Accession Number : ADA303126

Title :   A Method for Improving Night Vision Device Depth of Field.

Descriptive Note : Interim rept. Nov 94-Nov 95,

Corporate Author : ARMSTRONG LAB WRIGHT-PATTERSON AFB OH CREW SYSTEMS DIRECTORATE

Personal Author(s) : Marasco, Peter L.

PDF Url : ADA303126

Report Date : JUN 1995

Pagination or Media Count : 30

Abstract : It is known that when using Night Vision Devices (NVDs) to view objects close to the observer, the depth of field, the volume of space that appears to be in focus, is extremely small. The depth of field of optical systems can be increased by slowing the system's f-number. A simple way to accomplish this is to add restrictive apertures onto the front of the objective lens. This noticeably increases NVD depth of field but causes a significant reduction in light gathering capability. This report addresses equations describing the phenomenon, assesses the tradeoffs that we are involved in using apertures to increase depth of field, and documents some experimental visual acuity data demonstrating an increased depth of field due to decreased lens aperture.

Descriptors :   *OPTICAL EQUIPMENT, *NIGHT VISION DEVICES, *VISUAL ACUITY, EXPERIMENTAL DATA, DEPTH, DIFFRACTION, FOCUSING, AVIATION GOGGLES, TRADE OFF ANALYSIS, EQUATIONS, RANGE(DISTANCE), APERTURES, RADIOMETRY, LENSES.

Subject Categories : Optical Detection and Detectors
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE