This paper presents a new concept of tomography LASAR (TomoLASAR) down-looking 3-D imaging technique based on multi-pass trajectory. In contrast to conventional Tomography SAR, TomoLASAR cab obtains a much larger 2-D ...
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This paper presents a new concept of tomography LASAR (TomoLASAR) down-looking 3-D imaging technique based on multi-pass trajectory. In contrast to conventional Tomography SAR, TomoLASAR cab obtains a much larger 2-D synthetic aperture and has capability of high resolution imaging in down-looking mode which can avoid shadowing effects. Firstly, the geometrical model and the received signal model of TomoLASAR using multi-pass trajectory are established. Secondly, a time domain back projection beamforming algorithm is presented for the non-uniform multi-pass dataprocessing. In the end, the feasibility of the TomoLASAR and the imaging algorithm are demonstrated by simulated data.
Synthetic aperture radar (SAR) is a remote sensing system producing images with high resolution. It is not influenced by time and weather. As the increase of resolution and bandwidth, the volume of data augments sharp...
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Synthetic aperture radar (SAR) is a remote sensing system producing images with high resolution. It is not influenced by time and weather. As the increase of resolution and bandwidth, the volume of data augments sharply, bringing great difficulties to store, transmission and processing. Nowadays there is a novel theory named Compressive Sensing (CS) which can recover signal with few samples. Its sample rate is lower than Nyquist rate. In this paper, a novel CS-based SAR imaging algorithm is proposed, in which a random Gaussian measurement matrix, a constructed sparsity matrix and OMP algorithm are employed. The new algorithm can largely reduce the number of samples. The simulation results show the feasibility of the proposed algorithm.
Based on the multi-channel data acquisition system with FPGA as the core, The article introduces the control circuit of A/D conversion chip containing FIFO memory in detail. Based on general data acquisition system, t...
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Based on the multi-channel data acquisition system with FPGA as the core, The article introduces the control circuit of A/D conversion chip containing FIFO memory in detail. Based on general data acquisition system, this system coordinate FPGA to have a good control of the A/D sampling timing, frequency conversion of multi-channel switch and the programming logic of FLASH memory. With single-chip computer cy7c68013 to realize USB communication, send data to PC for waveform display.
For a decade swarm Intelligence, an artificial intelligence discipline, is concerned with the design of intelligent multi-agent systems by taking inspiration from the collective behaviors of social insects and other a...
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For a decade swarm Intelligence, an artificial intelligence discipline, is concerned with the design of intelligent multi-agent systems by taking inspiration from the collective behaviors of social insects and other animal societies. Swarm Intelligence is a successful paradigm for the algorithm with complex problems. This paper focuses on the procedure of most successful methods of optimization techniques inspired by Swarm Intelligence: Ant Colony Optimization (ACO) and Particle Swarm Optimization (PSO). This paper also gives a comparative analysis of PSO and ACO for data clustering.
SAR tomography at L — and P-bands reveals 3-D structural information of forested areas. A drawback, however, are the large number of samples, i.e. overflights, typically used for such configurations. Based on two ful...
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SAR tomography at L — and P-bands reveals 3-D structural information of forested areas. A drawback, however, are the large number of samples, i.e. overflights, typically used for such configurations. Based on two fully-polarimetric tomographic SAR data sets, at L — and P-bands, we analyze the sensitivity of backscattering from a forest volume as measured by means of SAR tomography with respect to (1) a reduction of the total baseline by subsequently reducing the number of baselines, and (2), with respect to a variation of the incidence angle. In this paper, an excerpt of this sensitivity analysis is presented and discussed.
With the increasing demands of the data transmission system of information, wireless data transmission systems has been widely studied and applied. Especially the limited and specified environment, take the undergroun...
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With the increasing demands of the data transmission system of information, wireless data transmission systems has been widely studied and applied. Especially the limited and specified environment, take the underground mine environment for example, has a high demand of flexibility. The paper describes the wireless video image data transmission system which is formed on the basis of DSP and RF chips, and provides the general systematic design and functional design. Furthermore, on this basis of the previous study, the paper has also completed the hardware and software design of the modules which consist two parts: data capture and compression modules; wireless data transfer and communication module. Regarding the further improvement of the use of DSP embedded technology in exploring the real-time wireless data transmission and communication system as well as its application level, there is a certain reference.
In high squint mode, the difficulty of the SAR imaging is how to remove the coupling between the range parameter and azimuth parameter in the received signal. The Keystone Transform (KT) is well suitable for the remov...
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In high squint mode, the difficulty of the SAR imaging is how to remove the coupling between the range parameter and azimuth parameter in the received signal. The Keystone Transform (KT) is well suitable for the removal of the moving target range walk. With a short synthetic aperture, the SAR receiver only obtains several sample data in the slow-time domain, which results in the poor azimuth resolution. The rank-deficient Capon algorithm defined as azimuth resolution by an efficient non-diagonal loading spectral estimation method is improved in this paper. The simulation proved that the method can effectively solve the conflicts of the range walk and improve the azimuth resolution.
Despite being studied extensively, the performance of blind source separation (BSS) is still limited especially for the sensor data collected in adverse environments. Recent studies show that such an issue can be miti...
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Despite being studied extensively, the performance of blind source separation (BSS) is still limited especially for the sensor data collected in adverse environments. Recent studies show that such an issue can be mitigated by incorporating multimodal information into the BSS process. In this paper, we propose a method for the enhancement of the target speech separated by a BSS algorithm from sound mixtures, using visual voice activity detection (VAD) and spectral subtraction. First, a classifier for visual VAD is formed in the off-line training stage, using labelled features extracted from the visual stimuli. Then we use this visual VAD classifier to detect the voice activity of the target speech. Finally we apply a multi-band spectral subtraction algorithm to enhance the BSS-separated speech signal based on the detected voice activity. We have tested our algorithm on the mixtures generated artificially by the mixing filters with different reverberation times, and the results show that our algorithm improves the quality of the separated target signal.
Void characterization under pavements is an important aspect of airfield pavement evaluation and maintenance. This paper studies the thickness estimation of void-layer in runways based on the spectrum optimization inv...
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Void characterization under pavements is an important aspect of airfield pavement evaluation and maintenance. This paper studies the thickness estimation of void-layer in runways based on the spectrum optimization inversion method, in which the impulse pair in the time domain corresponding to the upper and bottom interface of void-layer can be extracted based on the improved EM wave propagation model and system identification method we have proposed in other paper. The results demonstrate the method is valid and the estimation error of thickness is within 5%.
In recent years, according to the bandwidth of SAR in X-band would be legally expanded up to 500 MHz in order to improve the resolution of SAR images, the bandwidth of SAR would be overlapped with that of the many gro...
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In recent years, according to the bandwidth of SAR in X-band would be legally expanded up to 500 MHz in order to improve the resolution of SAR images, the bandwidth of SAR would be overlapped with that of the many ground-based radars in same band. This paper analyzes the interference effect to Spaceborne SAR by ground based radar operating in the Korea peninsula. The point target and SAR data is used to show interference effect based on mathematical modeling. The point target simulation is analyzed that sidelobe level of the point target increases as -40dB and the range resolution could be worse by narrowing IRW. The result based on SAR real data is shown to verify the interference effect from ground based radar.
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