Recent research has reported the application of image fusion technologies in medical images in a wide range of aspects, such as in the diagnosis of brain diseases, the detection of glioma and the diagnosis of Alzheimer’s disease. In our study, a new fusion method based on the combination of the shuffled frog leaping algorithm (SFLA) and the pulse coupled neural network (PCNN) is proposed for the fusion of SPECT and CT images to improve the quality of fused brain images. First, the intensity-hue-saturation (IHS) of a SPECT and CT image are decomposed using a non-subsampled contourlet transform (NSCT) independently, where both low-frequency and high-frequency images, using NSCT, are obtained. We then used the combined SFLA and PCNN to fuse the high-frequency sub-band images and low-frequency images. The SFLA is considered to optimize the PCNN network parameters. Finally, the fused image was produced from the reversed NSCT and reversed IHS transforms. We evaluated our algorithms against standard deviation (SD), mean gradient (Ḡ), spatial frequency (SF) and information entropy (E) using three different sets of brain images. The experimental results demonstrated the superior performance of the proposed fusion method to enhance both precision and spatial resolution significantly.
This paper investigates the robust finite-time rendezvous maneuver control for spacecraft via sliding mode control technology. Two control architectures are devised for realizing the control objective, where a novel-developed sliding mode surface (SMS) is designed by resorting to the hyperbolic tangent function. Without considering the chattering problem inherent in sliding mode control, a basis control scheme is constructed to force the tracking errors entering a compact set in finite time. To reduce the effect of the chattering phenomenon, a modified controller is established by resorting to the well-designed adaptive laws. Both of these two controllers can ensure finite-time convergence for the entire system. Theoretical analysis and numerical simulations have shown the effectiveness and superiorities of the proposed methods. INDEX TERMS Spacecraft rendezvous maneuver, finite-time control, sliding mode control, chattering problem, adaptive control.
US-guided percutaneous MWA for T1a RCC achieved a relatively low LTP incidence rate. Tumors adjacent to the renal pelvis or bowel increased the potential of LTP occurrence.
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