In this article, the comparison of two noncontact measurement methods dedicated to civil engineering structures’ state examination is presented. The vision-based method computes the displacement field of the analyzed structure by means of the digital image correlation coefficient. The system consists of one or more high-resolution digital cameras mounted on a head or on portable tripods. The developed methodology and created software application embedded in an MS-Windows operating system are presented. The second system measures the deflection of the structures by means of a radar interferometer. In both cases, it is possible to measure many points on the structure simultaneously. This article presents a comparison of the displacement field measurement performed on a field setup, as well as the span of a steel bridge designed for tram traffic. Both systems are described, with special attention given to their application in measurements of civil engineering structures. This article demonstrates a preliminary test performed to verify both of the noncontact systems in relation to high-accuracy measurement devices, the precise surveying level, and the electronic dial indicator of displacement. The experiment was designed intentionally to simulate the geometric conditions of the real structure, but the displacement values were generated and controlled by the operator. As a key study, a steel viaduct subjected to an operational load was measured, as a type of structure for which the observation is required in terms of structural health monitoring. It was subjected to the operational load caused by tram traffic. Both examined systems were applied. The accuracy analysis of both systems was investigated, and the obtained results were discussed.

Investigations of the thermal properties of a raw material or a ceramic product under a hot-stage microscope allow, among others, determining the characteristic temperatures corresponding to the changes of the shape and the cross-section area of samples being heated. They are based on observing and analysing images of the sample recorded with the growth of its temperature. The pictures of changes allow establishing—for the raw materials with the ability of thermal expansion—the technological temperatures of sintering, softening, thermal expansion, melting and flowing. Their knowledge is necessary in determining optimum ranges of manufacture conditions for a number of ceramic processes. Considering some difficulties with precise determination of these characteristic temperatures and with the problem of measuring the coefficient of thermal expansion S of clay raw materials, the authors have proposed hereby a new method of measuring a sample cross-section area on heating under a hot-stage microscope. It has been invented and implemented in the Matlab software environment on the basis of an image analysis of the expanding sample. The changes of its cross-section area (i.e. an outline area visible under a hot-stage microscope) are continuously recorded on the film and can be converted after digital processing into sample volume changes. The method is applicable to precise measuring the coefficient of thermal expansion S of clay raw materials, among others those used in the manufacture of lightweight ceramic aggregates.

The paper contains a survey of mobile scanning systems for measuring the railway clearance gauge. The research was completed as part of the project carried out for the PKP (PKP Polish Railway Lines S.A., Warsaw, Poland) in 2011–2013. The authors conducted experiments, including a search for the latest solutions relating to mobile measurement systems that meet the basic requirement. At the very least, these solutions needed to be accurate and have the ability for quick retrieval of data. In the paper, specifications and the characteristics of the component devices of the scanning systems are described. Based on experiments, the authors did some examination of the selected mobile systems to be applied for measuring the clearance gauge. The Riegl (VMX-250) and Z+F (Zoller + Fröhlich) Solution were tested. Additional test measurements were carried out within a 30-kilometer section of the Warsaw-Kraków route. These measurements were designed so as to provide various elements of the railway infrastructure, the track geometry and the installed geodetic control network. This ultimately made it possible to reduce the time for the preparation of geodetic reference measurements for the testing of the accuracy of the selected systems. Reference measurements included the use of the polar method to select profiles perpendicular to the axis of the track. In addition, the coordinates selected were well defined as measuring points of the objects of the infrastructure of the clearance gauge. All of the tested systems meet the accuracy requirements initially established (within the range of 2 cm as required by the PKP). The tested systems have shown their advantages and disadvantages.