- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Automatic bathymetry retrieval from SAR images
摘要： Bathymetry, the topography of the sea floor, is in high demand due to the increase in offshore constructions like wind parks. It is also an important dataset for climate change modelling, when sea level rises and changes in circulation currents are to be simulated. The retrieval of accurate bathymetry data is a cost-intensive task usually requiring a survey vessel charting the respective area. However, bathymetry can also be retrieved remotely using data from Earth observation satellites. The main point of this study is the development of a processor that allows the automatic derivation of gridded bathymetry information from spaceborne Synthetic Aperture Radar (SAR) data. Observations of sea state modifications in SAR images are used to derive the bathymetry in shelf areas using the shoaling effect, which causes wavelengths to become shorter when reaching shallower waters. The water depth is derived using the dispersion relation for surface water waves, which requires wavelength and wave period as input parameters. While the wavelength can be directly retrieved from the SAR image, for the peak period additional information and procedures are required, e.g. local measurements or complex SAR data. A method for automatically deriving the wave period for swell waves in SAR images was developed and tested in this paper. It uses depth data from public databases as initial values which are compared to derived depths iterating through possible peak periods along the calculation grid; the peak period resulting in a minimal root-mean-square deviation is then used for bathymetry calculation. The bathymetry derived from a TerraSAR-X acquisition of the Channel Islands is presented; the resulting peak wave period of 11.3 s fits well to nearby in situ measurement data.
关键词： Bathymetry,Remote sensing,Near-real time processing,Synthetic aperture radar
更新于2025-09-23 15:23:52
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[IEEE 2018 Signal Processing: Algorithms, Architectures, Arrangements, and Applications (SPA) - Poznan, Poland (2018.9.19-2018.9.21)] 2018 Signal Processing: Algorithms, Architectures, Arrangements, and Applications (SPA) - Hardware implementation of the Gaussian Mixture Model foreground object segmentation algorithm working with ultra-high resolution video stream in real-time
摘要： In this paper a hardware implementation of the Gaussian Mixture Model algorithm for background modelling and foreground object segmentation is presented. The proposed vision system is able to handle video stream with resolution up to 4K (3840x2160 pixels) and 60 frames per second. Moreover, the constraints caused by memory bandwidth limit are also discussed and a few different solutions to tackle this issue have been considered. The designed modules have been verified on the ZCU102 development board with Xilinx Zynq UltraScale+ MPSoC device. Additionally, the computing performance and power consumption have been estimated.
关键词： FPGA,4K video,background modelling,real-time processing,GPU,Gaussian Mixture Model,foreground object segmentation
更新于2025-09-23 15:23:52
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[IEEE 2018 Conference on Design and Architectures for Signal and Image Processing (DASIP) - Porto, Portugal (2018.10.10-2018.10.12)] 2018 Conference on Design and Architectures for Signal and Image Processing (DASIP) - Real-Time Implementation of Contextual Image Processing Operations for 4K Video Stream in Zynq UltraScale+ MPSoC
摘要： In this paper hardware implementation of selected contextual based image pre-processing modules for a 3840×2160@60fps video stream in a Zynq UltraScale+ MPSoC is discussed. The following operations are considered: simple averaging (box filter), Gaussian filter, edge detection using the Sobel and Canny methods, median filter and morphological erosion and dilation operations. The scheme for implementing contextual based operations for a video stream in the format of 2 and 4 pixels per clock and challenges related to the pipelined implementation of processing such data are described. Also the use of logic resources and energy efficiency of modules described in the Verilog hardware description language and using the High Level Synthesis tools (Vivado HLS, SDSoC and xfOpenCV library) are compared. All designed modules support real-time processing of a 4K@60fps video stream.
关键词： FPGA,Zynq SoC,Canny,Vivado HLS,xfOpenCV,real-time processing,SDSoC,image pre-processing,Sobel,contextual based filtering
更新于2025-09-23 15:22:29
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Digital Circuit Methods to Correct and Filter Noise of Nonlinear CMOS Image Sensors
摘要： Nonlinear complementary metal-oxide semiconductor (CMOS) image sensors (CISs), such as logarithmic (log) and linear–logarithmic (linlog) sensors, achieve high/wide dynamic ranges in single exposures at video frame rates. As with linear CISs, fixed pattern noise (FPN) correction and salt-and-pepper noise (SPN) filtering are required to achieve high image quality. This paper presents a method to generate digital integrated circuits, suitable for any monotonic nonlinear CIS, to correct FPN in hard real time. It also presents a method to generate digital integrated circuits, suitable for any monochromatic nonlinear CIS, to filter SPN in hard real time. The methods are validated by implementing and testing generated circuits using field-programmable gate array (FPGA) tools from both Xilinx and Altera. Generated circuits are shown to be efficient, in terms of logic elements, memory bits, and power consumption. Scalability of the methods to full high-definition (FHD) video processing is also demonstrated. In particular, FPN correction and SPN filtering of over 140 megapixels per second are feasible, in hard real time, irrespective of the degree of nonlinearity.
关键词： FPGA,salt-and-pepper noise,digital circuits,real-time processing,fixed pattern noise,CMOS image sensors
更新于2025-09-23 15:22:29
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[IEEE 2018 Conference on Design and Architectures for Signal and Image Processing (DASIP) - Porto, Portugal (2018.10.10-2018.10.12)] 2018 Conference on Design and Architectures for Signal and Image Processing (DASIP) - Energy and Execution Time Comparison of Optical Flow Algorithms on SIMD and GPU Architectures
摘要： This article presents and compares optimized implementations of two optical flow algorithms on several target boards comprising multi-core SIMD processors and GPUs. The two algorithms are Horn-Schunck (HS) and TV-L1, and have been chosen because they are both well-known, and because of their different computational complexity and accuracy. For both algorithms, we have made parallel optimized SIMD implementations, while HS has also been implemented on GPUs. For each algorithm, the comparison between the different versions and target boards is carried out in a two-dimensional fashion: in terms of computing speed – in order to achieve real-time computation – and in terms of energy consumption since we target embedded systems. The results show that for HS, the GPUs are the most efficient in both dimensions, able to process in real-time performances (25 frames per second) up to 8 Mpix images for 0.35 J per image, against 1.8 Mpix images for 0.24 J per image on CPU. The results also highlight the impact of optimizations on TV-L1: far slower than HS without optimization, it can almost match its performance after optimization on CPU, and can achieve real-time performances with 0.25 J for 1.4 Mpix images. We hope these results will help developers design optical flow embedded systems.
关键词： embedded systems,TV-L1,optical flow,real-time processing,energy consumption,GPU,Horn-Schunck,SIMD
更新于2025-09-23 15:22:29
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Multiview Layer Fusion Model for Action Recognition Using RGBD Images
摘要： Vision-based action recognition encounters different challenges in practice, including recognition of the subject from any viewpoint, processing of data in real time, and offering privacy in a real-world setting. Even recognizing profile-based human actions, a subset of vision-based action recognition, is a considerable challenge in computer vision which forms the basis for an understanding of complex actions, activities, and behaviors, especially in healthcare applications and video surveillance systems. Accordingly, we introduce a novel method to construct a layer feature model for a profile-based solution that allows the fusion of features for multiview depth images. This model enables recognition from several viewpoints with low complexity at a real-time running speed of 63 fps for four profile-based actions: standing/walking, sitting, stooping, and lying. The experiment using the Northwestern-UCLA 3D dataset resulted in an average precision of 86.40%. With the i3DPost dataset, the experiment achieved an average precision of 93.00%. With the PSU multiview profile-based action dataset, a new dataset for multiple viewpoints which provides profile-based action RGBD images built by our group, we achieved an average precision of 99.31%.
关键词： privacy-preserving surveillance,layer fusion model,real-time processing,Multiview action recognition,RGBD images,depth-based features
更新于2025-09-23 15:22:29
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Realization of real‐time OFDM‐based visible light communication using an InGaN/GaN multiquantum‐wells LED
摘要： This paper presents a real-time OFDM-based visible light communication (VLC) system utilizing a single InGaN/GaN multiquantum-wells (MQWs) light emitting diode (LED). An MQWs LED with 3 dB electrical bandwidth of 23.8 MHz is developed as the transmitting device. Orthogonal frequency division multiplexing (OFDM) is employed to ensure the LED bandwidth is fully used, and the system is designed and implemented on a field-programmable gate array platform to realize real-time communication. The real-time OFDM-VLC system achieves a rate of 96 Mbit/s at the distance of 2 m, and the bit error ratio (BER) is 2.25 × 10?3, which is below the forward error correction (FEC) limit.
关键词： OFDM,Real-time processing,Visible light communication,InGaN/GaN MQWs LED,FPGA
更新于2025-09-16 10:30:52
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[IEEE 2018 IEEE East-West Design & Test Symposium (EWDTS) - Kazan, Russia (2018.9.14-2018.9.17)] 2018 IEEE East-West Design & Test Symposium (EWDTS) - An FPGA-Optimized Architecture of Variational Optical Flow
摘要： The variational methods for dense optical flow estimation are widely known and adopted techniques for motion detection, object tracking, 3D reconstruction and autonomous navigation image processing applications. A non-linear model of variational optical flow estimation is the most accurate but also most complicated and computationally intensive method and its implementation in an FPGA is compromise from both a design complexity and a performance. The article is devoted to the specific FPGA-based solution which has been implemented using Verilog hardware description language. The suggested solution is able to process the non-linear optical flow in real time and might be applied as FPGA-accelerator for optical flow processing.
关键词： variational methods,optical flow,real-time processing,FPGA,Verilog
更新于2025-09-09 09:28:46
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Real-Time Optronic Beamformer on Receive in Phased Array Radar
摘要： The development of phased array radar beamforming technologies has led to an ever-increasing demand for large antenna arrays and multiple beams. However, real-time processing becomes a difficulty for large array or multibeam beamforming due to huge data amount. To overcome the electronic mass data processing speed limitations, optronic technique is developed for beamforming in this letter. We present a novel real-time multibeam optronic beamforming (OPBF) system specially designed for large phased array. In our system design, beamforming is formulated as a finite-impulse response filtering process, of which radar raw data and weighting coefficients are encoded onto the laser beam by joint amplitude and phase control (JAPC) modules and two-dimension adding is performed by a lens. Ultrafast optical calculation and the proposed high-speed JAPC module make the system powerful for real-time processing. The proposed system has good expansibility in data capacity, which makes it applicable to massive data processing. What’s more, a practical low-power optronic beamformer is demonstrated. Measured results show that the presented OPBF system is able to accurately synthesize flexible and controllable multibeams and performs well in channel equalization.
关键词： phase modulation,digital micromirror device (DMD),optronic processing,Amplitude modulation,real-time processing,beamforming
更新于2025-09-04 15:30:14