Ultrasonic imaging in highly attenuating materials with Walsh-Hadamard codes and the decomposition of the time reversal operator

In this work, the total focusing method is used to image defects in a high density polyethylene pipe. The viscoelastic attenuation of this material corrupts the images with a high electronic noise. To improve the image quality, the decomposition of the time reversal operator method is combined with spatial Walsh-Hadamard coded transmissions before calculating the images.