Keywords : reflectivity

Reflectivity

CARAIBES processes sidescan sonar and multibeam echosounder reflectivity data, in a single environment. The main processing stages are :

  • raw data corrections (time correction, antenna gain correction, etc.)
  • mosaic preparation, including the geometric correction and projection following a given cartographic context,
  • mosaic computation and interpolation,
  • mosaic visualization and printing.

Image analysis

The image analysis module lets you visualize raw and image mosaics and interactively correct them, with the following main functionalities :

  • contrast enhancement,
  • interpolation of regions of interest,
  • value modifications,
  • image analysis : pixel value, cross section, etc.

Image mosaic

The main features of image mosaic generation are :

  • supporting Mercator, Lamber, MTU, polar stereographical and equidistant cylindrical projections,
  • mosaic computation for a given pixel resolution with specification of inter-profile overlapping processing method (front, back, mixed, …),
  • cartographic extraction,
  • mosaic of mosaics computation.

Sidescan sonar specific processing modules

Some processing applications are specifically used with sidescan sonar data :

  • navigation speed correction,
  • smoothing and correction of the towed-fish immersion,
  • towed-fish navigation correction (offset from the ship and drift corrections),
  • antenna gain diagram computation and image gain correction,
  • swath narrowing.

Visualizations and printings

The reflectivity data can be visualized at various steps :

  • raw data as output by the sensor,
  • geometrically corrected straight image,
  • image mosaic cartographic display, with bathymetry superimposed,
  • image mosaic wrapped on top of the corresponding 3D bathymetry.

The available printing formats are PostScript, Dowty plotter and Oce Graphics plotter (raster image only).