Compared to typical scanners, handheld cameras offer convenient, flexible, portable, and non-contact image capture, which enables many new applications and breathes new life into existing ones. However, camera-captured documents may suffer from distortions caused by non-planar document shape and perspective projection, which lead to failure of current OCR technologies. We present a geometric rectification framework for restoring the frontal-flat view of a document from a single camera-captured image. Our approach estimates 3D document shape from texture flow information obtained directly from the image without requiring additional 3D/metric data or prior camera calibration. Our framework provides a unified solution for both planar and curved documents and can be applied in many, especially mobile, camera-based document analysis applications. Experiments show that our method produces results that are significantly more OCR compatible than the original images.
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http://dx.doi.org/10.1109/TPAMI.2007.70724 | DOI Listing |
ACS Appl Electron Mater
January 2025
Electrical Engineering Division, Engineering Department, University of Cambridge, Cambridge CB3 0FA, U.K.
Nanoscale semiconductors offer significant advantages over their bulk semiconductor equivalents for electronic devices as a result of the ability to geometrically tune electronic properties, the absence of internal grain boundaries, and the very low absolute number of defects that are present in such small volumes of material. However, these advantages can only be realized if reliable contacts can be made to the nanoscale semiconductor using a scalable, low-cost process. Although there are many low-cost "bottom-up" techniques for directly growing nanomaterials, the fabrication of contacts at the nanoscale usually requires expensive and slow techniques like e-beam lithography that are also hard to scale to a level of throughput that is required for commercialization.
View Article and Find Full Text PDFBiosensors (Basel)
November 2024
Institute of Laser Engineering, Osaka University, Suita 565-0871, Osaka, Japan.
Biosensors operating in the terahertz (THz) region are gaining substantial interest in biomedical analysis due to their significant potential for high-sensitivity trace-amount solution detection. However, progress in compact, high-sensitivity chips and methods for simple, rapid and trace-level measurements is limited by the spatial resolution of THz waves and their strong absorption in polar solvents. In this work, a compact nonlinear optical crystal (NLOC)-based reflective THz biosensor with a few arrays of asymmetrical meta-atoms was developed.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2024
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455.
Randomly moving active particles can be herded into directed motion by asymmetric geometric structures. Although such a rectification process has been extensively studied due to its fundamental, biological, and technological relevance, a comprehensive understanding of active matter rectification based on single particle dynamics remains elusive. Here, by combining experiments, simulations, and theory, we study the directed transport and energetics of swimming bacteria navigating through funnel-shaped obstacles-a paradigmatic model of rectification of living active matter.
View Article and Find Full Text PDFNano Lett
September 2024
Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea.
Two-dimensional trigonal tellurium (2D Te), a narrow-bandgap semiconductor with a bandgap of approximately 0.3 eV, hosts Weyl points near the band edge and exhibits a narrow, strong Berry curvature dipole (BCD). By applying a back-gate bias to align the Fermi level with the BCD, a sharp increase in the dissipationless transverse nonlinear Hall response is observed in 2D Te.
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