Case Study CS-LDTC11 Rev. A

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Figure 5. Camera imagery, large-aperture integrated camera signals (red), and small-aperture integrated camera signals

(green) are shown for four propagation cases: in air (batch 1, 0-m depth, upper-left panel), deeper ocean (batch 5, 179.0-m

depth, upper-right panel), moderate ocean (batch 17, 62.0-m depth, lower-left panel), and shallower ocean (batch 23,

16.1-m depth, lower-right). The camera images provide the median frame from each batch for visual comparison. Plots of

integrated camera signal vs. frame number facilitate test-case comparisons of frame-to-frame similarity.1

Supporting sensors also measured temperature, beam

attenuation, backscattering, and temperature gradient

in

Figure 6. The thermocline region shows a significant

change in ocean temperature and gradient which is

related to the refractive index structure and inner scale of

turbulence. In this region, the effect on beam propagation is

clear. The beam attenuation and backscattering are both at

extreme maximums, diminishing the resolution of imaging

in the thermocline region.

When temperature and temperature gradient have minimal

changes, the beam attenuation and backscattering also

decrease. The thermocline upper and lower limits are

seen at 15 m and 70 m, respectively, highlighted in yellow.

The pronounced attenuation and scattering in plots result

from biological matter and particulates residing within the

thermocline.1