A new control strategy applied in X-ray source to improve imagining quality

Abstract

ABSTRACT Image quality of X-Ray tubes will deteriorate with age. Experiment shows that the rise time of long-term service X-Ray source is long, leading to decrease in image black and white contrast. In order to acquire good consistency of image quality, the control parameters must be modified with service time. However, small signal model of X-ray sources is uncertain. Thus, it’s necessary to acquire accurate small signal model of system online. Then two types of software phase lock loop (SPLL) are proposed for online small signal model estimation of system with X-Ray tube: SPLL with notch filter and SPLL based on synchronous reference frame. More accurate online small signal model can be obtained by employing the latter method. Next piece-wise proportional integral (PI) control strategy based on online small signal model estimation of system with X-Ray tube is proposed to ensure that X-Ray sources, in use for different time periods have almost the same transient time. Finally simulation and experimental results show that black and white contrast of image obtained by X-ray system with long service time tube is improved dramatically to meet detection requirement.