Based on structured-light vision measurement technology, we study a measuring method for microdiameter. The measurement principle and mathematical model are described. A novel grayscale barycenter extraction algorithm...Based on structured-light vision measurement technology, we study a measuring method for microdiameter. The measurement principle and mathematical model are described. A novel grayscale barycenter extraction algorithm along the radial direction is proposed, which can precisely gather the image coor- dinates of the ellipse-shaped light-stripe centers. The accuracy of the measurement result shows marked improvement by using the algorithm. The method executes circle fitting to the measured three-dimensional （3D） data using linear least square method, which can acquire the diameter, surface profile, and other information of the object effectively. On the scene, a line-structured light vision system using the presented method is applied to measure the curvature radius of metal blades. Experimental results show that the measurement precision of the system is higher than 2 μm.展开更多
In order to improve the performance of estimating the fundamental matrix, a key problem arising in stereo vision, a novel method based on stripe constraints is presented. In contrast to traditional methods based on al...In order to improve the performance of estimating the fundamental matrix, a key problem arising in stereo vision, a novel method based on stripe constraints is presented. In contrast to traditional methods based on algebraic least-square algorithms, the proposed approach aims to minimize a cost function that is derived from the minimum radius of the Hough transform. In a structured-light system with a particular stripe code pattern, there are linear constraints that the points with the same code are on the same surface. Using the Hough transform, the pixels with the same code map to the Hough space, and the radius of the intersections can be defined as the evaluation function in the optimization progress. The global optimum solution of the fundamental matrix can be estimated using a Levenberg- Marquardt optimization iterative process based on the Hough transform radius. Results illustrate the validity of this algorithm, and prove that this method can obtain good performance with high efficiency.展开更多
On-demand and real-time generation of arbitrary complex fields directly from the laser source holds significant appeal for myriad applications. In this Letter, we demonstrate a ring laser configuration capable of dyna...On-demand and real-time generation of arbitrary complex fields directly from the laser source holds significant appeal for myriad applications. In this Letter, we demonstrate a ring laser configuration capable of dynamically generating arbitrary transverse fields. In a ring laser resonator, two cascaded phase modulations are utilized, which permits the control of two beams with high efficiency and high fidelity. The zeroth-order beam is a fundamental Gaussian field that self-reproduces itself in the resonator. The first-order beam serves as the desired output field, which is separated from the selfreproduction mode to facilitate the on-demand manipulation of amplitude and phase. In the verification experiments,a series of typical Hermite–Gaussian(HG) modes, Laguerre–Gaussian(LG) modes, flat-top mode, and amplitude-only pattern“A” are generated from the ring laser configuration. This innovative ring laser resonator may open up new perspectives for the design of structured-light lasers, with potential impacts in applications such as particle manipulation, advanced microscopy, and next-generation optical communication.展开更多
Propelled by the rapidly growing demand for function incorporation and performance improvement,various specular components with complex structured surfaces are broadly applied in numerous optical engineering arenas.Fo...Propelled by the rapidly growing demand for function incorporation and performance improvement,various specular components with complex structured surfaces are broadly applied in numerous optical engineering arenas.Form accuracy of the structured surfaces directly impacts the functioning of the specular components.Because the scales of these structures and/or the importance of their functions are usually designed differently,the structures require different measurement demands in scale,lateral resolution,and accuracy.In this paper,a multiscale form measurement technique is proposed based on triple-sensor phase measuring deflectometry for measuring structured specular surfaces.The proposed technique contains two sub-phase measuring deflectometry(PMD)-systems.Each sub-system works as a single segmentation PMD(SPMD)system and is designed to have different measurement scales,lateral resolutions,and accuracies to meet the measurement demands of the targeted surfaces.Two imaging sensors in the proposed technique cover the measured full-scale surface.The specular surface is separated into several continuous segments through algorithms and the spatial relationship of the continuous segments is established based on absolute depth data calculated through the triangular relationship between the two imaging sensors.The third imaging sensor with a long working distance only captures thefield of the small-scale structures and reconstructs the structures based on gradient data to improve the structures’reconstruction resolution and accuracy.In order to make it suitable for portable and embedded measurement,a compact configuration is explored to reduce system volume.Data fusion techniques are also studied to combine the measurement data of the two sub-systems.Experimental results demonstrate the validity of a portable prototype developed based on the proposed technique by measuring a concave mirror with small-scale structures.展开更多
文摘Based on structured-light vision measurement technology, we study a measuring method for microdiameter. The measurement principle and mathematical model are described. A novel grayscale barycenter extraction algorithm along the radial direction is proposed, which can precisely gather the image coor- dinates of the ellipse-shaped light-stripe centers. The accuracy of the measurement result shows marked improvement by using the algorithm. The method executes circle fitting to the measured three-dimensional （3D） data using linear least square method, which can acquire the diameter, surface profile, and other information of the object effectively. On the scene, a line-structured light vision system using the presented method is applied to measure the curvature radius of metal blades. Experimental results show that the measurement precision of the system is higher than 2 μm.
文摘In order to improve the performance of estimating the fundamental matrix, a key problem arising in stereo vision, a novel method based on stripe constraints is presented. In contrast to traditional methods based on algebraic least-square algorithms, the proposed approach aims to minimize a cost function that is derived from the minimum radius of the Hough transform. In a structured-light system with a particular stripe code pattern, there are linear constraints that the points with the same code are on the same surface. Using the Hough transform, the pixels with the same code map to the Hough space, and the radius of the intersections can be defined as the evaluation function in the optimization progress. The global optimum solution of the fundamental matrix can be estimated using a Levenberg- Marquardt optimization iterative process based on the Hough transform radius. Results illustrate the validity of this algorithm, and prove that this method can obtain good performance with high efficiency.
基金supported by the National Key R&D Program of China (No.2023YFB3610701)the Hubei Provincial Central-Guided Local Science and Technology Development Special Program (2023CGB001)+3 种基金the Hubei Provincial Key Research and Development Program (No.2022BAA009)the Major Science and Technology Special Project of Hubei Province (No.2021AAA009)the Wuhan Science and Technology Project (No.20210120020234244)the Major Program (JD) of Hubei Province (No.2023BAA015)。
文摘On-demand and real-time generation of arbitrary complex fields directly from the laser source holds significant appeal for myriad applications. In this Letter, we demonstrate a ring laser configuration capable of dynamically generating arbitrary transverse fields. In a ring laser resonator, two cascaded phase modulations are utilized, which permits the control of two beams with high efficiency and high fidelity. The zeroth-order beam is a fundamental Gaussian field that self-reproduces itself in the resonator. The first-order beam serves as the desired output field, which is separated from the selfreproduction mode to facilitate the on-demand manipulation of amplitude and phase. In the verification experiments,a series of typical Hermite–Gaussian(HG) modes, Laguerre–Gaussian(LG) modes, flat-top mode, and amplitude-only pattern“A” are generated from the ring laser configuration. This innovative ring laser resonator may open up new perspectives for the design of structured-light lasers, with potential impacts in applications such as particle manipulation, advanced microscopy, and next-generation optical communication.
基金supported by the UK’s Engineering and Physical Sciences Research Council(EPSRC)funding of“The EPSRC Future Advanced Metrology Hub”(EP/P006930/1)the funding of“A Multiscale Digital Twin-Driven Smart Manufacturing System for High Value-Added Products”(EP/T024844/1).
文摘Propelled by the rapidly growing demand for function incorporation and performance improvement,various specular components with complex structured surfaces are broadly applied in numerous optical engineering arenas.Form accuracy of the structured surfaces directly impacts the functioning of the specular components.Because the scales of these structures and/or the importance of their functions are usually designed differently,the structures require different measurement demands in scale,lateral resolution,and accuracy.In this paper,a multiscale form measurement technique is proposed based on triple-sensor phase measuring deflectometry for measuring structured specular surfaces.The proposed technique contains two sub-phase measuring deflectometry(PMD)-systems.Each sub-system works as a single segmentation PMD(SPMD)system and is designed to have different measurement scales,lateral resolutions,and accuracies to meet the measurement demands of the targeted surfaces.Two imaging sensors in the proposed technique cover the measured full-scale surface.The specular surface is separated into several continuous segments through algorithms and the spatial relationship of the continuous segments is established based on absolute depth data calculated through the triangular relationship between the two imaging sensors.The third imaging sensor with a long working distance only captures thefield of the small-scale structures and reconstructs the structures based on gradient data to improve the structures’reconstruction resolution and accuracy.In order to make it suitable for portable and embedded measurement,a compact configuration is explored to reduce system volume.Data fusion techniques are also studied to combine the measurement data of the two sub-systems.Experimental results demonstrate the validity of a portable prototype developed based on the proposed technique by measuring a concave mirror with small-scale structures.
