Two-beam interferogram intensity modulation decoding using spatial carrier phase shifting interferometry is discussed. Single frame recording, simplicity of experimental equipment, and uncomplicated data processing are the main advantages of the method. A comprehensive analysis of the influence of systematic errors (spatial carrier miscalibration, nonuniform average intensity profile, and nonlinear recording) on the modulation distribution determination using automatic fringe pattern analysis techniques is presented. The results of searching for the optimum calculation algorithm are described. Extensive numerical simulations are compared with laboratory findings obtained when testing vibrating silicon microelements under various experimental conditions.

The paper presents the automated on-line system for wood logs 3D geometry scanning. The system consists of 6 laser triangulation scanners and is able to scan full wood logs which can have the diameter ranging from 250 mm to 500 mm and the length up to 4000 mm. The system was developed as a part of the BIOSTRATEG project aiming to optimize the cutting of logs in the process of wood planks manufacturing by intelligent positioning in sawmill operation. This paper illustrates the detailed description of scanner construction, full measurement process, system calibration and data processing schemes. The full 3D surface geometry of products and their applied portion of selected wood logs formed after cutting out the cant is also demonstrated.

The phase shifting method is an effective tool to determine the intensity modulation distribution of a two-beam interferogram. We present numerical studies of the influence of two experimental errors on the results obtained using temporal phase stepping, i.e., the phase step miscalibration and average intensity changes between the component interferograms. Experimental studies of vibration mode patterns by time-average interferometry provide excellent verification of numerical findings. Comparative analysis of interferogram contrast and intensity modulation determination is included.

Temporal phase shifting in automatic interferogram analysis offers very high accuracy of phase retrieval providing that several experimental conditions are met. The paper is focused on the calibration error of unequal phase changes across the interferogram field, i.e., tilt-shift error. For its detection the lattice-site representation of phase shift angles is proposed. The error can be readily discerned using (N+1) algorithms with the last frame overlapping the first one. Four and five frame algorithms are considered. The influence of experimental parameters on the error detection sensitivity is discussed. Numerical studies are complemented by experimental results.

This paper presents a photogrammetry-based volume measurement framework for the particle density estimation of Lightweight expanded clay aggregate (LECA). The results are compared with computed tomography (CT) and Archimedes’ method measurements. All of the steps required in order to apply the proposed approach are explained. Next, we discuss how the interpretation of open pores affects the results of volume measurements. We propose to process the shapes obtained from different methods by applying an Ambient Occlusion algorithm with the same threshold, t = 0.175. The difference between the CT and SfM methods is less than 0.006 g/cm³, proving that the photogrammetry-based approach is accurate enough. The Archimedes’ method significantly overestimates the density of the particles. Nevertheless, its accuracy is acceptable for most engineering purposes. Additionally, we evaluate the accuracy of shape reconstruction (in terms of the Hausdorff distance). For 95% of the grain’s surface, the maximum error is between 0.073 mm and 0.129 mm (depending on the grain shape). The presented approach is helpful for measuring the particle density of porous aggregates. The proposed methodology can be utilized in order to estimate intergranular porosity, which is valuable information for the calibration of DEM models.