A robust digital watermarking algorithm is proposed based on quaternion wavelet transform(QWT) and discrete cosine transform(DCT) for copyright protection of color images. The luminance component Y of a host color ima...A robust digital watermarking algorithm is proposed based on quaternion wavelet transform(QWT) and discrete cosine transform(DCT) for copyright protection of color images. The luminance component Y of a host color image in YIQ space is decomposed by QWT, and then the coefficients of four low-frequency subbands are transformed by DCT. An original binary watermark scrambled by Arnold map and iterated sine chaotic system is embedded into the mid-frequency DCT coefficients of the subbands. In order to improve the performance of the proposed algorithm against rotation attacks, a rotation detection scheme is implemented before watermark extracting. The experimental results demonstrate that the proposed watermarking scheme shows strong robustness not only against common image processing attacks but also against arbitrary rotation attacks.展开更多
A new simple method is presented for the wavelength calibration and measurement of poloidal rotation velocities with X-ray imaging crystal spectrometer（XICS）in magnetic fusion devices.In this method,the toroidal rot...A new simple method is presented for the wavelength calibration and measurement of poloidal rotation velocities with X-ray imaging crystal spectrometer（XICS）in magnetic fusion devices.In this method,the toroidal rotation of plasma is applied for high precise alignment and wavelength calibration of the poloidal XICS.The measurement threshold of poloidal rotation velocity can be lowered to 1-3 km/s with this method.展开更多
The paper puts forward a method on controlling the AM-OLED panel to display image with high gray scale levels. It also gives an ASIC design sample to implement this method. A twenty sub-fields scan scheme has been tak...The paper puts forward a method on controlling the AM-OLED panel to display image with high gray scale levels. It also gives an ASIC design sample to implement this method. A twenty sub-fields scan scheme has been taken into use in the chip to display 256 gray scale levels on a QVGA resolution AM-OLED display screen. The functions of image scaling and rotating have also been implemented for multiply application. The simulation and chip test result show that the chip design has met the design requirements.展开更多
This short review describes the capabilities of magnetic resonance （MR） to image opaque single- and two-phase granular systems, such as rotating cylinders and gas-fluidized beds operated in different fluidization re...This short review describes the capabilities of magnetic resonance （MR） to image opaque single- and two-phase granular systems, such as rotating cylinders and gas-fluidized beds operated in different fluidization regimes. The unique capability of MR to not only image the solids＇ distribution （voidage） but also the velocity of the particulate phase is clearly shown. It is demonstrated that MR can provide measurements over different length and time scales. With the MR equipment used for the studies summarized here, temporal and spatial scales range from sub-millisecond to hours and from a few hundred micrometres to a few centimetres, respectively. Besides providing crucial data required for an improved understanding of the underlying physics of granular flows, multi-scale MR measurements were also used to validate numerical simulations of granular systems. It is shown that predictions of time-averaged properties, such as voidage and velocity of the particulate phase, made using the Discrete Element Model agree very well with MR measurements.展开更多
基金supported by the National Natural Science Foundation of China(Nos.61601467,61379102,61502498,U1433105 and U1433120)the Fundamental Research Funds for the Central Universities(3122017044)
文摘A robust digital watermarking algorithm is proposed based on quaternion wavelet transform(QWT) and discrete cosine transform(DCT) for copyright protection of color images. The luminance component Y of a host color image in YIQ space is decomposed by QWT, and then the coefficients of four low-frequency subbands are transformed by DCT. An original binary watermark scrambled by Arnold map and iterated sine chaotic system is embedded into the mid-frequency DCT coefficients of the subbands. In order to improve the performance of the proposed algorithm against rotation attacks, a rotation detection scheme is implemented before watermark extracting. The experimental results demonstrate that the proposed watermarking scheme shows strong robustness not only against common image processing attacks but also against arbitrary rotation attacks.
基金supported by National Natural Science Foundation of China(Nos.11175208,11305212 and 11405212)the National Magnetic Confinement Fusion Science Program of China(No.2013GB112004)JSPS-NRF-NSFC A3 Foresight Program in the Field of Plasma Physics(No.11261140328)
文摘A new simple method is presented for the wavelength calibration and measurement of poloidal rotation velocities with X-ray imaging crystal spectrometer（XICS）in magnetic fusion devices.In this method,the toroidal rotation of plasma is applied for high precise alignment and wavelength calibration of the poloidal XICS.The measurement threshold of poloidal rotation velocity can be lowered to 1-3 km/s with this method.
基金Project supported by the Science and Technology Commission of Shanghai Municipality(Grant No.09530708600)the Shanghai AM Foundation(Grant No.09700714000)
文摘The paper puts forward a method on controlling the AM-OLED panel to display image with high gray scale levels. It also gives an ASIC design sample to implement this method. A twenty sub-fields scan scheme has been taken into use in the chip to display 256 gray scale levels on a QVGA resolution AM-OLED display screen. The functions of image scaling and rotating have also been implemented for multiply application. The simulation and chip test result show that the chip design has met the design requirements.
基金Financial support from the EPSRC (EP/C547195/1and GR/S20789/01)
文摘This short review describes the capabilities of magnetic resonance （MR） to image opaque single- and two-phase granular systems, such as rotating cylinders and gas-fluidized beds operated in different fluidization regimes. The unique capability of MR to not only image the solids＇ distribution （voidage） but also the velocity of the particulate phase is clearly shown. It is demonstrated that MR can provide measurements over different length and time scales. With the MR equipment used for the studies summarized here, temporal and spatial scales range from sub-millisecond to hours and from a few hundred micrometres to a few centimetres, respectively. Besides providing crucial data required for an improved understanding of the underlying physics of granular flows, multi-scale MR measurements were also used to validate numerical simulations of granular systems. It is shown that predictions of time-averaged properties, such as voidage and velocity of the particulate phase, made using the Discrete Element Model agree very well with MR measurements.
