三维水声数据的可视技术研究

发布时间：2019-06-20 10:21

【摘要】：水声数据可视化的研究与应用为海底地貌观测,海洋资源勘探,水下救险以及海洋军事等方面提供了有力的技术保障。本文针对水声数据可视化中的数据预处理以及体绘制中的传输函数作了深入地研究,主要研究内容和成果如下:首先,针对三维水声数据背景复杂、受噪声干扰严重等特点,提出一种结合三维FMF的HFCM水声数据分割算法,以提高水声数据分割的精度和效率。该算法首先选取三维滤波窗口,利用最大熵阈值法计算出模糊阈值;再结合半高斯模糊隶属度函数对水声数据进行模糊中值滤波;最后采用HFCM算法对滤波后的数据进行分割。对两组不同的三维水声数据进行分割处理的结果表明该算法能够有效地降低噪声干扰,分割效果要优于未滤波的HFCM以及均衡FMF的HFCM分割算法,并且在分割效率上要明显优于传统的模糊C均值算法。其次,为了获得良好的水声数据三维显示效果,设计不透明度传输函数和颜色传输函数。首先将体数据的标量值映射为不透明度值;再计算体数据的梯度,根据所有体数据点的梯度幅值设计不透明度传输函数,最终设计出基于标量值和梯度幅值的二维不透明度传输函数;然后设计了把标量值、梯度幅值以及二阶导数映射到HSV彩色空间的颜色传输函数。将设计的传输函数应用到体绘制中,相比于标量值不透明度传输函数,引入梯度的二维不透明度传输函数的绘制结果强化了边界信息,突出了目标。颜色传输函数的设计使得水下物体更加容易辨识。本文首先对水声数据进行降噪分割处理,然后设计不透明度和颜色传输函数,利用光线投射算法对处理后的水声数据进行体绘制。实验结果表明,本文的研究工作能够获得良好的水下环境显示效果,不仅突出了目标物,而且绘制出的图像也十分清晰,更加有利于后续工作的观察和分析。
[Abstract]:The research and application of the visualization of underwater acoustic data provide a powerful technical guarantee for the observation of the submarine topography, the exploration of marine resources, the underwater rescue and the marine military. In this paper, the data pre-processing in the visualization of underwater acoustic data and the transfer function in volume rendering are studied in-depth. The main research contents and results are as follows: First, the background of the three-dimensional underwater acoustic data is complicated, the noise is seriously disturbed, etc. An HFCM underwater acoustic data segmentation algorithm combined with three-dimensional FMF is proposed in order to improve the accuracy and efficiency of underwater acoustic data segmentation. The method comprises the following steps of: firstly, selecting a three-dimensional filtering window, calculating a fuzzy threshold by using a maximum entropy threshold method, and performing fuzzy median filtering on the underwater acoustic data in combination with a semi-Gaussian fuzzy membership function; and finally, dividing the filtered data by using an HFCM algorithm. The result of dividing the two groups of different three-dimensional underwater acoustic data shows that the algorithm can effectively reduce the noise interference, and the segmentation effect is better than the non-filtered HFCM and the HFCM segmentation algorithm of the balanced FMF, and the segmentation efficiency is obviously better than the traditional fuzzy C-means algorithm. Secondly, in order to obtain good underwater acoustic data three-dimensional display effect, the opacity transfer function and the color transfer function are designed. firstly, the scalar value of the volume data is mapped into an opacity value; the gradient of the body data is calculated, the non-transparent transmission function is designed according to the gradient amplitude of all the body data points, the two-dimensional opacity transmission function based on the scalar value and the gradient amplitude is finally designed, and the scalar value is designed, The gradient magnitude and the second derivative are mapped to the color transfer function of the HSV color space. The design transfer function is applied to volume rendering. Compared with the scalar value non-transparency transfer function, the drawing result of the two-dimensional opacity transfer function of the gradient is reinforced with the boundary information, and the target is highlighted. The design of the color transfer function makes it easier for the underwater object to be recognized. In this paper, the underwater acoustic data is subjected to noise reduction and segmentation, then the opacity and the color transfer function are designed, and the processed underwater acoustic data is subjected to volume rendering by using the light projection algorithm. The experimental results show that the research work of this paper can get good underwater environment display effect, not only has the target object been highlighted, but also the drawn image is very clear, which is more beneficial to the observation and analysis of the follow-up work.
【学位授予单位】：杭州电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB56

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