Chesapeake Times
Technical Review, Issue 4
January 2021
Letter from the General Manager

Happy New Year!

Looking in the rear-view mirror now that 2020 is over, I would have lost every bet on what the year would bring us here at Chesapeake. None of us could have predicted what would transpire, and like everyone else, we quickly adapted to the changes needed to keep our clients going. With no travel, we could not visit our clients, show off the software at a trade show, or do our classroom trainings. We learned how to do many of these things on zoom and GotoMeeting, and had to take a rain check on the lunch or coffee meeting we had planned to do in 2020. We saw companies suddenly become a remote workplace and we expanded our DFL license use to keep everyone working. Through all this uncertainly, we kept our focus; to continue the work on the software everyone expected from us.

The most important thing we did was to try to put blinders on, to not let the Covid pandemic impact our work. And although it was hard – as it affected all of us – our friends, our industry, and our family, Chesapeake ended 2020 with a successful training event last month, with 250 attendees – folks wanting to see what we did this year. And It was a lot. Throughout the year, we had 11 releases – from SonarWiz 7.5.4 through to 7.7.1 – adding in hundreds of features, programs, (bug fixes along the way).

Years ago, our phones were designed to call folks. Technology made them typing machines, with texting and email somewhat new (speaking for those in an older generation). In 2020, we went back to this mode of using the phone to speak with others. We know folks were WFH (I had to learn that term) and isolated, and sometimes speaking to someone makes a big difference – more than a text message. As we spoke with our friends and clients to make sure everything was ok, we also learned from them what is needed for their work. The hundreds of updates and features (and bug fixes) we did in 2020 were because you asked for them.

Looking ahead to 2021, I still cannot say when we will meet for lunch or coffee. A raincheck does not expire, so we will do it at some point. But I can tell you that our team here is working away, with SonarWiz 7.8 release later this year. Up next is SonarWiz 7.7.2, planned for release later this month.

In this edition of the Chesapeake Times, you will read about our Q4 features and some ideas we had in place for future releases. I wrote an article about of Globalization of SonarWiz – our software translation to a dozen languages. Check that one out, along with the listing of our workshops and seminars plans for the next few months.

All the best for 2021!

- Harold Orlinsky, General Manager
SonarWiz 7.7.x New Features and Technical Notes

New Editing Capabilities in ZEdit .................................. Jonathan Fleetwood, Engineer
Updates to SonarWiz Magnetometer........................... David Finlayson, Chief Scientist
Side Scan Drawing Improvement.................................. Christopher Favreau, CTO
Language Support in SonarWiz .................................... Harold Orlinsky, General Mgr
Speed and Efficient Survey Pattern .............................. Patrick Zynda, Support Engr
SonarWiz Annual Training & Upcoming Events ........... Stephen D'Andrea/Ashley Chan
Founders' Corner.......................................................... John and Eileen Gann
New Editing Capabilities in ZEdit
ZEdit is Chesapeake's utility program for editing series data in CSF, CMF (magnetometer) and XTF files. A common operation there is smoothing and removing anomalies from one-dimensional data, via its bottom "graph" view. We've added a few features in recent versions that are aimed at helping out with some of these series-editing tasks; these are highlighted below.

First, CSF sound velocity is now an editable field. Many of the file types SonarWiz can import allow for a per-ping sound velocity, but the ability to edit those values after import wasn't present except for the case of setting the whole file to a given value. For files having a per-ping sound velocity, but some spikes or roughness in them that need to be cleaned up, ZEdit now allows for edits to be made, correcting a few erroneous records without changing the whole file.
Second, the smoothing filter can now be applied based on a user-specified time in seconds rather than a record count. For files with areas of differing ping rate, this allows for application of a same-sized filter throughout the file. Maximum window width is entered in seconds, and ZEdit builds and uses a filter window with half of that time on each side of each record, narrowing the window as necessary at the file ends so as to maintain symmetry around the target ping.

Lastly, the ZEdit filtering function can be applied to many CSFs in a batch operation. With a CSF file open, you can open the filter window, adjust settings, and test with the "Apply" button until a good set of filter settings are found. After that, clicking the "Apply to CSFs..." button will allow you to select a batch of CSFs to apply the filter to. When the process is completed, SonarWiz will automatically launch any processing operations against the edited files.
Altogether, these are relatively minor, though useful changes. The last of them, though, offers a number of possibilities for future improvements to save time on many common tasks.

- Jonathan Fleetwood, Engineer
Updates to SonarWiz Magnetometer
During the first quarter of this year we are rolling out several improvements to the SonarWiz Magnetometer module. Here, I would like to highlight some of the more interesting changes.

The first group of changes are in the Project Explorer and the Properties Window. We have shortened the display name of the magnetometer CMF lines to just the filename and removed the full path display. Selecting a CMF file populates the Properties window where you can review and modify all relevant settings for the selected file. We have also flushed out the CMF and anomaly context menus so that it is easier to find all of the relevant commands that can apply to the selected object. These changes are designed to standardize the user interface of magnetometer files to be more like working with sidescan or sub-bottom files.
Figure 1: Updated Project Explorer and Properties window
shown with the new Magnetometer context menu open

The next area we have improved is the Magnetometer File Editor. In this window, we have added the ability to display the residual trace after the ambient background has been removed. This will make it easier to identify magnetic anomalies. We have moved the Ambient Smoothing Constant and the Observed Smoothing Constant into this window where these filters can be manipulated on the fly. Also, these filter settings are now properties of the selected line and no longer global settings for the whole project.
Figure 2 New Magnetometer File Editor with new draw residual trace option and controls for manipulating the Ambient Smoothing Constant and Observed Smoothing Constant filters
Finally, we have changed how magnetic anomalies are named. In current versions of SonarWiz, anomalies are named with a sequential number only and the user has no control. We have changed this behavior to be more consistent with Sonar Contact naming. In the SonarWiz Preferences and Settings menu, you will now have the same options for naming magnetic anomalies as sonar contacts.

Figure 3 New Magnetometer anomaly naming options in Preferences and Settings
These automatic naming rules can be overridden manually by the user to whatever name they want to use. These anomaly names are used in the Project Explorer, the main display window and all anomaly reports.
Figure 4 SonarWiz using new Anomaly names in place of sequential numbers

Many of these changes were requested by users. As we consider what additional changes should be made to Magnetometer, we’d love to hear from you about how you use the tool and what would make your work easier with SonarWiz. 

-David Finlayson, Chief Scientist
Side Scan Drawing Improvements

This month some of CTI's development resources have been focused on updating our Side Scan drawing routines to more accurately map samples to pixels in the display. These drawing routines and their accuracy become more important as users require higher and higher resolutions due to increasing accuracy of navigation, sonar equipment, and project requirements. Years ago placement of data had to be to the meter. Now we are looking at projects that require down to 10cm and sometimes lower.
What's the Problem?

There are two main issues we have been focusing our efforts on. These issues are:

Along track ping to ping alignment also known as jitter. This is shown to the right, in an artificially constructed sonar data set with 0.2m along track lines (running vertically). The measurement shows the area between the lines. Note how the edges of the lines are not smooth. This uneven variation is the jitter.
We found this to be caused by aliasing of the data. Aliasing is the non perfect placement of pixels when converting data to pixels. This can best be described as jagged lines we used to see in video games and computer graphics. This concept is illustrated below by fitting a line to a grid. Note that the resulting pixelated line is not smooth. Sometimes the line is close to or falls on a pixel boundary. 
This can result in non-uniformity when parallel lines are drawn next to each other as shown in the Drawing Lines illustration. Note that the top line and the bottom line are parallel, however, the sample points fall into a different pixel pattern. This causes the top line to appear to have a larger gap in one section. This combined with Side Scan Sonar pings, which are mostly parallel and can vary with the across track positioning from ping to ping, adds to the error when drawing.
Another issue is an offset in the across track samples when subsampling to lower resolutions. This is illustrated in the image to the left, using a GeoTiff shown in the background with a semi-transparent mosaic overlay of a 1m x 1m square. Note the 0.43m offset. This is 1.7x the maximum offset of up to 1 pixel we should see from aliasing alone.
How Do We Improve?

In order to examine the problems in a controlled manner we created several artificial test XTF files that simulate sonar data with the different features that we need to test. These include a 1m x 1m cube, along track lines, and across track lines.
The test data allowed us to identify the areas of our code that need improvement.

We found that the ping to ping alignment/jitter is caused by small accumulative errors in converting our samples to pixels. This includes the placement of the pixel using the geolocation of the sample and the subsampling that figures out which sample is to be placed in a pixel.
We implemented an improved across track interpolation algorithm so that we can utilize fractional samples. This helps eliminate aliasing in the across track direction by effectively placing samples between pixels.

By improving our subsampling we also improved our across track offset when exporting the data to lower resolutions. In the screenshot to the right, we have improved the offset of our 1m x 1m cube when exported to a 25cm resolution GeoTIFF to less than 1 pixel.
In conclusion, we will continue working on new updates to our drawing routines to improve accuracy and image production so our user's data is accurate and looks great. We will have these improvements to Side Scan drawing and mosaicking in the upcoming release of SonarWiz.

-Christopher Favreau, Chief Technology Officer
Language Support for SonarWiz
During the past few months, we have been working on the translation of SonarWiz into a dozen languages. The goal is to allow for all user interfaces in SonarWiz and the text files created during operation of the program to be translated into the user desired language. The program will run in the same way as before, but now a bit easier for our international clients to navigate through the menus of SonarWiz.

The change requires the program to convert the ASCII project to the UNICODE version. Not a trivial task, as the program has thousands of lines of code.  To verify the process, we took the NavInjectorPro program as our test candidate.  This test run proved successful, as we made the translation into the 12 different languages. Along with this program – and like many other programs in SonarWiz, a text file is created with the operation and results. This too had to get translated, which is done in real time (operator display) and written as a translation into the text file.
NavInjectorPro in Japanese. The entire GUI translated, along with the text written in the dialog bog. 
Example of the log file created by NavInjectorPro.
The stored text file will also contain the translation. We decided that this log file also needs to be written in English, and two log files will automatically be written. This allows us to help support and view client logs that are written into their native language.

We still have some work to do, and our goal is to release the globalization feature in a few months. I look forward to this feature, as we make SonarWiz a little easier to use for our international clients.

-Harold Orlinsky, General Manger
Goal for 2021 – Speed and Efficient Survey Pattern

The support team at CTI wants you to succeed on your surveyor’s New Year’s resolution, to record higher resolution data using less track lines! Unlike canceling your new gym membership in February, these tips can be helpful long into 2021.

The first item to take into consideration to improve the resolution of your sidescan data is to slow down when you are recording. For the across track resolution, SonarWiz will always down sample your data to one of three options (1024, 2048, or 4096) so it doesn’t matter how many samples your sidescan actually collected.

You can determine your sample spacing by dividing your slant range by the samples per channel. For example, a 100m slant range divided by 1024 samples per channel would result in 9cm spacing. Determine what required resolution your clients desire as each option (1024, 2048, or 4096) will increase the processing time x2

The important thing to remember is that the resolution of your sidescan lines is more consequently set by your speed over water. You can record the highest density possible in the across track resolution but if you are surveying at 8 knots you are going to have 30cm between pings.

Now that we are running slower speeds, we need to limit the number of track lines. SonarWiz has a built in Efficient Survey Pattern that reduces the time required to cover the same area by over 40% by using the Efficient Survey Pattern formula, which can be found by simply calculating the interline distance required base on the sonar range, maximum planned altitude, and the overlap (helmsman's accuracy) and enter that number in the Spacing Between Lines fields.

For example, Minor Distance = 75m – (10m + 10m) = 55m Major Distance = 2 x 75m – 10m = 140m will result in this survey pattern.

- Patrick Zynda, Support Engineer
Attendance Tripled for December Training
This year Chesapeake Technology held our Annual Training event virtually, allowing easy participation from the comfort and safety of home offices. We had over 200 trainees, more than triple our normal attendance.

Registrants were provided with a two week license of SonarWiz 7.7, sample data sets, training materials and other guides, 24 hours of recorded training and PowerPoint slides. Based on polls taken at the beginning of the class, nearly 40% were first time users of SonarWiz. To learn more please see the Training Agenda and our Press Release.

Custom and Hybrid Training Options
Last year we performed several custom trainings remotely out of necessity. One of the advantages of remote training is the ability to record them and watch them again. This is especially helpful for our users worldwide who can review and train during their normal business hours. This year we will offer hybrid training options with a mix of recorded and live custom training.

Training, Webinars, Events in 2021
Looking ahead, here are some of the many learning opportunities in store for 2021. 

On January 21, Klein Marine Technology will host a webcast about their demonstration of MA-X View 600 gap filler sonar for US Navy Advanced Naval Technology Exercise (ANTX). The webcast will be held 11:00AM EST. Register here.

On February 24 we plan to co-host a one day training in the UK with reseller partner Saderet. SonarWiz sidescan and sub-bottom will be the main focus of the training event. Later in February we will also co-host webinar: CTI/QPS - a streamline processing flow for sidescan - late February (details to be posted on website)

In March we will again host a Seminar web series called "Hot Cocoa with Chesapeake" and covering the following topics in three consecutive weeks:
  • March 4: A magnetometer lesson - a look at some of our new features
  • March 11: Gain settings for use in Sidescan - why are there so many?
  • March 18: Bathymetry - tools for cleaning a really poor quality data set

In June we plan to hold a two day virtual training on post processing of sidescan, sub bottom, bathymetry and magnetometer data. It will be held June 9-10 from 10:00am - 6:00pm EST. We may also include a half day or more about real time data collection with SonarWiz, date to be announced.

We will be back at Mesotech for onsite or virtual training for two days, September 28-29. Finally we have tentatively scheduled our Annual Winter training workshop for Dec 7 - 9 at the College of Charleston. Stay tuned for further details. 

In addition to our own events, we hope to see you soon in person or virtually at any of the many other events firming up this year. 

-Stephen D'Andrea, Ashley Chan
Founder's Corner

Over the years with CTI, I’ve been fortunate to get to know many of our customers and more importantly to make some deeper friendships. As I think back over the last year we’ve just lived through, the memories of those friendships continues to put a smile on my face. Some of these work friendships were born out of a shared adversity (usually around SonarWiz crashing) and others from a common interest (playing music, cycling, fishing or ice hockey). 

The friendships that surprise me the most are the ones where you and I are from different cultures, speak different languages and were born 30 years apart but still found a human connection. I won’t embarrass anyone by using names, you know who you are. Instead, I’ll just say thanks for the good times and for your part in helping me make a life, and not just a living. Hope to see folks in 2021!

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