Irregular layout of fiber-optical lines for tomographic monitoring of nautical structures

В статье рассматривается решение волоконно-оптической томографической задачи для мониторинга морских конструкций на основе новой, впервые публично представляемой, схемы укладки волоконно-оптических измерительных линий распределенной сети. В предлагаемой схеме укладки устраняется сдерживающий фактор линейности линий малоракурсной томографии и впервые анализируются возможности неравномерной схемы укладки. Сравнение предложенной схемы укладки с классическими схемами показало преимущество в точности определения места воздействия при уменьшении числа измерительных линий. Численное сравнение полученных результатов вычислительных экспериментов с ранее полученными результатами по другим схемам сканирования показали перспективность предлагаемого способа. Использование неравномерных схем укладок волоконно-оптических линий, наряду с применением систем искусственного интеллекта к информации на выходе этих линий, позволяет их изгибать теоретически на любых поверхностях морских конструкций, огибая углы балок, шпангоутов, неровных уплотнений и других подобных выпуклых поверхностей, для проектирования на их основе систем мониторинга состояния медленных физических полей на поверхностях со сложным произвольным профилем. The article discusses the solution of fiber-optical tomographic problem for monitoring nautical structures based on new layout of fiber-optic measuring lines. In the proposed scheme, the limiting factor of linearity of low-angle tomography lines is eliminated. The possibilities of Irregular layouts are analyzed. Comparison of the proposed layout with classical options showed gain in the accuracy of determining the location of the impact while reducing the number of measuring lines. A numerical comparison of the obtained results of computational experiments with previously obtained results for other scanning schemes showed the promise of the proposed method. Artificial intelligence systems are applied to the output data of these lines. This allows, in theory, to use uneven fiber-optic lines on any surfaces of nautical structures. At the same time, they will be able to bend around the corners of girders, ribs, uneven seals and other similar convex surfaces. All this will make it possible to design on their basis monitoring systems for slow physical fields on random profile surfaces.

Monitoring system of changes in air composition

The article considers a new approach to air monitoring based on phase-measurement in the SHF range and homodyne frequency conversion. Information about the change in the air composition is obtained by determining the phase progression of the microwave signal when it passes through the environment under study. At the same time, to determine the change in the content of exclusively harmful gases in the air composition, the meteorological component of the environment is subtracted from the information signal. The implementation of the method involves the organization of a monitoring system consisting of several microwave measuring lines synchronized with a monitoring center through a VHF communication channel, which will allow for global and continuous monitoring of changes in the composition of the air environment. The block diagram of the developed system is presented and its individual blocks, the theoretical possibilities of its operation are considered. An experimental study of the influence of meteorological characteristics of the environment on the phase progression of the microwave signal was also carried out.

Pomiary wysokości i prędkości lotu małego samolotu bezzałogowego z wykorzystaniem rurek Prandtla

Reliable measurements of the air velocity flowing around the wings of the aircraft and the altitude at which the aircraft is located are necessary for controlling the unmanned aircraft. Due to the need to use automatic flight stabilization processes, unmanned aircraft require a minimal delay in the measuring path. For correct measurement of these quantities, a system based on two measuring lines using backflow tubes was built. This article describes the effects of a research project carried out by the Student Scientific Group of Electronics at the Rzeszów University of Technology, who were seeking a reliable and quick solution with increased accuracy.

INFLUENCE OF RAW IMAGE PREPROCESSING AND OTHER SELECTED PROCESSES ON ACCURACY OF CLOSE-RANGE PHOTOGRAMMETRIC SYSTEMS ACCORDING TO VDI 2634

This paper examines the influence of raw image preprocessing and other selected processes on the accuracy of close-range photogrammetric measurement. The examined processes and features includes: raw image preprocessing, sensor unflatness, distance-dependent lens distortion, extending the input observations (image measurements) by incorporating all RGB colour channels, ellipse centre eccentricity and target detecting. The examination of each effect is carried out experimentally by performing the validation procedure proposed in the German VDI guideline 2634/1. The validation procedure is based on performing standard photogrammetric measurements of high-accurate calibrated measuring lines (multi-scale bars) with known lengths (typical uncertainty = 5 μm at 2 sigma). The comparison of the measured lengths with the known values gives the maximum length measurement error LME, which characterize the accuracy of the validated photogrammetric system. For higher reliability the VDI test field was photographed ten times independently with the same configuration and camera settings. The images were acquired with the metric ALPA 12WA camera. The tests are performed on all ten measurements which gives the possibility to measure the repeatability of the estimated parameters as well. The influences are examined by comparing the quality characteristics of the reference and tested settings.

INFLUENCE OF RAW IMAGE PREPROCESSING AND OTHER SELECTED PROCESSES ON ACCURACY OF CLOSE-RANGE PHOTOGRAMMETRIC SYSTEMS ACCORDING TO VDI 2634

This paper examines the influence of raw image preprocessing and other selected processes on the accuracy of close-range photogrammetric measurement. The examined processes and features includes: raw image preprocessing, sensor unflatness, distance-dependent lens distortion, extending the input observations (image measurements) by incorporating all RGB colour channels, ellipse centre eccentricity and target detecting. The examination of each effect is carried out experimentally by performing the validation procedure proposed in the German VDI guideline 2634/1. The validation procedure is based on performing standard photogrammetric measurements of high-accurate calibrated measuring lines (multi-scale bars) with known lengths (typical uncertainty = 5 μm at 2 sigma). The comparison of the measured lengths with the known values gives the maximum length measurement error LME, which characterize the accuracy of the validated photogrammetric system. For higher reliability the VDI test field was photographed ten times independently with the same configuration and camera settings. The images were acquired with the metric ALPA 12WA camera. The tests are performed on all ten measurements which gives the possibility to measure the repeatability of the estimated parameters as well. The influences are examined by comparing the quality characteristics of the reference and tested settings.

Experimental Study on Hydraulic Characteristics of Pool-Type Fishway

Fishway is an effective engineering measure to keep the river longitudinal connectivity and maintain aquatic biodiversity. In this experiment, the pool-type fishway with asymmetric notches and orifices was studied, the ADV was employed to measure the velocity data in the pools, the flow velocity and flow regimes in the pools with the length of 0.5m, 0.6m and 0.7m at different measuring lines were analyzed. The results show that the maximum velocity is 0.35±0.025m/s in the three kinds of pools, and both the backflow region and the backflow velocities are correspondingly increased with the increasing length of the pool.

Development of Plus Ultrasonic Doppler Method for Flow Rate Measurements of Power Plant: Multiline Flow Rate Measurement for Non Developed Flow

Flow metering system is being developed using plus ultrasonic Doppler method. The principle is an integration of instantaneous velocity profile over a pipe diameter so that it is expected to be able to eliminate installation problems such as entry length as well as to follow transient flow rate precisely. Flow metering principle by plus ultrasonic Doppler method in a circular pipe depends on the alignment of measuring lines. In this paper, influence of number of measuring lines on the flow rate measurements for power plant have been investigated for non developed flows in a vertical pipe.