Although the structured light system that uses digital fringe projection has been widely implemented in three-dimensional surface profile measurement, the measurement system is susceptible to non-linear error. In this...Although the structured light system that uses digital fringe projection has been widely implemented in three-dimensional surface profile measurement, the measurement system is susceptible to non-linear error. In this work, we propose a convenient look-up-table-based （LUT-based） method to compensate for the non-linear error in captured fringe patterns. Without extra calibration, this LUT-based method completely utilizes the captured fringe pattern by recording the full-field differences. Then, a phase compensation map is established to revise the measured phase. Experimental results demonstrate that this method works effectively.展开更多
Band-to-band registration accuracy is an important parameter of multispectral data. A novel band-to-band registration approach with high precision is proposed for the multi-spectral images of HJ-1A/B. Firstly, the mai...Band-to-band registration accuracy is an important parameter of multispectral data. A novel band-to-band registration approach with high precision is proposed for the multi-spectral images of HJ-1A/B. Firstly, the main causes resulted in misregistration are analyzed, and a high-order polynomial model is proposed. Secondly, a phase fringe filtering technique is employed to Phase Correlation Method based on Singular Value Decomposition (SVD-PCM) for reducing the noise in phase difference matrix. Then, experiments are carried out to build nonlinear registration models, and images of green band and red band are aligned to blue band with an accuracy of 0.1 pixels, while near infrared band with an accuracy of 0.2 pixels.展开更多
In this paper,we present a phase multiplication algorithm(PMA)to obtain scalable fringe precision in laser self-mixing interferometer under a weak feedback regime.Merely by applying the double angle formula on the sel...In this paper,we present a phase multiplication algorithm(PMA)to obtain scalable fringe precision in laser self-mixing interferometer under a weak feedback regime.Merely by applying the double angle formula on the self-mixing signal multiple times,the continuously improved fringe precision will be obtained.Theoretical analysis shows that the precision of the fringe could be improved toλ/2^(n+1).The validity of the proposed method is demonstrated by means of simulated SMI signals and confirmed by experiments under different amplitudes.A fringe precision ofλ/128 at a sampling rate of 500 k S/s has been achieved after doing 6 th the PMA.Finally,an amplitude of 50 nm has been proved to be measurable and the absolute error is 3.07 nm,which is within the theoretical error range.The proposed method for vibration measurement has the advantage of high accuracy and reliable without adding any additional optical elements in the optical path,thus it will play an important role in nanoscale measurement field.展开更多
Phase unwrapping is one of the key roles in fringe projection three-dimensional(3D)measurement technology.We propose a new method to achieve phase unwrapping in camera array light filed fringe projection 3D measuremen...Phase unwrapping is one of the key roles in fringe projection three-dimensional(3D)measurement technology.We propose a new method to achieve phase unwrapping in camera array light filed fringe projection 3D measurement based on deep learning.A multi-stream convolutional neural network(CNN)is proposed to learn the mapping relationship between camera array light filed wrapped phases and fringe orders of the expected central view,and is used to predict the fringe order to achieve the phase unwrapping.Experiments are performed on the light field fringe projection data generated by the simulated camera array fringe projection measurement system in Blender and by the experimental 3×3 camera array light field fringe projection system.The performance of the proposed network with light field wrapped phases using multiple directions as network input data is studied,and the advantages of phase unwrapping based on deep learning in light filed fringe projection are demonstrated.展开更多
基金the financial support provided by the National Natural Science Foundation of China(11472267 and 11372182)the National Basic Research Program of China(2012CB937504)
文摘Although the structured light system that uses digital fringe projection has been widely implemented in three-dimensional surface profile measurement, the measurement system is susceptible to non-linear error. In this work, we propose a convenient look-up-table-based （LUT-based） method to compensate for the non-linear error in captured fringe patterns. Without extra calibration, this LUT-based method completely utilizes the captured fringe pattern by recording the full-field differences. Then, a phase compensation map is established to revise the measured phase. Experimental results demonstrate that this method works effectively.
文摘Band-to-band registration accuracy is an important parameter of multispectral data. A novel band-to-band registration approach with high precision is proposed for the multi-spectral images of HJ-1A/B. Firstly, the main causes resulted in misregistration are analyzed, and a high-order polynomial model is proposed. Secondly, a phase fringe filtering technique is employed to Phase Correlation Method based on Singular Value Decomposition (SVD-PCM) for reducing the noise in phase difference matrix. Then, experiments are carried out to build nonlinear registration models, and images of green band and red band are aligned to blue band with an accuracy of 0.1 pixels, while near infrared band with an accuracy of 0.2 pixels.
基金supported by the Natural Science Foundation of Fujian Province(No.2020J01705)the School Foundation of Jimei University(No.C150345)。
文摘In this paper,we present a phase multiplication algorithm(PMA)to obtain scalable fringe precision in laser self-mixing interferometer under a weak feedback regime.Merely by applying the double angle formula on the self-mixing signal multiple times,the continuously improved fringe precision will be obtained.Theoretical analysis shows that the precision of the fringe could be improved toλ/2^(n+1).The validity of the proposed method is demonstrated by means of simulated SMI signals and confirmed by experiments under different amplitudes.A fringe precision ofλ/128 at a sampling rate of 500 k S/s has been achieved after doing 6 th the PMA.Finally,an amplitude of 50 nm has been proved to be measurable and the absolute error is 3.07 nm,which is within the theoretical error range.The proposed method for vibration measurement has the advantage of high accuracy and reliable without adding any additional optical elements in the optical path,thus it will play an important role in nanoscale measurement field.
基金the National Natural Science Foundation of China(No.61905178)the Science&Technology Development Fund of Tianjin Education Commission for Higher Education(No.2019KJ021)the Natural Science Foundation of Tianjin(No.18JCQNJC71100)。
文摘Phase unwrapping is one of the key roles in fringe projection three-dimensional(3D)measurement technology.We propose a new method to achieve phase unwrapping in camera array light filed fringe projection 3D measurement based on deep learning.A multi-stream convolutional neural network(CNN)is proposed to learn the mapping relationship between camera array light filed wrapped phases and fringe orders of the expected central view,and is used to predict the fringe order to achieve the phase unwrapping.Experiments are performed on the light field fringe projection data generated by the simulated camera array fringe projection measurement system in Blender and by the experimental 3×3 camera array light field fringe projection system.The performance of the proposed network with light field wrapped phases using multiple directions as network input data is studied,and the advantages of phase unwrapping based on deep learning in light filed fringe projection are demonstrated.
