Experimentally Measured MTF's Associated With Imaging Through Turbid Water

Witherspoon, Ned H.; Strand, Michael P.; Holloway, John H.; Price, Brandon J.; Brown, David P.; Miller, Robert O.; Estep, Lee

doi:10.1117/12.945744

Cited by 8 publications

(4 citation statements)

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“…All copepods were of a similar size (3·10 0·05 mm long 1·04 0·03 mm wide=3·2 0·12 mm 2 ). To test the influence of turbidity on reaction distance, eight different turbidity levels were created (0,15,20,25,30,40,50 and 100 JTU) by mixing diatomaceous earth into the aquarium water (1 JTU is defined as 1 mg diatomaceous earth per litre of water; Witherspoon et al, 1988). Diatomaceous earth is colourless white sand, chosen to minimize changes in wavelength associated with increasing turbidity.…”

Section: Turbiditymentioning

confidence: 99%

The effect of prey mobility, prey contrast, turbidity and spectral composition on the reaction distance of Gobiusculus flavescens to its planktonic prey

Utne‐Palm

1999

Journal of Fish Biology

152

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The reaction distance of Gobiusculus flavescens to mobile and immobile copepod prey of different transparency was studied in water conditions with different turbidity levels or spectral composition. Both prey contrast (red or transparent Calanus spp.) and prey mobility caused reaction distance of G. flavescens to increase. The effect of prey mobility or prey transparency on reaction distance was independent of turbidity level. Longest reaction distances were measured for mobile and red prey at intermediate turbidity levels (10-20 JTU). Contrast threshold decreased with increasing turbidity. Although contrast of red and transparent copepod prey increased with increasing wavelength, longest reaction distances were observed at shorter wavelengths (blue-green). Lowest contrast threshold was found at shorter wavelengths. Visual pigments of G. flavescens are adapted to its natural environment. Both turbidity and spectral composition influenced G. flavescens contrast threshold. 1999 The Fisheries Society of the British Isles

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Section: Turbiditymentioning

confidence: 99%

The effect of prey mobility, prey contrast, turbidity and spectral composition on the reaction distance of Gobiusculus flavescens to its planktonic prey

Utne‐Palm

1999

Journal of Fish Biology

152

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“…In order to test the influence of turbidity on D, six different turbidity levels between 0-111 JTU were chosen. Turbidity was created by mixing diatomaceous earth (DE) into the water [1 JTU was defined as 1 mg DE per litre of water (Witherspoon et al, 1988)]. DE, a colourless white sand, was chosen to minimize the risk of wavelength alterations associated with increased turbidity.…”

Section: Reaction Distance Experimentsmentioning

confidence: 99%

The effect of turbidity and illumination on the reaction distance and search time of the marine planktivore Gobiusculus flavescens

Utne

1997

Journal of Fish Biology

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Both reduced illumination and increased turbidity caused a significant reduction in reaction distance of Gobiusculus flavescens. The longest reaction distance, 18.9 cm for larger prey (Calanus finmarchicus), occurred at a light level of 80 μmol m −2 s −1 compared to 12.9 cm for a smaller prey (Acartia clausi) at 8 μmol m−2 s−1. Above a light saturation level of 10 μmol m−2 s−1, additional light had little influence on reaction distance. In the turbidity experiments, the longest reaction distances were measured at turbidity levels of 10–20 JTU. Prey size influenced reaction distance at all tested light levels. Search time was influenced by prey size only at low illumination. With increasing turbidity, reaction distance to a group of prey was longer than to one prey.

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“…for typical Fig.1 configurations) quantitative methods are a reasonable alternative. In order to quantitatively evaluate the apparent depth resolution, scene modulation (SM) has been proposed [15] (the alternatively used name is contrast transfer function [16], [17]). By adopting the cut off point at 2% of SM (the threshold value of noticeable difference for the human eye response) the depth resolution for a given case can be quantitatively estimated [15], [18], [19] as explained below.…”

Section: Apparent Depth Detection Analysismentioning

confidence: 99%

Three-dimensional Machine Vision Using Gated Imaging System: A Numerical Analysis

Tan

Sluzek

Seet

et al. 2006

2006 IEEE Conference on Robotics, Automation and Mechatronics

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Various researchers have suggested techniques in gated imaging and "smart" pixels technologies that achieve simultaneous depth mapping and optical imaging with enhanced depth detection accuracy and resolutions range from a few cm to less than 1 mm. In this paper, we demonstrate how depth accuracy and resolution can be studied more systematically (and depending on the range detection technique). We propose that the depth detection and resolution study should be treated as two separate configurations. In particular, we recommend statistical approach for camera gating shorter than (or equal to) target irradiance and quantitative approach for gating time longer than target irradiance. A very accurate method by J. Busck is analyzed as an example of the statistical approach. The results indicate that the depth accuracy is less affected by the reflected Gaussian noise for longer range targets. The numerical analysis shows that it is necessary to introduce a correction based on the gating and target irradiance profiles to achieve accurate depth detection. An objective quantitative evaluation method is also discussed. It is suggested to replace the existing subjective measure in determining the depth resolution by the proposed approach. Supporting data for this approach will be presented in future works.

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Experimentally Measured MTF's Associated With Imaging Through Turbid Water

Cited by 8 publications

References 0 publications

The effect of prey mobility, prey contrast, turbidity and spectral composition on the reaction distance of Gobiusculus flavescens to its planktonic prey

The effect of prey mobility, prey contrast, turbidity and spectral composition on the reaction distance of Gobiusculus flavescens to its planktonic prey

The effect of turbidity and illumination on the reaction distance and search time of the marine planktivore Gobiusculus flavescens

Three-dimensional Machine Vision Using Gated Imaging System: A Numerical Analysis

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