1. Civil Engineering College, Hunan University, Changsha 410082, China;
2. School of Info-Physics and Geomatics Engineering, Central South University, Changsha 410083, China
To solve the problem of excessively big file, the authors studied the file format of SIR ground prospecting radar. A practical method was designed to read and cut the big radar image by means of Matlab programme. The efficiency of using GPR testing tunnel will be improved in field work.