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公开(公告)号：US11961244B2
公开(公告)日：2024-04-16
申请号：US17769230
申请日：2020-08-27
Applicant: NANJING UNIVERSITY OF SCIENCE AND TECHNOLOGY
Inventor： Chao Zuo , Jiaming Qian , Qian Chen , Shijie Feng , Tianyang Tao , Yan Hu , Wei Yin , Liang Zhang , Kai Liu , Shuaijie Wu , Mingzhu Xu , Jiaye Wang
CPC classification number: G06T7/337 , G06T3/14 , G06T7/85 , H04N23/90 , G06T2207/10012 , G06T2207/10028
Abstract: Disclosed is a high-precision dynamic real-time 360-degree omnidirectional point cloud acquisition method based on fringe projection. The method comprises: firstly, by means of the fringe projection technology based on a stereoscopic phase unwrapping method, and with the assistance of an adaptive dynamic depth constraint mechanism, acquiring high-precision three-dimensional (3D) data of an object in real time without any additional auxiliary fringe pattern; and then, after a two-dimensional (2D) matching points optimized by the means of corresponding 3D information is rapidly acquired, by means of a two-thread parallel mechanism, carrying out coarse registration based on Simultaneous Localization and Mapping (SLAM) technology and fine registration based on Iterative Closest Point (ICP) technology. By means of the invention, low-cost, high-speed, high-precision, unconstrained and rapid-feedback omnidirectional 3D real-time molding becomes possible, and a new gate is opened into the fields of 360-degree workpiece 3D surface defect detection, rapid reverse forming, etc.
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Patent Agency Ranking
12.发明公开公开(公告)号：US20240020866A1
公开(公告)日：2024-01-18
申请号：US18025815
申请日：2021-08-18
Applicant: Nanjing University of Science and Technology
Inventor： Chao Zuo , Qian Chen , Shijie Feng , Jiasong Sun , Yuzhen Zhang , Guohua Gu
CPC classification number: G06T7/593 , G06T3/4007 , G06T7/194 , G06V10/44 , G06T2207/20228
Abstract: The invention discloses a three-dimensional (3D) measurement method based on end-to-end deep learning for speckle projection. First, the speckle pattern was projected by the projector and collected simultaneously by the stereo camera. The speckle images after stereo rectification are fed into the stereo matching network. A feature extraction sub-network based on shared weights processes the speckle images to obtain a series of low-resolution 3D feature tensors, The feature tensor is fed into the saliency object detection sub-network to detect foreground information in the speckle images, producing a full-resolution valid mask map. A 4D matching cost volume is generated using the feature tensor of both views based on the candidate disparity range, filtered by a series of 3D convolutional layers to achieve cost aggregation, so that the initial disparity map is obtained by disparity regression. The final disparity map is obtained by combining the mask map and the initial disparity map to achieve a single-frame, robust, and absolute 3D shape measurement. The invention achieves a single-frame, robust, and absolute 3D shape measurement by projecting a single speckle pattern.
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13.发明授权公开(公告)号：US11555992B2
公开(公告)日：2023-01-17
申请号：US16633037
申请日：2018-02-26
Applicant: NANJING UNIVERSITY OF SCIENCE AND TECHNOLOGY
Inventor： Qian Chen , Chao Zuo , Jiasong Sun , Shijie Feng , Yuzhen Zhang , Guohua Gu
Abstract: The invention discloses a programmable annular LED illumination-based high efficiency quantitative phase microscopy imaging method, the proposed method comprising the following steps: the derivation of system optical transfer function in a partially coherent illumination imaging system; the derivation of phase transfer function with the weak object approximation under the illumination of tilted axially symmetric coherent point illumination source; the extension of illumination from an axially symmetric coherence point source to a discrete annular point source, and the optical transfer function can be treated as an incoherent superposition of each pair of tilted axially symmetric coherent point sources. The acquisition of raw intensity dataset; the implementation of deconvolution for quantitative phase reconstruction. The invention derives the system phase transfer function under the tilted axially symmetric point light source in the case of partially coherent illumination, and promotes the optical phase transfer function of the discrete annular point light source. The programmability characteristic of LED array enables the annular illumination aperture to be flexibly adjustable, being applicable to different microscopic objects with different numerical apertures, and improving the compatibility and flexibility of the system.
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公开(公告)号：US11029144B2
公开(公告)日：2021-06-08
申请号：US16496815
申请日：2018-02-26
Applicant: NANJING UNIVERSITY OF SCIENCE AND TECHNOLOGY
Inventor： Qian Chen , Chao Zuo , Shijie Feng , Jiasong Sun , Yuzhen Zhang , Guohua Gu
IPC: G01B11/25
Abstract: A super-rapid three-dimensional measurement method and system based on an improved Fourier transform contour technique is disclosed. The method comprises: firstly calibrating a measurement system to obtain calibration parameters, then cyclically projecting 2n patterns into a measured scene using a projector, wherein n patterns are binary sinusoidal fringes with different high frequency, and the other n patterns are all-white images with the values of 1, and projecting the all-white images between every two binary high-frequency sinusoidal fringes, and synchronously acquiring images using a camera; and then performing phase unwrapping on wrapped phases to obtain initial absolute phases, and correcting the initial absolute phases, and finally reconstructing a three-dimensional topography of the measured scene by exploiting the corrected absolute phases and the calibration parameters to obtain 3D spatial coordinates of the measured scene in a world coordinate system, thereby accomplishing three-dimensional topography measurement of an object. In this way, the precision of three-dimensional topography measurement is ensured, and the speed of three-dimensional topography measurement is improved.
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15.发明授权公开(公告)号：US11487096B2
公开(公告)日：2022-11-01
申请号：US17294322
申请日：2019-07-05
Applicant: Nanjing University of Science and Technology
Inventor： Qian Chen , Chao Zuo , Yao Fan , Jiasong Sun , Jiaji Li , Shijie Feng , Yuzhen Zhang
Abstract: The patent discloses a differential phase contrast (DPC) quantitative phase microscopy method based on the optimal illumination pattern design. Firstly, the optimal illumination pattern corresponding to the isotropic phase transfer function of DPC quantitative phase imaging is derived, which is determined as a semi-annular illumination pattern with the illumination numerical aperture NAill equal to the numerical aperture NAobj of the objective lens. The illumination intensity distribution varies with the cosine of the illumination angle, and it can be expressed as S(θ)=cos(θ). This patent effectively compensates for the frequency loss of phase transfer, not only the high-frequency responses of PTF are enhanced, but also the transfer responses of low-frequency phase information is significantly improved. As a result, the optimal illumination scheme ensures the correctness and achieves high resolution phase reconstruction, while the number of illuminations is reduced to a minimum of two, which greatly increases the imaging speed, allowing for real-time dynamic, high-correctness, high-resolution phase imaging results.
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公开(公告)号：US11106029B2
公开(公告)日：2021-08-31
申请号：US16496548
申请日：2018-02-26
Applicant: NANJING UNIVERSITY OF SCIENCE AND TECHNOLOGY
Inventor： Qian Chen , Chao Zuo , Jiasong Sun , Shijie Feng , Yuzhen Zhang , Guohua Gu
Abstract: An annular-irradiation high-resolution quantitative phase microimaging based on light intensity transfer equation is proposed here includes designing an annular aperture for the imaging system illumination; invoking the weak object approximation by using the parameters of annular illumination aperture and bright field microscopy to calculate a weak object optical transfer function (WOTF) on the basis of a partially coherent imaging theory; and collecting three intensity images by a camera and obtaining the quantitative phase image of object by resolving the light intensity transfer equation with a deconvolution algorithm.
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