427-0011-00-10 Revision 140
Copyright © FLIR Systems, Inc.
7
The Foveal Concept
The PTZ-35x140MS and SR-35x140MS feature a completely new concept in image
presentation based on the foveal vision of the human eye. Foveal vision allows the operator to
enjoy a wide angle view for situational awareness while maintaining a high resolution area in the
center of the screen for object identification and tracking.
The PTZ-35x140MS and SR-35x140MS accomplish this with two independent thermal cameras
and a unique patented image processing technique that provides both the foveal imaging mode
as well as a continuous zoom between the wide and narrow fields of view.
The Foveus thermal imagery is provided as continually zoomed video from the wide 20°
horizontal field-of-view (from the 35mm lens) to the more narrow 5° field-of-view (from the
140mm lens). The thermal imagery is presented by blending the two thermal images to provide
high visual acuity in the critical 5° center area while simultaneously providing medium resolution
in the 20° situational awareness zone. This presentation is an application of the design of the
human eye, with the foveal region of the retina employing higher sensitivity than the peripheral
area, thus the moniker Foveus™.
When the system is zoomed out, the video output comes from the 20° field-of-view and the 5°
field-of-view disappears. After zooming in slightly, the wide 5° field-of-view appears as a small
inset window in the center. Continuing to zoom in causes the inset window to grow until it fills
the video screen, eliminating the wide field-of-view.
Figure 2-2: Foveal View (note the inset 5° field-of-view in both pictures)
The image on the left shows the wide overall perspective of the 20° field-of-view, and the
camera is partially zoomed in to show with the narrower field-of-view. The image on the right
shows the camera nearly fully zoomed in, and the 5° field-of-view dominates the image.
The 5° horizontal field-of-view of the 140mm lens provides long range surveillance with high
visual acuity of distant targets. The 35mm lens provides a short to medium field-of-view of 20°
and is well-suited for short range threat detection in all circumstances. The wide field-of-view
allows it to cover a large area and provide excellent situational awareness. And the patented
technology of FLIR allows continuous zoom between both fields of view.
