视觉假体中小波边缘检测算法的VLSI结构设计
发布时间：2018-08-07 11:39
【摘要】：视觉系统是人类最为重要的感知器官。经研究发现,大部分盲人都只是在视觉通路上部分发生病变,这就为视觉假体的研究奠定了生理基础。视觉假体技术属于功能点刺激技术的一种,通过在盲人眼中植入微电极阵列来刺激其视觉通路中未受损伤的部分,产生光幻视。但目前视觉假体技术受低分辨率、光幻视的不稳定性以及光幻视延时等问题的限制,这就需要通过图像预处理在少量的像素点下实时为盲人提供识别物体的主要信息。边缘是图像信息最集中的部分,盲人通过对边缘图像的识别能保证基本的视觉感受。而小波分析是近年来逐渐兴起的热门信号处理方法,其良好的时频局部分析的特性以及多尺度多分辨率思想在图像处理中具有高度的应用价值。本文在小波变换的理论基础上设计了基于提升小波的边缘检测算法。重点设计了基于FPGA的提升小波变换VLSI电路结构,提出了一种9输入的并行计算电路,保证了少量像素点的边缘连续性,并在每级变换的高频运算中加入阈值截取,提取出更为精细的边缘曲线。论文中首先在MATLAB软件上设计算法并对各类边缘提取算法的效果进行对比分析,之后详细设计介绍了算法的硬件电路并对算法各个模块进行RTL级设计及仿真,最后通过CMOS摄像头、SDRAM存储器、VGA显示器等搭建视频处理系统来对算法进行系统级验证。本文设计的提升小波运算属于整数域的运算,具有同址计算、相比传统小波速度更快、易重构等适合硬件实现的特性,并在视频流处理的过程中围绕SDRAM进行分时复用,在提取出较为准确的边缘信息的同时能够满足视觉假体所需求的分辨率大小的视频实时传输,丰富了视觉假体图像处理的研究内容。
[Abstract]:Visual system is the most important organ of human perception. It is found that most blind people are only partially affected in the visual pathway, which lays a physiological foundation for the study of visual prosthesis. Visual prosthesis is a kind of function point stimulation technology, which stimulates the undamaged parts of visual pathway by implanting microelectrode array in blind eyes, which produces optical illusion. However, the current visual prosthesis technology is limited by the problems of low resolution, optical illusion instability and optical illusion delay, which need to provide the blind with the main information of object recognition in real time under a small number of pixels through image preprocessing. Edge is the most concentrated part of image information. Blind people can guarantee basic visual feeling by recognizing edge image. Wavelet analysis is a popular signal processing method in recent years. Its good characteristics of time-frequency local analysis and multi-scale and multi-resolution theory have high application value in image processing. Based on the theory of wavelet transform, an edge detection algorithm based on lifting wavelet is designed in this paper. The VLSI circuit structure of lifting wavelet transform based on FPGA is mainly designed. A 9-input parallel computing circuit is proposed, which ensures the edge continuity of a small number of pixels, and the threshold is added to the high frequency operation of each level transform. Finer edge curves are extracted. Firstly, the algorithm is designed on MATLAB software, and the effect of all kinds of edge detection algorithms is compared and analyzed. Then, the hardware circuit of the algorithm is introduced in detail, and each module of the algorithm is designed and simulated at RTL level. Finally, the video processing system is built by CMOS camera, SDRAM memory and VGA display to verify the algorithm at system level. The lifting wavelet operation designed in this paper belongs to the integer domain operation, has the same address calculation, is faster than the traditional wavelet, easy to reconstruct and so on suitable for the hardware realization, and carries on the time-sharing multiplexing around the SDRAM in the video stream processing process. While extracting more accurate edge information, it can meet the need of visual prosthesis resolution of real-time video transmission, enrich the research content of visual prosthesis image processing.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TP391.41
本文编号：2169905
[Abstract]:Visual system is the most important organ of human perception. It is found that most blind people are only partially affected in the visual pathway, which lays a physiological foundation for the study of visual prosthesis. Visual prosthesis is a kind of function point stimulation technology, which stimulates the undamaged parts of visual pathway by implanting microelectrode array in blind eyes, which produces optical illusion. However, the current visual prosthesis technology is limited by the problems of low resolution, optical illusion instability and optical illusion delay, which need to provide the blind with the main information of object recognition in real time under a small number of pixels through image preprocessing. Edge is the most concentrated part of image information. Blind people can guarantee basic visual feeling by recognizing edge image. Wavelet analysis is a popular signal processing method in recent years. Its good characteristics of time-frequency local analysis and multi-scale and multi-resolution theory have high application value in image processing. Based on the theory of wavelet transform, an edge detection algorithm based on lifting wavelet is designed in this paper. The VLSI circuit structure of lifting wavelet transform based on FPGA is mainly designed. A 9-input parallel computing circuit is proposed, which ensures the edge continuity of a small number of pixels, and the threshold is added to the high frequency operation of each level transform. Finer edge curves are extracted. Firstly, the algorithm is designed on MATLAB software, and the effect of all kinds of edge detection algorithms is compared and analyzed. Then, the hardware circuit of the algorithm is introduced in detail, and each module of the algorithm is designed and simulated at RTL level. Finally, the video processing system is built by CMOS camera, SDRAM memory and VGA display to verify the algorithm at system level. The lifting wavelet operation designed in this paper belongs to the integer domain operation, has the same address calculation, is faster than the traditional wavelet, easy to reconstruct and so on suitable for the hardware realization, and carries on the time-sharing multiplexing around the SDRAM in the video stream processing process. While extracting more accurate edge information, it can meet the need of visual prosthesis resolution of real-time video transmission, enrich the research content of visual prosthesis image processing.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TP391.41
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