Light-field displays typically consist of a two-dimensional(2D)display panel and a light modulation device.The 2D panel presents synthesized parallax images,with the total information content of the three-dimensional(...Light-field displays typically consist of a two-dimensional(2D)display panel and a light modulation device.The 2D panel presents synthesized parallax images,with the total information content of the three-dimensional(3D)light feld dictated by the panel's total resolution.Angular resolution serves as a critical metric for light-field displays,where higher angular resolution correlates with a more realistic 3D visual experience.However,the improvement of angular resolution is typically accompanied by a reduction in spatial resolution,due to the limitations of the 2D display panel's total resolution.To address this challenge,a light-feld display method with enhanced information utilization is introduced,achieved through the independent modulation of chrominance and luminance.A static light-field image display system is proposed to verify the feasibility of this method.The system employs a bidirectional angular modulation grating(BAMG)and a collimated light source(CLS)to create uniformly distributed viewpoints in space.A luminance modulation film(LMF)and a chrominance modulation film(CMF)are utilized to modulate the light-field information,with chrominance and luminance synthesized images printed at pixel densities of 720 pixels per inch(PPl)and 8000 dots per inch(DPl),respectively,to align with the differential sensitivities of the human visual system.In the experiment,the proposed display system achieves a full-parallax,high-fidelity color display with a 98.2°horizontal and 97.7°vertical field of view(FOV).So,the light-feld display method of modulating chrominance and luminance separately has been proven to achieve high-fidelity display effects.展开更多
Fringe projection profilometry(FPP)is a method that determines height by analyzing distortional fringes,which is widely used in high-accuracy 3D imaging.Now,one major reason limiting imaging speed in FPP is the projec...Fringe projection profilometry(FPP)is a method that determines height by analyzing distortional fringes,which is widely used in high-accuracy 3D imaging.Now,one major reason limiting imaging speed in FPP is the projection device;the capture speed of high-speed cameras far exceeds the projection frequency.Among various devices,an LED array can exceed the speed of a high-speed camera.However,non-sinusoidal fringe patterns in the LED array systems can arise from several factors that will reduce the accuracy,such as the spacing between adjacent LEDs,the inconsistency in brightness across different LEDs,and the residual high-order harmonics in binary defocusing projection.It is challenging to resolve by other methods.In this paper,we propose a method that creates a look-up table using system calibration data of phase-height models.Then we utilize the look-up table to compensate for the phase error during the reconstructing process.The foundation of the proposed method relies on the time-invariance of systematic error;any factor that impacts the sinusoidal characteristic would present as an anomaly in the unwrapped phase.Experiments have demonstrated that the root mean square errors(RMSEs)of the results yielded by the proposed method were reduced by over 90%compared to those yielded by the traditional method,reaching 20μm accuracy.This paper offers an alternative approach for high-speed and high-accuracy 3D imaging with an LED array and presents a workable solution for addressing complex errors from non-sinusoidal fringes.展开更多
基金supported by the National Key Research and Development Program of China(2023YFB3611500)National Natural Science Foundation of China(62175015,62335002,62075016).
文摘Light-field displays typically consist of a two-dimensional(2D)display panel and a light modulation device.The 2D panel presents synthesized parallax images,with the total information content of the three-dimensional(3D)light feld dictated by the panel's total resolution.Angular resolution serves as a critical metric for light-field displays,where higher angular resolution correlates with a more realistic 3D visual experience.However,the improvement of angular resolution is typically accompanied by a reduction in spatial resolution,due to the limitations of the 2D display panel's total resolution.To address this challenge,a light-feld display method with enhanced information utilization is introduced,achieved through the independent modulation of chrominance and luminance.A static light-field image display system is proposed to verify the feasibility of this method.The system employs a bidirectional angular modulation grating(BAMG)and a collimated light source(CLS)to create uniformly distributed viewpoints in space.A luminance modulation film(LMF)and a chrominance modulation film(CMF)are utilized to modulate the light-field information,with chrominance and luminance synthesized images printed at pixel densities of 720 pixels per inch(PPl)and 8000 dots per inch(DPl),respectively,to align with the differential sensitivities of the human visual system.In the experiment,the proposed display system achieves a full-parallax,high-fidelity color display with a 98.2°horizontal and 97.7°vertical field of view(FOV).So,the light-feld display method of modulating chrominance and luminance separately has been proven to achieve high-fidelity display effects.
基金National Key Research and Development Program of China(2023YFB2806800)Open Research Projects of KLOMT(2022KLOMT02-02)。
文摘Fringe projection profilometry(FPP)is a method that determines height by analyzing distortional fringes,which is widely used in high-accuracy 3D imaging.Now,one major reason limiting imaging speed in FPP is the projection device;the capture speed of high-speed cameras far exceeds the projection frequency.Among various devices,an LED array can exceed the speed of a high-speed camera.However,non-sinusoidal fringe patterns in the LED array systems can arise from several factors that will reduce the accuracy,such as the spacing between adjacent LEDs,the inconsistency in brightness across different LEDs,and the residual high-order harmonics in binary defocusing projection.It is challenging to resolve by other methods.In this paper,we propose a method that creates a look-up table using system calibration data of phase-height models.Then we utilize the look-up table to compensate for the phase error during the reconstructing process.The foundation of the proposed method relies on the time-invariance of systematic error;any factor that impacts the sinusoidal characteristic would present as an anomaly in the unwrapped phase.Experiments have demonstrated that the root mean square errors(RMSEs)of the results yielded by the proposed method were reduced by over 90%compared to those yielded by the traditional method,reaching 20μm accuracy.This paper offers an alternative approach for high-speed and high-accuracy 3D imaging with an LED array and presents a workable solution for addressing complex errors from non-sinusoidal fringes.
