What is it?
Since humans
are visually oriented, the ability to assimilate and understand
data is enhanced once they are seen. Data collected by underwater
acoustic instruments are particularly difficult to understand because,
unlike marine mammals, we do not use sound to directly evaluate
aqueous environments. Computer visualization provides an initial
inspection and restores the spatial and temporal dimensionality
of acoustic backscatter and model data.
Webfish3d - Visualizing acoustic backscatter of fish
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The webfish3d
application allows you to explore the world of backscattered sound.
You can see how we represent a fish body and swimbladder in KRM
models and how amplitudes of echoes will change depending on the
acoustic frequency and the orientation of the fish. You get to chose
the species, the frequency, and the final appearance of the model.
Fish3d was first
developed in IDL
and is implemented on the web using RSI's ION
Script. We continue to tweak the programs to maximize graphics
quality. Visit often and let us know how things work.
Here is the
"quickstart" guide to webfish3d, a help guide is available
(and worth a look anyway) when you download a 3-d model:
- select
a species to render
- select
the frequency to view the backscatter
- select
the model type
- wireframe
- all objects are displayed as wire frames.
- solid
- objects are displayed as solids with the ability to display
texture maps. The tested VRML viewers have trouble rendering
the solid model VRML files correctly and we are unable to
determine the cause. We are working to correct this problem.
- select
the resolution
- low -
low resolution input files are used. This allows for faster
rendering and smaller VRML files at the cost of detail.
- high
- high resolution input files are used. The high resolution
files take longer to process and create larger VRML files
but look oh so good.
- check
your fish body display options - check off the objects you
wish to view.
- select
a fish body texture map option
- none
- display the fish body in it's default color (white).
- radiograph
- display the fish body with an x-ray texture map. This will
increase the VRML file size.
- photograph
- display the fish body with a photograph texture map. This
too increases VRML file size.
- set the
fish body opacity
- applies to solid models only. 0% is completely transparent while
100% is completely opaque.
- check
the ambit display options
- set the
ambit opacity
- applies to solid models only. 0% is completely transparent while
100% is completely opaque.
- click
an output button
- output
PNG - clicking this button will return a .png image of the
model output. This is the best bet when you're just starting.
- output
VRML - clicking this button will return a VRML (.wrl) file
for a 3-dimensional, interactive exploration of the model
output. You must have a VRML client installed on your computer
and it must be configured correctly. Also note that these
files range from 2 to 10 megs in size and aren't for the bandwidth
impaired. Read the fish heads
guide to VRML if you're not really sure what VRML is or
if your having problems viewing VRML models.
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