Automated Video Tracker AVT
Closed Loop Pan and Tilt Tracking System with CCD Camera and Laser Illumination for Continuous Object Tracking
The AVT Automated Video Tracker mounts a tracking camera and laser illumination source on a two axis elevation over azimuth pedestal, using closed loop motion control to keep a target continuously tracked in the camera’s field of view. The system supports centroid, correlation and edge tracking algorithms, selectable to match the specific target and scene conditions, and combines a high zoom CCD camera with laser illumination of the target along the track axis to maintain tracking reliability under varied contrast and visibility conditions. It is suited for homeland surveillance, radar surveillance, airborne surveillance and mobile telescopic mast communication deployments.
What is theAutomated Video Tracker?
In the AVT system, a tracking camera and laser source mounted on a two axis pedestal are used to track an object, with the laser illuminating the target along the track axis. The pedestal uses an elevation over azimuth configuration, and closed loop motion control in each axis keeps the object continuously tracked as it moves. The CCD camera images the object within its field of view, and the operator can select between centroid, correlation and edge tracking algorithms depending on the target and scene conditions.
| Parameter | Specification |
|---|---|
| Pan and Tilt System | |
| Degree of Freedom | Two Axis |
| Azimuth Range | ±90° |
| Elevation Range | -20° to +50° |
| Payload | 15 kg (Laser Source and Two CCD Cameras with Zoom Lens) |
| Maximum Slew Rate | 1 rad/sec |
| Acceleration | 1 rad/sec² |
| Position Accuracy (Azimuth and Elevation) | 200 μrad |
| Residual Jitter | Better than 20 μrad |
| Tracking Rate (Closed Loop) | 10°/sec |
| Torque Motors | Direct Drive |
| Operating Modes | Position (Joysticks), Home, Scan, Lock, Auto (Video Track in Closed Loop) |
| CCD Camera | |
| Type | 1/2 inch Progressive Scan CCD |
| Resolution | 782 × 582 pixels |
| Video Output | 1.0 Vpp – 75 ohm |
| Lens Mount | C Mount |
| Signal to Noise Ratio | 56 dB |
| Gain Control | Fixed and Manual |
| Focal Length | 23mm to 506mm (22X Zoom) |
| Zoom and Focus | Motor Drive with Feedback |
| Video Tracker Performance | |
| Video Inputs | Two (Second as Spare) |
| Video Standard | Composite Video |
| Track Algorithm | Centroid, Correlation, Edge (User Selectable) |
| Track Window | Position at Centre |
| Track Window Size – Minimum | 32 × 24 pixels |
| Track Window Size – Maximum | 200 × 150 pixels |
| Minimum Contrast for Tracking | Better than 10% |
| Tracking Accuracy | ±1 pixel |
| Coast Mode | Up to 3 sec with Prediction Algorithm |
| Environmental | |
| Operating Temperature | 0°C to +70°C |
| Humidity | 95% RH |
Three Tracking Algorithms, Each Suited to Different Target and Scene Conditions
No single video tracking algorithm performs best across every scenario, which is why AVT offers a choice rather than a fixed method. Centroid tracking follows the geometric center of the target's brightness within the gate and holds up well even at low signal to noise ratio, but can lose precision if the target grows to fill the entire camera frame at close range. Correlation tracking compares each frame against a stored reference image and follows the best match, which performs more reliably when the target's appearance shifts due to changing aspect angle or a cluttered, changing background. Edge tracking locates a specific boundary of the target rather than its overall mass, useful when a precise reference point matters more than the target's general position. Giving the operator the choice means the system can be tuned to whichever algorithm actually suits the target being tracked, rather than forcing every scenario through one method.
Adjustable Track Window Sized to the Target, Not a Fixed Default
The track window is the region of the image the algorithm actually analyses, and getting its size wrong in either direction causes problems. Too small, and the target can outrun the gate during fast motion, with part of the target falling outside the analysed region. Too large, and background clutter or a second object entering the frame can confuse the tracking calculation. AVT allows the window to be sized anywhere from 32x24 up to 200x150 pixels, giving the operator the ability to match the gate to the target's actual apparent size and expected motion rather than working with a single compromise setting across every scenario.
Laser Illumination Solving What the Camera Alone Cannot
A tracking camera depends on contrast to keep the algorithm locked onto its target, and contrast is exactly what degrades in low light, fog, or against a low-feature background. Rather than relying solely on passive imaging and hoping ambient conditions cooperate, AVT mounts a laser source on the same pedestal that actively illuminates the target along the track axis. This directly increases the visual contrast the camera has to work with, improving the tracker's ability to maintain lock under conditions where the camera alone would be marginal or unreliable.
Coast Mode for Surviving Brief Loss of Visual Contact
Tracking systems inevitably encounter moments where the target is briefly obscured, whether by smoke, foliage, or another object passing through the line of sight. Without any handling for this, the tracker would either stop, drift, or lose the target entirely the moment video contact breaks. AVT's Coast Mode addresses this with a prediction algorithm that estimates the target's continued path based on its trajectory immediately before the obscuration, keeping the pedestal pointed at the predicted position for up to 3 seconds. This gives the system a real chance to reacquire the target the instant it becomes visible again, rather than starting the tracking process over from scratch.
Need Help? Start Here...
Get expert assistance in selecting the right solution tailored to your performance, integration, and operational needs.
Centroid tracking follows the geometric center of the target's brightness and performs reliably at low signal to noise ratio. Correlation tracking compares each frame against a stored reference image, holding up better when the target's appearance or background changes. Edge tracking locates a specific boundary of the target rather than its overall mass. AVT lets the operator choose whichever fits the specific target and scene.
A window too small risks losing part of the target during fast motion. A window too large increases the chance of background clutter or a second object confusing the tracking calculation. The adjustable range from 32x24 to 200x150 pixels lets the operator size the gate to the actual target rather than using one fixed setting for everything.
Coast Mode uses a prediction algorithm to estimate the target's continued movement based on its trajectory just before contact was lost, keeping the pedestal pointed at the predicted position for up to 3 seconds. This gives the tracker a real chance to reacquire the target once it becomes visible again.
In low light, fog or low-feature scenes, the camera alone may not have enough contrast for reliable tracking. The laser illuminates the target along the track axis, improving contrast and helping the tracker maintain lock under conditions where passive imaging alone would be marginal.
The azimuth axis rotates the entire assembly around a vertical axis, while the elevation axis, mounted on top, tilts the camera and laser up or down. This is a standard pan and tilt configuration where the elevation axis only needs to move the camera and laser, not the azimuth drive itself.
200 microradians corresponds to roughly 0.01 degrees of pointing error. At a target distance of one kilometre, this keeps pointing error to a few centimetres, which matters for applications like laser illumination or precision tracking where small angular errors compound into meaningful miss distance at range.
