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Tham khảo tài liệu 'biomedical engineering trends in electronics communications and software part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 430 Biomedical Engineering Trends in Electronics Communications and Software arrangement of intensity color or shape. Texture features could be easily spoiled by imperfect imaging conditions mentioned above. As a result a single image feature is usually not sufficient to produce satisfactory segmentation for biomedical images. Multiple image features can be combined to enhance segmentation. This chapter provides three applications illustrating how multiple image features are integrated for segmentation of images generated from different modalities. 2. Fetal abdominal contour measurement in ultrasound images Because of its noninvasiveness ultrasound imaging is the most prevalent diagnostic technique used in obstetrics. Fetal abdominal circumference AC an indicator of fetal growth is one of the standardized measurements in antepartum ultrasound monitoring. In the first application a method that makes effective use of the intensity and edge information is provided to outline and measure the fetal abdominal circumference from ultrasound images Yu et al. 2008a Yu et al. 2008b . 2.1 Algorithm overview Fig. 1 summarizes the segmentation algorithm for abdomen measurement. Fig. 1. Flowchart of segmentation algorithm for abdomen measurement. In the first step a rectangle enclosing the contour of the target object is given by the operator as shown in Fig. 2 a then a region of interest ROI is defined in the form of an elliptical ring within the manually defined rectangle. The outer ellipse of the ring inscribes the rectangle. The inner ellipse is 30 smaller than the outer ellipse. To accommodate edge strength variations the ROI is equally partitioned into eight sub-regions. In the second step the initial diffusion threshold is calculated for each sub-region. Instantaneous coefficient of Biomedical Image Segmentation Based on Multiple Image Features 431 variation ICOV is used to detect the edges of the abdominal contour in the third step. The detected edges are shown in Fig. 2