Signal restoration algorithm for photoacoustic imaging systems

In a photoacoustic (PA) imaging system, the detectors are bandwidth-limited. There-fore, they capture PA signals with some unwanted ripples. This limitation degrades the resolution/contrast and induces sidelobes and artifacts in the reconstructed images along the axial direction. To compensate for the limited bandwidth effect, we present a PA signal restoration algorithm, where a mask is designed to extract the signals at the absorber positions and remove the unwanted ripples. This restoration improves the axial resolution and contrast in the reconstructed image. The restored PA signals can be considered as the input of the conventional reconstruction algorithms (e.g., Delay-and-sum (DAS) and Delay-multiply-and-sum (DMAS)). To compare the performance of the proposed method, DAS and DMAS reconstruction algorithms were performed with both the initial and restored PA signals on numerical and experimental studies (numerical targets, tungsten wires, and human forearm). The results show that, compared with the initial PA signals, the restored PA signals can improve the axial resolution and contrast by 45% and 16.1 dB, respectively, and suppress background artifacts by 80%.

Automated summary

In a photoacoustic imaging system, limitations in detector bandwidth result in unwanted ripples in the signals, degrading resolution and contrast and producing artifacts in reconstructed images along the axial direction. To address this, a signal restoration algorithm is proposed which uses a mask to extract signals at absorber positions and remove unwanted ripples. The restoration improves axial resolution and contrast in reconstructed images.