关键词: 针检测，超声图像导引，实时灰度Hough变换，粗一精搜索策略，相位编组法

Abstract: Rcal-time needle segmentation and tracking arc very important technique in imagcguided surgery, biopsy, and therapy. We proposed a needle segmentation technique based on a Real-Time Gray-Scale Hough Transform (RTGHT)，which is composed of an improved Gray Hough transformation using phascgrouping algorithm with the coarscfine searching strategy. Furthermore, the RTGHT technique was evaluated by patient breast biopsy images. Experiments with patient breast biopsy ultrasound (US) image sectuences showed that our approach can segment the biopsy needle in real time with the angular rms error of about 10 and the position rms error of about 0. 5~on an affordable PC computer without the help of specially designed hardware. It can be applied in image-guided surgery and therapy.

Key words: Needle segmentation, US image guidance, Real-time gray-level Hough transform, Coarscfine search, Phase-grouping algorithm