Image binarization under non-uniform lighting conditions is required in many industrial machine vision applications. Many local adaptive thresholding algorithms have been proposed in the literature for this purpose. However, existing local adaptive thresholding algorithms are either not robust enough or too expensive for real-time implementation due to very high computation costs. This paper presents a new algorithm for local adaptive thresholding based on a multi-stage framework. In the first stage, a mean filtering algorithm, with kernel-size independent computation cost, is proposed for background modeling to eliminate the non-uniform lighting effect. In the second stage, a background-corrected image is generated based on the background color. In the final stage, a global thresholding algorithm is applied to the background-corrected image. The kernel-size independent computation algorithm reduces the order of computation cost of background modeling from NML2 to ML+NL+6NM for an N x M image with an L x L kernel, which enables the real-time processing of objects of arbitrary size. Experiments show that the proposed algorithm performs better than other local thresholding algorithms, such as the Niblack algorithm, in terms of both speed and segmentation results for many machine vision applications under non-uniform lighting conditions.
Color representation and comparison based on the histogram has proved to be very efficient for image indexing in content-based image retrieval and machine vision applications. However, the issues of color constancy and accurate color similarity measures remain unsolved. This paper presents a new algorithm for intensity- insensitive color characterization for image retrieval and machine vision applications. The color characterization algorithm divides the HSI (hue, saturation and intensity) color space into a given number of bins in such a way that the color characterization represents all the colors in the hue/saturation plane as well as black, white and gray colors. The color distribution in these bins of the HSI space is represented in the form of a one-dimensional vector called Color Spectrum Vector (CSV). The color information that is stored in the CSV is insensitive to changes in the luminance. A weighted version of CSV called WCSV is introduced to take the similarity of the neighboring bins into account. A Fuzzy Color Spectrum Vector (FCSV) color representation vector that takes into account the human uncertainty in color classification process is also introduced here. The accuracy and speed of the algorithm is demonstrated in this paper through a series of experiments on image indexing and machine vision applications.
The population vector algorithm has been developed to combine the simultaneous direction- related activities of a population of motor cortical neurons to predict the trajectory of the arm movement. In our study, we consider a self-organizing model of a neural representation of the arm trajectory based on neuronal discharge rates. Self-organizing feature mapping (SOFM) is used to select the optimal set of weights in the model to determine the contribution of individual neuron to the overall movement. The correspondence between the movement directions and the discharge patterns of the motor cortical neurons is established in the output map. The topology preserving property of the SOFM is used to analyze real recorded data of a behavior monkey. The data used in this analysis were taken while the monkey was drawing spirals and doing the center out movement. Using such a statistical model, the monkey's arm moving directions could be well predicted based on the motor cortex neuronal firing information.
In this paper, we present a general theory of time-resolved x-ray diffraction. To show the application of the theory, we calculate the time-resolved x-ray diffraction patterns for the laser-induced vaporization kinetics of a finite system. Effect of the system size and laser- intensity will be examined.
When the CS2 vapor of 350 to 450 mTorr in a tube was irradiated by the output of a pulsed laser at wavelength 343.6 nm, and was optically excited to the R(J) equals 29, v equals 0, 10, 0, R3B2 state, collective emissions were observed at six wavelengths. The emissions are terminated on the highly vibrational states of the ground electronic state, and exhibit a third power dependence. A rate equation including stimulated emission is proposed to explain this phenomenon.
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