The coefficient of variation (CV ) and the ratio of arithmetic to geometric mean( A/G ) are two methods of
heterogeneity measurement for SAR image, they are widely used in SAR image processing. Lopes pointed out that the
behavior of the traditional adaptive filter (Lee, Frost, etc) using for speckle was under the control of the coefficient
of variation in essence, and Lopes also deduced the enhanced adaptive filter algorithm. The filter algorithm for speckle
based on the A/G is immature. In this paper, A/G is used to replace the coefficient of variation and applied into the
enhanced adaptive filters. The novel class of adaptive filters, which are based on A/G and are designed for speckle, are
proposed. Through simulation, we verify the effectiveness and superiority of the novel class filters.
Synthetic aperture radar (SAR) images are inherently affected by a signal dependent noise known as speckle, which is due to the radar wave coherence. In this paper, we propose a novel adaptive despeckling filter and derive a maximum a posteriori (MAP) estimator for the radar cross section (RCS). We first employ a logarithmic transformation to change the multiplicative speckle noise into additive noise. We model the RCS using the recently introduced Generalized Gaussian density function, Which was proved to be the best described for the SAR Amplitude. We estimate model parameters from noisy observations by means of second-kind statistics theory, which relies on the Mellin transform. Finally, we compare the proposed algorithm with several classical speckle filters applied on actual SAR images. Experimental results show that the MAP filter based on the Generalized Gaussian prior for the RCS is among the best for speckle removal.
The application of position servo synchronously tracking system constituted with PLC and general AC servo system in digitalization control intelligence can-body high-speed resistance welding machine is introduced in this paper. By studying the digitalization control system of automatic can-body resistance welding machine, technologic upgrade of product is made, and application of PLC in controlling general AC servo motor multi-axes ganged system to replace conventional mechanical ganged mechanism is developed. It makes the coordination of movements between machine actions can be ensured and every correlative actions can quickly and precisely run synchronously, quondam mechanical branching driving can be replaced, and "mechanical locking" between quondam movements can be changed to the "electronic locking," complex mechanical structures such as cams, stepless speed changing machines and universal joints and so on can be omitted, so the working capability of whole machine can effectively be enhanced and synchronization between the machine actions can rapidly be reached. The application realizes digitalization process control, enhances reliability, stability and manufacturing efficiency of the machine, and reduces the manufacturing cost.