Here is what I meant by the classic "waterfall" stripchart display.
Ahh...thanks Walt. The screen shot of the anomaly from the .csf file that I posted on May 16 is actually from the "waterfall" strip chart. I rotated it to make it more understandable. I've attached it here in it's original orientation.
A sonar mosaic tries to put everything into a nice 2-D display but in the process hides a lot of the details about how the sonar beam is impinging upon the target. The waterfall display preserves all of the original information about the sonar beam. What you can't immediately see on it is where the AUV is (GPS coordinates), what the heading of the scan line was, and what the speed of the AUV was (i.e. scale in the vertical direction). Like you say, you need the software that comes from the manufacturer (EdgeTech, in this case) to pull out those details. But this is a case where you should really be looking at the raw data, since you have no idea looking at the mosaic what the computer has done to "adjust" the picture.
Yes. The sonar expert (I'll see if I can get permission to release his name) who examined the image had all of the raw data. His opinion, after several days of working on it, was:
"I looked over everything and agree that your missed target is viable and should be checked out. Very probably a manmade object. Only other option is that it is a rock ledge but it doesn't look like the other ledges seen from the entire SS mosaic."
In fairness, another expert who has not yet examined all of the data feels that it's "probably geology."
The ROV pilot I sat beside for day after day as we checked out sonar targets feels that the target looks "VERY promising, definitely NOT a rock." His full response is priceless but I need to get his permission before I can share it.
We're still casting the net for opinions but, as one expert pointed out, interpreting sonar imagery is an art, not a science.
For instance, if the AUV navigation was set to overlap it's scan strips (this should have been done), then, depending upon the amount of overlap, it's either possible or quite likely that there are two different sonar images of the anomaly, taken at different angles. The mosaic software throws out much of this data in order to present what it assumes is a nice 2-D picture of the seabed.
You make a good point. The runs did supposedly overlap. There should be a second image buried somewhere in the data but finding it could be difficult. The raw data is not organized in any way I can make sense of and I can only read the files that were rendered as .bmp. It's becoming apparent that the original contractor dropped the ball big time. I can get an assortment of experts to give us quick opinions on specifics but it may be that what we need is for someone with the software, knowledge and experience to really spend time digging into all the data to see what we have. That's going to cost money - money that we don't have right now.