Spatially variant and coherent illumination method for undersea object detection and recognition

Caimi, Frank M.; Bailey, B.C.; Blatt, Joel H.

doi:10.1109/oceans.1998.726270

Cited by 6 publications

(5 citation statements)

References 5 publications

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“…Methods using coherency of spatial gratings formed by structured lighting methods, such as proposed some years ago by Blatt and Caimi have not been investigated due to practical implementation problems (Bailey et al, 2003;Caimi et al, 1998).…”

Section: Spatial Coherency Techniquesmentioning

confidence: 99%

A Focus on Recent Developments and Trends in Underwater Imaging

Kocak¹,

Dalgleish²,

Caimi³

et al. 2008

mar technol soc j

231

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Section: Spatial Coherency Techniquesmentioning

confidence: 99%

A Focus on Recent Developments and Trends in Underwater Imaging

Kocak¹,

Dalgleish²,

Caimi³

et al. 2008

mar technol soc j

231

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“…The design benefits and implications of source-receiver separation, contrast, and power in underwater optical imaging systems have been reviewed (Funk et al 1972) and modeled elsewhere (Jaffe 1990(Jaffe , 1995. A brief review of underwater imaging methods has also been documented by Caimi (1996).…”

Section: Introductionmentioning

confidence: 99%

“…Object range and plane orientation measurements have been obtained using laser patterns projected onto the target (Caimi and Tusting 1988;Davis and Tusting 1991). Interference methods using video moiré techniques have been utilized to provide higher resolution for underwater mapping and surface shape determination, although they require additional instrumentation to determine target range (Caimi et al 1993;Blatt et al 1992). Other interference methods have included holographic systems (Carder et al 1982;Katz et al 1984;Katz et al 1999).…”

Section: Introductionmentioning

confidence: 99%

“…However, interference methods are dependent on the preservation of the illumination coherency in the water, which is degraded by turbulence, thermal gradients, relative motion, and from spectral broadening by scattering processes encountered from collisions of moving particles (Swanson et al 1993). Use of interference meth-ods in seawater at range have been proposed and laboratory tested using quasi-coherent spatial techniques (Caimi et al 1998). Quasi-coherent temporal interferometry has been used to produce range images (Scott 1990).…”

Section: Introductionmentioning

confidence: 99%

“…The geometry of synchronous scanning systems, with fixed source-receiver separation, presents a means of calculating depth by triangulation. Laboratory versions in clear water and short range (0.2-0.4 m) have been developed using a low-power 10-mW laser and a proprietary position sensitive detector to achieve Ͻ1-mm resolutions (Caimi and Kocak 1997;Caimi and Smith 1995). In general, dependent on the technology, triangulation based systems can provide higher resolutions at close range (Ͻ5 m), whereas range-gated systems may provide better resolution at range (Ͼ10 m) (Massey 1991).…”

Section: Introductionmentioning

confidence: 99%

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Development of a New Underwater Bathymetric Laser Imaging System: L-Bath

Moore¹,

Jaffe²,

Ochoa³

2000

J. Atmos. Oceanic Technol.

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The design, construction, and performance of a new high-resolution underwater bathymetric prototype system (L-Bath) with extended imaging capability is presented. The design offers simultaneous reflectance and depth information on a pixel-by-pixel basis so that high-resolution reflectance and bathymetric maps of underwater targets can be provided with exact registration. The design supports operation in shallow coastal waters under daylight conditions where high turbidity and the influence of ambient backscatter are particularly limiting for underwater imaging systems. Its configuration is similar to existing laser line scanning systems but uses a pulsed laser for the source and a fixed field-of-view high-resolution linear charge-coupled device (CCD) as receiver. The pulsed laser allows short camera integration times, thereby reducing the influence of the ambient daylight signal, and the fixed field of view of the detector provides a precision nonmoving multielement receiver with imaging capability. As the laser sweeps across the field of view of the CCD, the position and signal strength of each laser target spot is imaged, permitting a measure of bathymetry and reflectance. Using the CCD, a highresolution slice through the reflected target spot radiance distribution is imaged so that system resolution can exceed the target spot size. The image of the target spot radiance distribution, modified by in-water scattering and target reflectance, provides new opportunities for image manipulation compared to typical underwater laser line scanning based systems. The simultaneous acquisition of reflectance and bathymetric maps permits discrimination capability between real objects of relief from scene reflectance variations.

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