Time of flight ultrasonic CT based on ML-EM for wooden pillars

The ML-EM method was applied to ultrasonic TOF CT. The numerical phantom and the wood phantom were prepared. In the experiments, the number of obtained TOF data is 306. Considering the measurement time and phantom size, it often becomes an upper bound in our ultrasonic system. When the image was reconstructed by only 306 data, the image had many artifacts. To obtain clear image, the interpolation was used. After interpolation, the defect was clearly recognized by CT image.