一种无需乘法器的光斑质心定位方法  

High-speed Centroid Calculation of Spot Image without Multipliers

作　　者：樊志华[1,2,3] 王春鸿[1,2] 

机构地区：[1]中国科学院光电技术研究所自适应光学研究室,成都610209 [2]中国科学院自适应光学重点实验室,成都610209 [3]中国科学院研究生院,北京100039

出　　处：《光电工程》2010年第12期17-24,共8页Opto-Electronic Engineering

基　　金：863高技术计划项目;中国科学院知识创新工程重要方向项目(KGCX2-Y11-920)

摘　　要：光斑质心定位在光学精密跟踪和精密测量中是一项关键技术,其精度和速度直接影响了光学测量的精度和响应速度。在实际应用中,往往把灰度重心法与图像预处理方法结合起来,以提高光斑质心计算的可靠性。运用图像预处理技术有效地抑制了噪声的影响,同时也会消耗大量的逻辑资源。针对在资源受限的条件下采用灰度重心法计算光斑质心的问题,本文提出了一种无需乘法器的光斑质心计算方法,用加法运算代替乘法运算,使用递推方法完成质心计算所需的低阶矩的运算。该方法的硬件仅为5个累加器,结构简单,能够以更低的资源消耗实现光斑质心定位。通过并行技术和流水线技术,其工作频率达到515MHz。实验证明:本文的结构在FPGA内实现,在100MHz的工作频率下,完成一帧质心计算的延时为0.35μs,误差与传统质心方法一致,占用214个Slices,其资源消耗仅为常规灰度重心法的50%。Spot centroiding is the key technique used in optical precise tracking and measurement, and its precision and speed affect those of optical tracking systems directly. In the applications, image pre-processing methods, which suppress the noise effectively at the expense of logic resources, are combined with the conventional mass of gravity to improve the reliability of spot centroid calculation. In order to realize real-time spot detection with resources limited, a high-speed spot centroid calculation method without multipliers is proposed. Instead of multiplications, it uses additions in recursive way to compute all low order moments needed by spot centroding. Compared with the architecture of the conventional mass of gravity method, our method needs only five accumulators, thus the resource cost is much lower than that of multipler-based spot detection. Moreover, the operating frequency of the hardware implementation of our method is up to 515 MHz with parallel and pipeline architecture. Experimental results indicate that when implemented in Field Programmable Gate Array at 100 MHz, our design can determine the spot centroid accurately with latency no more than 0.35 s at the cost of 214 slices, which is only half of resource consumption of the conventional method.

关 键 词：FPGA 光斑质心 灰度重心法 精密跟踪 

分 类 号：TP751.1[自动化与计算机技术—检测技术与自动化装置]