- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Development of a new high-speed readout system for SOI pixel detectors
摘要： We are developing a new high-speed readout system for silicon on insulator (SOI) pixel detectors. The SOI detector is a monolithic radiation imaging detector based on a 0.2 μm FD-SOI CMOS process. Previously, we used a Xilinx Virtex-4/5 FPGA readout board for the SOI detector and developed many facilities for this board. However, the Virtex-4/5 FPGA is now obsolete and does not have sufficiently high performance for recent experiments that require more than 1-kHz high-speed imaging with a large number of pixels. Thus, we started to develop a new high-speed readout system using the KC705, which is the evaluation board for the Xilinx Kintex-7 FPGA. We developed a new data acquisition structure that has backward compatibility with the previous environment on this board and implements several functions for practical purposes such as micro Computed Tomography. The transfer speed achieved by the new system is 95.3 fps for a 426k pixel detector in continuous data-taking mode, and 762.5 fps in maximum-speed mode. The details of the new readout system are presented.
关键词： X-ray imaging,SOI,FPGA,DAQ,Pixel detector
更新于2025-09-23 15:23:52
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[IEEE 2017 MIXDES - 24th International Conference "Mixed Design of Integrated Circuits and Systems" - Bydgoszcz, Poland (2017.6.22-2017.6.24)] 2017 MIXDES - 24th International Conference "Mixed Design of Integrated Circuits and Systems - Algorithms for elimination of charge sharing effects in single photon counting pixel detectors
摘要： This paper presents an analysis of various algorithms for hit allocation in pixel detectors for charged particle tracking. The algorithms aim to compensate the charge sharing effect and improve the detection efficiency and allocation accuracy in terms of detection efficiency and allocation accuracy. The presented algorithms compare the performance of three algorithms in total: a standard Single Threshold Counting method (STC), a Compressed Sensing algorithm (CS), and a Pattern Recognition algorithm (PR). The simulation results show that the CS and PR algorithms achieve higher detection efficiency and better allocation accuracy compared to the STC method, especially in the presence of noise and charge sharing effects.
关键词： pixel detectors,hit allocation,charge sharing
更新于2025-09-23 15:23:52
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Adaptive LSB quantum watermarking method using tri-way pixel value differencing
摘要： As an important way to protect copyright by embedding watermark in digital images, quantum watermarking catches more and more attentions. In this study, a novel quantum watermarking method on the basis of tri-way pixel value differencing and modified least significant bit (LSB) substitution is proposed. A quantum cover image using the novel-enhanced quantum image representation is partitioned into non-overlapping 2 × 2 blocks with four pixels firstly. To classify the block as a smooth area or an edge area, the tri-way pixel value differences are calculated and compared with a predefined threshold. The quantum watermark image, which is expanded and scrambled, is then embedded into a quantum cover image by the k-bit LSB substitution method, where k is decided by the level of each block. The embedded quantum watermark can be extracted from the quantum stego-image without the assistance of original quantum cover image. Theoretical analysis and simulation-based experiments demonstrate both the feasibility and capabilities of the proposed quantum watermarking method, which has good visual quality, better robustness, and higher security.
关键词： Pixel value difference,Visual quality,Quantum image watermarking,Least significant bit
更新于2025-09-23 15:23:52
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Optimized angles of the swing hyperspectral imaging system for single corn plant
摘要： During recent years, hyperspectral imaging systems have been widely applied in the greenhouses for plant phenotyping purposes. Current systems are typically designed as either top view or side view imaging mode. Top view is an ideal imaging angle for top leaves with flat leaf surfaces. However, most bottom leaves are either blocked or shaded. From side view, the entire plant structure is viewable. However, most leaf surfaces are not facing the camera, which impacts measurement quality. Besides, there could be advantages with certain tilted angle(s) between top view and side view. It’s interesting to explore the impact of different imaging angles to the phenotyping quality. For this purpose, a swing hyperspectral imaging system capable of capturing images at any angle from side view (0°) to top view (90°) by rotating the camera and the lighting source was designed. Corn plants were grown and allocated into 3 different treatments: high nitrogen (N) and well-watered (control), high N and drought-stressed, and low N and well-watered. Each plant was imaged at 7 different angles from 0° to 90° with an interval of 15°. The soil plant analysis development (SPAD) values and relative water content (RWC) ground truth measurements were used to establish treatment effects. The results showed that averaged plant-level Normalized Difference Vegetation Index (NDVI) values of plants in different treatments changed at different imaging angles. The results also indicated that for pixel-level NDVI distributions, the titled imaging angle of 75° was optimal to distinguish different water treatments, whereas, the tilted imaging angle of 15° was optimal to distinguish different N treatments. For pixel-level RWC distributions, the distribution difference between different water treatments was larger at higher imaging angles.
关键词： Pixel-level NDVI and RWC distributions,Optimal imaging angle,Swing hyperspectral imaging system,Plant phenotyping system,Tilted imaging angle
更新于2025-09-23 15:22:29
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Monolithic Wafer Scale Integration of Silicon Nanoribbon Sensors with CMOS for Lab-on-Chip Application
摘要： Silicon ribbons (SiRi) have been well-established as highly sensitive transducers for biosensing applications thanks to their high surface to volume ratio. However, selective and multiplexed detection of biomarkers remains a challenge. Further, very few attempts have been made to integrate SiRi with complementary-metal-oxide-semiconductor (CMOS) circuits to form a complete lab-on-chip (LOC). Integration of SiRi with CMOS will facilitate real time detection of the output signal and provide a compact small sized LOC. Here, we propose a novel pixel based SiRi device monolithically integrated with CMOS ?eld-effect-transistors (FET) for real-time selective multiplexed detection. The SiRi pixels are fabricated on a silicon-on-insulator wafer using a top-down method. Each pixel houses a control FET, ?uid-gate (FG) and SiRi sensor. The pixel is controlled by simultaneously applying frontgate (VG) and backgate voltage (VBG). The liquid potential can be monitored using the FG. We report the transfer characteristics (ID-VG) of N- and P-type SiRi pixels. Further, the ID-VG characteristics of the SiRis are studied at different VBG. The application of VBG to turn ON the SiRi modulates the subthreshold slope (SS) and threshold voltage (VTH) of the control FET. Particularly, N-type pixels cannot be turned OFF due to the control NFET operating in the strong inversion regime. This is due to large VBG (≥25 V) application to turn ON the SiRi sensor. Conversely, the P-type SiRi sensors do not require large VBG to switch ON. Thus, P-type pixels exhibit excellent ION/IOFF ≥ 106, SS of 70–80 mV/dec and VTH of 0.5 V. These promising results will empower the large-scale cost-ef?cient production of SiRi based LOC sensors.
关键词： silicon ribbon biosensor,SiRi backgate mode,silicon ribbon pixel,selective multiplexed detection,SiRi CMOS integration,SiRi frontgate mode,lab-on-chip
更新于2025-09-23 15:22:29
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Inversion of Aerosol Optical Depth Based on the CCD and IRS Sensors on the HJ-1 Satellites
摘要： To perform a high-resolution aerosol optical depth (AOD) inversion from the HJ-1 satellites, a dark pixel algorithm utilizing the HJ-1 satellite data was developed based on the Moderate-Resolution Imaging Spectroradiometer (MODIS) algorithm. By analyzing the relationship between the apparent reflectance from the 1.65 μm and 2.1 μm channels of MODIS, a method for estimating albedo using the 1.65 μm channel data of the HJ-1 satellites was established, and a high-resolution AOD inversion in the Chengdu region based on the HJ-1 satellite was completed. A comparison of the inversion results with CE318 measured data produced a correlation of 0.957, respectively, with an absolute error of 0.106. An analysis of the AOD inversion results from different aerosol models showed that the rural aerosol model was suitable as a general model for establishing an aerosol inversion look-up table for the Chengdu region.
关键词： dark pixel,albedo,aerosol optical depth,HJ-1 satellite
更新于2025-09-23 15:22:29
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Estimating Savanna Clumping Index Using Hemispherical Photographs Integrated with High Resolution Remote Sensing Images
摘要： In contrast to herbaceous canopies and forests, savannas are grassland ecosystems with sparsely distributed individual trees, so the canopy is spatially heterogeneous and open, whereas the woody cover in savannas, e.g., tree cover, adversely affects ecosystem structures and functions. Studies have shown that the dynamics of canopy structure are related to available water, climate, and human activities in the form of porosity, leaf area index (LAI), and clumping index (CI). Therefore, it is important to identify the biophysical parameters of savanna ecosystems, and undertake practical actions for savanna conservation and management. The canopy openness presents a challenge for evaluating canopy LAI and other biophysical parameters, as most remotely sensed methods were developed for homogeneous and closed canopies. Clumping index is a key variable that can represent the clumping effect from spatial distribution patterns of components within a canopy. However, it is a difficult task to measure the clumping index of the moderate resolution savanna pixels directly using optical instruments, such as the Tracing Radiation and Architecture of Canopies, LAI-2000 Canopy Analyzer, or digital hemispherical photography. This paper proposed a new method using hemispherical photographs combined with high resolution remote sensing images to estimate the clumping index of savanna canopies. The effects of single tree LAI, crown density, and herbaceous layer on the clumping index of savanna pixels were also evaluated. The proposed method effectively calculated the clumping index of moderate resolution pixels. The clumping indices of two study regions located in Ejina Banner and Weichang were compared with the clumping index product over China's landmass.
关键词： hemispherical photograph,clumping index,moderate resolution pixel,high resolution images,leaf area index
更新于2025-09-23 15:22:29
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UTILIZA??O DE ALVOS CODIFICADOS DO TIPO ARUCO NA AUTOMA??O DO PROCESSO DE CALIBRA??O DE C?MARAS
摘要： This paper presents a proposal for the automation of the camera calibration process, locating and measuring image points in coded targets with sub-pixel precision. This automatic technique helps minimize localization errors, regardless of camera orientation and image scale. To develop this technique, several types of coded targets were analyzed and the ARUCO type was chosen due to its simplicity, ability to represent up to 1024 different targets and availability of source code implemented with the OpenCV library. ARUCO targets were generated and two calibration sheets were assembled to be used for the acquisition of images for camera calibration. The developed software can locate targets in the acquired images and it automatically extracts the coordinates of the four corners with sub-pixel accuracy. Experiments were conducted with real data showing that the targets are correctly identified unless excessive noise or fragmentation occurs mainly in the outer target square. The results with the calibration of a low cost camera showed that the process works and that the measurement accuracy of the corners achieves sub-pixel precision.
关键词： Calibration Chambers,Targets Coded,Photogrammetry,ARUCO,OpenCV,Sub-Pixel
更新于2025-09-23 15:22:29
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Improving the Signal-to-noise Ratio of Super Resolution Imaging Based on Single Pixel Camera
摘要： Based on the theories of single pixel camera and compressed sensing image reconstruction, the sparse basis, the projection method of measurement matrix and the signal reconstruction algorithm are optimized. Firstly, for the sparse representation of image, the restraint matrix is designed combining the characteristics of wavelet sparse coefficients to enhance the sparse representation ability of the discrete wavelet base, which improves the quality of image reconstruction and imaging by single pixel camera. Then in the single pixel camera system, the projection method is improved according to the characteristics of the DMD micro-mirror, and a new bilateral projection method based on the block diagonal measurement matrix is proposed to realize the super resolution imaging of the outdoor scene, reducing the number of measurement and improving the imaging quality. Finally, for the algorithm of image reconstruction, combining the characteristics of convex optimization and non-convex optimization algorithms, a new algorithm from convex optimization approximately to non convex optimization algorithm is proposed, and compared with traditional image reconstruction algorithm such as greedy pursuit algorithm, minimum norm algorithm and image interpolation, the peak signal to noise ratio (PSNR) and imaging quality of reconstructed images are effectively improved. The feasibility of the proposed methods is demonstrated by simulation experiments and imaging experiments of single pixel camera.
关键词： measurement matrix,Single pixel camera,sparse representation,super resolution,image reconstruction
更新于2025-09-23 15:22:29
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A three-step displacement measurement method for a 3-DOF macro-micro positioning stage
摘要： A high-performance displacement measurement method for the displacement measurement of a three degree of freedom (3-DOF) macro-micro positioning stage based on the micro-vision measurement system is proposed. The method is built up by three steps. In the first step, a fast search algorithm combined with triangular relations and a ring projection with illumination and noise correction is adopted to achieve the selection of candidate pixels. Subsequently, an orientation code based algorithm is adopted to determine the integer-pixel displacement and rotation angle estimation. The third step is to obtain the sub-pixel displacement through a similarity function based algorithm. Simulations are carried out, and the results show that the proposed method has the characteristics of translation and rotation invariance, and the matching accuracy can reach 0.01-pixel theoretically. Moreover, the proposed method consumes less time than that of the orientation code and pseudo-Zernike moment based algorithm. Finally, a capacitance sensor measurement system is established to compare the accuracy of the proposed method. The experiment results demonstrate that it has a high accuracy.
关键词： sub-pixel displacement,orientation code,displacement measurement,macro-micro positioning stage,micro-vision measurement system
更新于2025-09-23 15:21:21