Additionally, the US Navy has funded research into how dolphin sonar sensing and released a report in 1998 that demonstrated the generation of 2D images using "

Additionally, the US Navy has funded research into how dolphin sonar sensing and released a report in 1998 that demonstrated the generation of 2D images using "back projection acoustic tomography" of "synthetic dolphin signals". It's worth a read if you want to build your own DIY sonar system :) I include it here because the work suggests dolphin echolocation pulses may contain sufficient information for dolphins to form something like a mental image of an object, although whether or not they actually do so is unknown. (They cite a 1995 paper by the lead author of the other paper I referenced, but not the potentially more-conclusive 1998 work). "Tomographic Image Reconstruction of MCM Targets Using Synthetic Dolphin Signals", R. Altes, P. Moore, and D. Helweg. 1998. Accession Number: ADA337008, PDF Url: http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA337008 http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDo... "Extra information from elevation can be used to adaptively improve focusing and to construct a 3-D surface that represents the physical shape of an object as it would be perceived with vision. Such a surface is different from a representation of reflectivity as a function of position, and it allows direct comparison with visual representations (e.g., photographs) of objects. A visual analogue would be very useful to an animal that tries to perform sensor fusion by combining spatially registered feature maps from vision and echolocation. There is some speculation that dolphins may be capable of such a vision-like target representation (Pack & Herman, 1995), although the issue of the cognitive representation of targets formed by echolocating dolphins remains open to debate (Heiweg et al., 1996; Harley et al., 1995; Roitblat et al., 1995), and the lay concept of "seeing with echolocation" remains unsubstantiated. However, a vision-like target representation is well-suited to human observers and could have application to improvement of MCM performance." The synthetic images are pretty neat. If you want to check them out but avoid the pdf, here is an imgur of the paper's figures: http://imgur.com/a/RLqF8 http://imgur.com/a/RLqF8