The Experts below are selected from a list of 174 Experts worldwide ranked by ideXlab platform

Chuong Nguyen - One of the best experts on this subject based on the ideXlab platform.

  • Fixed-Lens camera setup and calibrated image registration for multifocus multiview 3D reconstruction
    Neural Computing and Applications, 2021
    Co-Authors: Shah Ariful Hoque Chowdhury, Chuong Nguyen, Richard Hartley
    Abstract:

    Image-based 3D reconstruction or 3D photogrammetry of small-scale objects including insects and biological specimens is challenging due to the use of a high magnification Lens with inherently limited depth of field, and the object’s fine structures. Therefore, the traditional 3D reconstruction techniques cannot be applied without additional image preprocessing. One such preprocessing technique is multifocus stacking/fusion that combines a set of partially focused images captured at different distances from the same viewing angle to create a single in-focus image. We found that the image formation is not properly considered by the traditional multifocus image capture and stacking techniques. The resulting in-focus images contain artifacts that violate the perspective projection. A 3D reconstruction using such images often fails to produce accurate 3D models of the captured objects. This paper shows how this problem can be solved effectively by a new multifocus multiview 3D reconstruction procedure which includes a new Fixed-Lens multifocus image capture and a calibrated image registration technique using analytic homography transformation. The experimental results using the real and synthetic images demonstrate the effectiveness of the proposed solutions by showing that both the fixed-Lens image capture and multifocus stacking with calibrated image alignment significantly reduce the errors in the camera poses and produce more complete 3D reconstructed models as compared with those by the conventional Moving Lens image capture and multifocus stacking.

  • Perspective-consistent multifocus multiview 3D reconstruction of small objects
    arXiv: Computer Vision and Pattern Recognition, 2019
    Co-Authors: Chuong Nguyen
    Abstract:

    Image-based 3D reconstruction or 3D photogrammetry of small-scale objects including insects and biological specimens is challenging due to the use of high magnification Lens with inherent limited depth of field, and the object's fine structures and complex surface properties. Due to these challenges, traditional 3D reconstruction techniques cannot be applied without suitable image pre-processings. One such preprocessing technique is multifocus stacking that combines a set of partially focused images captured from the same viewing angle to create a single in-focus image. Traditional multifocus image capture uses a camera on a macro rail. Furthermore, the scale and shift are not properly considered by multifocus stacking techniques. As a consequence, the resulting in-focus images contain artifacts that violate perspective image formation. A 3D reconstruction using such images will fail to produce an accurate 3D model of the object. This paper shows how this problem can be solved effectively by a new multifocus stacking procedure which includes a new Fixed-Lens Multifocus Capture and camera calibration for image scale and shift. Initial experimental results are presented to confirm our expectation and show that the camera poses of fixed-Lens images are at least 3-times less noisy than those of conventional Moving Lens images.

  • DICTA - Perspective-Consistent Multifocus Multiview 3D Reconstruction of Small Objects
    2019 Digital Image Computing: Techniques and Applications (DICTA), 2019
    Co-Authors: Chuong Nguyen
    Abstract:

    Image-based 3D reconstruction or 3D photogrammetry of small-scale objects including insects and biological specimens is challenging due to the use of high magnification Lens with inherent limited depth of field, and the object's fine structures and complex surface properties. Due to these challenges, traditional 3D reconstruction techniques cannot be applied without suitable image pre-processings. One such preprocessing technique is multifocus stacking that combines a set of partially focused images captured from the same viewing angle to create a single in-focus image. Traditional multifocus image capture uses a camera on a macro rail. Furthermore, the scale and shift are not properly considered by multifocus stacking techniques. As a consequence, the resulting in-focus images contain artifacts that violate perspective image formation. A 3D reconstruction using such images will fail to produce an accurate 3D model of the object. This paper shows how this problem can be solved effectively by a new multifocus stacking procedure which includes a new Fixed-Lens Multifocus Capture and camera calibration for image scale and shift. Initial experimental results are presented to confirm our expectation and show that the camera poses of fixed-Lens images are at least 3-times less noisy than those of conventional Moving Lens images.

Joel Meyers - One of the best experts on this subject based on the ideXlab platform.

  • Optimal filters for the Moving Lens effect
    Physical Review D, 2021
    Co-Authors: Selim C. Hotinli, Matthew C. Johnson, Joel Meyers
    Abstract:

    We assess the prospects for detecting the Moving Lens effect using cosmological surveys. The bulk motion of cosmological structure induces a small-scale dipolar temperature anisotropy of the cosmic microwave radiation (CMB), centered around halos and oriented along the transverse velocity field. We introduce a set of optimal filters for this signal, and forecast that a high significance detection can be made with upcoming experiments. We discuss the prospects for reconstructing the bulk transverse velocity field on large scales using matched filters, finding good agreement with previous work using quadratic estimators.

  • Transverse Velocities with the Moving Lens Effect.
    Physical review letters, 2019
    Co-Authors: Selim C. Hotinli, Joel Meyers, Neal Dalal, Andrew H. Jaffe, Matthew C. Johnson, James B. Mertens, Moritz Münchmeyer, Kendrick M. Smith, Alexander Van Engelen
    Abstract:

    Gravitational potentials that change in time induce fluctuations in the observed cosmic microwave background (CMB) temperature. Cosmological structure Moving transverse to our line of sight provides a specific example known as the Moving Lens effect. Here, we explore how the observed CMB temperature fluctuations, combined with the observed matter overdensity, can be used to infer the transverse velocity of cosmological structures on large scales. We show that near-future CMB surveys and galaxy surveys will have the statistical power to make a first detection of the Moving Lens effect, and we discuss applications for the reconstructed transverse velocity.

Selim C. Hotinli - One of the best experts on this subject based on the ideXlab platform.

  • Optimal filters for the Moving Lens effect
    Physical Review D, 2021
    Co-Authors: Selim C. Hotinli, Matthew C. Johnson, Joel Meyers
    Abstract:

    We assess the prospects for detecting the Moving Lens effect using cosmological surveys. The bulk motion of cosmological structure induces a small-scale dipolar temperature anisotropy of the cosmic microwave radiation (CMB), centered around halos and oriented along the transverse velocity field. We introduce a set of optimal filters for this signal, and forecast that a high significance detection can be made with upcoming experiments. We discuss the prospects for reconstructing the bulk transverse velocity field on large scales using matched filters, finding good agreement with previous work using quadratic estimators.

  • Transverse Velocities with the Moving Lens Effect.
    Physical review letters, 2019
    Co-Authors: Selim C. Hotinli, Joel Meyers, Neal Dalal, Andrew H. Jaffe, Matthew C. Johnson, James B. Mertens, Moritz Münchmeyer, Kendrick M. Smith, Alexander Van Engelen
    Abstract:

    Gravitational potentials that change in time induce fluctuations in the observed cosmic microwave background (CMB) temperature. Cosmological structure Moving transverse to our line of sight provides a specific example known as the Moving Lens effect. Here, we explore how the observed CMB temperature fluctuations, combined with the observed matter overdensity, can be used to infer the transverse velocity of cosmological structures on large scales. We show that near-future CMB surveys and galaxy surveys will have the statistical power to make a first detection of the Moving Lens effect, and we discuss applications for the reconstructed transverse velocity.

Alexander Van Engelen - One of the best experts on this subject based on the ideXlab platform.

  • Transverse Velocities with the Moving Lens Effect.
    Physical review letters, 2019
    Co-Authors: Selim C. Hotinli, Joel Meyers, Neal Dalal, Andrew H. Jaffe, Matthew C. Johnson, James B. Mertens, Moritz Münchmeyer, Kendrick M. Smith, Alexander Van Engelen
    Abstract:

    Gravitational potentials that change in time induce fluctuations in the observed cosmic microwave background (CMB) temperature. Cosmological structure Moving transverse to our line of sight provides a specific example known as the Moving Lens effect. Here, we explore how the observed CMB temperature fluctuations, combined with the observed matter overdensity, can be used to infer the transverse velocity of cosmological structures on large scales. We show that near-future CMB surveys and galaxy surveys will have the statistical power to make a first detection of the Moving Lens effect, and we discuss applications for the reconstructed transverse velocity.

Matthew C. Johnson - One of the best experts on this subject based on the ideXlab platform.

  • Optimal filters for the Moving Lens effect
    Physical Review D, 2021
    Co-Authors: Selim C. Hotinli, Matthew C. Johnson, Joel Meyers
    Abstract:

    We assess the prospects for detecting the Moving Lens effect using cosmological surveys. The bulk motion of cosmological structure induces a small-scale dipolar temperature anisotropy of the cosmic microwave radiation (CMB), centered around halos and oriented along the transverse velocity field. We introduce a set of optimal filters for this signal, and forecast that a high significance detection can be made with upcoming experiments. We discuss the prospects for reconstructing the bulk transverse velocity field on large scales using matched filters, finding good agreement with previous work using quadratic estimators.

  • Transverse Velocities with the Moving Lens Effect.
    Physical review letters, 2019
    Co-Authors: Selim C. Hotinli, Joel Meyers, Neal Dalal, Andrew H. Jaffe, Matthew C. Johnson, James B. Mertens, Moritz Münchmeyer, Kendrick M. Smith, Alexander Van Engelen
    Abstract:

    Gravitational potentials that change in time induce fluctuations in the observed cosmic microwave background (CMB) temperature. Cosmological structure Moving transverse to our line of sight provides a specific example known as the Moving Lens effect. Here, we explore how the observed CMB temperature fluctuations, combined with the observed matter overdensity, can be used to infer the transverse velocity of cosmological structures on large scales. We show that near-future CMB surveys and galaxy surveys will have the statistical power to make a first detection of the Moving Lens effect, and we discuss applications for the reconstructed transverse velocity.