【作者】 张林；

【导师】 胡丹峰；

【作者基本信息】 苏州大学 ， 电子与通信工程（专业学位）， 2022， 硕士

【摘要】 数字微镜器件(DMD)是一种被广泛应用于数字光刻、旋转体3D显示等领域的高性能空间光调制器(SLM),且不同的应用场景对DMD的性能需求有所不同。在数字光刻应用中,3D光刻要求DMD显示灰度图像,扫描光刻要求DMD能够滚动显示大尺寸灰度图像,但现有方法无法很好地完成大尺寸灰度图像数据的传输与存储。为实现灰度图像滚动显示需要对图像进行分割拆分与位平面拆分,影响系统效率。旋转体3D显示要求DMD以非常高的帧率刷新计算全息图,因此现有的DMD产品通常只能完成二值图像的超高帧率显示,而二值图像会丢失部分全息信息。本文针对上述问题展开基于FPGA的DMD控制方法研究,具体工作内容如下:(1)在数字光刻应用中,根据DMD芯片使用规范,实现了419.6Hz的高帧率8位灰度调制方法,并基于FPGA完成DMD驱动设计。同时改进了上位机软件和FPGA中数据接收模块,使系统能够直接传输大尺寸灰度图像数据,省去图像分割和位平面拆分的步骤,简化了上位机软件流程。(2)提出并实现了间隔存储法来完成对任意尺寸灰度图像数据的存储,基于此方法可以很好地完成灰度图像滚动显示。改进DDR2读写模块,提高了DDR2内存的等效数据读取带宽,使DDR2数据带宽不再成为制约DMD显示帧率的因素。此外,DDR2读写模块与FIFO配合可以在DMD数据加载的同时完成对上位机发送的图像数据的接收与存储。(3)根据旋转体3D显示对DMD的性能需求,优化了DMD驱动模块。设计了高帧率4位灰度图像调制方法,在保证显示帧率足够的同时,将DMD显示内容从二值图像提升至4位灰度图像,可减少全息图像信息损失,提高重建的3D图像显示质量。更多还原

【Abstract】 Digital micromirror device(DMD)is a highly-performed spatial light modulator(SLM).It is widely used in the digital lithography,the 3D volumetric display with rotating mirror and other fields.The performance requirements of DMD are discrepant in different applications.In digital lithography,DMD is used to display grayscale images to complete 3D lithography.At the same time,DMD is used to scroll the display to complete scanning lithography.However,the transmission and storage of large-scale gray image data cannot be performed well by current methods.The gray images and their bit-planes must be split when they are rolling displayed,which is inefficiency.DMD is required to refresh the hologram at ultra-high frame rate in the 3D volumetric display.The binary image can be displayed at ultra-high frame rate by existing DMD equipment,while part of the holographic information will be lost.The controlling methods of DMD based on FPGA are researched to address the above mentioned issues.The main work of this thesis are as follows:(1)In the application of digital lithography,a high frame rate 8-bit gray-scale with 419.6Hz modulation method is completed according to the specifications of DMD by FPGA.At the same time,the computer software and the data receiving module in FPGA are improved so that the large-size gray image data can be directly transmitted,which simplifies the workflow of the DMD display device.(2)An interval storage method is proposed to realize the storage of large-size image data.The scrolling display of grayscale images is completed by the method.The DDR2 readwrite controller is ameliorated to increase the reading bandwidth of DDR2 Memory.Hence the DDR2 bandwidth is no longer a factor restricting the frame rate of DMD display.At the same time,the image data can be stored by the DDR2 read-write controller and FIFOs while loading the DMD data.(3)The DMD controller is optimized to meet the performance requirements of the 3D volumetric display with rotating mirror.A high-frame rate image modulation method is designed in order to reduce the loss of holographic information and improve the quality of 3D object reconstructions.Thus the display content of DMD is promoted from 1-bit images to 4-bits images and the frame rate is maintained highly enough simultaneously.更多还原