CONCENTRIC PORTS

The dominant aberration associated with concentric dome ports is field curvature which causes images of underwater objects to be formed on a curved surface. Displacement of a curved image surface from planar sensor surface causes blurred image formation on image sensor. Field Curvature and Distortion, (FCD), Plots show separation of curved image surface and planar image sensor surface. Field curvature increases when concentric dome radii are reduced and/or when sensor size is increased.

Spot diagrams show blurred images of a sharp point at various image heights on sensor.  UHD/4K image formation becomes compromised when the diameter of blurred spots exceeds dimensions of a few sensor pixels.  Spot diagrams for a large 10 inch dome show blurred spots at image corners ranging from 120 to 200 microns.  Assuming a sensor pixel size of 5 microns, the image blur generated by a ten inch concentric dome is 25 to 40 times the size of an image sensor pixel.  With an 8 inch concentric dome the size of blurred spots increases dramatically.

FCD Plot for 10 inch Concentric Dome and Full Frame Sensor
Spot Diagram for 10 inch Concentric Dome and Full Frame Sensor
FCD Plot for 10 inch Concentric Dome and Medium Format Sensor
Spot Diagram for 10 inch Concentric Dome and Medium Format Sensor
FCD Plot for 8 inch Concentric Dome and Full Frame Sensor
Spot Diagram for 8 inch Concentric Dome and Full Frame Sensor
FCD Plot for 8 inch Concentric Dome and Medium Format Sensor
Spot Diagram for 8 inch Concentric Dome and Medium Format Sensor