VisCPT Image Processing, Hardware Modification and Application Development

视锥贯入计（vis锥贯入计）是一种包含两个微型CCD摄像机的电子锥贯入计。当探头垂直穿过土壤时，照相机以两种放大倍率连续收集土壤地层学图像。通过计算机图像处理，它可以描绘出土壤类型，并有助于对一个地点进行非常高分辨率的地层表征。目前的研究工作将包括三个部分：基于小波变换图像功率谱的土壤粒度标准指标的开发；对现有的vispt仪器进行修改，包括适应彩色摄像机和实时数字图像采集；并在旧金山金银岛的国家岩土实验（NGES）站点收集现场数据。收集到的土壤粘度测试数据将被评估，特别关注图像纹理和小波变换技术，以确定土壤类型。将取连续的高质量活塞管土样与粘度测试结果进行比较。此外，还将把测试结果与标准压锥（uCPT）测试结果进行比较，以说明和量化薄地层对uCPT读数的影响。预计对岩土力学指标表的修改将大大提高岩土工程师确定场地特征的能力，特别是在薄地层的识别和定位方面。这将显著改善液化潜力、沉降率和其他关键行为的预测。

The Vision Cone Penetrometer (VisCPT) is an electronic cone penetrometer containing two miniature CCD video cameras. The cameras collect a continuous stream of images of a soil stratigraphy at two levels of magnification as the probe is advanced vertically through a soil. The VisCPT delineates soil types and through computer image processing it facilitates very high-resolution stratigraphic characterization of a site. The present research effort will consist of three parts: Development of standard indices for soil grain size based on the power spectra of wavelet-transformed images; Modifications to the existing VisCPT instrumentation including adaptation of color cameras and real-time digital image acquisition; and field data collection at the National Geotechnical Experimentation (NGES) site on Treasure Island in San Francisco. The collected VisCPT data will be evaluated with specific focus on image-texture and wavelet transform techniques for determining soil type. Continuous high quality piston tube soil samples will be taken for comparison to VisCPT results. The VisCPT images will also be compared to standard piezocone (uCPT) test results to illustrate and quantify the effects of thin strata on uCPT readings. It is anticipated that the modifications to the VisCPT will substantially enhance the ability of geotechnical engineers to characterize a site, especially with regard to the identification and location of thin strata. This will lead to significant improvement in predictions of liquefaction potential, settlement rates and other critical behaviors.