• Home
  • Download PDF
  • Order CD-ROM
  • Order in Print
INFRARED IMAGING SYSTEMS
FORWARD-LOOKING INFRARED SYSTEM

Aviation Electronics Technician 1 (Organizational)
Page Navigation
  123    124    125    126    127  128  129    130    131    132    133  
achieve maximum resolution. A large number of detector elements can be grouped together to form an array (fig. 6-8, view A). The elements of this array are packed closely together in a regular pattern. Thus, the image of the scene is spread across the array like a picture or a mosaic. Each detector element views a small portion of the total scene. The disadvantage of this type of system is that each detector element requires a supporting electronic circuit to process the information that it provides. Also, each detector element requires a preamplifier to boost the signal to a usable level. SINGLE DETECTOR.— Another method that is used to provide the operator with information is the single detector (fig. 6-8, view B). Here, there is one detector requiring one set of supporting circuitry. In this type of system, the detector is scanned across the image so that the detector can see the whole image. An optical system is required that can supply the scanning. This type of system is adequate if real-time information is not needed, or if the object of interest is stationary or not moving quickly. Scene Dissection System The scene dissection system is used to scan the scene image. There are many types of scanning-one associated with each type of detector array. When a single detector with one axis of fast scan and one axis of slow scan is used, the scene is scanned rapidly in the horizontal direction and slowly in the vertical direction. As a result, the line is scanned horizontally; then the next line is scanned horizontally, etc. A vertical linear array is scanned rapidly in the horizontal direction (fig. 6-8, view C). One detector element scans one line of the image. In the linear array, there is a space, one element wide, between each element. The scan is one axis with an interlace being used. A vertical linear array is scanned rapidly in the horizontal direction. After each horizontal scan, the mechanism shifts the image upward or downward one detector element width so that on the next scan, the lines that were missed are covered. Each system has an optimum configuration of detector array and image dissection. If the number of elements in the detector increases, the system becomes more complicated. Also, the cost of the Figure 6-8.-Detector arrays. 6-6







Western Governors University

Privacy Statement
Press Release
Contact

© Copyright Integrated Publishing, Inc.. All Rights Reserved. Design by Strategico.