On image quality enhancement in Photoacoustic image reconstruction by motion compensation

Photoacoustic (PA) imaging is a relatively new noninvasive medical imaging modality. It is a technique which is harmless for the human body and uses pulsed optical energy. The process is based on the absorption of the pulse of optical energy by an object leading to local temperature increases. This temperature distribution leads to the generation of pressure waves, which in term can be measured outside of the object. The measured acoustical signals at the boundary of the object can be used to reconstruct the original energy absorption distribution. Reconstruction of the absorption distribution involves back projecting of the ultrasound measurements in some spatial map. Unexpected movements of the object can distort this reconstruction and result in blurred images. The aim of this work is to research a technique that corrects for these unexpected and a priori unknown movements. The approach is based on tracking known landmarks in the received signal. By assuming rigidness of the object under consideration, the tracking of landmarks in the PA signal can be used to estimate small translations of the object during the signal acquisition. Keywords—Photoacoustic imaging, motion correction, state estimation