This paper presents an adaptive raster-scan thresholding algorithm which can deal with an image acquired under imperfect illumination. A statistical measurement called LSSD (Largest Static State Difference) relating t...
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This paper presents an adaptive raster-scan thresholding algorithm which can deal with an image acquired under imperfect illumination. A statistical measurement called LSSD (Largest Static State Difference) relating to the gray-level variation is found first, According to the measurement, the pixels are separated into static and transient states which are treated by two different procedures, respectively. A hardware implementation of this algorithm shows that the real-time requirement can be met. Experiments of applying this algorithm to extracting characters from documents confirmed that a reasonable binary image can be efficiently and effectively obtained from a gray-level image under various illuminations.
The paper presents a novel method of enhancing the interference rejection capability of a direct-sequence spread-spectrum system. The method is based on performing a frequency analysis of the received signal using a s...
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The paper presents a novel method of enhancing the interference rejection capability of a direct-sequence spread-spectrum system. The method is based on performing a frequency analysis of the received signal using a simple filter bank structure in such a way that the temporal information in the input signal is retained. A thresholding algorithm is used to suppress the interference by detecting its frequency and time localisation. This scheme is thus well suited for handling stationary as well as nonstationary interference, without resorting to traditional adaptive algorithms. The method does not affect the receiver performance when interference is not present and works particularly well for strong narrowband interference. Monte Carlo simulation results are given in terms of the bit error rate (BER) against (E(b)/N-0) for both stationary and nonstationary interference, and a comparison is made with transform domain processing.
A new technique for automatic channel characterisation and selection in spectrally congested environments, known as ‘template correlation’, is described. Its performance under simulated conditions is illustrated. Mo...
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A new technique for automatic channel characterisation and selection in spectrally congested environments, known as ‘template correlation’, is described. Its performance under simulated conditions is illustrated. Modification of the basic technique to reduce the computational load, via a thresholding algorithm, is also discussed.
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