Reconstruction of pulse noisy images via stochastic resonance

Magneto-optically reorientation-induced image reconstruction in bulk nematic liquid crystals

We theoretically propose the magneto-optically reorientation-induced image reconstruction in bulk nematic liquid crystals (NLCs). The underlying signals are reinforced and recovered at the expense of scattering noise under reorientation-induced self-focusing nonlinearity. The intensity perturbation gain is derived and the numerical results are presented to show the response of NLC molecules to the diffusive images. The nonlinear image recovery is influenced by the input light intensity, the magnetic field direction, and the correlation length. The results suggest an alternative approach to detect noisy images and promote the application of NLCs in image processing.

Discrete image recovery via stochastic resonance in optically induced photonic lattices

We demonstrate numerically the discrete image recovery via stochastic resonance in optically induced photonic lattices. The underlying signals are regularly reinforced at the expense of scattering noise with the interplay of the periodic potentials and the self-focusing nonlinearity. We founded that the energy redistribution tends to be periodic and the signal reinforcement is promoted with the help of periodic potentials. The lattice intensity levels, applied voltages, and correlation lengths are important parameters to influence the recovery effects. The dynamic nonlinear evolution including intensity and power spectrum is modeled according to the two-dimensional quasi-particle motion model. Our results suggest a potential technology to detect the noisy images.

Pulse signal restoration via stochastic resonance in a Fabry-Perot cavity with an intracavity nematic liquid crystal film

We theoretically propose a method to restore weak pulse signals submerged in noise via stochastic resonance, which is based on the optical bistability induced by the molecule reorientation in a Fabry-Perot cavity with an intracavity nematic liquid-crystal film. The bistable properties of this cavity are analyzed with different reflectance of the mirrors, initial phase shift and initial angle between the phase propagation vector and the director. The cross-correlation coefficient between pure input pulses and output is calculated to quantitatively evaluate the influence of noise intensity on output. The simulation results show a cross-correlation gain of 3.2 and that the buried signal can be recovered effectively by this device. It proves the potential of using this structure to recover noise-hidden pulse signals in an all-optical system.

Reconstruction of noisy images via stochastic resonance in nematic liquid crystals

We employ nematic liquid crystals as the nonlinear medium to recover noisy images via stochastic resonance, in which nonlinear coupling allows signals to grow at the expense of noise. The process is theoretically analyzed and the cross-correlation is numerically calculated. It is found that the quality of output images is affected by the input noise intensity, the applied voltage and the correlation length of noise light. Noise-hidden images can be effectively recovered by optimizing these parameters. The results suggest that nematic liquid crystals can be used for reconstruction of noisy images via stochastic resonance based on modulation instability with molecule reorientation nonlinearity.

Pulse noise-hidden image reconstruction and visualization via stochastic resonance

We investigate the nanosecond pulse noise-hidden image reconstruction and visualization using stochastic resonance implemented by modulation instability. In particular, this dynamical stochastic resonance holds with coupling between the pulse incoherent noise and pulse coherent signal, and provides a substantial enhancement of the signal-to-noise ratio and cross-correlation. This means that the pulse noise-hidden image can be effectively reconstructed with high visibility and fidelity via stochastic resonance at appropriate system parameters. Such a simple and convenient method has potential applications in image processing under noisy environment.

Effectiveness Testing of a Piezoelectric Energy Harvester for an Automobile Wheel Using Stochastic Resonance

The collection of clean power from ambient vibrations is considered a promising method for energy harvesting. For the case of wheel rotation, the present study investigates the effectiveness of a piezoelectric energy harvester, with the application of stochastic resonance to optimize the efficiency of energy harvesting. It is hypothesized that when the wheel rotates at variable speeds, the energy harvester is subjected to on-road noise as ambient excitations and a tangentially acting gravity force as a periodic modulation force, which can stimulate stochastic resonance. The energy harvester was miniaturized with a bistable cantilever structure, and the on-road noise was measured for the implementation of a vibrator in an experimental setting. A validation experiment revealed that the harvesting system was optimized to capture power that was approximately 12 times that captured under only on-road noise excitation and 50 times that captured under only the periodic gravity force. Moreover, the investigation of up-sweep excitations with increasing rotational frequency confirmed that stochastic resonance is effective in optimizing the performance of the energy harvester, with a certain bandwidth of vehicle speeds. An actual-vehicle experiment validates that the prototype harvester using stochastic resonance is capable of improving power generation performance for practical tire application.

Capacity of very noisy communication channels based on Fisher information

We generalize the asymptotic capacity expression for very noisy communication channels to now include coloured noise. For the practical scenario of a non-optimal receiver, we consider the common case of a correlation receiver. Due to the central limit theorem and the cumulative characteristic of a correlation receiver, we model this channel noise as additive Gaussian noise. Then, the channel capacity proves to be directly related to the Fisher information of the noise distribution and the weak signal energy. The conditions for occurrence of a noise-enhanced capacity effect are discussed, and the capacity difference between this noisy communication channel and other nonlinear channels is clarified.

Numerical analysis of pulse signal restoration by stochastic resonance in a buckled microcavity

A novel scheme is proposed to restore weak pulse signals immersed in noise by stochastic resonance based on photothermal-effect-induced optical bistability in a buckled dome microcavity. The bistable properties of the dome microcavity are analyzed with different initial detuning wavelengths and effective cavity lengths, and bistable transmission can be obtained for input powers in submilliwatt range. A theoretical model is derived to interpret the nonlinear process of pulse signal recovery through double-well potential theory. The cross-correlation coefficient between output signals and pure input pulses is calculated to quantitatively analyze the influence of noise intensity on stochastic resonance. A cross-correlation gain of 7 is obtained, and the noise-hidden signal can be recovered effectively though the buckled dome microcavity with negligible distortion. The simulation results show the potential of using this structure to restore low-level or noise-hidden pulse signals in all-optical integrated systems.

Nonlinear restoration of pulse and high noisy images via stochastic resonance

We propose a novel scheme for restoring pulse and high noisy images using stochastic resonance, which is based on the modulation instability and provides a cross-correlation gain higher than 8. As opposed to previously reported designs, this unique approach employs a continuous noise and pulse signal for the generation of modulation instability. The visibility and quality of output images can be improved by appropriately adjusting the system parameters. This provides a simple and feasible method for detecting low-level or hidden pulse images in various imaging applications.