How to Use Amped Replay’s Magnification and Annotation Tools for Forensic Video Analysis

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Dear friends, welcome to this week’s tip! As much as our users love their job, we know they’re often frustrated because they’ve been given some video frames and asked to extract the impossible from them. You’re not alone, it happens everywhere, also thanks to the non-sense enhancement scenes advertised by movies and TV series. The bad news: this tip is not about solving the impossible. So, if you’ve ever needed to highlight crucial details in a forensic video, you know how challenging it can be. That’s where Amped Replay’s magnification and annotation tools come in. These features allow investigators to zoom in on critical areas without distorting the image and add clear annotations to support their findings.

Now the good news: it’s about what you can do with Amped Replay to turn your “NO WAY, SIR!” into something clear and credible, that even the most tech-agnostic person can get. Keep reading to find out!

So, this is the scenario we’re dealing with today: your local police unit is looking for a missing person. Your boss forwards you this image received from a citizen, asking: “I need you NOW. We may have a picture of the missing guy! I’m sending it to you, it’s a good resolution! Tell me if we can get a positive ID.” As you move to your workstation equipped with Amped Replay, you already feel it won’t be as easy as it seemed to your boss. When the file arrives (a 4.5MB jpeg), you fire up Replay and load it. Yes, the image is a “good resolution one” (2560 x 1920). But… where’s the guy? Oh, he’s there!

arrow pointing at a person in amped replay

Just scrolling with the mouse (or clicking “CTRL” and “+” on the keyboard) we can get a better assessment of the situation. This is where Amped Replay’s magnification and annotation features make a difference. These allow investigators to zoom in and highlight crucial details without altering the image.

Notice that the Amped Replay viewer will not interpolate pixels (as opposed to common image viewers). Replay will simply “enlarge pixels” so that you can actually look at the available information.

pixelated image of a person in amped replay

The subject’s face is 4-5 pixels high, and mostly facing the other direction! What do you do now? Calling the boss saying “Are you crazy?” would be proper but not appropriate. We need to find a better way to calmly explain that no software can ever achieve what they’ve asked. If we just send the screenshot above, it’s not even clear that we’re dealing with the same image. This is a case where Amped Replay’s annotation tools will come in handy.

Using the Magnification and Annotation Features in Amped Replay

Using the Magnify tool, with the zoom slider boosted at its maximum value, we can simultaneously keep showing most of the image while exalting the subject at its original resolution.

magnify tool in amped replay

This is indeed the reason why Amped developers decided not to use interpolation when zooming with the Magnify tool. An annotation tool’s purpose is not to enhance poor-resolution regions (you have the Resize tool under the Enhance tab). No, the Magnify tool is made to show what you’ve got after your whole processing. In our case, there was no need for any enhancement tool. That’s because no filter could (nor should) invent information not in the original frame.

Still using Amped Replay’s annotation tool, we can add additional context to help our boss understand that face identification isn’t possible with these pixels.

magnification and annotation

We borrowed the standard face height from this nice sheet. We could complement this annotated image by saying that Axis (one of the main IP surveillance camera manufacturers) recommends a minimum of 40 pixels across the face to identify a person (which roughly means 2.5 pixel/cm resolution, which is more than 10 times the resolution we have in our image).

Conclusion

Will all of this make your boss happy? Apparently not, if you think they wanted an enhanced face. But if you think twice, they wanted more than that. They wanted information they could trust to take further action. This is where Amped Replay’s magnification and annotation tools prove invaluable, allowing you to present clear, unaltered visual evidence. If the needed information is blatantly absent, the best answer you can give is: “It just can’t be done with Amped Replay, nor with any other tool on Earth (not even Amped FIVE!).” Instead, if you’re still unsure whether something could be done with more powerful tools, forward the case to your reference unit equipped with Amped FIVE. In both cases, as long as you’re able to justify your findings using Amped Replay’s annotation and magnification features, your boss should be happy with the work you did.

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