Optical density measurement

Optical device for measuring the turbidity of a liquid

Optical device for monitoring clarity of a fluid

Optical inspection apparatus for pressurized vessels

Optical inspection insertion apparatus for pressurized vessels

Optical inspection systems

Optical multiple-reflection arrangement

Optical reflectance gauge and method therefor

Optical sight tube for flowing fluid materials

Optical sight tube for fluid conduits

Optical tube inspection apparatus

Organic vapor detection with liquid crystals

Orientation indicator for a flexible fiberscope or endoscope inc

Panoramic view bore examining apparatus

Photometer circuitry for the digital indication of the light abs

Photometric method and apparatus for measuring packing fraction

Pin receptacle inspection apparatus and method

Pipeline inspection apparatus

Portable photometer

Precision radiation source regulation circuit