| 摘要 |
PURPOSE:To correctly image a carved character by detecting a reflected wave from a carved surface and the reflected wave from a carved groove bottom surface and imaging the carved character by using both the reflection waves. CONSTITUTION:A time gate is set by a gate circuit 13 in the time region of reflected waves from a carved surface and from a carved groove bottom surface. The reflected wave in the time gate is binary-coded by a binary-coding circuit 14 at a specific threshold value and, when the reflected wave is present, a time from the incidence of an ultrasonic wave to the detection of the reflected wave is measured. The time for discriminating the reflected wave from the carved surface from the reflected wave from the carved bottom surface is calculated from the measured time. Then, the binary-coded data of the reflected wave are divided 23 into marked surface reflected wave data and groove bottom surface reflected wave data from the calculated time and both the data are stored in a memory A 18 and a memory A 19 in correspondence with the positions of an ultrasonic prober 1 in X and Y directions, respectively, at time points when the reflected waves are detected. Then, the contents of the memory A 18 and the memory A 19 are sequentially read out by a memory reading circuit 20. The contents are transferred to a picture image memory 21, the contents of the picture images corresponding to the memories A, B, 18 and 19 are synthesized to be displayed on a CRT 22. |
