Active illumination 3D imaging systems based on Time-of-flight (TOF) and Structured Light (SL) projection are in rapid development, and are constantly finding new areas of application. In this paper, we present a theoretical design tool that allows prediction of 3D imaging precision. Theoretical expressions are developed for both TOF and SL imaging systems. The expressions contain only physically measurable parameters and no fitting parameters. We perform 3D measurements with both TOF and SL imaging systems, showing excellent agreement between theoretical and measured distance precision. The theoretical framework can be a powerful 3D imaging design tool, as it allows for prediction of 3D measurement precision already in the design phase.

This study presents an initiative aimed at developing a real-time optical measurement system for non-contact measurement of airborne fungal spores in protected crops such as strawberries, tomatoes, and cucumbers. The system is based on a customized microscope and an automatic system for trapping fungal spores. It has been tested in the field under real conditions, and image processing algorithms have been developed to identify fungal spores in high-resolution microscope images.

The mining and metal processing industries are undergoing a transformation through digitization, with sensors and data analysis playing a crucial role in modernization and increased efficiency. Vibration sensors are particularly important in monitoring production infrastructure in metal processing plants. This paper presents the installation of vibration sensors in an actual industrial environment and the results of spectral vibration data analysis. The study demonstrates that vibration sensors can be installed in challenging environments such as metal processing plants and that analyzing vibration patterns can provide valuable insights into predicting machine failures and different machine states. By utilizing dimensionality reduction and dominant frequency observation, we analyzed vibration data and identified patterns that are indicative of potential machine states and critical events that reduce production throughput. This information can be used to improve maintenance, minimize downtime, and ultimately enhance the production process’s overall efficiency. This study highlights the importance of digitization and data analysis in the mining and metal processing industries, particularly the capability not only to predict critical events before they impact production throughput and take action accordingly but also to identify machine states for legacy equipment and be part of retrofitting strategies.

This study presents an initiative aimed at developing a real-time optical measurement system for non-contact measurement of fungal spores in protected crops such as strawberries, tomatoes and cucumbers. The system is based on a customized microscope. It has been tested in the field under real conditions and image processing algorithms have been developed to identify fungal spores in high resolution microscope images.

A conventional refractive lens surface can act as a positive (converging) or negative (diverging) lens, but the same surface cannot act as both. We show that a geometric phase metasurface lens can have the unique property of acting both as a positive or negative lens upon transmission through its front or rear side, respectively. This offers certain freedom in compound lens design, where one combines focusing and defocusing operations. We utilize this property to make an ultra-compact, varifocal reflective lens, where a metasurface is placed in front of a novel long-stroke piezoelectric MEMS-micromirror. A large theoretical diopter tunability of 6330 m$^{-1}$ is enabled due to innovative thin-film piezoelectric MEMS design, offering 62 $μ$m displacement at 40V and low power, along with rapid actuation in the kHz region. The achieved MEMS-displacement is an order of magnitude larger than previously reported out-of-plane mechanical metasurface actuation. Since both metasurface and micromirror are flat, the presented reflective lens can be assembled without need for a spacer. It is therefore well suited for wafer-level silicon fabrication at high volumes and low cost. A proof-of-concept implementation using a 1550nm NIR metalens is demonstrated, attaining on the order of 1121 m$^{-1}$ diopter change for a focal length shift of 270 $μ$m caused by a 53 $μ$m micromirror displacement.