The Experts below are selected from a list of 32664 Experts worldwide ranked by ideXlab platform
Hon Ki Tsang - One of the best experts on this subject based on the ideXlab platform.
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investigation of 4 ask modulation with Digital Filtering to increase 20 times of direct modulation speed of white light led visible light communication system
Optics Express, 2012Co-Authors: Chienhung Yeh, Y F Liu, Chiwai Chow, Yang Liu, P Y Huang, Hon Ki TsangAbstract:In this demonstration, we propose and experimentally investigate the quaternary-amplitude-shift-keying (4-ASK) modulation with Digital Filtering to enhance the direct modulation speed of white-light light-emitting-diode (LED) in visible light communication (VLC) system. Here, an ordinary LED commercially available for lighting application with a direct modulation speed of 1 MHz is used. Data rate of 20 Mbit/s can be achieved in a 1 m free space transmission without using optical blue filter. In the previous studies, the transmission rate of LED VLC could only be increased by 2 to 10 times of the direct modulation speed of the white-light LED if using electrical equalization only. Moreover, the adaptive-controlled FIR filter makes the system closer to the matched Filtering condition for reducing the inter-symbol-interference (ISI) for the LED VLC. A recorded 20 times enhancement of the direct modulation speed of white-light LED VLC system is demonstrated by using Digital filter only and without using optical blue filter.
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investigation of 4 ask modulation with Digital Filtering to increase 20 times of direct modulation speed of white light led visible light communication system
Optics Express, 2012Co-Authors: C W Chow, P Y Huang, Hon Ki TsangAbstract:In this demonstration, we propose and experimentally investigate the quaternary-amplitude-shift-keying (4-ASK) modulation with Digital Filtering to enhance the direct modulation speed of white-light light-emitting-diode (LED) in visible light communication (VLC) system. Here, an ordinary LED commercially available for lighting application with a direct modulation speed of 1 MHz is used. Data rate of 20 Mbit/s can be achieved in a 1 m free space transmission without using optical blue filter. In the previous studies, the transmission rate of LED VLC could only be increased by 2 to 10 times of the direct modulation speed of the white-light LED if using electrical equalization only. Moreover, the adaptive-controlled FIR filter makes the system closer to the matched Filtering condition for reducing the inter-symbol-interference (ISI) for the LED VLC. A recorded 20 times enhancement of the direct modulation speed of white-light LED VLC system is demonstrated by using Digital filter only and without using optical blue filter.
Georg Wilckens - One of the best experts on this subject based on the ideXlab platform.
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control bounded analog to Digital conversion transfer function analysis proof of concept and Digital filter implementation
arXiv: Signal Processing, 2020Co-Authors: Hans-andrea Loeliger, Hampus Malmberg, Georg WilckensAbstract:Control-bounded analog-to-Digital conversion has many commonalities with delta-sigma conversion, but it can profitably use more general analog filters. The paper describes the operating principle, gives a transfer function analysis, presents a proof-of-concept implementation, and describes the Digital Filtering in detail.
Hans-andrea Loeliger - One of the best experts on this subject based on the ideXlab platform.
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control bounded analog to Digital conversion transfer function analysis proof of concept and Digital filter implementation
arXiv: Signal Processing, 2020Co-Authors: Hans-andrea Loeliger, Hampus Malmberg, Georg WilckensAbstract:Control-bounded analog-to-Digital conversion has many commonalities with delta-sigma conversion, but it can profitably use more general analog filters. The paper describes the operating principle, gives a transfer function analysis, presents a proof-of-concept implementation, and describes the Digital Filtering in detail.
P Y Huang - One of the best experts on this subject based on the ideXlab platform.
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investigation of 4 ask modulation with Digital Filtering to increase 20 times of direct modulation speed of white light led visible light communication system
Optics Express, 2012Co-Authors: Chienhung Yeh, Y F Liu, Chiwai Chow, Yang Liu, P Y Huang, Hon Ki TsangAbstract:In this demonstration, we propose and experimentally investigate the quaternary-amplitude-shift-keying (4-ASK) modulation with Digital Filtering to enhance the direct modulation speed of white-light light-emitting-diode (LED) in visible light communication (VLC) system. Here, an ordinary LED commercially available for lighting application with a direct modulation speed of 1 MHz is used. Data rate of 20 Mbit/s can be achieved in a 1 m free space transmission without using optical blue filter. In the previous studies, the transmission rate of LED VLC could only be increased by 2 to 10 times of the direct modulation speed of the white-light LED if using electrical equalization only. Moreover, the adaptive-controlled FIR filter makes the system closer to the matched Filtering condition for reducing the inter-symbol-interference (ISI) for the LED VLC. A recorded 20 times enhancement of the direct modulation speed of white-light LED VLC system is demonstrated by using Digital filter only and without using optical blue filter.
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investigation of 4 ask modulation with Digital Filtering to increase 20 times of direct modulation speed of white light led visible light communication system
Optics Express, 2012Co-Authors: C W Chow, P Y Huang, Hon Ki TsangAbstract:In this demonstration, we propose and experimentally investigate the quaternary-amplitude-shift-keying (4-ASK) modulation with Digital Filtering to enhance the direct modulation speed of white-light light-emitting-diode (LED) in visible light communication (VLC) system. Here, an ordinary LED commercially available for lighting application with a direct modulation speed of 1 MHz is used. Data rate of 20 Mbit/s can be achieved in a 1 m free space transmission without using optical blue filter. In the previous studies, the transmission rate of LED VLC could only be increased by 2 to 10 times of the direct modulation speed of the white-light LED if using electrical equalization only. Moreover, the adaptive-controlled FIR filter makes the system closer to the matched Filtering condition for reducing the inter-symbol-interference (ISI) for the LED VLC. A recorded 20 times enhancement of the direct modulation speed of white-light LED VLC system is demonstrated by using Digital filter only and without using optical blue filter.
Jiang Liu - One of the best experts on this subject based on the ideXlab platform.
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universal Digital Filtering for denoising volumetric retinal oct and oct angiography in 3d shearlet domain
Optics Letters, 2020Co-Authors: Jianlong Yang, Liyang Fang, Jun Cheng, Jiang LiuAbstract:Retinal optical coherence tomography (OCT) and OCT angiography (OCTA) suffer from the degeneration of image quality due to speckle noise and bulk-motion noise, respectively. Because the cross-sectional retina has distinct features in OCT and OCTA B-scans, existing Digital filters that can denoise OCT efficiently are unable to handle the bulk-motion noise in OCTA. In this Letter, we propose a universal Digital Filtering approach that is capable of minimizing both types of noise. Considering that the retinal capillaries in OCTA are hard to differentiate in B-scans while having distinct curvilinear structures in 3D volumes, we decompose the volumetric OCT and OCTA data with 3D shearlets, thus efficiently separating the retinal tissue and vessels from the noise in this transform domain. Compared with wavelets and curvelets, the shearlets provide better representation of the layer edges in OCT and the vasculature in OCTA. Qualitative and quantitative results show the proposed method outperforms the state-of-the-art OCT and OCTA denoising methods. Also, the superiority of 3D denoising is demonstrated by comparing the 3D shearlet Filtering with its 2D counterpart.
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universal Digital Filtering for denoising volumetric retinal oct and oct angiography in 3d shearlet domain
arXiv: Image and Video Processing, 2019Co-Authors: Jianlong Yang, Liyang Fang, Jun Cheng, Jiang LiuAbstract:Retinal optical coherence tomography (OCT) and OCT angiography (OCTA) suffer from the degeneration of image quality due to speckle noise and bulk-motion noise, respectively. Because the cross-sectional retina has distinct features in OCT and OCTA B-scans, existing Digital filters that can denoise OCT efficiently are unable to handle the bulk-motion noise in OCTA. In this Letter, we propose a universal Digital Filtering approach that is capable of minimizing both types of noise. Considering the retinal capillaries in OCTA are hard to differentiate in B-scans while having distinct curvilinear structures in 3D volumes, we decompose the volumetric OCT and OCTA data with 3D shearlets thus efficiently separate the retinal tissue and vessels from the noise in this transform domain. Compared with wavelets and curvelets, the shearlets provide better representation of the layer edges in OCT and the vasculature in OCTA. Qualitative and quantitative results show the proposed method outperforms the state-of-the-art OCT and OCTA denoising methods. Besides, the superiority of 3D denoising is demonstrated by comparing the 3D shearlet Filtering with its 2D counterpart.