In this paper, we present a discussion about perceptual-based color correction of digital images in the framework of variational techniques. We propose a novel image functional whose minimization produces a perceptually inspired color enhanced version of the original. The variational formulation permits a more flexible local control of contrast adjustment and attachment to data. We show that a numerical implementation of the gradient descent technique applied to this energy functional coincides with the equation of automatic color enhancement (ACE), a particular perceptual-based model of color enhancement. Moreover, we prove that a numerical approximation of the Euler-Lagrange equation reduces the computational complexity of ACE from theta(N2) to theta(N log N), where N is the total number of pixels in the image.
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http://dx.doi.org/10.1109/tip.2007.891777 | DOI Listing |
Metasurface holograms offer advantages, such as a wide viewing angle, compact size, and high resolution. However, projecting a full-color movie using a single hologram without polarization dependence has remained challenging. Here, we report a full-color dielectric metasurface holographic movie with a resolution of 512 × 512.
View Article and Find Full Text PDFUnderwater optical imaging, especially in coastal waters, suffers from reduced spatial resolution and contrast by forward scattered light. With the increased number of hyper- and multi-spectral imaging applications, the effect of the point spread function (PSF) at different spectral bands becomes increasingly more relevant. In this work, extensive laboratory measurements of the PSF at 450, 500, 550, 600 and 650 nm in different turbidity have been carried out.
View Article and Find Full Text PDFThis paper proposes an imaging technique to remove strong reflections from specular surfaces using polarization characteristics combined with light field imaging. Firstly, the correct strong reflection region is found by studying the reflected light characteristics, and the strong reflection region highlights are filtered out using Stokes parameters based on polarization information. Then, a system of microlens arrays with different transmittances was built for imaging, and the system was image-corrected to enable more information about the scene to be captured.
View Article and Find Full Text PDFConventional refractive microscope objective lenses have limited applicability to a range of imaging modalities due to the dispersive nature of their optical elements. Designing a conventional refractive microscope objective that provides well-corrected imaging over a broad spectral range can be challenging, if not impossible. In contrast, reflective optics are inherently achromatic, so a system composed entirely of reflective elements is free from chromatic aberrations and, as a result, can image over an ultra-wide spectral range with perfect color correction.
View Article and Find Full Text PDFNat Commun
January 2025
University of Strasbourg and CNRS, CESQ and ISIS (UMR 7006), aQCess, 67000, Strasbourg, France.
High-rate quantum error correcting (QEC) codes with moderate overheads in qubit number and control complexity are highly desirable for achieving fault-tolerant quantum computing. Recently, quantum error correction has experienced significant progress both in code development and experimental realizations, with neutral atom qubit architecture rapidly establishing itself as a leading platform in the field. Scalable quantum computing will require processing with QEC codes that have low qubit overhead and large error suppression, and while such codes do exist, they involve a degree of non-locality that has yet to be integrated into experimental platforms.
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