3D imaging and metrology of complex micro-structures is a critical task for precision manufacturing and inspection. In this paper, an accurate and flexible calibration method for 3D microscopic structured light system with telecentric imaging and Scheimpflug projector is proposed. Firstly, a fringe projection 3D microscopy (FP-3DM) system consisting of a telecentric camera and a Scheimpflug projector is developed, which can take full advantage of the depth of field (DOF) and increase the measurement depth range. Secondly, an accurate and flexible joint calibration method is proposed to calibrate the developed system, which utilizes the established pinhole imaging model and Scheimpflug distortion model to calibrate telecentric imaging, and fully considers the correction and error optimization of the Scheimpflug projection model. Meanwhile, the optimized local homography is calculated to obtain more accurate sub-pixel correspondence between the camera and the projector, and the perspective-n-point (PnP) method make the 3D coordinate estimation of the feature point more accurate. Finally, a prototype and a dedicated calibration program are developed to realize high-resolution and high-precision 3D imaging. The experimental results demonstrate that the re-projection error is less than 1µm, and the 3D repeated measurement error based on feature fitting is less than 4µm, within the calibrated volume of 10(H)mm × 50(W)mm × 40(D)mm.
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http://dx.doi.org/10.1364/OE.480333 | DOI Listing |
Acc Chem Res
January 2025
Department of Chemistry, The University of Manchester, Manchester M13 9PL, United Kingdom.
ConspectusThe emergence of two-dimensional (2D) materials, such as graphene, transition-metal dichalcogenides (TMDs), and hexagonal boron nitride (h-BN), has sparked significant interest due to their unique physicochemical, optical, electrical, and mechanical properties. Furthermore, their atomically thin nature enables mechanical flexibility, high sensitivity, and simple integration onto flexible substrates, such as paper and plastic.The surface chemistry of a nanomaterial determines many of its properties, such as its chemical and catalytic activity.
View Article and Find Full Text PDFCarbohydr Polym
March 2025
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, 15 North Third Ring Road East, Chaoyang District, Beijing 100029, China. Electronic address:
Conductive hydrogels have emerged as excellent candidates for the design and construction of flexible wearable sensors and have attracted great attention in the field of wearable sensors. However, there are still serious challenges to integrating high stretchability, self-healing, self-adhesion, excellent sensing properties, and good biocompatibility into hydrogel wearable devices through easy and green strategies. In this paper, multifunctional conductive hydrogels (PCGB) with good biocompatibility, high tensile (1694 % strain), self-adhesive, and self-healing properties were fabricated by incorporating boric acid (BA) and glucose (Glu) simultaneously into polyacrylic acid (PAA) and chitosan (CS) polymer networks using a simple one-pot polymerization method.
View Article and Find Full Text PDFComput Biol Med
January 2025
Department of Computer Science, Jamia Hamdard University, Near Batra Hospital, New Delhi, 110062, India. Electronic address:
Schizophrenia detection involves identifying the schizophrenia by analyzing specific patterns in Electroencephalogram (EEG) signals, which reflect brain activity associated with symptoms, like hallucinations and cognitive impairments. Existing models face challenges due to the complex and variable nature of EEG data, which may struggle to accurately capture critical temporal dependencies and relevant features. Traditional approaches often lack adaptability, limiting their ability to differentiate schizophrenia patterns from other brain activities.
View Article and Find Full Text PDFArch Clin Neuropsychol
January 2025
Department of Psychology, Neuropsychology Track, Windsor University, Windsor, ON N9B 3P4, Canada.
Establishing the effect of limited English proficiency (LEP) on cognitive performance within linguistically diverse populations is central to cross-cultural neuropsychological assessments. The present study was designed to replicate previous research on cognitive profiles in Romanian-English bilinguals. Seventy-six participants (54 women, MAge = 23.
View Article and Find Full Text PDFObjectives: Comorbidity prediction models have been demonstrated to offer more comprehensive and accurate predictions of death risk compared to single indices. However, their application in China has been limited, particularly among maintenance hemodialysis (MHD) patients. Therefore, the objective of this study was to evaluate the utility of comorbidity index models in predicting mortality risk among Chinese MHD patients.
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