Increase in the accuracy of information measuring systems for measuring oil flow rate based on turbine oil discharge converters

Results are presented for theoretical research and modelling of a measuring channel for information measuring systems for the volume of oil with a turbine oil discharge converter. The possibility of increasing accuracy is established.     

Effect of image resolution on intensity based scene illumination classification using neural network

In this paper, a framework for testing scene illumination classification with different image resolutions is proposed. The testing aims to provide the researchers with valuable information about the effect of image resolution on scene illumination classification using a neural network. The experiment is done by extracting three types of features from the images. These three types consist of statistical features, physic based features and histogram based features. It has been demonstrated that scene illumination classification can be affected by changing the image resolution. Despite the popular belief that high resolution images lead to better results, scene illumination classification by the proposed method performed best using low resolution images. At the second part of discussion, the reason behind this phenomenon is mathematically analysed and explained.     

A practical approach for estimating illumination distribution from shadows using a single image

This article presents a practical method that estimates illumination distribution from shadows using only a single image. The shadows are assumed to be cast on a textured, Lambertian surface by an object of known shape. Previous methods for illumination estimation from shadows usually require that the reflectance property of the surface on which shadows are cast be constant or uniform, or need an additional image to cancel out the effects of varying albedo of the textured surface on illumination estimation. But, our method deals with an estimation problem for which surface albedo information is not available. In this case, the estimation problem corresponds to an underdetermined one. We show that the combination of regularization by correlation and some user‐specified information can be a practical method for solving the underdetermined problem. In addition, as an optimization tool for solving the problem, we develop a constrained Non‐Negative Quadratic Programming (NNQP) technique into which not only regularization but also multiple linear constraints induced by user‐specified information are easily incorporated. We test and validate our method on both synthetic and real images and present some experimental results. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 143–154, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20047     

Optical systems under broad-band illumination: Analysis based on a wigner distribution function approach

Abstract

The irradiance produced by an optical imaging system suffering from aberrations under broad-band illumination is analysed in the phase-space domain of the Wigner distribution function associated with a modified one-dimensional pupil aperture. To this end, a coordinate transformation is employed in such a way that the varying irradiance along different paths in the image space can be derived from different slices of the Wigner distribution function, which involve both the defocus distance and the dispersion properties of the optical system. The method is illustrated by comparing the axial irradiance distribution for different primary aberrations. Also, the irradiance along parabolic paths is obtained in order to analyse the coma effect.     

Testing statistical hypotheses concerning error characteristics of measuring devices irrespective of the distribution law form

A method for verification of error characteristics containing random components is proposed to be used in metrological trials of measuring devices. This method does not require the knowledge of the prior distribution law of the random error component but nevertheless assures the preassigned guarantees against erroneous decisions. It is based on R. A. Fisher's fiducial probabilities. Translated from Izmeritel'naya Tekhnika, No. 11, pp. 3–8, November, 1997.     

Effect of antenna scattering characteristics on the accuracy of measuring radiating station parameters in the near-field zone

The results are given of an investigating of errors in measuring the parameters of short-range radiating stations in the near-field zone, owing to the involvement of the scattering characteristics in measurements of the dimensions of receiving aperture antennae and phased antenna arrays. It is shown that such errors are systematic in character, and, at high levels of antenna effective scattering area, appreciably exceed phase errors arising from sphericity of the amplitude-phase front of the electromagnetic wave. Methods are proposed for metering and reducing the scattering errors. Translated from Izmeritel'naya Tekhnika, No. 5, pp. 56–58, May, 1995.     

Maximum accuracy and speed of response of measuring instruments and systems with amplitude adaptation

Two classes of amplitude-adaptation algorithms, steady random Gaussian measured signals, and measurement problems are considered: sampled and with subsequent restoration of the signal form. Expressions are derived for the errors of adaptive measurements in the case when the metrological characteristics of the components of the measuring channel are known. A method of determining the adaptation time and a numerical example are presented, as well as criteria of the quality of an adaptive measuring channel. The problem of making a rational choice of the algorithm is solved.Translated from Izmeritel'naya Tekhnika, No. 8, pp. 56–59, August, 1994.     

Increasing the measuring accuracy of electronic heat meters

Translated from Izmeritel'naya Tekhnika, No. 1, pp. 31–32, January, 1991.     

烟用层流流量传感器测量准确性研究

为探究烟用层流流量传感器测量准确性的影响因素,介绍烟用层流流量传感器的基本结构,分析烟用层流流量传感器的入口效应,采用Fluent软件进行数值仿真。结果表明:烟用层流流量传感器仿真曲线与实验曲线基本吻合;小流量时仿真值与理论值较为接近,大流量时仿真值与理论值相对误差超过1%;环境因素对烟用层流流量传感器测量准确性的影响,温度最为显著,大气压仅在大流量时有一定影响,湿度基本无影响。通过研究环境因素对烟用层流流量传感器测量准确性的影响,对提高实验室与车间卷烟通风率测量一致性具有指导意义。