数码相机处理器设计及系统集成研究

【作者】 周荣政；

【导师】 洪志良；

【作者基本信息】 复旦大学 ， 微电子学与固体电子学， 2004， 博士

【摘要】 论文详细分析和讨论了数码相机处理器的设计原理和实现方法，对处理器中的核心功能进行了探讨和研究，并进行了系统集成。 论文首先讨论了数码相机系统的基本构成，并着重讨论了图像采样和处理的原理。然后，研究重点集中在数码相机处理器的三个主要功能上：结构设计，图像处理和图像压缩。论文对这三个问题均进行了深入研究，并给出了创新结构、改进算法以及设计实现。最后，论文结合两个数码相机处理器的设计过程，对SoC设计方法进行了深入研究，并给出了芯片的测试结果。 在处理器结构的设计中，论文提出了一种新颖的、基于DMA总线的数码相机处理器结构，该处理器针对数码相机系统进行了优化，兼顾了总线带宽、系统性能和灵活性，能够有效地实现基于IP核的数码相机处理器。 在图像处理方面，论文分别对前处理和后处理两个阶段，进行了深入研究。在前处理阶段，论文提出了一种改进的、自适应自动曝光、自动聚焦和自动白平衡算法，在加快算法速度的同时保证计算精度，对实际的应用具有很大意义。在后处理阶段，论文实现了包括内插、白平衡、伽玛校正、色彩校正、色空间变换和边界增强等功能在内的实时图像处理器流程。 在图像压缩方面，论文讨论了JPEG和JPEG2000 IP核的设计。论文从数码相机的应用出发，讨论了基本算法，定义了合适的体系结构，并指出了JPEG和JPEG2000设计过程中一些值得注意的地方。测试结果表明，设计的IP核功能正确，并达到一定的性能。 最后，论文讨论了SoC设计方法，特别是IP核的设计流程，并结合芯片的设计过程讨论了SoC设计中比较典型的问题，包括设计的可综合性、时序优化、可测性设计、低功耗设计等方面，并运用上述设计方法设计了一个基于JPEG IP核的CCD数码相机处理器，以及一个基于JPEG2000的CMOS数码相机处理器。测试结果表明，设计达到了国际同类设计的水平。更多还原

【Abstract】 The thesis analyzes and researches the design theories and methodologies of digital camera processors, and proposes two system-on-a-chip (SoC) designs.At first, the architecture of digital still camera system is discussed, especially for the theory of image sampling and processing. Then, the research is emphasized on the three main functions of a digital camera processor: architecture design, image processing and image compression. These topics are discussed and realized with new architectures, advanced algorithms and SoC designs. The SoC design methodology is also discussed in the thesis.In the design of processor architecture, a novel DMA-based architecture for digital camera processor is proposed. The architecture has been optimized for digital camera system, and has a trade-off among bus bandwidth, system performance and flexibility. The architecture can achieve efficient application in IP-based digital camera processors.In image processing, the pre-processing and post-processing flows are both discussed. An advanced adaptive auto exposure (AE), auto white balance (AWB) and auto focus (AF) algorithm is proposed. The algorithm can improve searching speed when keeping enough precision. A real-time image processing flow involving color interpolation, white balance, gamma correction, color correction, color space conversion and edge enhancement is also included in the design.In image compression, the IP’s of JPEG and JPEG2000 are designed. The algorithm theories, standards and proper architectures are researched. Some design guidelines are also given. The designs are proven by the experimental results.At last, the SoC design methodologies, especially the IP design flow, are discussed. Some important design strategies are also discussed such as design for synthesis, timing optimization, design for test and low power design. Two digital camera processors are designed and tested. One is a JPEG-based CCD digital camera processor and another is a JPEG2000-based digital camera processor. The results show that the chips have achieved the advanced level in the world.更多还原