Due to event-triggered sampling in a system, or maybe with the aim of reducing data storage, tracking many applications will encounter irregular sampling time. By calculating the matrix exponential using an inverse Laplace transform, this paper transforms the irregular sampling tracking problem to the problem of tracking with time-varying parameters of a system. Using the common Kalman filter, the developed method is used to track a target for the simulated trajectory and video tracking. The results of simulation experiments have shown that it can obtain good estimation performance even at a very high irregular rate of measurement sampling time.
A compact differential wideband bandpass filter (WBPF) composed of a coupled full-wavelength loop is presented. The differential-mode circuit of the proposed filter is analyzed, showing that the proposed filter exhibits a three-pole differential-mode (DM) wideband bandpass filtering response. Moreover, both the fractional bandwidth (FBW) and the inband return loss can be adjusted by changing the parameter of the characteristics of coupled-line. Furthermore, the proposed filter provides a wider common-mode (CM) rejection characteristics owing to its multiple periodical transmission zeros. Additionally, the filter has a very compact size occupation. To verify the design concept, one filter example has been designed, fabricated and measured. The fabricated filter demonstrates good differential WBPF performance including a broad 3 dB fractional bandwidth of 66.6% centered at , a wider 14.5 dB CM rejection from dc to , and a very compact size of .Index Terms-Common-mode (CM), compact, differential-mode (DM), wide DM rejection, wideband bandpass filter (WBPF).
The brightness adjustment method for the night-vision image enhancement is considered in this paper. The color RGB night-vision image is transformed into an uncorrelated color space--- the YUV space. According to the characteristics of the night-vision image, we develop the modified Retinex algorithm based on the S curve firstly, by which the luminance component is enhanced and the brightness of the night-vision image is effectively improved. Then the luminance component of source image is enhanced by the selective and nonlinear gray mapping to retain the essential sunlight and shade information. Based on the two enhancement images, the night-vision image with enough bright and necessary sunlight and shade information is combined by the weighted parameter. According to experimental results, the night-vision image obtained is very fit for the visual observation
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