CPT Filter

The tool can filter out rod change noise for qc and fs. The filter algorithm works based on Penetration_Rate (mm/s), and if it is not in the data file, then it is calculated based on elapsed time. You can set the Filter_Threshold_Penetration_Rate on the CPT_PROJECT_PARAMETERS and CPT_POINT_PARAMETERS, or use the default of 6 mm/s. If you manually run the filter then the threshold rate increases 1 mm/s each run per CPT push, i.e. the applied threshold rate = Filter_Threshold_Penetration_Rate + Filter_Count.

Data is only filtered if it is less than 95% of the mean of the previous two values, and the third and fourth values ahead.

In order for the fs filtering to take place, the Cone_Sleeve_Offset on the CPT_CONE_INFORMATION table must be defined.

If the Auto_Filter_Calculation on the CPT_PROJECT_PARAMETERS or CPT_POINT_PARAMETERS tables is set to Automatic (whichever is lower in the hierarchy with data), then the Filter will run once on import and set the Filter_Count field on the CPT_GENERAL table to "1". If Filter_Count field on the CPT_GENERAL table is set to less than "1" or null, the filter will run On Save.

The filter can also be run manually by slecting INPUT | Add-Ins > Datgel CPT Tool > CPT Filter. However, the cursor must be in the bottom half of the CPT_DATA table.