用于体绘制可视化的交互式直方图传递函数设计研究  

Design of Interactive Histogram Transfer Function for Volume Rendering

作　　者：陈彦军[1] 张雷[2,3] 刘磊[2] 吴秋峰[2] 

机构地区：[1]哈尔滨师范大学数学科学学院,哈尔滨150025 [2]哈尔滨工业大学计算机科学与技术学院,哈尔滨150001 [3]哈尔滨学院艺术与设计学院,哈尔滨150086

出　　处：《智能计算机与应用》2012年第6期20-24,27,共6页Intelligent Computer and Applications

基　　金：黑龙江省自然科学基金项目(A201008)

摘　　要：医学图像体绘制可视化可以直接显示体数据的内部信息,成为可视化研究的一个重要的领域。由于医学图像数据本身的复杂性和传递函数的设计的灵活性,可视化传递函数成为研究的热点。通过CT,MRI设备获取的体数据,其质量受噪声影响严重,首先使用非线性增强方法对数据进行预处理,之后对体数据进行边界体素预判,并构造二维直方图用以设计传递函数,最终用光线投射算法绘制体数据。利用文中方法对大小为256×256×161的牙齿数据集进行非线性增强去噪,并设计传递函数,牙齿数据噪声得到了有效地抑制,不同边界区分比较明显。此外对牙齿体数据进行边界体素预判后,通过二维直方图查找边界的时间由78.2s减少至28.3s。实验结果表明,文中方法能有效地去除噪声、查找边界并提高绘制速度。基于构造出的直方图能够方便进行半自动化传递函数设计,提高绘制结果的质量。Visualization of volume rendering for medical image is an important field of visualization,which can display the details of the volume data intuitively.As the complexity of medical image data itself and flexibility during the design of transfer functions,the transfer function becomes a research hotspot.Since the quality of volume data which is acquired by CT and MRI device is impacted by noisy seriously, this paper first applies non-linear filters in preprocessing stage to improve the quality of 3D volume data,followed by construction of 2D histogram based on external voxels to design the transfer function.then,the paper uses ray-casting algorithm to render volume data.Finally, the paper applies the method presented above to the tooth dataset with the size of 256×256×161.The noise is suppressed effectively after denoising with Nonlinear Anisotropic Filtering.Boundary between materials can be differentiated clearly by designing transfer function with 2D histogram constructed in this paper.Furthermore since the boundary voxels in the tooth dataset is pre-identified,the time for searching boundaries by 2D histogram reduces from 78.2s to 28.3s.The results of the experiments show that the method we presented in the paper can remove the noise,help user to search for the boundary more effectively and greatly speed up the rendering.The advantage of 2D interactive histogram in this paper that facilitates the semi-atuomatic design of transfer function and improves quality of rendering result is also demonstrated.

关 键 词：体绘制 非线性增强 传递函数 二维直方图 边界体素预判结构光 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]