Single- and Multi-Step Image Enlargement for Medical Image Coding

Background: Some interpolators cannot be used in an image magnification problem in a freely scalable form. For instance, when we want to magnify an image to a 16-time bigger scale, some interpolators have to do this process in two steps including two 4-time magnification steps, however, some are able to do it directly. Materials and Methods: For generating data of this study, MATLAB as a simulator has been used. Bi-; Linear (BL) and Cubic Convolution (CC) interpolators are the two applied re-samplers in the reconstruction of digital images. Results: Data shows that the performance of both free-size interpolators (BL and CC) is obviously different in both direct and indirect pixel reconstruction. Conclusion: The acquired data shows a less error in the condition of direct interpolation. The relative results of experiments are different from the type of core interpolators (BL and CC).

Nonlinearity- and dispersion- less integrated optical time magnifier based on a high-Q SiN microring resonator

The ability to measure optical signals with fast dynamics is of significant interest in many application fields. Usually, single-shot measurements of non-periodic signals can be enabled by time magnification methods. Like an optical lens in the spatial domain, a time magnifier, or a time lens, stretches a signal in the time domain. This stretched signal can then be further processed with low bandwidth photonics and electronics. For a robust and cost-effective measurement device, integrated solutions would be especially advantageous. Conventional time lenses require dispersion and nonlinear optical effects. Integration of a strong dispersion and nonlinearities is not straightforward on a silicon photonics platform and they might lead to signal distortions. Here we present a time magnifier based on an integrated silicon nitride microring resonator and frequency-time coherence optical sampling, which requires neither a dispersion, nor a nonlinearity. Sampling of signals with up to 100 GHz bandwidth with a stretching factor of more than 100 is achieved using low bandwidth measurement equipment. Nevertheless, with already demonstrated integrated 100 GHz modulators, the method enables the measurement of signals with bandwidths of up to 400 GHz. Since amplitude and phase can be sampled, a combination with the spectrum slicing method might enable integrated, cost-effective, small-footprint analog-to-digital converters, and measurement devices for the characterization of single irregular optical signals with fast dynamics and bandwidths in the THz range.

Evaluation of Material Parameters of Multiphase Materials Using Drift Distortion Corrected SEM Imaging

In contrast to imaging in visible spectrum temporally-varying distortion (drift distortion) caused by positional errors of electron beam during the scanning process occurs in SEM devices. This effect is always present in the data from SEM and its magnitude depends on acquisition time, magnification and conductivity of the sample (where lower conductivity causes higher drift distortion). In this paper 2D digital image correlation based on Lucas-Kanade algorithm was used to assess drift distortion characteristics of MIRA II LMU SEM device during imaging of materials with different conductivity and microstructural properties. Using the DIC technique deformations in the micrographs were evaluated and tool for correction of positional errors was developed. As shown on a set of selected multiphase mixtures this tool enables qualitative backscattered electron analysis independently on the material type and imaging parameters including acquisition time. This enables reliable evaluation of material parameters that have influence on effective mechanical properties.