| 摘要 |
PROBLEM TO BE SOLVED: To measure the propagation time of sound wave in a measured space with high accuracy by removing an effect of noise components such as reverberations and to measure environmental conditions such as temperature distribution with high accuracy. SOLUTION: When the propagation time of sound wave from a node m disposed on the periphery of the measured space to a node n disposed in a different position on the periphery is measured two or more times, time intervals at which sound wave is generated from the node m, are determined (110) by the use of random numbers so that the time intervals become inconstant, and sound wave is generated from the node m at the determined time intervals (114 to 122). Two or more times of measurement removes components equating to reverberations or noises from a waveform equating to an average of waveforms obtained at the node n, and thus the propagation time of sound wave across a block extending from the node m to the node n can be measured with high accuracy. The temperature distribution in the measured space can be found with high accuracy based on the propagation time found in the above way for each of numbers of blocks in the measured space. |
