Assessment for image quality traditionally needs its original image as a reference. The conventional method for assessment like Mean Square Error (MSE) or Peak Signal to Noise Ratio (PSNR) is invalid when there is no reference. In this paper, we present a new No-Reference (NR) assessment of image quality using blur and noise. The recent camera applications provide high quality images by help of...

Magnetic resonance imaging (MRI) devices generate loud acoustical noise during operation. The sound pressure level of the MRI noise depends on the imaging sequence, but it is generally 100 dB or more. Our current study is aimed at the improvement of the acoustical environment for the MRI patient by means of an active noise control system. We propose using a feedforward system because acoustical...

Three distinct techniques exist for distributing an ultrastable frequency reference over optical fibers. For the distribution of a microwave frequency reference, an amplitude-modulated continuous wave (cw) laser can be used. Over kilometer-scale lengths this approach provides an instability at 1 s of approximately 3 x 10(-14) without stabilization of the fiber-induced noise and approximately 1 ...

In many applications of Wiener filtering to noise cancellation an external reference noise in— put is required. However, if an external reference is not available, it is still possible to suppress additive noise using a Wiener linear prediction filter (LPF) provided the signal bandwidth is significantly less than the noise bandwidth. The purpose of this paper is to provide an analytical basis f...

In reverberant and noisy environments, multichannel systems are designed for spatially filtering interfering signals coming from undesired directions. In case of incoherent or diffuse noise fields, beamforming alone does not provide sufficient noise reduction, and post-filtering is normally required. In this paper, we present a two-channel post-filtering approach for signal detection and speech...

We present an analytical frequency-domain phase noise model for fractional-N phase-locked loops (PLL). The model includes the noise of the crystal reference, the reference input buffer, the voltage-controlled oscillator (VCO), the loop filter, charge pump device noise, sigma-delta modulator (SDM) noise including its effect on the in-band phase noise. Thermal device noise of the charge pump and ...

Fixed-pattern noise is a common feature in several uncalibrated imaging systems, and it typically appears as striping and gridlike nonuniformity artifacts in hyperspectral and infrared cameras. In this work, we present a quantitative and comparative analysis of fixedpattern noise reduction, or calibrating techniques, by using several image quality indexes. A special emphasis is made in demonstr...

We present an optical frequency divider based on a 200 MHz repetition rate Er:fiber mode-locked laser that, when locked to a stable optical frequency reference, generates microwave signals with absolute phase noise that is equal to or better than cryogenic microwave oscillators. At 1 Hz offset from a 10 GHz carrier, the phase noise is below -100 dBc/Hz, limited by the optical reference. For off...

In a low dropout (LDO) linear regulator whose reference voltage is supplied by a bandgap reference, double stacked diodes increase the effective junction area ratio in the bandgap reference, which significantly lowers the output spectral noise of the LDO. A low noise LDO with the area-efficient bandgap reference is implemented in 0.18 μm CMOS. An effective diode area ratio of 105 is obtained wh...

This paper describes two algorithms to improve a previously proposed Jacobian adaptation (JA) technique for fast acoustic speech recognizer model adaptation in environmental noise. The rst technique introduces a new bias term, that is a function of the reference noise estimate to account for the mismatch between the reference noise estimate and noise component of the noisy speech spectrum. This...