HYCUBE

1. HYCUBE

2. HYCUBE: HYPACK’s implementation of CUBE

3. CUBE Combined Uncertainty and Bathymetric Estimator • Intended to Speed Processing of Multibeam Data. • Developed by Dr. Brian Calder of CCOM-UNH. • A statistical approach to cleaning multibeam data.

4. Introduction – The Basics Programming Flow HYSWEEP SURVEY MBMAX HYCUBE HS2 HS2x HSX XYZ CUBE Screens Z-Values Uncertainty Ratio # of Hypotheses Note: Only HS2 files can be input in HYCUBE

5. CUBE Terminology • CUBE Node: An X-Y point where CUBE will make depth estimates based on the surrounding data points. • CUBE Nodes are placed at fixed distances, resulting in a square grid. • HYPOTHESIS: A possible depth estimate at a node. • A CUBE Node can have multiple depth estimates. • CUBE Neighborhood: The area surrounding a CUBE Node where depths can influence the ‘hypotheses’

6. Cube Grid and Neighborhoods CUBE Nodes Data Points from HS2 File • A series of CUBE nodes make a CUBE GRID. • Soundings about the neighborhood of each node are used to generate possible depth estimates for the node (Hypotheses). • If there are multiple depth estimates at a node, CUBE selects one based on your input parameters. CUBE Neighborhood

7. HYCUBE Read Parameters

8. Node GenerationRead Parameters • Node Spacing: • Distance between depth estimates. • If too small, CUBE will not have enough depth samples assigned to the node to generate a depth estimation. • Capture Distance: • The ‘influence radius’ of a sounding is equal to the depth times the Capture Distance Scale percentage. • 5% seems to work well.

9. Disambiguation MethodRead Parameters • Disambiguation: Method used by CUBE to select a depth estimate for a node when multiple estimates exist. • Prior: Selects the hypothesis represented by the most data points. • Likelyhood: Searches for adjacent nodes with a single depth estimate and bases it’s selection off those z-values. • Posterior: A combination of the above two methods.

10. Running HYCUBE • Load HS2/HS2x files • (Single file or LOG containing HS2 or HS2x files) • Select Configuration: • Sonar Type • Vessel • Error Model • Read Parameters • Node Spacing • Min/max depth • Max angle (optional filters to use)

11. Sonar DeviceCUBE Configuration • CUBE has error models for some sonars. • This information improves the TPU computation. • If your sonar is not listed: • Select ‘Not Listed’. • It’s not a big deal. List of sonars with built-in error models in HYCUBE

12. Vessel SettingsCUBE Configuration • CUBE uses the Vessel Settings to assist in the computation of Total Propagated Uncertainty (TPU). • Most items are populated from HYPACK’s TPU EDITOR.

13. Error Model CUBE Configuration • There are two error models that CUBE can use when calculating the TPU. • Simple (IHO S-44) • Full MBES • CUBE rejects depths that have a TPU above the specified Survey Order

14. Cube Grid Window • Displays CUBE surfaces. • Depth Surface • Uncertainty • Ratio • # of Hypotheses per Node • Left-click to select node and load the node data into the CUBE Node Window.

15. Depth SurfaceCUBE Grid Window • Shows a 3D display of CUBE Depth Surface. • Left-click to set cursor position. • CUBE Node window updates to show distribution at selected node. • Click-and-drag to change viewing angles. • Right-click to pan. • Color-coded using Depth Color Scheme

16. Uncertainty SurfaceCUBE Grid Window • Useful for quality control. • User can export an XYZ file where ‘z’ is the uncertainty for the depth representing each node. • User can ‘force’ CUBE to select the hypotheses with the minimum uncertainty at each node. • Fixed color-code: • Dark Blue = Minimal • Bright Red = Maximum

17. RatioCUBE Grid Window • Useful for quality control. • The lower the better…. • Ratio = 5 – NS / ( NA – NS ) where • NS = # depth samples in selected hypothesis and, • NA = # depth samples in all hypotheses. 2 examples: • GOOD: 40 depths in selected hypothesis, 10 in alternate, 5 – [40/(50-40)] -> Ratio = 1 • BAD: 10 depths in selected hypothesis, 40 in alternate, 5 – [10/(50-10)] -> Ratio = 4.75

18. Hypothesis CountCUBE Grid Window • Shows how many depth estimates are generated at each node. • Color Code: • Dark Blue = 1 est. • Light Blue = 2 • Green = 3 • Yellow = 4 • Red = 5+

19. CUBE Node Window • Displays: • Distribution of z-values in the node’s neighborhood. • CUBE Hypothesis (selected) with uncertainty boundaries. • Modifies: • Allows you to select an alternative depth estimate for a CUBE node. • Searches: • Search for a CUBE node with multiple depth estimates. • Select alternative depth estimate. Left-click on the alternate hypothesis to select it.

20. Cube Hypothesis Window • Selected depth estimate is white. • Size of disk relates to number of supporting depths • Color of non-selected depth estimates is based on uncertainty. • Left-click on a disk to select it. AVI

21. Save Options Saves to XYZ file. Z-value can be one of 5 selections: CUBE Depth Estimate CUBE Uncertainty Ratio Hypothesis Count Sounding Nearest CUBE Depth Estimate

22. Sample CUBE Session

23. Comparison: CUBE vs. Sort Min/Max • Green: Check Lines Processed in CUBE. • Black: Processed Only in MBMAX: Sorted for Min and Max. The HYCUBE surface usually resembles a smoother median surface. Do not use CUBE if you are interested in the minimum depth over a rock or obstruction.