Pulse decomposition-based analysis of PAT/TAT error caused by negative lobes in limited-view conditions**Project supported by the National Basic Research Program of China (Grant No. 2012CB921504), the National Natural Science Foundation of China (Grant Nos. 11274167, 11274171, 61201450, 61201495, and 61302175), and the Chongqing Science and Technology Commission of China (Grant Nos. 2012jjA40058 and 2012jjA40006).

Abstract

Pulse decomposition has been proven to be efficient to analyze complicated signals and it is introduced into the photo-acoustic and thermo-acoustic tomography to eliminate reconstruction distortions caused by negative lobes. During image reconstruction, negative lobes bring errors in the estimation of acoustic pulse amplitude, which is closely related to the distribution of absorption coefficient. The negative lobe error degrades imaging quality seriously in limited-view conditions because it cannot be offset so well as in full-view conditions. Therefore, a pulse decomposition formula is provided with detailed deduction to eliminate the negative lobe error and is incorporated into the popular delay-and-sum method for better reconstructing the image without additional complicated computation. Numerical experiments show that the pulse decomposition improves the image quality obviously in the limited-view conditions, such as separating adjacent absorbers, discovering a small absorber despite disturbance from a big absorber nearby, etc.