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The stochastic resonance in a bistable system subject to asymmetric dichotomous noise and multiplicative and additive white noise is investigated. By using the properties of the dichotomous noise, under the adiabatic approximation condition, the expression of the signal-to-noise ratio (SNR) is obtained. It is found that the SNR is a non-monotonic function of the asymmetry of the dichotomous noise, and it varies non-monotonously with the intensities of the multiplicative and additive noise as well as with the system parameters. Moreover, the SNR depends on the correlation rate of the dichotomous noise.

The effect of time delay and noise color in a time-delayed bistable system subject to asymmetric dichotomous noise and colored noise as well as to square-wave signal is studied. Applying small delay-time approximation, under the adiabatic limit condition, we obtain the expression of the signal-to-noise ratio (SNR) of the system. By virtue of the SNR expression, we find that, the SNR varies non-monotonously with the delayed-time and the correlation of the colored noise. Moreover, the SNR exhibits SR behavior as a function of the strength of the colored noise

Operation of two-dimensional Power Spectral Density (2-D PSD) of large optics wavefront is briefly described and PSD collapse is introduced to evaluate the intermediate frequency error property of wavefront. As PSD collapse is Radon transform projection of 2-D Power Spectral Density at any angle, all valid data of wavefront of optics are used in calculation of the PSD collapse and the features of 1-D PSD were inherited in PSD collapse. Although PSD collapse is as same as 1-D PSD in unit and behavior style, it is better for evaluating intermediate frequency error property of optics wavefront than 1-D PSD or 2-D PSD. As PSD collapse calculation uses all valid data of evaluated optics wave front and can be directly perceived through its profile, the PSD collapse may possibly be the standard evaluating method of PSD.