scholarly journals Squint Model InISAR Imaging Method Based on Reference Interferometric Phase Construction and Coordinate Transformation

2021 ◽  
Vol 13 (11) ◽  
pp. 2224
Author(s):  
Yu Li ◽  
Yunhua Zhang ◽  
Xiao Dong
Keyword(s):  
Coordinate Transformation ◽  
Cross Correlation ◽  
Three Dimensional ◽  
Image Distortion ◽  
Imaging Method ◽  
Phase Ambiguity ◽  
Correlation Algorithm ◽  
Interferometric Phase ◽  
Isar Imaging

The imaging quality of InISAR under squint geometry can be greatly degraded due to the serious interferometric phase ambiguity (InPhaA) and thus result in image distortion problems. Aiming to solve these problems, a three-dimensional InISAR (3D ISAR) imaging method based on reference InPhas construction and coordinate transformation is presented in this paper. First, the target’s 3D coarse location is obtained by the cross-correlation algorithm, and a relatively stronger scatterer is taken as the reference scatterer to construct the reference interferometric phases (InPhas) so as to remove the InPhaA and restore the real InPhas. The selected scatterer needs not to be exactly in the center of the coarsely located target. Then, the image distortion is corrected by coordinate transformation, and finally the 3D coordinates of the target can be accurately estimated. Both simulation and practical experiment results validate the effectiveness of the method.

Application of cross-correlation algorithm in moving target range-gated three-dimensional laser active imaging

2016 ◽  
Vol 45 (6) ◽  
pp. 0617003
Author(s):  
范有臣 Fan Youchen ◽  
赵洪利 Zhao Hongli ◽  
孙华燕 Sun Huayan ◽  
郭惠超 Guo Huichao ◽  
赵延仲 Zhao Yanzhong
Keyword(s):  
Cross Correlation ◽  
Three Dimensional ◽  
Target Range ◽  
Moving Target ◽  
Correlation Algorithm ◽  
Active Imaging

scholarly journals Three-Dimensional ISAR Imaging Method for High-Speed Targets in Short-Range Using Impulse Radar Based on SIMO Array

Sensors ◽  
2016 ◽  
Vol 16 (3) ◽  
pp. 364 ◽  
Author(s):  
Xinpeng Zhou ◽  
Guohua Wei ◽  
Siliang Wu ◽  
Dawei Wang
Keyword(s):  
High Speed ◽  
Short Range ◽  
Three Dimensional ◽  
Imaging Method ◽  
Isar Imaging

scholarly journals Three-Dimensional Interferometric ISAR Imaging Algorithm Based on Cross Coherence Processing

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5073
Author(s):  
Qian Lv ◽  
Shaozhe Zhang
Keyword(s):  
3D Imaging ◽  
High Efficiency ◽  
Imaging System ◽  
Computational Cost ◽  
Three Dimensional ◽  
Reconstruction Algorithm ◽  
Image Plane ◽  
Interferometric Phase ◽  
Isar Imaging ◽  
Reflectivity Function

Interferometric inverse synthetic aperture radar (InISAR) has received significant attention in three-dimensional (3D) imaging due to its applications in target classification and recognition. The traditional two-dimensional (2D) ISAR image can be interpreted as a filtered projection of a 3D target’s reflectivity function onto an image plane. Such a plane usually depends on unknown radar-target geometry and dynamics, which results in difficulty interpreting an ISAR image. Using the L-shape InISAR imaging system, this paper proposes a novel 3D target reconstruction algorithm based on Dechirp processing and 2D interferometric ISAR imaging, which can jointly estimate the effective rotation vector and the height of scattering center. In order to consider only the areas of the target with meaningful interferometric phase and mitigate the effects of noise and sidelobes, a special cross-channel coherence-based detector (C3D) is introduced. Compared to the multichannel CLEAN technique, advantages of the C3D include the following: (1) the computational cost is lower without complex iteration and (2) the proposed method, which can avoid propagating errors, is more suitable for a target with multi-scattering points. Moreover, misregistration and its influence on target reconstruction are quantitatively discussed. Theoretical analysis and numerical simulations confirm the suitability of the algorithm for 3D imaging of multi-scattering point targets with high efficiency and demonstrate the reliability and effectiveness of the proposed method in the presence of noise.

Vision-based fast location of multi-bar code in any direction

2017 ◽  
Vol 31 (19-21) ◽  
pp. 1740047 ◽  
Author(s):  
Sheng-Xin Lin ◽  
Xiao-Fang Zhao ◽  
Hua-Zhu Liu
Keyword(s):  
Cross Correlation ◽  
Recognition System ◽  
Cumulative Distribution ◽  
Bar Code ◽  
Bar Codes ◽  
Correlation Algorithm ◽  
Automatic Location ◽  
Localization Algorithms ◽  
Location Algorithm

The automatic location of the bar code is a key step in the bar code image recognition system. It is extremely confined that the generalization of the traditional bar code localization algorithms due to the requirements of both direction and quality of bar code, and most of them are only aimed at the single barcode localization. In this paper, we have proposed a novel multi-barcode location algorithm in arbitrary direction based on the accumulation of the linear gray value. First, the line coordinates of the barcode region is determined by the image normalized cross-correlation algorithm. Then the center line of gray value of cumulative distribution is used to analyze the barcode boundary and to determine the number of bar code within the region. Finally, the precise positioning of the barcode region is obtained. The experiments have demonstrated that our proposed method can be used to identify all the bar codes in any area, and automatically locate the bar codes in any direction.

scholarly journals In Situ Investigation of the 3D Mechanical Microstructure at Nanoscale: Nano-CT Imaging Method of Local Small Region in Large Scale Sample

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Bo Dong ◽  
Feng Xu ◽  
Xiao-fang Hu ◽  
Hong-yan Qu ◽  
Dan Kang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Small Region ◽  
Projection Data ◽  
Imaging Method ◽  
Reconstruction Method ◽  
Localization Property ◽  
Local Tomography ◽  
In Situ Investigation

To investigate the local micro-/nanoscale region in a large scale sample, an image reconstruction method for nanometer computed tomography (nano-CT) was proposed in this paper. In the algorithm, wavelets were used to localize the filtered-backprojection (FBP) algorithm because of its space-frequency localization property. After the implementation of the algorithm, two simulation local reconstruction experiments were performed to confirm its effectiveness. Three evaluation criteria were used in the experiments to judge the quality of the reconstructed images. The experimental results showed that the algorithm proposed in this paper performed best because (1) the quality of its results had improved 20%–30% compared to the results of FBP and 10%–30% compared to the results of another wavelet algorithm; (2) the new algorithm was stable under different circumstances. Besides, an actual reconstruction experiment was performed using real projection data that had been collected in a CT experiment. Two-dimensional (2D) and three-dimensional (3D) images of the sample were reconstructed. The microstructure of the sample could be clearly observed in the reconstructed images. Since much attention has been directed towards the nano-CT technique to investigate the microstructure of materials, this new wavelet-based local tomography algorithm could be considered as a meaningful effort.

scholarly journals Modified Three-Dimensional Multicarrier Optical Prime Codes

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Rajesh Yadav ◽  
Gurjit Kaur
Keyword(s):  
Mathematical Model ◽  
Cross Correlation ◽  
Three Dimensional ◽  
Prime Numbers ◽  
Time Space ◽  
Proposed Model ◽  
Prime Sequence ◽  
The Mathematical Model ◽  
Prime Codes

We propose a mathematical model for novel three-dimensional multicarrier optical codes in terms of wavelength/time/space based on the prime sequence algorithm. The proposed model has been extensively simulated on MATLAB for prime numbers (P) to analyze the performance of code in terms of autocorrelation and cross-correlation. The simulated outcome resembles the mathematical model and gives better results over other methods available in the literature as far as autocorrelation and cross-correlation are concerned. The proposed 3D optical codes are more efficient in terms of cardinality, improved security, and providing quality of services.

Fitting optimization based on weighted Gaussian imaging method for auto body taillight assembly

2014 ◽  
Vol 34 (3) ◽  
pp. 255-263 ◽  
Author(s):  
Xiang Gao ◽  
Hua Wang ◽  
Guanlong Chen
Keyword(s):  
Automotive Industry ◽  
Three Dimensional ◽  
Scanning System ◽  
Imaging Method ◽  
Assembly Model ◽  
Content Type ◽  
Three Dimensional Objects ◽  
Data Points ◽  
Auto Body

Purpose – Fitting evenness is one key characteristic for three-dimensional objects' optimal fit. The weighted Gaussian imaging method is developed for fitting evenness of auto body taillight fitting optimization. Design/methodology/approach – Fitting boundary contours are extracted from scanning data points. Optimal fitting target is represented with gap and flushness between taillight and auto body. By optimizing the fitting position of the projected boundary contours on the Gaussian sphere, the weighted Gaussian imaging method accomplishes optimal requirements of gap and flushness. A scanning system is established, and the fitting contour of the taillight assembly model is extracted to analyse the quality of the fitting process. Findings – The proposed method accomplishes the fitting optimization for taillight fitting with higher efficiency. Originality/value – The weighted Gaussian imaging method is used to optimize the taillight fitting. The proposed method optimized the fitting objects' 3-D space, while the traditional fitting methods are based on 2-D algorithm. Its time complexity is O(n3), while those of the traditional methods are O(n5). The results of this research will enhance the understanding of the 3-D optimal fitting and help in systematically improving the productivity and the fitting quality in automotive industry.

scholarly journals Echo Preprocessing to Enhance SNR for 2D CS-Based ISAR Imaging Method

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4409 ◽  
Author(s):  
Zhiping Yin ◽  
Xinfei Lu ◽  
Weidong Chen
Keyword(s):  
Imaging Method ◽  
Convex Optimization Problem ◽  
Reconstruction Process ◽  
Recovery Algorithm ◽  
Low Snr ◽  
Matrix Optimization ◽  
Isar Imaging ◽  
The One ◽  
Image Performance

A new CS-based inverse synthetic aperture radar (ISAR) imaging framework is proposed to enhance both the image performance and the robustness at a low SNR. An ISAR echo preprocessing method for enhancing the ISAR imaging quality of compressed sensing (CS) based algorithms is developed by implementing matched filtering, echo denoising and matrix optimization sequentially. After the preprocessing, the two-dimensional (2D) SL0 algorithm is applied to reconstruct an ISAR image in the range and cross-range plane through a series of 2D matrices using the 2D CS theory, rather than converting the 2D convex optimization problem to the one-dimensional (1D) problem in the image reconstruction process. The proposed preprocessing framework is verified by simulations and experiment. Simulations and experimental results show that the ISAR image obtained by the 2D sparse recovery algorithm with our proposed method has a better performance.

Scanning Electron Microscopy in Hybrid Microelectronics

1976 ◽  
Vol 34 ◽  
pp. 456-457
Author(s):  
S. Khadpe ◽  
R. Faryniak
Keyword(s):  
Integrated Circuits ◽  
Thick Film ◽  
Integrated Circuit ◽  
Failure Modes ◽  
Three Dimensional ◽  
Circuit Components ◽  
Hybrid Microcircuit ◽  
Electrical Connections ◽  
Scanning Electron

The Scanning Electron Microscope (SEM) is an important tool in Thick Film Hybrid Microcircuits Manufacturing because of its large depth of focus and three dimensional capability. This paper discusses some of the important areas in which the SEM is used to monitor process control and component failure modes during the various stages of manufacture of a typical hybrid microcircuit.Figure 1 shows a thick film hybrid microcircuit used in a Motorola Paging Receiver. The circuit consists of thick film resistors and conductors screened and fired on a ceramic (aluminum oxide) substrate. Two integrated circuit dice are bonded to the conductors by means of conductive epoxy and electrical connections from each integrated circuit to the substrate are made by ultrasonically bonding 1 mil aluminum wires from the die pads to appropriate conductor pads on the substrate. In addition to the integrated circuits and the resistors, the circuit includes seven chip capacitors soldered onto the substrate. Some of the important considerations involved in the selection and reliability aspects of the hybrid circuit components are: (a) the quality of the substrate; (b) the surface structure of the thick film conductors; (c) the metallization characteristics of the integrated circuit; and (d) the quality of the wire bond interconnections.

Semi-automated methods for 3-D reconstruction of macromolecular complexes

1995 ◽  
Vol 53 ◽  
pp. 42-43
Author(s):  
B. Carragher ◽  
M. Whittaker
Keyword(s):  
Three Dimensional ◽  
Time Saving ◽  
Macromolecular Complexes ◽  
Symmetry Properties ◽  
Dimensional Reconstruction ◽  
Experienced Operator ◽  
Projection Images ◽  
The Individual ◽  
Natural Symmetry

Techniques for three-dimensional reconstruction of macromolecular complexes from electron micrographs have been successfully used for many years. These include methods which take advantage of the natural symmetry properties of the structure (for example helical or icosahedral) as well as those that use single axis or other tilting geometries to reconstruct from a set of projection images. These techniques have traditionally relied on a very experienced operator to manually perform the often numerous and time consuming steps required to obtain the final reconstruction. While the guidance and oversight of an experienced and critical operator will always be an essential component of these techniques, recent advances in computer technology, microprocessor controlled microscopes and the availability of high quality CCD cameras have provided the means to automate many of the individual steps.During the acquisition of data automation provides benefits not only in terms of convenience and time saving but also in circumstances where manual procedures limit the quality of the final reconstruction.

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