Imaging of Underwater Objects

Kinsler, Lawrence E.

doi:10.1119/1.1990716

Cited by 12 publications

(13 citation statements)

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“…Finally, light rays are refracted as they pass from water to air (5). This refraction displaces the optical image and causes distortions in the apparent size, distance, and direction of the object.…”

Section: S M Luria and Jo Ann S Kinneymentioning

confidence: 99%

Underwater Vision

Luria

Kinney

1970

Science

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31. M. L. Hair (private communication) states that, at pressures of 16 torr and above, the very rapid increase in the amount of absorbed water makes it difficult to make precise measurements, and a fairly broad range of values for the number of molecules absorbed per hydrogen-bonded hydroxyl pair may be indicated. Hair's failure to produce anomalous water may have been due to the special nature of the surface treatment, which may prevent a clustering of hydroxyl pairs sufficient to form successive layers. Fortunately all that is needed for understanding the formation process is identification of hydrogen-bonded surface hydroxyl pairs with an increased absorption under the pressure condiitons favorable to the formation of anomalous water.Hair also proposed the anomalous water geometry given in Fig. 4h, but this has a higher energy than either squares or planar hexagons. 32. Even though the asymmetric cyclic hexamer has a per-bond binding energy comparable to, or slightly greater than, tetrahedral coordination, its geometry is not favorable for formation of the normal liquid because of its very low entropy relative to the tetrahedral arrangements. 33. There is a further decrease in the free energy, due to the lower vibration frequency, hence the higher entropy, of the symmetric hexamer over the asymmetric hexamer. 34. L. Pedersen and K. Morokuma, J. Chem. Phys. 46, 3941 (1967). 35. When an anomalous-water bond is broken, the energy of the conformation immediately after breakage is close to that of a symmetric bonded chain. A concerted motion of each. symmetric hydrogen to a corresponding asymmetric position is highly unlikely because of the between-layer interconnections.

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Section: S M Luria and Jo Ann S Kinneymentioning

confidence: 99%

Underwater Vision

Luria

Kinney

1970

Science

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“…If its depth is assumed to be 2 m below the panel elevation on the riverbank (an increase in distance of a factor 17/15), then its true length would be increased by about 1.13 without refraction (119 ± 9 cm). Furthermore, accounting for the refractive index differences between freshwater and air (Kinsler 1945), the true size of the fish is next reduced by the factor (4/3) −1 . Therefore, the true estimated length of the fish seen in Figure 3 is 89 ± 6 cm.…”

Section: Resultsmentioning

confidence: 99%

Perspectives on the Application of Unmanned Aircraft for Freshwater Fisheries Census

et al. 2018

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This work provides an overview of the use of small unmanned aircraft systems for freshwater fisheries survey and fish identification. As an example, a series of river reaches in Mongolia was surveyed for identification and sizing of the endangered Taimen Hucho taimen, the world's largest salmonid. Using polarized video imagery, Taimen were positively identified in depths of over 2 m. River reaches were chosen for survey to include likely Taimen holding grounds as well as areas that were unlikely Taimen habitat. Large areas of river reaches were quickly surveyed with video imagery stored for analysis. Using land‐based targets for sizing and flying autonomous search patterns, we found that Taimen were easily identifiable based on their swimming patterns and could be remotely sized; furthermore, the fish did not appear to be disturbed by the presence of overhead aircraft. Lessons learned from the experiments and recommendations for future advances are provided. The use of small unmanned aircraft systems for fisheries is shown to be a novel and inexpensive alternative to traditional fisheries survey methods.

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“…If its depth is assumed to be 2 m below the panel elevation on the riverbank (an increase in distance of a factor 17/15), then its true length would be increased by about 1.13 without refraction (119 ± 9 cm). Furthermore, accounting for the refractive index differences between freshwater and air (Kinsler 1945 ), the true size of the fi sh is next reduced by the factor (4/3) −1 . Therefore, the true estimated length of the fi sh seen in Figure 3 is 89 ± 6 cm.…”

Section: Resultsmentioning

confidence: 99%

Fisheries Volume 43 Number 11 November 2018

2018

Fisheries

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Imaging of Underwater Objects

Cited by 12 publications

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Underwater Vision

Underwater Vision

Perspectives on the Application of Unmanned Aircraft for Freshwater Fisheries Census

Fisheries Volume 43 Number 11 November 2018

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