Even under passive sonar, and without help from
our bag of sonar-processing tricks, we compute
those red dots which are, mostly, on the target.
Additional points, improving the images, can be
obtained by using more sensors.
Each grid line is 6 inches from a nearest neighbor.
So, one can estimate the size of the little fish, seen at a range of 25 feet.
A side view of the fish is shown in the lower part of the picture.
Its colored dots were computed using active sonar methods.
The latest simulations program (May 2013) has
no active sonar component, eliminating one
source of possible programmer-error.
This animation suggests what we will be able to
see by decoding echoes of actual clicks of a real dolphin.
A more recent animation