Marija Strojnik

Accurate three-dimensional reconstruction of discontinuous and discrete objects remains challenging in fringe projection profilometry because abrupt depth changes, self-occlusion, and shadowed regions can introduce fringe-order ambiguities and phase artifacts. We propose a dual-projector color-coded fringe projection method that combines hierarchical staircase phase coding, guide-phase refinement, and complementary phase measurements for absolute phase reconstruction. For each projector, four grayscale phase-shifting patterns are used for wrapped-phase recovery, while four color-encoded patterns simultaneously provide fine and coarse fringe-order information. The red-channel code determines the local fringe-order state, whereas the blue-channel code resolves periodicity ambiguities over the measurement range. The decoded fringe-order map is combined with the wrapped phase to obtain an initial absolute phase. A median-filtered version of this phase is then used as a guide in a G = 1 phase-refinement formulation to suppress localized artifacts while preserving the measured phase variation. Finally, modulation-based validity masks combine complementary phase maps from the two projection directions, improving surface coverage in self-occluded regions. Experimental results with discontinuous and discrete three-dimensional objects demonstrate successful fringe-order decoding, artifact suppression, and complementary surface reconstruction. The proposed method provides absolute phase recovery using eight projected patterns per projector and enables efficient reconstruction of complex surfaces containing abrupt depth discontinuities and limited-visibility regions.

First held in 1992, AITA is an international conference that aims to present state-of-the-art research and recent applications in the field of infrared spectral range technology

We previously introduced the concepts of optical centroid efficiency (OCE) and enclosed energy within a rectangular pixel (EOD). We applied them to an ideal lens with and without a central obscuration for two different detector pixel sizes. Also, we analyzed the performance of OCE vs. EOD for the following three Seidel primary aberrations of an ideal lens: spherical, coma, and astigmatism, plus defocus. In this paper, we concentrate on three different optical remote sensing instrument configurations. We burden them with a set of aberrations to mimic realistic generalized error budgets that cover potential ground, lunch, and on-orbit environmental conditions. The shape of the OCE vs. EOD curve depends to a large degree on the dominant aberration. With the proper choice of detector pixel size, OCE increases with EOD when EOD is larger than 0.6. The increased detector pixel size is advantageous for structures that enhance diffraction effects, and for off-axis and asymmetrical configurations. Analytical and experimental tests are proposed for original critical cases. Furthermore, OCE and EOD, as functional figures of merit, may be effectively applied to instruments for monitoring tumors and their evolution to cancerous tissue, leading to timely diagnosis.

This paper presents a comprehensive mathematical derivation and simulation for the application of a rotationally shearing interferometer (RSI) in the detection of exoplanets. The study focuses on the interaction between wavefronts from a distant star and its orbiting planet, exploring the generation and manipulation of interferometric patterns. Key optical elements, such as Dove prisms and Risley prisms, are analyzed for their role in isolating the planet’s signal by introducing phase shifts and rotations. A rigorous mathematical model is developed to describe these wavefront interactions, phase modulations, and spatial frequency shifts. The theoretical framework provided serves as the foundation for understanding signal processing within the RSI and facilitating future experimental validation. The simulation results demonstrate the potential of RSI in exoplanet detection by effectively distinguishing planetary signals from stellar noise through precise phase and spatial frequency manipulation.

Loop-Mediated Isothermal Amplification (LAMP) is a widely used technique for nucleic acid amplification due to its high specificity, sensitivity, and rapid results. Advances in microfluidic lab-on-chip (LOC) technology have enabled the integration of LAMP into miniaturized devices, known as μ-LAMP, which require precise thermal control for optimal DNA amplification. This paper introduces a novel thermal bed design using PCB copper traces and FR−4 dielectric materials, providing a reliable, modular, and repairable heating platform. We present the design, fabrication, and control mechanisms of the thermal bed, demonstrating its ability to maintain accurate temperatures essential for μ-LAMP applications. The thermal bed’s performance is validated through finite element method (FEM) simulations, confirming its effectiveness in diverse applications such as disease diagnostics, biological safety, and forensic analysis.

We previously proposed that the optical centroid efficiency (OCE) might be a preferred figure-of-merit to the enclosed energy of a rectangular pixel (EOD) for an instrument subject to unpredictable environmental jitter and alignment conditions. Here we follow the same symbols for the corresponding quantities, particularly the width of the pixel as being equal to 2d. Here we analyze the performance of the OCE vs. the EOD for the three Seidel primary aberrations of an optical component: spherical, coma, and astigmatism, plus defocus. We show that the OCE has an approximate U-shape when graphed against the EOD, for the aberrations ranging from 0 to 1.25λ. We conclude that for pixels larger than 2d = 3λF/#, a small pixel will feature better performance when expecting jitter, misalignment, and other environmental and unpredictable conditions. When evaluating the performance of low-aberration instruments in dynamic and unpredictable environments, the choice of the lager pixel 2d = 7λF/# might be advantageous. Its selection will result in the deterioration of image resolution.

AITA is an international conference that has run since 1992 and is aimed at assessing the state of the art of the infrared spectral range technology and to present its most interesting applications

Guest Editors Marija Strojnik, Wen Chen, Sarath Gunapala, Joern Helbert, Esteban Vera, and Eric Shirley introduce the Special Section on Advanced Infrared Technology and Remote Sensing Applications II.

The noise-equivalent power is used to predict performance of infrared (IR) sensors. In a general IR or remote sensing system, the axes of the incoming chief ray of each pixel in the optical system and the center of that detector pixel are slightly misaligned, due to optical tolerances, jitter, and other environmental conditions, leading to error in the sensor performance prediction and estimates. A new figure-of-merit, the optical centroid efficiency (OCE), considers the energy on the rectangular detector pixel, averaged over all positions on the pixel. We calculate the OCE as a function of energy on detector (EOD) for a popular IR imaging system, a three-mirror reflector.