This paper presents an approach to assess the quality of the data extracted with computed tomography (CT) measuring systems to perform geometrical evaluations. The approach consists in analyzing the error features introduced by the CT measuring system during the extraction operation. The analysis of the features is performed qualitatively (using graphical analysis tools) and/or quantitatively (by means of the root-mean-square deviation parameter of the error features). The approach was used to analyze four sets of measurements performed with an industrial x-ray cone beam CT measuring system. Three test parts were used in the experiments: a high accuracy manufacturing multi-wave standard, a calibrated step cylinder and a calibrated production part. The results demonstrate the usefulness of the approach to gain knowledge on CT measuring processes and improve the quality of CT geometrical evaluations. Advantages and limitations of the approach are discussed.

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Periodic calibration of electronic distance meters is required to assess measurement errors and ensure metrological traceability. The high cost of reference measurement systems has been a barrier for the broader availability of calibration services. A method based on a short length standard and a leapfrogging technique to materialize traceable reference distances is proposed. A 50 m distance could be materialized with an expanded uncertainty of 0.0028 m using a simple prototype. Improving the mechanical design of the prototype may reduce uncertainty significantly.

The proper calibration of a transducer has direct influence on its measurement accuracy. Procedures for calibrating MEMS-type IMUs generally require sophisticated and expensive equipment. An alternative procedure called multi-position calibration has shown to be efficient and only demands that the transducer be moved in different orientations. We investigate the influence of the repeatability of these orientations by comparing two different experimental procedures – robotic-motion and hand-motion of the IMU sensor. Statistical analysis of the results makes it clear that there are no significant differences for either variances or means of calibrated parameters between both experimental procedures

The dimensional characterization of capillary tubes is a recurring issue in microfluidic applications, since they are often used to connect microfluidic devices to injection and monitoring systems. In this work three experimental methods were applied and discussed for measuring the inner diameter of thin tubes, allowing the comparison and determination of the most accurate procedure, taking into account the application and involved measurement uncertainty. The methods analysed are based on (i) sizing by stereo microscope software, (ii) image analysis (binarization) and (iii) internal fluid mass. The results show that the three methods applied can provide accurate values, but the best choice in terms of simplicity and efficiency is that one based on image analysis.