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Perspective Stabilization and Perspective Super Resolution

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Perspective stabilization and perspective super resolution

In our latest update to Amped FIVE, you’ll find two new filters that work together to stabilize and enhance video with an object that has some change in perspective as it moves: Perspective Stabilization and Perspective Super Resolution.

Let’s take a look at how they work!

You can also watch the two filters in action in our latest video found here:

Perspective Stabilization

Screenshot of the Filters panel in Amped FIVE software showing a list of filter categories and options. The “Stabilization” category is selected, revealing four stabilization tools: Local Stabilization, Global Stabilization, Perspective Stabilization (highlighted), and Perspective Registration. A search bar labeled “Quick Search: select and press enter” is visible at the top.

Perspective Stabilization, found under the Stabilization filter category, is capable of stabilizing a planar object that has some sort of perspective distortion.

CCTV footage dated 2018-08-29 at 10:02:32 from camera CAM01 showing a gray Volkswagen vehicle with license plate reversing out of a parking space in an outdoor lot, with other parked cars visible and trees in the background.

So, we want the license plate from the vehicle above. However, the way the car moves means that there is a change in perspective of the license plate as it travels. No problem! With Perspective Stabilization, rather than selecting just the area immediately around the license plate, I select more of the rear of the vehicle, in this case including the lights and logo.

Zoomed-in CCTV image of a gray Volkswagen vehicle reversing in a parking lot, with a red bounding box highlighting the rear license plate; timestamp reads 2018-08-29 10:02:32, and surrounding vehicles and trees are visible in the background.

Once we have selected the area, the points will be automatically added to the filter parameters. We can now choose Motion Type, Tracking Method and Interpolation.

Screenshot of the "Perspective Stabilization" filter settings in Amped FIVE, showing four coordinate points for selection, with motion type set to "Perspective", tracking method as "Static Tracking", and interpolation as "Bicubic"; includes a tip for optimal planar surface selection to improve video stabilization results.

Motion Type refers to the type of motion the filter needs to track. More complex motions can give more accurate result. However, do take longer to compute and may be more sensitive to motion blur or video noise.

Dropdown menu in Amped FIVE software under "Motion Type" settings showing four options for video stabilization: Translation, Rotation, Rotation and Zoom, and Perspective; "Perspective" is currently selected.

Translation is quite similar to the Local Stabilization filter, however provides sub-pixel accuracy. Rotation is suitable for small rotation movement types, whilst Rotation and Zoom supports large rotation angles. It could be helpful when stabilizing a static object captured by a hand-held camera.

Perspective is the most general setting, and is what we are using here.

Three Tracking Options

You can choose from three different types of tracking to suit your project:

  • Static Tracking compares the current frame with the reference frame where the selection has been set: it offers the most precise stabilization, but may fail if the shape of the region changes too much.
  • Dynamic Tracking compares each frame with the previous one, which is able to stabilize larger deformations but the position in the stabilized video may drift slightly over time. In practice, it is more robust (works in most situations), but less precise for later frames.
  • Hybrid Tracking is available only for Rotation and Zoom and Perspective motion types but it compares the current frame with both the first and the previous, allowing for the tracking of large deformations but keeping the object steady. It is the method that usually provides the best compromise between robustness and precision.

Output

Under the Output tab, you can select what type of output you would like from the filter.

Screenshot of the "Output" tab in Amped FIVE's Perspective Stabilization filter settings, showing the "Output Mode" dropdown menu with three selectable options: "Stabilized Video," "Prepare for Perspective Super Resolution" (highlighted), and "Selection Overlay." The interface includes a grid layout and a button labeled "Prepare for Perspective Super Resolution."

There are three options here:

  • Stabilize Video will produce a stabilized video, should you need only to stabilize or there are more steps in your workflow or you are thinking of using something like Frame Averaging to reduce noise and perform integration.
  • Selection Overlay will draw the warped selection onto the input video.
  • Prepare for Super Resolution will leave the video unaltered but adds the transformation matrix to each frame, should you want to use Perspective Super Resolution later on in a workflow.

The ability to simply stabilize the video means you can compare the results from both Frame Averaging and Super Resolution, giving you more options and increasing the chances of a successful enhancement.

Clicking the “Prepare for Perspective Super Resolution” button at the bottom of the Output tab will automatically add the Perspective Super Resolution filter.

Perspective Super Resolution

Screenshot of the "History" panel in Amped FIVE software, displaying a filter chain consisting of "Video Loader," "Perspective Stabilization," and "Perspective Super Resolution" filters applied in sequence.

Perspective Super Resolution works alongside Perspective Stabilization to apply the Super Resolution effect to an object that has been the subject of some perspective disturbance. It is automatically loaded into the Chain History after clicking “Prepare for Super Resolution”.

Screenshot of the "Perspective Super Resolution" filter settings in Amped FIVE software, showing adjustable options for Zoom (set to 3), Output Size (set to "Keep Original"), and Sharpening (set to 3), used for enhancing video resolution and clarity.

Increasing the Zoom level will further apply the Super Resolution effect. There are two options under Output Size, Resize Frame or Keep Original, depending on the desired output frame size, as well as the ability to increase the level of detail using Sharpening.

Close-up of a gray Volkswagen vehicle captured from the rear in a parking lot, showing the license plate number "EX764PZ" clearly. The car is angled slightly to the right, and the image appears to be taken from a surveillance camera.

These two filters, either working together or used separately, now give you more workflow choices for your case. It means you have a greater chance of success when performing enhancements!

Don’t Delay – Update Today

These filters are only available in our latest update so make sure to update today!

If you have an active support plan you can update straight away by going into the menu “Help” > “Check for Updates Online” within Amped FIVE. If you need to renew your SMS plan, please contact us or one of our authorized partners.


 Lucy Carey-Shields

Lucy Carey-Shields is a forensic analyst with Amped Software, primarily providing technical support to Amped users. Her career started as a front-line officer with UK law enforcement in 2010 where she spent six years before graduating from her degree in computer forensics in 2014, when she shortly afterwards started work in a digital forensics unit alongside her front-line duties. She now has over ten years of law enforcement and digital forensics experience in both video, mobile and computer forensics cases.

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