The gamma effect of phase-measuring profilometry systems yields nonlinear errors, which will substantially reduce the 3D shape measurement accuracy. Here, a robust and flexible gamma correction method based on the probability distribution function (PDF) of the wrapped phase is presented. First, a series of PDF curves are generated from the simulated wrapped phase distributions with different gamma values. Second, an experimental PDF curve will be produced after obtaining the wrapped phase from the captured three-step phase-shift fringe images. Then, a correlation procedure will be used to find the most similar PDF curve from the simulated PDF curves, and the gamma value of the matched PDF curve is that of the current system. Note that the gamma value detected by this method will be smaller than the true value due to the defocusing effect of the projection system with a large aperture. Therefore, an improved PDF-based algorithm, which projects two sets of three-step phase-shifting sinusoidal fringe patterns with different pre-coded gamma values and produces two PDF curves, is also added. Then after one more correlation procedure, a more accurate systematic gamma value could be calculated. It does not need large-step phase-shift images and 2×3 fringe images are quite enough. The experimental results show that the technique is very fast, easy to use and quite accurate.

Download full-text PDF

Source
http://dx.doi.org/10.1364/OE.27.032047DOI Listing

Publication Analysis

Top Keywords

wrapped phase
12
pdf curves
12
pdf curve
12
flexible gamma
8
based probability
8
probability distribution
8
distribution function
8
projection system
8
gamma values
8
fringe images
8

Similar Publications

A novel emulsifier for Pickering emulsion composed of whey protein and OSA-pectin loaded with Monascus pigments.

Int J Biol Macromol

January 2025

Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, United States.

Protein-polysaccharide complex carrier can solve the problem of insufficient stability of Monascus pigments (MPs), a kind of natural pigments, against heat and light. It also has the function to stabilize Pickering emulsion (PE) that can be used as fat replacer in meat products. In this study, heat denatured whey protein (HWP) and pectin modified by octenyl succinic anhydride (OSA-pectin) were prepared into complex by adding Ca loaded with MPs.

View Article and Find Full Text PDF

Near-Infrared Spectroscopy (NIRS) to Assess Infection Complications During the Acute Phase of Acute Pancreatitis.

Diagnostics (Basel)

November 2024

Division of Emergency and Critical Care Medicine, Department of Acute Medicine, Nihon University School of Medicine, Tokyo 173-8610, Japan.

Background: Acute pancreatitis (AP) severity is correlated with systemic infection incidence in the acute phase, and it is important to assess inflammation during the disease course and to recognize infection at an early stage. As in sepsis, inflammation in AP impairs tissue oxygen metabolism and disrupts microcirculation. We performed a vascular occlusion test (VOT) via near-infrared spectroscopy (NIRS), which noninvasively monitors local oxygen in peripheral tissues, to evaluate tissue oxygen metabolism and blood circulation during the acute AP phase.

View Article and Find Full Text PDF

Oxidative polyacrylonitrile nanofiber-based solid-phase microextraction coatings via wrapping strategy for polychlorinated biphenyls determination coupled to GC-MS.

Talanta

December 2024

Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007, PR China. Electronic address:

A straightforward approach to fabricating robust and versatile solid-phase microextraction (SPME) fibers is crucial for the extensive research and application of this notable sample preparation technique. Herein, we proposed a strategy for preparation of oxidative polyacrylonitrile (O-PAN) and O-PAN/ZIF-67 nanofiber-based SPME coatings by wrapping an electrospinning membrane on the stainless-steel wire, following with thermal oxidation at 300 °C. The shrinkage of membrane during thermal treatment resulted in the nanofibers being securely affixed to the stainless-steel wire, thereby creating a robust nanofiber-based SPME fiber.

View Article and Find Full Text PDF

We present a facile strategy for synthesizing magnetically retrievable carbon-wrapped CNT/Ni nanospheres (C-wrapped CNT/Ni) that enhance the catalytic performance of metals for environmental pollutant reduction. Structural and compositional analyses using X-ray diffraction (XRD), Raman spectroscopy, energy-dispersive X-ray spectroscopy (EDS), and field emission scanning electron microscopy (FESEM) confirmed the phase purity, morphology, and structure of the C-wrapped CNT/Ni. XRD, Raman, and EDS data validate the formation of the nanospheres, while FESEM images reveal uniform Ni nanospheres wrapped with a carbon layer through interconnected, evenly dispersed CNTs.

View Article and Find Full Text PDF

Musculoskeletal pain (MSP), which impacts bones, muscles, tendons, and ligaments, is a substantial worldwide pain disorder, characterized by muscle soreness, fatigue, inflammation, muscle spasms, sleep disruptions, and functional limitations. MSP is predominantly managed within the primary care setting. Recent consensus recognizes that heat therapy (HT) may provide potential benefits, especially in treating chronic MSP.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!