Resolution of Image Compounding with a Ring Array Transducer

This work describes an automated system based on a ring transducer aimed to the early detection of breast cancer. Such equipment allows compounding multiple sector echographic images acquired at angular intervals around the breast in a water bath. A theoretical analysis of the resolution of this kind of image is presented. First, the impulse response (Point Spread Function) in any point of the imaged area is computed by numerical means. From this, several quality maps were built to quantify resolution, homogeneity and sensitivity of the resulting image. The effect of aperture size, number of partial images and ring dimensions is also analyzed. A low cost prototype has been used to validate the model. A thin wire has been accurately positioned in different locations of the imaged area, using a 128-element and 3.5 MHz linear array transducer. Experimental results are in agreement with developed theory.