Aiming at a novel missile-borne detector in the optional burst height proximity fuze, a self-adaptive high-resolution forward-looking imaging algorithm (SAHRFL-IA) is presented. The echo data are captured by the missi...Aiming at a novel missile-borne detector in the optional burst height proximity fuze, a self-adaptive high-resolution forward-looking imaging algorithm (SAHRFL-IA) is presented. The echo data are captured by the missile-borne detector in the target regions;thereby the azimuth angulation accuracy at the same distance dimension is improved dynamically. Thus, azimuth information of the targets in the detection area may be obtained accurately. The proposed imaging algorithm breaks through the conventional misconception of merely using azimuth discrimination curves under ideal conditions during monopulse angulation. The real-time echo data from the target region are used to perform error correction for this discrimination curve, and finally the accuracy of the azimuth angulation may reach the optimum at the same distance dimension. A series of experiments demonstrate the validity, reliability and high performance of the proposed imaging algorithm. Azimuth angulation accuracy may reach ten times that of the detection beam width. Meanwhile, the running time of this algorithm satisfies the requirements of missile-borne platforms.展开更多
In this paper,we proposed a monopulse forward-looking high-resolution imaging algorithm based on adaptive iteration for missile-borne detector.Through iteration,the proposed algorithm automatically selects the echo si...In this paper,we proposed a monopulse forward-looking high-resolution imaging algorithm based on adaptive iteration for missile-borne detector.Through iteration,the proposed algorithm automatically selects the echo signal of isolated strong-scattering points from the receiving echo signal data to accurately estimate the actual optimal monopulse response curve(MRC) of the same distance range,and we applied optimal MRC to realize the azimuth self-focusing in the process of imaging.We use real-time echo data to perform error correction for obtaining the optimal MRC,and the azimuth angulation accuracy may reach the optimum at a certain distance dimension.We experimentally demonstrate the validity,reliability and high performance of the proposed algorithm.The azimuth angulation accuracy may reach up to ten times of the detection beam-width.The simulation experiments have verified the feasibility of this strategy,with the average height measurement error being 7.8%.In the out-field unmanned aerial vehicle(UAV) tests,the height measurement error is less than 25 m,and the whole response time can satisfy the requirements of a missile-borne detector.展开更多
The spatial resolution of a commercial two-dimensional(2D)ionization chamber(IC)array is limited by the size of the individual detector and the center-to-center distance between sensors.For dose distributions with are...The spatial resolution of a commercial two-dimensional(2D)ionization chamber(IC)array is limited by the size of the individual detector and the center-to-center distance between sensors.For dose distributions with areas of steep dose gradients,inter-detector dose values are derived by the interpolation of nearby detector readings in the conventional mathematical interpolation of 2D IC array measurements.This may introduce significant errors,particularly in proton spot scanning radiotherapy.In this study,by combining logfile-based reconstructed dose values and detector measurements with the Laplacian pyramid image blending method,a novel method is proposed to obtain a reformatted dose distribution that provides an improved estimation of the delivered dose distribution with high spatial resolution.Meanwhile,the similarity between the measured original data and the downsampled logfilebased reconstructed dose is regarded as the confidence of the reformatted dose distribution.Furthermore,we quantify the performance benefits of this new approach by directly comparing the reformatted dose distributions with 2D IC array detector mathematically interpolated measurements and original low-resolution measurements.The result shows that this new method is better than the mathematical interpolation and achieves gamma pass rates similar to those of the original low-resolution measurements.The reformatted dose distributions generally yield a confidence exceeding 95%.展开更多
Purpose We developed a low-complexity,high-resolution depth-of-interaction(DOI)capable positron emission tomography(PET)detector and tested its performance to prove that it can be applied to practical PET instruments....Purpose We developed a low-complexity,high-resolution depth-of-interaction(DOI)capable positron emission tomography(PET)detector and tested its performance to prove that it can be applied to practical PET instruments.Methods The detector module consists of a 24×24 LYSO crystal matrix,each with dimension of 1.04×1.04×15mm^(3),optically coupled to an 8×8 SiPM photo-sensor array with TOFPET2 ASIC single-ended readout.By only adding a light guide at the top of the crystal to reflect scintillation light back to the SiPM array,the continuous DOI information is extracted using a light sharing and redirection encoding method without adding system complexity.Results The crystal array with 9-to-1 coupling between scintillators and photo-sensors can be clearly separated in the flood image.The other detector performance in terms of DOI resolution,energy resolution and coincidence time resolution are measured on average as 4.1 mm,15.0%and 432 ps,respectively.Conclusion The test results confirm that the light sharing and redirection DOI encoding method can provide reasonably high DOI resolution without deteriorating other performance,even for highly pixelated PET detectors readout with commercially available ASIC chip.It has great potential for applications in future pre-clinical and organ-dedicated PET scanners.展开更多
In this work,we extend the characteristic-featured shock wave indicator based on artificial neuron training to 3D high-speed flow simulation on unstructured meshes.The extension is achieved through dimension splitting...In this work,we extend the characteristic-featured shock wave indicator based on artificial neuron training to 3D high-speed flow simulation on unstructured meshes.The extension is achieved through dimension splitting.This leads to that the proposed indicator is capable of identifying regions of flow compression in any direction.With this capability,the indicator is further developed to combine with h-adaptivity of mesh refinement to improve resolution with less computational costs.The present indicator provides an attractive alternative for constructing high-resolution,high-efficiency shock-processing methods to simulate high-speed inviscid flows.展开更多
基金supported by the Key Army Pre-research Projects of China(30107030803)
文摘Aiming at a novel missile-borne detector in the optional burst height proximity fuze, a self-adaptive high-resolution forward-looking imaging algorithm (SAHRFL-IA) is presented. The echo data are captured by the missile-borne detector in the target regions;thereby the azimuth angulation accuracy at the same distance dimension is improved dynamically. Thus, azimuth information of the targets in the detection area may be obtained accurately. The proposed imaging algorithm breaks through the conventional misconception of merely using azimuth discrimination curves under ideal conditions during monopulse angulation. The real-time echo data from the target region are used to perform error correction for this discrimination curve, and finally the accuracy of the azimuth angulation may reach the optimum at the same distance dimension. A series of experiments demonstrate the validity, reliability and high performance of the proposed imaging algorithm. Azimuth angulation accuracy may reach ten times that of the detection beam width. Meanwhile, the running time of this algorithm satisfies the requirements of missile-borne platforms.
基金The name of the project that funded this article is 13th Five-Year Plan"equipment pre-research project,the number of this project is 30107030803。
文摘In this paper,we proposed a monopulse forward-looking high-resolution imaging algorithm based on adaptive iteration for missile-borne detector.Through iteration,the proposed algorithm automatically selects the echo signal of isolated strong-scattering points from the receiving echo signal data to accurately estimate the actual optimal monopulse response curve(MRC) of the same distance range,and we applied optimal MRC to realize the azimuth self-focusing in the process of imaging.We use real-time echo data to perform error correction for obtaining the optimal MRC,and the azimuth angulation accuracy may reach the optimum at a certain distance dimension.We experimentally demonstrate the validity,reliability and high performance of the proposed algorithm.The azimuth angulation accuracy may reach up to ten times of the detection beam-width.The simulation experiments have verified the feasibility of this strategy,with the average height measurement error being 7.8%.In the out-field unmanned aerial vehicle(UAV) tests,the height measurement error is less than 25 m,and the whole response time can satisfy the requirements of a missile-borne detector.
文摘The spatial resolution of a commercial two-dimensional(2D)ionization chamber(IC)array is limited by the size of the individual detector and the center-to-center distance between sensors.For dose distributions with areas of steep dose gradients,inter-detector dose values are derived by the interpolation of nearby detector readings in the conventional mathematical interpolation of 2D IC array measurements.This may introduce significant errors,particularly in proton spot scanning radiotherapy.In this study,by combining logfile-based reconstructed dose values and detector measurements with the Laplacian pyramid image blending method,a novel method is proposed to obtain a reformatted dose distribution that provides an improved estimation of the delivered dose distribution with high spatial resolution.Meanwhile,the similarity between the measured original data and the downsampled logfilebased reconstructed dose is regarded as the confidence of the reformatted dose distribution.Furthermore,we quantify the performance benefits of this new approach by directly comparing the reformatted dose distributions with 2D IC array detector mathematically interpolated measurements and original low-resolution measurements.The result shows that this new method is better than the mathematical interpolation and achieves gamma pass rates similar to those of the original low-resolution measurements.The reformatted dose distributions generally yield a confidence exceeding 95%.
基金This work was supported by the National Natural Science Foundation of China[Grant Number 11735013].
文摘Purpose We developed a low-complexity,high-resolution depth-of-interaction(DOI)capable positron emission tomography(PET)detector and tested its performance to prove that it can be applied to practical PET instruments.Methods The detector module consists of a 24×24 LYSO crystal matrix,each with dimension of 1.04×1.04×15mm^(3),optically coupled to an 8×8 SiPM photo-sensor array with TOFPET2 ASIC single-ended readout.By only adding a light guide at the top of the crystal to reflect scintillation light back to the SiPM array,the continuous DOI information is extracted using a light sharing and redirection encoding method without adding system complexity.Results The crystal array with 9-to-1 coupling between scintillators and photo-sensors can be clearly separated in the flood image.The other detector performance in terms of DOI resolution,energy resolution and coincidence time resolution are measured on average as 4.1 mm,15.0%and 432 ps,respectively.Conclusion The test results confirm that the light sharing and redirection DOI encoding method can provide reasonably high DOI resolution without deteriorating other performance,even for highly pixelated PET detectors readout with commercially available ASIC chip.It has great potential for applications in future pre-clinical and organ-dedicated PET scanners.
基金supported by the National Numerical Wind Tunnel Project,the National Natural Science Foundation of China(No.12001031)the Academic Excellence Foundation of BUAA for PhD Students,China Postdoctoral Science Foundation(No.2020M680284).
文摘In this work,we extend the characteristic-featured shock wave indicator based on artificial neuron training to 3D high-speed flow simulation on unstructured meshes.The extension is achieved through dimension splitting.This leads to that the proposed indicator is capable of identifying regions of flow compression in any direction.With this capability,the indicator is further developed to combine with h-adaptivity of mesh refinement to improve resolution with less computational costs.The present indicator provides an attractive alternative for constructing high-resolution,high-efficiency shock-processing methods to simulate high-speed inviscid flows.
