SubscribePanavision Federal Systems, LLC has developed a breakthrough compound zoom lens technology which enables extremely high zoom ratios.
The first product, which was developed by private funds initially as a sports broadcast application, provides a zoom range of 300:1, approximately three times more powerful than other commercially available zoom lenses.
This zoom lens system, coupled with High Definition Television (HDTV) camera technology, comprises a new imaging system that enables an entirely new type of surveillance and reconnaissance capability.
It is now possible to observe targets from a 76 degree angular wide field of view in order to detect activity and then zoom in for identification and location to within 0.3 degree angular field of view (a 24 feet x 13 feet field of view at a range of one mile).
HDTV's resolution of 1280 x 720 can resolve a pixel at that distance to approximately 0.2 inches square which means objects such as people, vehicles, small weapons, and small structures can be easily resolved from ranges in excess of 12,000 feet. Facial recognition can be achieved up to ½ mile away.
The new innovative enabling technology for our system is the 300x compound zoom optical lens. The compound zoom optical design principle is based upon multiple zoom units separated by intermediate images as shown in the following figure 1.
Figure 1 300x Compound Zoom Lens
In its simplest form there are two zoom units separated by one intermediate image. This zoom group configuration distributes lens group powers throughout the entire system so that aberration correction is provided through zoom and the second zoom grouping, either in whole or in part, acts as a relay for entrance pupil control.
The resulting variation in F/number at the intermediate image through zooming enables exceptional correction of many aberrations simultaneously at all focal lengths with some of the long focal length correction in the first zoom grouping, which may include an objective lens group, and the short focal length correction in the second zoom grouping which may include other relay lens groups.
The intermediate images at the long and short focal lengths have fast and slow F/numbers, respectively, while at the final image the reverse exists. Also, the intermediate image size varies through zoom and is smallest at the longest focal length and is largest at the shortest focal length. This arrangement is key to the overall high performance of compound zoom lenses because it facilitates aberration correction in different areas of the lens at low zoom grouping magnifications while controlling the entrance pupil position.
The main advantage of this co-axial refractive compound zoom lens design approach for the visible through near IR wavebands of interest is: a very wide field of view (76 degrees for the 300x zoom lens) in an extremely small diameter (6 inches) and short length space envelope (38 inches).
This compactness is a direct result of the intrinsic and excellent entrance pupil control afforded by compound zoom lenses and is not available from conventional zoom lens designs. Assuming electronic position control of the two movable lens groups, a further advantage is that of providing zoom, focus and, if necessary, thermal compensation without the need for additional movable lens groups.
In the case where a zoom cam is preferred over electronic position control of the two movable groups then another movable lens group is utilized for focusing and thermal compensation. No matter which configuration is chosen only two drive motors are required for all movable lens groups. Optionally, a variable aperture iris can be placed at the optical stop that resides towards the rear of the lens system.
Panavision's imaging technology coupled with Compression and Automatic Target Recognition software is used to greatly increase the standoff distance for autonomous covert surveillance and reconnaissance operations. This software can detect probable targets of interest, locate the targets, and determine probability of match. Based on that probability, the system could zoom in to increase the probability of the match and provide the location, target identification, probability of match, and image for final human verification and/or validation.
One scenario identified for the use of the LRSS is to mount the Remote Camera Unit outdoors on top of a two-story building in order to provide autonomous surveillance for a wide area of ground while watching for specified, pre-prioritized targets.
Target ranges from 100 meters to 5,000 meters would be observed. When the automated software detects a possible pre-specified target, it would alert the user to that detection and automatically pan the camera to the azimuth and elevation location of the possible target and begin to zoom in on that target.
This action would provide more optical resolution on the target and enable a higher level of confidence in target recognition. During this process, images from the Remote Camera Unit would be transmitted via a communication link to the Remote Monitoring Station where users can observe the imagery data being provided autonomously. Users could also assume manual control of the camera in order to confirm whether the observed target is a "specified target".
We are currently analyzing the system for other applications to include shipboard and airborne applications. Ships can obtain high resolution imagery from targets/objects from a range of 2 miles and air vehicles flying 15,000 feet and below would be able to capture very detailed imagery and video for surveillance, reconnaissance, and search and rescue applications.
LRSS System Description
The Wide Area Surveillance System (refer to figure 2 below) consists of a Remote Camera Unit (RCU) with automated zoom lens, pan & tilt and data compression software capabilities, a Remote Monitoring Station (RMS) having data de-compression software and automatic target recognition software, and a Communications Link between these two major units.
Figure 2 LRSS System Architecture and Configuration
Remote Camera Unit
The Remote Camera Unit (RCU) of the LRSS consists of a high-power camera with Panavision 300x zoom lens and processor mounted on a remotely controllable pan and tilt unit, which is then mounted on a stable tripod unit. The Remote Camera Unit also has a transmitter/receiver to send compressed imagery (video and stills) and metadata from the RCU to a Remote Monitoring Station (RMS).
The Remote Camera Unit (RCU) of the LRSS consists of a high definition camera (1280 x 720 pixels) with 300x zoom lens and processor mounted on a remotely controllable pan & tilt unit. The pan and tilt provides -45 to +60 degrees tilt capability and +180 to -180 (+170 to -170) degrees pan capability. The entire unit is mounted on a very sturdy tripod unit which could be firmly mounted and affixed to a floor or deck area. The tripod provides height adjustment of the tripod from at least +4 to +8 feet above the floor level.
The compression and automatic target recognition software resides on the remote control processor because the image spatial quality and image frame rate would be superior at that point as compared to the quality after transmission over the RF link to the Remote Monitoring Station.
Remote Monitoring Station
The RMS has a Tx/Rx for receiving data from the RCU and for sending commands back to the RCU. The Remote Monitoring Station would contain a monitor for viewing and reviewing all imagery, a processor, and de-compression software. The software would de-compress imagery and display it on the monitor for users.
Communications Link
The communication link will be medium range (0 to 5.0 miles), 5.8 GHz band, and have variable data rate capability to assist in evaluation of the compression performance of the compression software.
To simplify the construction of the demonstration unit, two communication data links could be used initially - one for the compressed video feed and another for control and metadata from the camera head. Future versions should concentrate on using a single communication data link to handle both data streams.
Compression and ATR Software
The compression software would provide high rates of compression of imagery data, allowing it to be transmitted over very small communication links without loss. Other software would provide automatic target recognition (ATR) of specified targets previously entered into an imagery database.
This ATR software would also indicate the presence and identification probability of possible pre-selected targets. This data would then be used to send commands back to the Remote Camera Unit to cause movement of the pan and tilt and zoom lens. Alerts would constantly be displayed at the RMS for users.
Environmental
The LRSS system can be fieldable to operate under these conditions:
- -30 to +65 degrees C temperature operation
- Shielded for dust, sand, rain, and fog
- Stabilized for ground, sea, and airborne type vibrations
- Transport up to 50,000 feet altitude
Other Applications
We have proposed the LRSS for several other applications including on ships for surveillance, reconnaissance, and target tracking. Our internal optical stabilization system can be coupled to a ship based stabilized platform to eliminate the effects of high and low frequency ship movements.
