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Image contrast enhancement is a very critical step for automatic medical image processing and analyzing applications. In this paper, we described a novel image enhancement algorithm based on the singlescale Retinex (SSR) theory to enhance the tiny anatomical structures and other regions of interest on the Low-dose CT LDCT images. This algorithm applies a three-stage approach: (a) separating the input images into illumination component and reflectance component, and calculating the approximate luminance of the original images; (b) normalizing the illumination component for the image dynamic range adaptively and manipulating the reflectance component with a nonlinear function; and (c) Finally, combining the normalized illuminance with the Gamma corrected reflectance to obtain the results. We have tested the proposed algorithm on 2 CT data sets. Comparing with the conventional histogram equalization, the Frankle-McCann Retinex algorithm and McCann99 algorithm, the proposed algorithm yields better performance for LDCT images enhancement.

The hydraulic pipeline is subject to the aero-engine base excitation and the pump fluid pulsation which can always damage the pipeline through overload to fatigue. So, the health monitoring technique of hydraulic pipeline is essential for the maintenance of the aero-engine. In this article, the Kalman filter combined with fiber Bragg grating method is proposed to detect the location faults of the hydraulic pipeline system. In this method, the description of state equations for the hydraulic pipeline vibration signals are presented based on autoregressive model. Then, a practical strategy detection method is proposed to investigate the vibration signals of hydraulic pipeline based on the Kalman filter technique. Finally, the clamp loosening and the collision faults of the hydraulic pipeline are conducted as an example to validate the proposed approach. The obtained results show that the present technique is convenient and efficient to detect the location faults of hydraulic pipeline where the fiber Bragg grating sensors are fixed, which can serve as an effective guidance for the health monitoring of hydraulic pipeline in aero-engine.

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