- 标题
- 摘要
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- 实验方案
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Quenched Stochastic Optical Reconstruction Microscopy (qSTORM) with Graphene Oxide
摘要： Quenched Stochastic Optical Reconstruction Microscopy (qSTORM) was demonstrated with graphene oxide sheets, peptides and bacteria; a method of contrast enhancement with super-resolution fluorescence microscopy. Individual sheets of graphene oxide (GO) were imaged with a resolution of 16 nm using the quenching of fluorescence emission by GO via its large Resonant Energy Transfer (RET) efficiency. The method was then extended to image self-assembled peptide aggregates (resolution 19 nm) and live bacterial cells (resolution 55 nm, the capsular structure of E. coli from urinary tract infections) with extremely low backgrounds and high contrasts (between one and two orders of magnitude contrast factor improvements that depended on the thickness of the graphene oxide layer used). Graphene oxide films combined with STORM imaging thus provide an extremely convenient method to image samples with large backgrounds due to non-specifically bound fluorophores (either due to excess labelling or autofluorescent molecules), which is a common occurrence in studies of both biological cells and soft-condensed matter. The GO quenches the fluorescence across a thin layer at distances of less than 15 nm. Graphene oxide films coated with thin layers (≤15 nm) of polystyrene, polymethylmethacrylate and polylysine are shown to be effective in producing high contrast qSTORM images, providing a convenient modulation of sample/substrate interactions. The GO coatings can also provide an increased image resolution and a factor of 2.3 improvement was observed with the peptide fibres using a feature of interest metric,when there was a large non-specifically bound background.
关键词： Quenched Stochastic Optical Reconstruction Microscopy,contrast enhancement,peptide aggregates,qSTORM,fluorescence quenching,RET,bacterial cells,Resonant Energy Transfer,graphene oxide,super-resolution fluorescence microscopy
更新于2025-09-10 09:29:36
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[Institution of Engineering and Technology 2015 IET International Conference on Biomedical Image and Signal Processing (ICBISP 2015) - Beijing, China (19 Nov. 2015)] 2015 IET International Conference on Biomedical Image and Signal Processing (ICBISP 2015) - Iterative reconstruction for bioluminescence tomography based on an adaptive region shrinking strategy
摘要： The main challenge of bioluminescence tomography (BLT) is the ill-posed, non-unique nature of the inverse problem. To get reliable reconstruction, permissible source region is a commonly used a priori knowledge in the inverse procedure. In this paper, to accurately reveal 3D distribution of bioluminescent sources from limited boundary measurement, we propose an iterative reconstruction method incorporating adaptive algebraic reconstruction technique (AART) and adaptively shrinking permissible source region. AART algorithm is applied to get the solution without permissible region. Base on the distribution of the solution, we calculate the expectation and the covariance matrix and then derive the parameters for determining a cuboid-shaped region. Simulation experiments on a 3D digital mouse and an in vivo experiment are conducted to validate the feasibility and evaluate the performance of the proposed reconstruction method. The reconstructed results demonstrate the shrinking strategy is helpful for improving the stability of inverse algorithm.
关键词： iterative reconstruction method,finite element method,inverse problems,bioluminescence tomography
更新于2025-09-10 09:29:36
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Membership Function-Weighted Non-Linear Fitting Method for Optical-Sensing Modeling and Reconstruction
摘要： Imprecise measurements present universally due to variability in the measurement error. We devised a very simple membership function to evaluate fuzzily the quality of optical sensing with a small dataset, where a normal distribution cannot be assumed. The proposed membership function was further used as a weighting function for non-linear curve fitting under expected mathematical model constraints, namely the membership function-weighted Levenberg–Marquardt (MFW-LM) algorithm. The robustness and effectiveness of the MFW-LM algorithm were demonstrated by an optical-sensing simulation and two practical applications. (1) In laser-absorption spectroscopy, molecular spectral line modeling was greatly improved by the method. The measurement uncertainty of temperature and pressure were reduced dramatically, by 53.3% and 43.5%, respectively, compared with the original method. (2) In imaging, a laser beam-profile reconstruction from heavy distorted observations was improved by the method. As the dynamic range of the infrared camera increased from 256 to 415, the detailed resolution of the laser-beam profiles increased by an amazing 360%, achieving high dynamic-range imaging to capture optical signal details. Therefore, the MFW-LM algorithm provides a robust and effective tool for fitting a proper physical model and precision parameters from low-quality data.
关键词： non-linear curve fitting,sensing modeling and reconstruction,image reconstruction-restoration,optical-sensing signal processing,laser-absorption spectroscopy
更新于2025-09-09 09:28:46
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A Stochastic Gradient Approach for Robust Heartbeat Detection with Doppler Radar Using Time-Window-Variation Technique
摘要： Heart rate variability (HRV) indicates health condition and mental stress. The development of non-contact heart rate (HR) monitoring technique with Doppler radar is attracting great attentions. However, the performance of heartbeat detection via radar signal easily degrades, due to respiration and body motion. In this paper, first, a stochastic gradient approach is applied to reconstruct high-resolution spectrum of heartbeat, by proposing the zero-attracting sign least-mean-square (ZA-SLMS) algorithm. To correct the quantized gradient of cost function, and penalize the sparse constraint on the updating spectrum, more accurate heartbeat spectrum is reconstructed. Then, to better adapt to the noises with different strengths caused by subjects’ movements, an adaptive regularization parameter (AREPA) is introduced in the ZA-SLMS algorithm as an improved variant, which can adaptively regulate the proportion between gradient correction and sparse penalty. Moreover, in view of the stability of location of spectral peak associated with HR when the size of time window slightly changes, a time-window-variation (TWV) technique is further incorporated in the improved ZA-SLMS (IZA-SLMS) algorithm, for more stable HR estimation. Through the experiments on five subjects, our proposal is demonstrated to bring a significant improvement of accuracy against existing detection methods. Specifically, the IZA-SLMS algorithm with TWV achieves the smallest average error of 3.79 beats per minute (BPM), when subjects type with a laptop.
关键词： Doppler radar,Non-contact heartbeat detection,sparse spectrum reconstruction (SSR),adaptive filter,time-window-variation (TWV),heart rate (HR)
更新于2025-09-09 09:28:46
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Convergence of SART + OS + TV iterative reconstruction algorithm for optical CT imaging of gel dosimeters
摘要： Computational simulations are used to investigate the convergence of a hybrid iterative algorithm for optical CT reconstruction, i.e. the simultaneous algebraic reconstruction technique (SART) integrated with ordered subsets (OS) iteration and total variation (TV) minimization regularization, or SART+OS+TV for short. The influence of parameter selection to reach convergence, spatial dose gradient integrity, MTF and convergent speed are discussed. It’s shown that the results of SART+OS+TV algorithm converge to the true values without significant bias, and MTF and convergent speed are affected by different parameter sets used for iterative calculation. In conclusion, the performance of the SART+OS+TV depends on parameter selection, which also implies that careful parameter tuning work is required and necessary for proper spatial performance and fast convergence.
关键词： iterative reconstruction algorithm,gel dosimeters,SART+OS+TV,optical CT imaging,convergence
更新于2025-09-09 09:28:46
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The Precision Exploration of Image Super-Resolution Applied into Motion Measurement
摘要： This paper proposes a new evaluation parameter of image super-resolution reconstruction quality, which is used to determine the influence of super-resolution reconstruction on motion measuring precision. Based on this new evaluation parameter, we respectively employ different algorithms of super-resolution reconstruction with different reconstruction scales, then calculate the motion measuring precision using the corresponding super-resolution image, analyze the impact of image super-resolution technology on the precision of image motion measuring. The experimental results show that only part of the super-resolution algorithms can improve the measuring precision slightly, and prove that under the background of image motion measurement, image super-resolution reconstruction method has the potential to apply to the actual measurement.
关键词： reconstruction algorithms,image super-resolution,motion measurement,precision evaluation
更新于2025-09-09 09:28:46
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A Spectral–Temporal Patch-Based Missing Area Reconstruction for Time-Series Images
摘要： Clouds, cloud shadows (CCS), and numerous other factors will cause a missing data problem in passive remote sensing images. A well-known reconstruction method is the selection of a similar pixel (with an additional clear reference image) from the remaining clear part of an image to replace the missing pixel. Due to the merit of filling the missing value using a pixel acquired on the same image with the same sensor and the same date, this method is suitable for time-series applications when a time-series profile-based similar measure is utilized for selecting the similar pixel. Since the similar pixel is independently selected, the improper reference pixel or various accuracies obtained by different land covers causes the problem of salt-and-pepper noise in the reconstructed part of an image. To overcome these problems, this paper presents a spectral–temporal patch (STP)-based missing area reconstruction method for time-series images. First, the STP, the pixels of which have similar spectral and temporal evolution characteristics, is extracted using multi-temporal image segmentation. However, some STP have Missing Observations (STPMO) in the time series, which should be reconstructed. Next, for an STPMO, the most similar STP is selected as the reference STP; then, the mean and standard deviation of the STPMO is predicted using a linear regression method with the reference STP. Finally, the textural information, which is denoted by the spatial configuration of color or intensities of neighboring pixels, is extracted from the clear temporal-adjacent STP and “injected” into the missing area to obtain synthetic cloud-free images. We performed an STP-based missing area reconstruction experiment in Jiangzhou, Chongzuo, Guangxi with time-series images acquired by wide field view (WFV) onboard Chinese Gao Fen 1 on 12 different dates. The results indicate that the proposed method can effectively recover the missing information without salt-and-pepper noise in the reconstructed area; also, the reconstructed part of the image is consistent with the clear part without a false edge. The results confirm that the spectral information from the remaining clear part of the same image and textural information from the temporal-adjacent image can create seamless time-series images.
关键词： missing area reconstruction,cloud-free time-series image,cloud and cloud shadow,multi-temporal image segmentation
更新于2025-09-09 09:28:46
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Low-dose CT imaging of the acute abdomen using model-based iterative reconstruction: a prospective study
摘要： Objectives Performance of a modified abdominopelvic CT protocol reconstructed using full iterative reconstruction (IR) was assessed for imaging patients presenting with acute abdominal symptoms. Materials and methods Fifty-seven patients (17 male, 40 female; mean age of 56.5 ± 8 years) were prospectively studied. Low-dose (LD) and conventional-dose (CD) CTs were contemporaneously acquired between November 2015 and March 2016. The LD and CD protocols imparted radiation exposures approximating 10–20% and 80–90% those of routine abdominopelvic CT, respectively. The LD images were reconstructed with model-based iterative reconstruction (MBIR), and CD images with hybrid IR (40% adaptive statistical iterative reconstruction (ASIR)). Image quality was assessed quantitatively and qualitatively. Independent clinical interpretations were performed with a 6-week delay between reviews. Results A 74.7% mean radiation dose reduction was achieved: LD effective dose (ED) 2.38 ± 1.78 mSv (size-specific dose estimate (SSDE) 3.77 ± 1.97 mGy); CD ED 7.04 ± 4.89 mSv (SSDE 10.74 ± 5.5 mGy). LD-MBIR images had significantly lower objective and subjective image noise compared with CD-ASIR (p < 0.0001). Noise reduction for LD-MBIR studies was greater for patients with BMI < 25 kg/m2 than those with BMI ≥ 25 kg/m2 (5.36 ± 3.2 Hounsfield units (HU) vs. 4.05 ± 3.1 HU, p < 0.0001). CD-ASIR studies had significantly better contrast resolution, and diagnostic acceptability (p < 0.0001 for all). LD-MBIR studies had significantly lower streak artifact (p < 0.0001). There was no difference in sensitivity for primary findings between the low-dose and conventional protocols with the exception of one case of enteritis. Conclusions Low-dose abdominopelvic CT performed with MBIR is a feasible radiation dose reduction strategy for imaging patients presenting with acute abdominal pain.
关键词： Iterative reconstruction,Computed tomography,Acute abdominal imaging,Dose optimization,Radiation dose reduction
更新于2025-09-09 09:28:46
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Terahertz two-pixel imaging based on complementary compressive sensing
摘要： A compact terahertz (THz) imaging system based on complementary compressive sensing has been proposed using two single-pixel detectors. By using a mechanical spatial light modulator, sampling in the transmission and re?ection orientations was achieved simultaneously, which allows imaging with negative mask values. The improvement of THz image quality and anti-noise performance has been veri?ed experimentally compared with the traditional reconstructed image, and is in good agreement with the numerical simulation. The demonstrated imaging system, with the advantages of high imaging quality and strong anti-noise property, opens up possibilities for new applications in the THz region.
关键词： image reconstruction techniques,terahertz imaging,spatial light modulators
更新于2025-09-09 09:28:46
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[IEEE 2017 IEEE 17th International Conference on Communication Technology (ICCT) - Chengdu (2017.10.27-2017.10.30)] 2017 IEEE 17th International Conference on Communication Technology (ICCT) - Research on spectral reconstruction technology based on fourier transform
摘要： This paper introduces the working principle and characteristics imaging spectrometer, and analyzes the acquisition methods, the advantages and disadvantages of several commonly used imaging spectrometers. Secondly, interference data acquisition method, interference image data recombination, interference image data preprocessing, spectral reconstruction and the specific processes of spectral calibration are analyzed and discussed. Finally, the experimental platform is built to test the influence of different focal length of lens on the interference image, and the concrete implementation of the background matlab code.
关键词： spectral reconstruction,interference,polarization,transform,imaging spectrometer
更新于2025-09-09 09:28:46