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IR Imaging Bundles Made fr om Chalcogenide Glass Fibers 205

when the camera, with maximum sensitivity at 1.4 µm, was used
with our microscope. The intense light source provided ample light
transmitted through C1 fiber bundles for images and red light trans-
mitted through 1-m C2 bundles. However, no red light was visible
through a 10-m C2 bundle. Also, the relay lens used on the micro-
scope limited the image to a small area. For the 10-m bundle evalua-
tion, AMI had a special relay lens and objective lens designed by Gary
Wiese of Panoptics for use in the evaluation of the 10-m C2 bundles.
The NIR camera was removed from the microscope and used directly
with the relay lens designed to fill the camera with the image of the
7 mm × 7 mm bundle end. We did not use the Panoptics objective
lens. Instead we used the intense visible light source with the AF
resolution pattern on the arsenic trisulfide glass disk with the bundle
end in direct contact with different patterns. No visible light was
transmitted, but enough NIR light passed through to form an image.
Video recordings were made for study and record. Most efforts con-
cerned evaluating the resolution of the bundle from the U.S. Air Force
1951 resolution target patterns transmitted by the bundle. For this
program, the patterns used have been the −2 (0.25 to 0.45 lp/mm), the
−1 (0.5 to 0.9 lp/mm), the 0 (1 to 1.8 lp/mm), the 1 (2 to 3.6 lp/mm),
the 2 (4 to 7 lp/mm), and the 3 (8 to 14 lp/mm). The upper image in
Fig. 8.19 shows a low contrast number transmitted by 10-M-2 as
viewed using the NIR camera. The middle figure shows a number
transmitted through 10-M-3 as viewed by the Agema 210 camera. In
this case the light source was a globar which results in a small bar
image as a background. Notice the high contrast for the number 5.
The bottom image shows the uniformity of bundle 10-M-4.
Figure 8.20 shows resolution elements transmitted through 10-M-4
as imaged by the NIR camera. A limiting resolution limit of 10 lp/mm
was estimated. Figure 8.21 shows the same type of evaluation except
using the Agema 210 camera. Also, a flat hot plate was used as a light
source. Contrast improved. The rectangular shape of the infrared
detector elements used in the Agema 210 becomes obvious in the
image. We were fortunate in that we had a visit from Jim Davidson of
Thermalscan. Davidson uses a Raytheon Radiance IT camera in his
business. He was kind enough to use it in greater evaluation of the
bundle 10-M-4. The top image in Fig. 8.22 made by Davidson shows
an excellent image of the uniformity of the bundle. We tried without
success to form images of human subjects at a distance. Using a 1-m
C2 bundle with the sensitive camera, we were able to observe our
first human images in natural light. The results led to the work that
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improved performance of 1-m bundles reported in Sec. 8.2. The
second image in Fig. 8.22 is that of a ceramic doll taken a few feet
away from bundle 10-M-4 using an AMI Amtir 1 planoconvex lens as
the objective. The camera used was the Agema 210 with the hot plate
light source.