- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Dual-modality optical projection tomography reconstruction method from fewer views
摘要： In optical projection tomography (OPT), for longitudinal living model studies, multiple measurements of the same sample are required at different time points. It is important to decrease both the total acquisition time and the light dose to the sample. We improved the ordered subsets expectation maximization reconstruction algorithm for OPT, which reduces the acquisition time and number of projections greatly compared with filtered back projection (FBP), and satisfactory reconstructed images are obtained. Using zebrafish, in transmission and fluorescence mode, we demonstrate the capability of the method to reconstruct image from downsampled projection subsets. The result shows that the reconstruction image quality of the proposed method using 30 projections is comparable to that of FBP using 720 projections. The total acquisition procedure can be finished in a few seconds. The method also provides OPT with the remarkable capability to resist noises and artifacts.
关键词： molecular imaging,image reconstruction,dual-modality OPT,preimaging calibration
更新于2025-09-23 15:22:29
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Caracterización y simulación de ruido en las imágenes de PET reconstruidas con OSEM: desarrollo de un método para la generación de imágenes sintéticas
摘要： Introduction: The goals of the study are to characterize imaging properties in 2D PET images reconstructed with the iterative algorithm ordered-subset expectation maximization (OSEM) and to propose a new method for the generation of synthetic images. Material and methods: The noise is analyzed in terms of its magnitude, spatial correlation, and spectral distribution through standard deviation, autocorrelation function, and noise power spectrum (NPS), respectively. Their variations with position and activity level are also analyzed. This noise analysis is based on phantom images acquired from 18F uniform distributions. Experimental recovery coefficients of hot spheres in different backgrounds are employed to study the spatial resolution of the system through point spread function (PSF). The NPS and PSF functions provide the baseline for the proposed simulation method: convolution with PSF as kernel and noise addition from NPS. Results: The noise spectral analysis shows that the main contribution is of random nature. It is also proven that attenuation correction does not alter noise texture but it modifies its magnitude. Finally, synthetic images of 2 phantoms, one of them an anatomical brain, are quantitatively compared with experimental images showing a good agreement in terms of pixel values and pixel correlations. Thus, the contrast to noise ratio for the biggest sphere in the NEMA IEC phantom is 10.7 for the synthetic image and 8.8 for the experimental image. Conclusions: The properties of the analyzed OSEM-PET images can be described by NPS and PSF functions. Synthetic images, even anatomical ones, are successfully generated by the proposed method based on the NPS and PSF.
关键词： PET,Autocorrelation function,OSEM,Iterative reconstruction,Noise power spectrum,Point spread function
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 3rd International Conference on Signal and Image Processing (ICSIP) - Shenzhen, China (2018.7.13-2018.7.15)] 2018 IEEE 3rd International Conference on Signal and Image Processing (ICSIP) - Long Baseline Linear Array SAR Signal Reconstruction and Imaging
摘要： Due to the minimum antenna area constraint, conventional single-satellite SAR cannot obtain the image with wide swaths as well as high-resolution. This problem can be solved by using single-platform multi-phase center SAR or constellation SAR, which divides the large antenna into small antennas. Compared with single-platform multi-phase center SAR, there are several advantages but also challenges for constellation SAR. In this paper, point-target imaging simulations are performed for linear array constellation SAR with long baseline. And the effect of the long baseline on imaging is discussed. And then the methods to overcome the effect and to reconstruct the unambiguity signal is given.
关键词： long baseline,constellation SAR,linear array SAR,signal reconstruction
更新于2025-09-23 15:22:29
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Robust 3D object reconstruction based on camera clustering with geodesic distance
摘要： This Letter presents a method that reconstructs 3D object using camera clustering and key camera selection to resolve scalability problem. To perform camera clustering, camera similarity is defined using geodesic distance and overlap constraint between cameras. Key cameras are then selected to reconstruct an object considering overlapping cameras and high curvature regions. As a result, it is achievable to relax increases in the execution time and the accumulated errors due to the scalability problems with a large number of cameras.
关键词： three-dimensional displays,image reconstruction,Clustering methods,Robot vision systems
更新于2025-09-23 15:22:29
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[IEEE 2018 Eighth International Conference on Image Processing Theory, Tools and Applications (IPTA) - Xi'an, China (2018.11.7-2018.11.10)] 2018 Eighth International Conference on Image Processing Theory, Tools and Applications (IPTA) - Interval-valued JPEG decompression for artifact suppression
摘要： JPEG is the most used image compression algorithm but block wise DCT compression methods produce artifacts due to coefficient quantization. JPEG decompression can be seen as a reconstruction problem constrained by quantization. In this context, we propose to handle this problem by using interval-valued arithmetic. Our method allows to produce interval-valued image that includes the non-compressed original image. The produced convex set allows to apply constrained Total Variation (TV) reconstruction in order to reduce JPEG artifacts (blocking, grainy effects and high frequency noise). Experiments show visual improvement of JPEG decoding assessed by non-reference quality metric. In addition, the stopping criterion of the TV algorithm is given by this metric which provides evidence about JPEG decompression improvement.
关键词： JPEG artifact removing,image reconstruction,interval-valued arithmetic,image selection,JPEG decompression
更新于2025-09-23 15:22:29
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[ACM Press SIGGRAPH Asia 2018 Posters - Tokyo, Japan (2018.12.04-2018.12.07)] SIGGRAPH Asia 2018 Posters on - SA '18 - Panoramic depth reconstruction within a single shot by optimizing global sphere radii
摘要： Depth estimation in scene reconstruction remains one of the main issues in the world of virtual reality. We propose a method that uses low cost camera facilities from previous papers and their specified procedures for stereoscopic 360 imaging. However, instead of using angular disparity, we use the spherical radius for labeling depth values for scene reconstruction. The experimental results show that the reconstructed shape is less distorted by directly optimizing spherical radii than optimizing the angular disparities.
关键词： Matching cost map,Polycamera,Inverse radius disparity depth estimation,Depth Reconstruction,Depth map
更新于2025-09-23 15:22:29
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[IEEE 2018 5th IEEE International Workshop on Metrology for AeroSpace (MetroAeroSpace) - Rome, Italy (2018.6.20-2018.6.22)] 2018 5th IEEE International Workshop on Metrology for AeroSpace (MetroAeroSpace) - Shape Measurement of Large Structures in Space: Experiments
摘要： A method to reconstruct the shape of a large planar structure in space is introduced and demonstrated through a lab-scale experiment. Lightweight sun sensors are distributed on the structure to measure local angles relative to the sun. The methodology to integrate the measured angles into the shape of the structure, based on a decomposition of the shape into basis functions is introduced. This methodology has been implemented on a lab-scale experiment. The design of the sensors is based on a 4 pixel pinhole camera. The calibration method for these sensors is presented as well as the techniques to integrate and communicate with them. A 1.2 m by 20 cm structure was designed and populated with sensors to show the performance of an integrated system. Preliminary results show an accuracy of 1 mm RMS on the shape reconstruction of this structure.
关键词： reconstruction,shape,measurement,sensor,sun,solar,laboratory,experiment,structure,sail,antenna array
更新于2025-09-23 15:22:29
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Maximum entropy based non-negative optoacoustic tomographic image reconstruction
摘要： Objective: Optoacoustic (photoacoustic) tomography is aimed at reconstructing maps of the initial pressure rise induced by the absorption of light pulses in tissue. In practice, due to inaccurate assumptions in the forward model, noise and other experimental factors, the images are often afflicted by artifacts, occasionally manifested as negative values. The aim of the work is to develop an inversion method which reduces the occurrence of negative values and improves the quantitative performance of optoacoustic imaging. Methods: We present a novel method for optoacoustic tomography based on an entropy maximization algorithm, which uses logarithmic regularization for attaining non-negative reconstructions. The reconstruction image quality is further improved using structural prior based fluence correction. Results: We report the performance achieved by the entropy maximization scheme on numerical simulation, experimental phantoms and in-vivo samples. Conclusion: The proposed algorithm demonstrates superior reconstruction performance by delivering non-negative pixel values with no visible distortion of anatomical structures. Significance: Our method can enable quantitative optoacoustic imaging, and has the potential to improve pre-clinical and translational imaging applications.
关键词： inverse problems,image reconstruction,Optical parameters,regularization theory,photoacoustic tomography
更新于2025-09-23 15:22:29
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Sparse Reconstruction-Based Thermal Imaging for Defect Detection
摘要： This paper proposes an idea of employing sparse reconstruction-based technique for thermal imaging defect detection. The implementation of the reconstruction technique is tested on a carbon fiber reinforced polymer test piece with artificially drilled defects and the test results are compared with the established cross correlation method. The two processes are compared in terms of defect detectability, their SNR variation with defect depth and their computation complexity. When compared with cross correlation algorithm, the technique is expected to solve memory space problems by compressing all information from large cross-correlated pulse video into a single reconstructed image as an output. Furthermore, in existing cross correlation methods, the pulse peak time shifts with defect depth. Hence, defect quantification algorithms, such as SNR calculation, require multiple frame analysis. Such algorithms are comparatively simplified in sparse reconstruction technique. This paper explores sparse reconstruction algorithm for resolving close-spaced defects. This paper further describes cross-validation method for optimization of a user parameter in sparse reconstruction method.
关键词： thermal nondestructive testing,sparse reconstruction,pulse compression,nondestructive evaluation and remote sensing,frequency modulated thermal wave imaging,Cross correlation algorithm
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 3rd International Conference on Image, Vision and Computing (ICIVC) - Chongqing (2018.6.27-2018.6.29)] 2018 IEEE 3rd International Conference on Image, Vision and Computing (ICIVC) - Distributed Compressive Video Sensing with Adaptive Reconstruction Based on Temporal Correlation
摘要： Aiming at enhance reconstruction quality, this paper proposes an adaptive reconstruction scheme with no feedback channel for distributed compressive video sensing, effectively exploiting temporal correlation. Specifically, the proposed scheme divides each block of non-key frames into different classifications based on temporal correlation in the encoding side and selects corresponding reconstruction mode which adaptively utilizes side information in the decoding side. The simulation results show that the proposed scheme achieves superior performance over existing methods in terms of reconstruction quality and computation cost.
关键词： adaptive reconstruction,distributed compressive video sensing,temporal correlation
更新于2025-09-23 15:22:29