The quasi-static method with application of half-sine pressure pulse is presented to calibrate the piezoelectric
sensor, which is used for the dynamic pressure measurement of weapons. A pressure generator based on the drop
hammer hydraulic system is manufactured to get the half-sine pressure pulse. The oil cylinder of the generator is
reconstructed to install four standard pressure sensors and two calibrated sensors simultaneously. With pressure taken
from four standard sensors as calibrating excitation, and response data obtained from calibrated sensors, the working
sensitivities of sensors are worked out through regression analysis. The experimental results obtained with sensor 6215 at
the national shooting range shows that it is effective to calibrate piezoelectric sensors using half-sine pressure pulse. The
residual standard deviation of the equation fitting is less than 0.7%; the linearity is less than 0.21%; and the relative
uncertainty of the four standard sensors is less than 0.7%, under the precision target of the calibration system acceptance.
All objects emit radiation in amounts related to their temperature and their ability to emit radiation. The infrared image
shows the invisible infrared radiation emitted directly. Because of the advantages, the technology of infrared imaging is
applied to many kinds of fields. But compared with visible image, the disadvantages of infrared image are obvious. The
characteristics of low luminance, low contrast and the inconspicuous difference target and background are the main
disadvantages of infrared image. The aim of infrared image enhancement is to improve the interpretability or perception
of information in infrared image for human viewers, or to provide 'better' input for other automated image processing
techniques.
Most of the adaptive algorithm for image enhancement is mainly based on the gray-scale distribution of infrared image,
and is not associated with the actual image scene of the features. So the pertinence of infrared image enhancement is not
strong, and the infrared image is not conducive to the application of infrared surveillance. In this paper we have
developed a scene feature-based algorithm to enhance the contrast of infrared image adaptively. At first, after analyzing
the scene feature of different infrared image, we have chosen the feasible parameters to describe the infrared image. In
the second place, we have constructed the new histogram distributing base on the chosen parameters by using Gaussian
function. In the last place, the infrared image is enhanced by constructing a new form of histogram. Experimental results
show that the algorithm has better performance than other methods mentioned in this paper for infrared scene images.
Scene Classification refers to as assigning a physical scene into one of a set of predefined categories. Utilizing the
method texture feature is good for providing the approach to classify scenes. Texture can be considered to be repeating
patterns of local variation of pixel intensities. And texture analysis is important in many applications of computer image
analysis for classification or segmentation of images based on local spatial variations of intensity. Texture describes the
structural information of images, so it provides another data to classify comparing to the spectrum. Now, infrared thermal
imagers are used in different kinds of fields. Since infrared images of the objects reflect their own thermal radiation,
there are some shortcomings of infrared images: the poor contrast between the objectives and background, the effects of
blurs edges, much noise and so on. Because of these shortcomings, it is difficult to extract to the texture feature of
infrared images.
In this paper we have developed an infrared image texture feature-based algorithm to classify scenes of infrared images.
This paper researches texture extraction using Gabor wavelet transform. The transformation of Gabor has excellent
capability in analysis the frequency and direction of the partial district. Gabor wavelets is chosen for its biological
relevance and technical properties In the first place, after introducing the Gabor wavelet transform and the texture
analysis methods, the infrared images are extracted texture feature by Gabor wavelet transform. It is utilized the
multi-scale property of Gabor filter. In the second place, we take multi-dimensional means and standard deviation with
different scales and directions as texture parameters. The last stage is classification of scene texture parameters with least
squares support vector machine (LS-SVM) algorithm. SVM is based on the principle of structural risk minimization
(SRM). Compared with SVM, LS-SVM has overcome the shortcoming of higher computational burden by solving linear
equations, and has been widely used in classification and nonlinear function estimation. Some experimental results are
given in the end. The result shows that Gabor wavelet transform is successful to extract the texture feature of infrared
image. Compared with other methods the method mentioned in this paper reduces the probability of recognition and
enhances the robustness.
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