Page:Glossary of NPIC Terminology (1965).pdf/11

Rh heavy cloud cover (HC) —- Clouds cover most of a target area.

hold revetment -— An on-site prepared posi— tion(s) used for parking spare missiles.

holiday —— A gap in the photographic coverage of a surface.

hot target —— See emissivity.

hyperstereoscopy —— Stereoscopic viewing in which the scale along the line of sight is ex- aggerated in comparison with scale perpen- dicular to line of sight.

identify -- To establish the descriptive and/or functional name of some object or pattern detected on photography.

Immediate Photographic Interpretation Report (IPIR) -- A first—phase photographic inter— pretation report presenting the results of the initial scan and analysis of new photog- raphy in answer to specific requirements on the highest priority targets.

immediate report -— See first-phase report.

inactive -- Status of an identified target or com- ponent thereof determined from photography to be currently not in use, although the capa— bility for immediate use may exist.

incendiary bomb -- A bomb designed to start fires which will destroy the usefulness of a target area. In size, they can range from 4 to 500 pounds, with the smaller bombs usually carried in bomb clusters. (damage assess— ment)

infrared —- Electromagnetic radiations of wave— length between 0.72 microns (7,200 ang- stroms) and about 1,000 microns (l milli- meter).

infrared film —- Film which is chemically sensi— tized so as to respond to both infrared radia— tions and visible light in that portion of the electromagnetic spectrum where visible light and infrared overlap (approximately 0.72 microns). The resolution of this film is has- ically dependent on visible light.

NPIC/R—isz/és

infrared imagery --- Imagery which is sensed as an electromagnetic signal (radiation) by a detector, which is sensitive in aparticular portion of the electromagnetic spectrum, and then electronically processed through either a cathode ray tube or a glow modulator tube which converts the signal to a visible image and projects it optically onto a recording film.

infrared radiation —— Energy emitted in the form of electromagnetic waves which include, in order of increasing wavelength, cosmic rays, gamma rays, X rays, ultraviOlet radiation, visual light, infrared radiation, microwave radiation, and radio waves.

infrared resolution —— The size of the smallest element that can be resolved which is ap- proximately equal to the dimensions of the instantaneous field of view (IFV). The IFV is determined by the detector size, the focal length of the optical system, and the altitude of the aircraft. The lFV varies with obliquity.

instantaneous field ofview (IFV) -— The smallest solid angle resolvable by a scanner when ex— pressed in degrees. When expressed in feet, it is the projected area of the detector image on the ground and is ameasure of the resolu— tion of a scanner. (infrared)

intercontinental ballistic missile (ICBM) —— An arbitrary designation for missiles having a range in excess of 3,000 nautical miles.

intermediate range ballistic missile (IRBM) —— An arbitrary designation for missiles having ranges from 1,101 to 3,000 nautical miles. interpretability —- Suitability of the imagery with respect to answering requirements on a given type of target. Various factors affect interpretability such as halation, uncompen— sated image motion, poor contrast, incorrect focus, vacuum plat failure, improper film processing, atmospheric conditions (both nat— ural and manmade), ground resolution, and insufficient natural or artifical lighting of the target. The 3 levels of interpretability are: