, an adjustable slit, an object to be measured, a first three-dimensional translation stage, a multi-focus photon sieve, a second three-dimensional translation stage, an X-ray detector and a computer; the imaging device has the characteristics of single optical path, compactness, simplicity and easy operation, and only a single intensity image needs to be recorded, so that the imaging device robustness can be improved by avoiding multiple operations; the imaging method can be used for X-ray to terahertz band imaging, and can realize accurate reproduction of a complex amplitude image of the object to be measured in real time and on line.

The present invention provides a computational phase imaging method and system. This method collects the noise-containing far-field diffracted light intensity after an illumination beam impinges on a sample. It then uses coherent diffraction imaging to iteratively reconstruct the complex amplitude information of the sample and illumination beam. A dynamic activation function is applied to the iterative process to suppress noise perturbations on computational convergence, enabling the system to escape local optimal traps and ultimately achieve a globally optimal solution. This method addresses technical issues with existing phase computational imaging methods, such as severe loss of imaging resolution and algorithmic non-convergence in the presence of noise.

The present application belongs to the field of coherent diffraction imaging, and specifically discloses a method and system for automatic focusing of coherent diffraction imaging. The present application simulates multiple groups of samples to be tested at different positions through a near-field propagation model, performs wavelet transformation on the simulated samples to be tested to obtain wavelet coefficients, calculates clarity based on the wavelet coefficients, and uses the clarity weights of all simulated samples to update the axial distance to gradually approach the actual value of the axial distance between the sample and the detector, thereby achieving automatic focusing of coherent diffraction imaging. The present application proposes for the first time the use of operators in the frequency domain to calculate the clarity of the reconstructed image. This method has higher axial contrast and noise robustness, greatly improving the convergence speed, accuracy and robustness; through wavelet transform, the detail components of the image in the horizontal, vertical and diagonal directions are extracted in the frequency domain to evaluate the clarity of the reconstructed image, and the weights of different directions can be flexibly adjusted, which has better generalization.

The invention provides a coherent diffraction imaging method, device and system. The coherent diffraction imaging system comprises an off-axis illumination module, a displacement table, a detector and control equipment, the off-axis illumination module is used for synthesizing the coherent point light sources into off-axis illumination light spots and irradiating the off-axis illumination light spots on the surface of a measured object; the displacement table is used for placing a measured object and moves under the control of the control equipment so as to enable the light spots to irradiate different areas on the surface of the measured object; the detector is used for detecting a diffraction intensity pattern of an area irradiated by the light spot on the surface of the detected object in the moving process of the displacement table; and the control equipment is used for reconstructing the surface information of the measured object according to the diffracted intensity patterns of different areas on the surface of the measured object. The coherent point light sources are synthesized into light spots of off-axis illumination through the off-axis illumination module, the numerical aperture of illumination can be effectively improved, and therefore the resolution of coherent diffraction imaging is improved.

The invention belongs to the technical field of imaging, and discloses a monochromatization method applied to wide-spectrum coherent diffraction imaging, which aims at a wide-spectrum coherent diffraction imaging experiment and reconstructs an obtained multi-wavelength diffraction pattern into a diffraction pattern under a single wavelength through spectral characteristic analysis. According to the method, based on a theoretical model in which a wide-spectrum diffraction pattern is a non-coherently superposed single-color wavelength diffraction pattern, the single-color wavelength diffraction pattern is accurately extracted in combination with a gradient descent optimization algorithm. According to the method, the dependence of traditional coherent diffraction imaging on a monochromatic source is broken through, and the calculation efficiency of monochromatization reconstruction is remarkably improved. The method is suitable for a coherent diffraction imaging scene of a wide-spectrum weak coherent light source, the problem of light intensity attenuation caused by a traditional light splitting scheme is effectively avoided, and a new solution is provided for high-resolution imaging under the weak light source. Meanwhile, the method is expected to be expanded to a desktop attosecond light source and other novel light source systems, and key technical support is provided for ultrafast process imaging under the attosecond scale.

The invention discloses a spectrum-image combined measurement device and system based on double networks, and relates to the field of wide spectrum coherent diffraction imaging, the spectrum-image combined measurement device comprises a light source, a first lens, an aperture diaphragm, a second lens, a third lens, an imaging object and a CMOS camera which are arranged along a light path direction, the CMOS camera receives a diffraction pattern and transmits the diffraction pattern to a processor, and the processor is used for processing the diffraction pattern. The processor reconstructs the received diffraction pattern by adopting a spectrum-image combined measurement method based on double networks, including collecting the diffraction pattern, and obtaining a fused diffraction pattern after high dynamic range fusion; a monochromatic diffraction pattern is collected, an actual diffraction distance is obtained in combination with the monochromatic diffraction propagation model, and an actual wide-spectrum physical propagation model is constructed based on the actual diffraction distance; and based on the fused diffraction pattern, reconstructing the image and the spectrum by using a spectrum-image joint reconstruction algorithm based on double networks to obtain a reconstructed diffraction pattern and spectrum. Spectrum calibration is not needed, the image and the spectrum can be reconstructed at the same time, and the difficulty of wide-spectrum diffraction imaging is greatly lowered.

This application belongs to the field of coherent diffraction imaging, specifically disclosing a method and system for reconstructing stacked diffraction imaging based on subgradient projection regularization. Through this application, based on the convex problem optimization theory of subgradient projection, a spatially varying gradient weighting function is further introduced into the stacked diffraction imaging reconstruction model to adaptively adjust the update step size, thereby improving the iterative convergence speed. This method can achieve a balanced improvement in convergence speed within the support domain without introducing any additional computational overhead by penalizing or suppressing extreme step sizes during the update process. Furthermore, this method requires no hardware modification, is directly compatible with stacked diffraction imaging models, and reduces the parameter sensitivity of the iterative algorithm during reconstruction, achieving robust convergence without fine-tuning.

The invention discloses a multi-wavelength coherent diffraction imaging phase recovery algorithm and system, and relates to the field of coherent diffraction imaging.The algorithm comprises the steps that a to-be-detected sample is irradiated with multiple incident light of different wavelengths, and a diffraction pattern corresponding to each incident light is obtained; and according to the diffraction patterns corresponding to all the incident light, based on an alternating direction method and a total variation algorithm, obtaining a phase recovery result of the to-be-detected sample. According to the invention, the total variation denoising technology and the alternating direction algorithm are combined, the noise in the image is effectively suppressed, and the phase recovery precision and convergence speed are improved.

This invention provides a weighted probe-based method for correcting the position of stacked diffraction, belonging to the field of coherent diffraction imaging. The method involves: acquiring diffraction light field intensity information, simultaneously initializing the information functions of the illumination probe and the sample under test, as well as the probe position; obtaining the exit wave and importing it into a propagation model to obtain a simulated diffraction light field, replacing the diffraction light field intensity information to obtain an updated diffraction light field; importing the updated diffraction light field into a reverse propagation model to obtain the diffraction exit wave, thereby updating the information functions of the sample under test and the illumination probe at each scanning position; forming a probe matrix around the probe position, calculating the correlation, and updating the probe position; repeating the above steps iteratively until a preset number of iterations is completed or a preset condition is met. This invention avoids crosstalk between local non-converged regions and global scanning position correction, greatly improving the convergence stability and convergence accuracy of the stacked diffraction position correction method.

The application relates to the technical field of optical detection, and discloses a material surface defect super-resolution optical detection system and method. The system and method utilize an evanescent wave chip to form a structured evanescent wave field on a surface as a near-field illumination probe, change the relative position of the probe and a sample through an angle or wavelength tuning non-mechanical scanning mode, and acquire a set of far-field polarization resolution diffraction patterns through a diffraction signal acquisition module. A central control and data processing unit carries out iterative calculation on the diffraction data set through a vector coherent diffraction imaging algorithm, and simultaneously reconstructs the complex amplitude distribution of the probe and a high-resolution Jones matrix image of the sample. Through analysis of the Jones matrix, quantitative detection of the morphology, size and anisotropic physical properties of the surface defect can be completed. The application avoids vibration caused by mechanical scanning, and realizes high-stability and high-resolution nondestructive detection.

The present application belongs to the technical field of coherent diffraction imaging, and discloses a kind of laminated diffraction position correction imaging method, system and electronic equipment, wherein the method comprises: for each scan position coordinate of motion platform, the minimum difference between the calculated diffraction light field intensity information and the collected diffraction light field intensity information is the optimal value by particle swarm algorithm, and the updated integer pixel position coordinate of motion platform is obtained by iterative updating;The cross-correlation peak position before and after the diffraction exit wave update of each updated integer pixel position coordinate of motion platform is calculated, and the updated sub-pixel position coordinate of motion platform is obtained by continuously searching and updating the irradiation probe position;The complex amplitude function of irradiation probe and sample to be measured is calculated, and the amplitude and phase of sample to be measured and irradiation probe are reconstructed from this.The convergence speed of position correction algorithm is improved by effectively combining particle swarm position correction method and cross-correlation position correction method, and the final accuracy is also guaranteed.