Self-shape estimation algorithm for flexible ultrasonic transducer array probe by minimizing entropy of reconstructed image

Abstract

Flexible ultrasonic transducer array probe can realize successive monitoring by pasting it to the body. Imaging with a flexible ultrasonic probe requires information of the elements’ relative position. In this paper, we propose an algorithm to estimate the array shape from radio frequency data acquired by synthetic aperture. With this algorithm, the array shape is estimated based on the entropy of the reconstructed image using the assumed array shape. Entropy is used to evaluate the sharpness of an image. The real array shape can be estimated by searching for the shape which minimizes the entropy. Simulation experiments to verify the proposed algorithm were conducted. A 16 elements, 5 MHz, 1mm pitch flexible transducer array was used. The average position error of all elements of 4 trials between the real shape and the estimated shape was 0.037 mm. These results indicate that the proposed algorithm has a possibility to enable medical imaging with flexible ultrasonic transducer array probe.