A temporal electronic speckle pattern interferometry (ESPI) system is proposed for in-plane rotation measurement. The relationship between the rotation angle and the phase change distribution is established and the rotation direction is indicated by the sign of the partial differential of the phase change distribution. Temporal phase modulation is applied in the proposed symmetric illumination ESPI system. The phase is recovered by the temporal intensity analysis method which uses the temporal evolution history of the light intensity. The system can perform dynamic measurements and provide results in off-line real-time. Preliminary experiments were carried out with a continuously rotating target to show the feasibility and the dynamic feature of the temporal ESPI system. At present, the mean absolute error of the experiment is 0.39 arcsec.

The surface structure, especially the roughness, has a significant influence on numerous parameters, such as friction and wear, and therefore estimates the quality of technical systems. In the last decades, a broad variety of surface roughness measurement methods were developed. A destructive measurement procedure or the lack of feasibility of online monitoring are the crucial drawbacks of most of these methods. This article proposes a new non-contact method for measuring the surface roughness that is straightforward to implement and easy to extend to online monitoring processes. The key element is a liquid-crystal-based spatial light modulator, integrated in an interferometric setup. By varying the imprinted phase of the modulator, a correlation between the imprinted phase and the fringe visibility of an interferogram is measured, and the surface roughness can be derived. This paper presents the theoretical approach of the method and first simulation and experimental results for a set of surface roughnesses. The experimental results are compared with values obtained by an atomic force microscope and a stylus profiler.

Measurement systems for online nondestructive full-field three-dimensional (3D) displacement based on the single-shot and multiplexing techniques attract more and more interest, especially throughout the manufacturing industries. This paper proposes an accurate and easy-to-implement method based on an electronic speckle pattern interferometer (ESPI) with single illumination-detection path to realize the online nondestructive full-field 3D displacement measurement. The simple and compact optical system generates three different sensitivity vectors to enable the evaluation of the three orthogonal displacement components. By applying the spatial carrier phase-shifting technique, the desired information can be obtained in real time. The theoretical analysis and the measurement results have proven the feasibility of this ESPI system and quantified its relative measurement error.

Electronic speckle-pattern interferometry (ESPI) is a powerful tool for precise, full-field, and non-contact contouring of optically rough surfaces. Due to the interferometric principle, the sensitivity of ESPI is directly related to the involved wavelengths and is thereby a global parameter. Surfaces with a broad variation of phase gradients, as, for instance, a target with both smooth and comparatively steep areas, result in just partially resolvable fringe interferograms. In recent studies, spatial light modulators (SLMs) have been implemented to adapt the interferometric reference phase front to the measurement task and broaden or squeeze the fringe spacing locally in critical areas. This method is limited by diffraction effects, observable for all types of phase-only SLMs. We demonstrate a straight-forward model, describing the diffraction-based intensity distortions occurring in interferograms after wavefront adaptation. The aim is to characterize the intensity distortions by means of the proposed model and minimize their impact, especially with regard to phase-only spatial light modulation in ESPI. For validation, the modeled behavior of SLMs is compared to the experimental results, obtained for two different SLM designs. Finally, experiments are presented, which demonstrate a successful adaptation of the interferometric reference phase front in compliance with the boundary conditions determined by the model.

En este artículo se estudia la calidad del proceso de fabricación pastillas de distinto origen, entre los que se incluyen productos genéricos. El resultado fundamental es que, las marcas oficiales y sus respectivos genéricos, no son iguales desde el punto de vista de su acabado, lo cual repercute directamente en su eficacia.Eine vollsUindige Charakterisierung von pharmazeutischen Tabletten besteht nicht nur in der Analyse der chemischen Zusammensetzung, sondern auch in der Untersuchung der Fertigung der inneren Struktur und der OberfUichenstruktur. Ziel dieser Arbeit ist es, die OberfUichenrauheit von Tabletten an Originalpra• paraten und Generika mittels Angularer Speckle Korre• lation (ASK) zu bestimmen. Die Ergebnisse zeigen un terschiedliche Rauheitswerte bei Tabletten mit gleichem Wirkstoff bei verschiedenen Tragerstoffen. Berührungslose Speckle-Rauheitsmessung konnte eingesetzt werden, um die Regelung des Produktionsprozesses zu verbessern, z. B. wahrend die Tabletten aus Pulver gepresst werden. A complete characterization of pharmaceutical tablets requires not only the analysis of its chemical com• pounds, but also of its inner and surface structure manufacturing. The aim of this work is to determine the sur face roughness of original and generic tablets by means of angular speckle correlation (ASC). The results show different roughness properties between tablets with the same active ingredients, but with different excipients. Contactless speckle roughness measurements could be used to im• prove the control of the production process, e. g., when tablets are pressed from powder