【作者】 孙明霞；

【导师】 杨济民；

【作者基本信息】 山东师范大学 ， 微电子学与固体电子学， 2009， 硕士

【摘要】 嵌入式系统和计算全息术的快速发展为实现图像的三维空间实时显示提供技术支持。本文首次运用具有独特双核结构的OMAP5910开发平台,由MPU核来完成控制以及接口方面的处理需要功能,由DSP核实现图像处理模块功能,在此基础上搭建了一种三维显示系统。该系统的特点是将全息编码、实时操作系统和硬件开发平台三者结合,充分利用OMAP双核特点,对实时操作系统μC/OS-Ⅱ内核进行裁剪修改,完成它在ARM核的移植,进行代码优化,减少程序运算量,在脱机状态下实现三维图像的编码及空间显示。论文详细介绍了此三维显示系统的硬件电路设计和软件开发。硬件设计主要包括三维图像获取电路模块、图像处理模块、液晶驱动显示电路模块和投影显示模块四部分。软件开发包括实时操作系统μC/OS-Ⅱ的移植、嵌入式系统应用程序的编译、装载、运行以及液晶显示驱动程序开发。本文系统首先提出一种利用程控高分辨液晶空间光调制器(LC-SLM)的衍射特性,通过对被记录物体进行适当的预处理来增大再现视角的计算全息编码方法。该方法是先对视角超出所用SLM允许范围的物波信息进行预处理,使预处理后的物波视角满足抽样定理;然后再进行计算全息编码。对空间光衍射的三维全息图像数据的处理首先通过应用软件进行算法的仿真,通过仿真,找到最优化的计算处理方案,在图像处理速度以及图像分辨率之间找到合适的平衡点。对被记录的物波信息进行预处理,获取相应的2D图像,图像经A/D变换,计算、全息编码后获得数字3D图像信号。然后利用OMAP5910的USB功能模块设计的USB接口电路实现全息编码图像信号与上位机的高速数据传输。在图像处理电路中,采用ARM925MPU核来进行主控,实现支持操作系统平台的硬件构架、用于数据传输、实现与DSP核间的双核通信、实现中断接口、显示图像和人机接口、实现外部控制器的接口等功能,以及实现操作系统μC/OS-Ⅱ的任务管理;传输的信号我们需要以数字形式对其进行变换、滤波等处理,并且处理速度要尽可能高,以提高显示图象的刷新速度,减少抖动。DSP核来实现图像的高速处理。在双核通信中,由于采集到的三维全息图像数据量比较大,并且ARM和DSP的任务也相对较多,因此采用邮箱寄存器来传递双核间的握手协议,利用DSP DMA来实现大量数据的传输将DSP从繁重的处理任务中解放出来,缩短数据处理时间,来提高整个系统的程序运行效率。DSP/BIOS桥把GPP OS和DSP OS连接在一起,此连接可以使GPP端的客户与DSP上的任务交换信息和数据。DSP/BIOS桥提供运行在ARM925上的应用程序和运行在DSP上的算法之间的通信管理服务。DSP程序通过DSP/BIOS标准API与GPP通信。最后处理好的图像数据经由SONY公司的相关集成芯片搭建的XGA液晶投影机的显示驱动电路模块,将采样/保持(S/H)后的图像信号直接输入到液晶屏,经光学系统投影显示在屏幕上。ARM擅于控制,DSP擅于复杂数据处理,这个系统充分利用其双核特点。DMA传输方式将DSP从繁重的处理任务中释放出来,缩短数据处理时间。本文建立了一套新型的基于计算全息术、操作系统与OMAP平台的三维显示方案。LCD屏分辨率和对比度的不断改善和提高、处理器性能的不断提高、全息技术的日益完善,为三维显示以后在生物科学、医学、地形侦察和军事等领域的进一步应用提供一定的设计参考。更多还原

【Abstract】 Three dimension Display technology benefits from the recent developments in the fields of computer-generated hologram (CGH) technology and embedded systems. This contribution explores this three dimension display hardware system based on Open Multimedia Application Platform (OMAP5910), the architecture of Dual-Core Processor including ARM 925 RISC GPP and TMS320C55X DSP. MPU is used to be responsible for controlling and the interface-pin’s configuration and controlling register etc. and DSP is mainly used to realize the image processing. This system makes the best of the features of three units of CGH, Real-Time Operation system (RTOS) and the hardware development platform, cutting down and revisingμC/OS-Ⅱsystematic kernel structure, completing the transplanting OS to the ARM core, making codes as effective as possible and reducing program algorithms. This paper firstly realizes the three dimension display under offline state.This paper introduces the hardware design and software development. The hardware design of this system includes four parts: three dimension display images capturing module, images processing module, LCD display module and projection display module. Software development is consisted of the transplanting of OS, the edit, loading and running of embedded application program, and LCD driver program development.At present, the technology of realizing the dynamic hologram three dimension display has become a research hotspot under the utilization of CGH images and program controlled liquid crystal spatial light modulators (LC-SLM).First of all, this paper proposes one CGH method which makes use of the liquid crystal spatial light modulators (LC-SLM) diffraction characteristics, to increase the reproduction perspective through the recorded objects appropriate pretreatment. The method is first to pre-process the object waveform information beyond the SLM perspective permitted scope, after pretreatment make the object waveform perspective meet the sampling theorem; and then to perform computer-generated hologram coding. The processing of three dimension holographic image data of the space-ray diffraction is first to be simulated by the application software MATLAB. Through simulation, the optimization calculation is found, and a suitable balance between the image processing speed and the image resolution is found. This system makes the processing of the recorded object waveform information, capturing the corresponding 2D images.Processing AD transfer, three angles images are processed based on new efficient CGH coding technology and the digital lasers’ dynamic wave-front transforming technology of high resolution micro-display, and then to calculate CGH, sampling, calculating and encoding must be done.Next, this paper designs one kind of USB interface circuit based on the OMAP5910 USB function module. This system uses the USB interface to realize the CGH image signals’high-data communication between OMAP5910 and the host computer. The OMAP hardware platform is consists of three parts: ARM core, DSP core and Traffic Controller (TC). Three parts can independently calculate clock management. In the image processing module, the ARM925MPU core is good at main controlling and interface processing, and supports the hardware frame of the operation system platform. It is also used to transfer data, realizing dual-core communication with DSP, display image, the interrupt interface, the external controller interface and the RTOSμC/OS-Ⅱtask management. The transferred signals are in need of being processed in the way of acquisition, transform, filtering, estimation, reinforcement, compression and recognition, etc. in digital form. At the same time, we need increasing the transforming speed greatly as much as possible in order to improve the display images refresh speed and decrease vibration. DSP core has the faster speed of processing. In the Dual-core communication, the data quantity of the collected 3D holographic images is much larger, and the ARM and DSP tasks are relative larger, so we use mailbox register to transfer the dual-core handshake protocol and use DSP DMA to realize the larger quantity transmissions. In this way, we can reduce the burden of the DSP CPU,shorten the data processing time and improve the whole system running efficiently. The DSP/BIOS bridge combines GPP OS with DSP OS, making GPP customer transfer information and data with DSP task. GPP application program communicates with DSP arithmetic based on DSP/BIOS.Finally, the image data is putting up the display driver circuit of the XGA LCD projector based on the related SONY integrated chips. I2 C Bus is integrated in the chips without other interface circuit. The CGH coded images by S/H circuit display on the LCD, and pass by the optics system,being projected on the screen to realize 3D images display.ARM is adept in controlling and DSP is adept in complicated data calculation. This system makes full use of the characteristics of the two cores. At the same time, DMA transmission releases the DSP from the heavy processing tasks, shortening the data processing time. A new type 3D display module is built based on CGH, OS and OMAP platform.The LCD’s resolution and contrast ratio are being continuously improved, the function of processor is also rapidly improved and CGH technology is being increasingly perfected. These lay the foundation for the CGH and 3D display’s further application in the fields of biological sciences, medicine, terrain reconnaissance and military etc.更多还原