A noise reduction method for non-stationary noise based on noise reconstruction system with ALE
N. Sasaoka*, Y. Itoh*, and K. Fujii
*Tottori University
IEICE Transaction Fundamentals, vol. E88-A, no. 2, pp. 593-596 (2005)
A noise reduction technique to reduce background noise in noisy speech is proposed. We have proposed the noise reduction method which uses a noise reconstruction system. However, since a residual speech signal is included in the input signal of a noise reduction filter (NRF) used for reconstructing the background noise, the long time average value of error signal for estimating the back ground noise is needed not to estimate the speech signal. Therefore, the ability of tracking the non-stationary noise is decreased. In order to solve this problem, we propose the noise reduction system with adaptive line enhancer (ALE). Since ALE works to obtain the signal occupied by noise components, the input signal of the NRF includes only a few speech components. Therefore, we can give the high tracking ability to NRF.
Performance improvement for distributed active noise control systems based on simultaneous equations method
M. Muneyasu*, K. Kagawa**, K.Fujii, and T. Hinamoto**
*Kansai University, Hiroshima University
IEICE Transaction Fundamentals, vol. E88-A, no. 7, pp. 1760-1764 (2005)
For multiple-channel active noise control (ANC) systems, distributed systems consisting of more than one controller are useful. In this paper, we propose a performance improvement algorithm for the distributed multiple-channel ANC system based on the simultaneous equations method. In the proposed algorithm, no estimation of error paths is required. This algorithm can provide good performance in canceling primary noises with auto-/cross-correlations and achieve stable noise reduction under a change of the error paths.
音声に重畳した周期性騒音の低減法
藤井健作，杉原裕司，笹岡直人*，伊藤良生*
*鳥取大学
日本音響学会誌，vol. 61, no. 11, pp.636-644 (2005)
本論文では，音声に重畳した周期性騒音を低減するシステムの一つを提案する．その原理はラインエンハンサに基づき，周期性騒音を音声とでは長期予測に対する難易度に差があることを利用して低減する．また，ラインエンハンサを構成する線形予測フィルタのタップ数と挿入する遅延量，その係数更新アルゴリズムを学習同定法とした場合のステップサイズと音質及び騒音低減量との関係を調べ，音質の確保と騒音の低減が同時に実現される制御法を導く．本手法によれば，電源周波数が異なる程度の差であれば周波数のずれに対して無調整で適用可能であり，線形予測が可能となる範囲であれば騒音強度の変動にも対応することができる．
An active noise control system based on simultaneous equations method without auxiliary filters
M. Muneyasu*, O. Hisayasu**, K.Fujii, and T. Hinamoto**
*Kansai University, Hiroshima University
Proceedings of 2005 IEEE International Symposium on Circuits and Systems
(ISCAS2005), pp. 256-259 (2005)
A simultaneous equations method is one of active noise control algorithms without estimating an error path. This algorithm requires identification of a transfer function from a reference microphone to an error microphone containing the effect of a noise control filter. It is achieved by system identification of an auxiliary filter. As a result, the amount of computation is increased. In this paper, a new simultaneous equations method without the identification of the auxiliary filter is proposed. By storing a small number of an input signal and an error signal, we avoid this identification. Therefore, the amount of computation can be reduced by approximately 25% and same noise reduction performance with an ordinary method is obtained. From simulation example, it is verified that the merits of the ordinary method is retained in the proposed method.
A new noise reduction system based on ALE and noise reconstruction filter
N. Sasaoka*, K. Sumi, Y. Itoh*, and K. Fujii
*Tottori University
Proceedings of 2005 IEEE International Symposium on Circuits and Systems
(ISCAS2005), pp. 272-275 (2005)
A noise reduction technique is proposed to reduce wideband and sinusoidal noise in noisy speech. In real environments, the background noise includes the sinusoidal noise, for example, ventilating fan noise. Therefore, it is important to reduce also the sinusoidal noise. The new noise reduction system uses two types of adaptive line enhancer (ALE) and noise reconstruction filter (NRF). First, two ALEs estimate the speech components. However, since two ALEs cannot estimate the unvoiced sound, the quality of the speech enhanced by the two ALEs is not enough. Thus, the NRF is used to improve the noise reduction ability. The NRF accurately estimates the background noise from the signal occupied by the noise components, which is obtained by subtracting the speech enhanced by two ALEs from noisy speech. The enhanced speech is obtained by subtracting the reconstructed noise from noisy speech. Additionally, the noise reduction system with feedback path is also proposed for more improvement of the quality of enhanced speech.
A method to update the coefficients of feedback control filter
K. Fujii, Y. Iwamatsu, and M. Muneyasu*
*Tottori University
Proceedings of Twelfth International Congress on Sound and Vibration
(ICSV12), paper no. 212 (2005)
This paper proposes a method for repeatedly updating the coefficients of the feedback control filter without feeding an extra noise to the secondary source. Instead of the feeding, the proposed method uses the estimation error involved in the coefficients of the noise control filter. By using the estimation error, the proposed method provides two independent equations and then identifies the feedback path by solving those. A problem is that the feedback component is extremely small in comparison to the primary noise. In this case, precisely estimating the coefficients is difficult. This paper hence presents a technique of estimating in the order of the primary noise and then the feedback path.
周期性騒音の低減法に関する検討
脇坂契一，藤井健作，笹岡直人*，伊藤良生*
*鳥取大学
電子情報通信学会応用音響研究会技術報告, EA2004-119 (2005)
提案マイクロホンアレーシステムの実機による検証
網谷智博，宮田哲*，前田和昭*，藤井健作，伊藤良生**
*TOA㈱, **鳥取大学
電子情報通信学会応用音響研究会技術報告, EA2004-121 (2005)
能動騒音制御下における周波数連立方程式方を用いた帰還制御フィルタの更新法
岩松祐輔，藤井健作，棟安実治*
*関西大学
電子情報通信学会応用音響研究会技術報告, EA2004-127 (2005)
マルチチャネルシステム同定アルゴリズムの提案
伊藤雅祐，藤井健作，棟安実治*
*関西大学
電子情報通信学会応用音響研究会技術報告, EA2004-128 (2005)
周期性騒音の低減法に関する検討
脇坂契一，藤井健作，笹岡直人*，伊藤良生*
*鳥取大学
電子情報通信学会応用音響研究会技術報告, EA2005-9 (2005)
反射波を利用するシステム同定法
田中正明，藤井健作，畑 豊
電子情報通信学会応用音響研究会技術報告, EA2005-18 (2005)
連立方程式法を用いた実験機による能動騒音制御効果の検証
藤井健作，山口航太郎，藤田裕介*，棟安実治**
*キャットシステム，**関西大学
電子情報通信学会応用音響研究会技術報告, EA2005-56 (2005)
周波数領域適応アルゴリズムの収束特性
岩松祐輔，伊藤雅祐，宇治野正，藤井健作，棟安実治*
*関西大学
第20回信号処理シンポジウム, B5-4 (2005)
適応フィルタの更新するタップを制限する周期性騒音低減法に関する研究
脇坂契一，藤井健作，笹岡直人*，伊藤良生*
*鳥取大学
第20回信号処理シンポジウム, B8-1 (2005)
反射波を利用するシステム同定
田中正明，藤井健作，畑 豊
電子情報通信学会2005年総合大会講演論文集, A-4-23(2005)
マルチチャネルシステム同定アルゴリズムの提案と自己相関に対する考察
伊藤雅裕，藤井健作，棟安実治*
*関西大学
電子情報通信学会2005年総合大会講演論文集, A-4-24(2005)
連立方程式法による帰還系の同定
藤井健作，岩松祐輔，棟安実治*
*関西大学
日本音響学会2005年春季研究発表会講演論文集, 1-6-9 (2005)
２マイクロホンを用いた騒音抑圧システムの実機による検証
宮田哲*，前田和昭*，網谷智博，藤井健作，伊藤良生**
*ＴＯＡ㈱，
**鳥取大学
日本音響学会2005年春季研究発表会講演論文集, 1-6-24 (2005)
周波数領域適応アルゴリズムにおける適応フィルタのタップ長とFFT区間長のふるまい
伊藤雅祐，岩松祐輔，宇治野正，藤井健作，棟安実治*
*関西大学
2005年電子情報通信学会基礎・境界ソサイエティ大会講演論文集, A-4-7 (2005)
周波数領域適応アルゴリズムの収束特性
岩松祐輔，伊藤雅祐，宇治野正，藤井健作，棟安実治*
*関西大学
2005年電子情報通信学会基礎・境界ソサイエティ大会講演論文集, A-4-8 (2005)
騒音再合成法のステップサイズ制御に関する検討
笹岡直人*，伊藤良生*，藤井健作
*鳥取大学
2005年電子情報通信学会基礎・境界ソサイエティ大会講演論文集, A-20-1 (2005)
周波数領域連立方程式法の実験機による検証
藤井健作，山口航太郎，藤田裕介*，棟安実治**
*キャットシステム
**関西大学
日本音響学会2005年秋季研究発表会講演論文集, 3-2-4 (2005)
電子ホログラフィによる３次元カラー画像の記録と再生
佐藤邦弘，杉田篤彦，濱田裕介，藤井健作，森本雅和
HODIC Circular, vol. 25, no. 4, pp. 12-17 (2005)
反射型LCDパネルを用いて光の位相をシフトする方法を提案し，この方法を利用して位相シフトホログラフィによる3次元カラー画像記録システムを開発する．また，記録ホログラムから雑音が少なく画質の高いカラー画像を再生する．提案した方法を使うと，高速かつ正確に位相をシフトさせることができ，しかもシフトする位相の大きさが光の波長に依存しないので， RGB画像を同時に記録することができる．また，高精細反射型LCDパネルを用いてRGB時分割によるカラー動画像再生システムを開発する． RGBの3次元画像の時分割表示により鮮明なフルカラー画像を再生することができる．再生画像を撮影して色評価を行い，色度の広い範囲で色表現が可能であることを示す．記録ホログラムからフルカラー画像の再生を行い，実物体においてもフルカラー画像再生が可能であることを示す．さらに， 6チャンネルCCDと6チャンネルLCDを用いて視野または視域の広い画像を記録・再生し，視野角または視域角を約18度まで広げることができる．
Information Reduction in Hologram and Reconstruction of Real-Time 3D Images
K. Sato, Y. Hamada, M. Morimoto, K. Fujii
Proceedings of SPIE, vol. 5742, pp. 120-129 (2005)
The superimposing method is described in order to reduce information in hologram. This method improves loss of resolution and increase of the speckle noise due to the information reduction as compared with the sampling method. Experiments are carried out for reconstruction of images from the computer-generated hologram or from the practical hologram. Results show that high-resolution images with low speckle noise are reconstructed from the continuous periodic hologram with reduced information. The image having no parallax is reconstructed on the Fourier transform plane from the hologram with reduced information, if the bandwidth is taken to be smaller than the diameter of observer’s pupil. A time-sharing system is developed in order to display real-time 3D images with full parallax using several Fourier transform holograms with reduced information.
Full-color holographic display and recording of 3D images
A. Sugita, K. Sato, Y. Hamada, M. Morimoto, K. Fujii
Proceedings of SPIE, vol. 5742, pp. 130-139 (2005)
A time-sharing holographic color display system is developed using a high-resolution reflective liquid-crystal display (LCD) panel that consists of a 1920x1080 array of square pixels with width of 8.1 micron. Red, green and blue images with high resolution are reconstructed from the holographic display system with a red laser diode (LD), a green diode-pumped laser and a blue diode-pumped laser. The reconstructed color image can clearly be observed under the room light. The images exhibit good color expression. A phase-shifting holography system is also developed in order to record 3D color images, where phase of the reference light is shifted by changing fringe patterns displayed on the reflective LCD. Color image of the practical object are recorded as RGB fringe patterns by adopting a high-resolution color CCD. Clear RGB holograms are obtained from recorded fringe patterns by the phase-shifting method, and moving color images with high quality are reconstructed from the holograms by using the developed holographic display system.
Reconstruction of Full-Color Images with a RGB Time-Sharing Holographic Display System
K. Sato, A. Sugita, M. Morimoto, K. Fujii
Proceedings of ICO-20, vol. 6030, 0700-10 (2005)
A time-sharing holographic color display system is developed using a high-resolution reflective liquid-crystal display (LCD) panel that consists of a 1920x1080 array of square pixels with width of 8.1 micron. Red, green and blue images with high resolution are reconstructed from the holographic display system with a low-power red laser diode (LD), a low-power green diode-pumped laser and a low-power blue diode-pumped laser. The reconstructed color image can clearly be observed under the room light. The image exhibits good color expression. Moving 3D color images with high quality are reconstructed from holograms displayed on the LCD panel of the developed holographic system.
Recording and Reconstruction of 3D Color Images of Practical Objects by Phase-Shifting Holography
Y. Hamada, K. Sato, M. Morimoto, K. Fujii
Proceedings of ICO-20, vol. 6030, 0700-11 (2005)
A phase-shifting holography system for recording 3D color images is developed with a color CCD, and red (R), green (G), and blue (B) lasers. Phase of reference lights in this recording system is precisely shifted by shifting fringe patterns displayed on a high-resolution reflective LCD panel. Color images of the practical object are able to be recorded at the same time as RGB interference fringe patterns by adopting a high-resolution color CCD. Holograms for reconstruction of fine RGB images are obtained from recorded fringe patterns by the phase-shifting holography, and animated high-quality color images of the practical object are reconstructed from the holograms using the developed holographic color display system..
Information Reduction in Hologram and a 3D Display with a Movable Light Source
S. Hamada, K. Sato, M. Morimoto, K. Fujii
Proceedings of ICO-20, vol. 6030, 0700-12 (2005)
The superimposing method is described in order to reduce information in hologram. This method improves loss of resolution and increase of the speckle noise which are caused by the information reduction in the sampling method. Experiments are carried out for reconstruction of images from the computer-generated hologram or from the practical hologram. Results show that high-resolution images with low speckle noise are reconstructed from the continuous periodic hologram with reduced information. The image without visual depth is reconstructed on the Fourier transform plane from the hologram with reduced information, if the bandwidth is taken to be smaller than the diameter of observer’s pupil. The visual field is divided into several fields in order to display images with visual depth, and images in divided fields are recorded on several Fourier transform holograms. A time-sharing system with a movable reference light source is developed in order to reconstruct real-time 3D images from several Fourier transform holograms with reduced information.
Hologram Information Reduction and a Real-Time 3D Display
K. Sato, S. Hamada, M. Morimoto, K. Fujii
Proceedings of SPIE, vol. 6016, pp. 0T1-0T9 (2005)
The superimposing method for information reduction in hologram is compared with the sampling method to clarify their features. Visual field is divided in several fields for displaying visual depth of the image under reduced information, and partial images in divided visual fields are separately recorded on several Fourier transform holograms (FTHs). A time-sharing display system is developed to reconstruct the 3D image in real time from several FTHs. The 3D image with motion parallax is reproduced in the wide viewing zone from holograms with reduced information by reconstructing overlapped two images. Experiments are carried out for reconstruction of the practical 3D image from recorded holograms. Results show that resolution of the image is improved and the speckle noise is suppressed by the superimposing method. Depth of the 3D image can be perceived by viewing partial images reconstructed on Fourier transform planes. Observer can perceive motion parallax of the image by viewing a pair of overlapped stereoscopic images from right-eye and left-eye positions.
Recording and Reconstruction of Practical 3D Color Images by Phase-Shifting Electro-Holography
Y. Hamada, K. Sato, M. Morimoto, K. Fujii
Proceedings of SPIE, vol. 6016, pp. 0X1-0X8 (2005)
A phase-shifting holography system for recording 3D color images is developed with a color CCD, and red (R), green (G), and blue (B) lasers. The phase of reference lights in this recording system is precisely shifted by changing fringe patterns displayed on a high-resolution reflective LCD panel. RGB interference fringe patterns are able to be recorded at the same time for a practical color object by adopting a high-resolution color CCD. Color images in the wide visual field are recorded by adopting a multi-channel CCD and are reconstructed from the recorded hologram by adopting a multi-channel LCD modulator. Holograms for reconstruction of RGB images are obtained from recorded fringe patterns by the phase-shifting holography, and fine color images with high quality are reconstructed from recorded phase-shifting holograms
by using the developed holographic color display system. The visual field of the holographic system is enlarged by adopting a multi-channel color CCD for recording of the image and a multi-channel LCD panel for reconstruction of the image
.
Full-Color Holographic Display with Wide Visual Field and Viewing Zone
A. Sugita, K. Sato, K. Fujii, M. Morimoto
Proceedings of SPIE, vol. 6016, pp. 0Y1-0Y8 (2005)
A time-sharing holographic color display system is developed using a high-resolution reflective liquid-crystal display (LCD) panel that consists of a 1920x1080 array of square pixels with width of 8.1 micron. Red, green and blue high-resolution images are reconstructed from the holographic display system with a red laser diode (LCD), a green diode-pumped laser and a blue diode-pumped laser. The reconstructed color images can clearly be observed under the room light. The images exhibit good color expression. Color images with high quality of the practical object are reconstructed from the holograms by using the developed holographic display system. The viewing zone or the visual field of the holographic display is enlarged by adopting a multi-channel LCD modulator. 3D full-color images are reconstructed in the wide visual field. Viewing zone angle or visual field angle of color images can be enlarged up to about 20 degrees by adopting 6-channel LCD modulator.
情報量低減ホログラムからの3次元画像再生―時分割方式による奥行き表示
濱田真吾，佐藤邦弘，藤井健作，森本雅和
電子情報通信学会2005年総合大会講演論文集, D-11-86 (2005)
RGB時分割方式によるホログラフィックカラー動画像の再生
杉田篤彦，佐藤邦弘，藤井健作，森本雅和
電子情報通信学会2005年総合大会講演論文集, D-11-87 (2005)
位相シフトホログラフィーによるカラー3次元画像の記録と再生
濱田裕介，佐藤邦弘，藤井健作，森本雅和
電子情報通信学会2005年総合大会講演論文集, D-11-88 (2005)
A Portable 3D Scanner based on Structured Light and Stereo Camera
M. Morimoto and K. Fujii
Proceedings of IEEE International Symposium on Communications and Information Technologies
(ISCIT 2005), paper no.383 (2005)
To reconstruct the 3D model of a large structure, multiple measurement from various angle are required. In this paper, we propose a portable 3D scanner system which combines narrow-baseline stereo camera and consumer video projector. In proposed system, we can settle camera and projector in arbitrary position and angle. The relative position of camera and projector is automatically calibrated from image sequences. The proposed system realizes high measuring flexibility, because stereo camera and projector do not need to be fixed.
パンチルトズームカメラを用いた視線・視点検出方式
池辺厚慈, 森本雅和，藤井健作
電子情報通信学会画像工学研究会技術報告, IE2005-47 (2005)
撮影の自由度を考慮した３次元計測システム
森本雅和，藤井健作
電気関係学会関西支部連合大会, G14-14 (2005)
Webカメラを用いた視線検出に関する検討
坊宣治, 森本雅和，藤井健作
電気関係学会関西支部連合大会, G15-6 (2005)