针对建筑外墙空鼓的检测要求,利用振动与声学理论进行敲击过程的建模和敲击声学特性分析,在此基础上设计了一个基于16位凌阳单片机SPCE61A的嵌入式墙体无损检测系统。由于SPCE61A片内资源有限,通过片内资源的高效调配设计及算法优化实现多点数快速傅立叶计算,提高系统检测性能。实验数据表现的敲击声中低频段能量比与墙体结构的关系与理论分析基本吻合。门限检测方法对墙体进行识别,取100个好墙体的敲击声在9kHz处平均能量的0.6倍作为门限进行检测。实测200次敲击,正确识别率高达99%。如果环境噪声较大,而仍利用门限检测方法,则正确率识别率下降较大。实验结果表明了该系统的有效性。To tackle the safety threats caused by the wall hollowing,this paper designs an acoustic no-ndestructive inspection system based on embedded Sunplus SPCE61A single-chip microcomputer. The imp-act process and the resulting sound emission are analyzed theoretically to obtain the relationship between the hollow wall and the corresponding acoustic feature. Due to the limited on-chip memory capacity of the SPCE61A,the present system adopts the memory distribution and Fast Fourier Transform (FFT) algorithm optimization to realize 256-point FFT computation to ensure the detection performance. Experimental res-ults demonstrate the effectiveness of the present system,which has the potential of being developed as a portable,convenient,accurate and low-cost inspection tool.福建省科技计划重点项目(No.2007H0030);; 香港特区政府RGC项目(No.CityU 1166/02E)资助
