Camera Match Overlay?

Following up on yesterday's post, we were dealing with an interesting issue that concerns the mixed methods approach of inserting a single frame taken from CCTV footage (previous event) into a laser-generated point cloud scan (current event) processed by [ fill in the blank ] software. Let's continue ...

Images from The Matrix. (c) 1999 Warner Bros.

One of my favourite scenes from the 1999 hit movie, The Matrix, gives us a clue to how this conundrum will be addressed in the near term.

Spoon boy: Do not try and bend the spoon. That's impossible. Instead... only try to realize the truth.

Neo: What truth?

Spoon boy: There is no spoon.

Neo: There is no spoon?

Spoon boy: Then you'll see, that it is not the spoon that bends, it is only yourself.

Over in southeast Washington, the folks behind iNPUT-ACE have come up with a novel approach, essentially telling us that there is no spoon to bend.

I've been curious about the Camera Match Overlay feature in ACE for a while now. I was aware of what folks were doing with point clouds and have seen some of the demonstratives in YouTube videos of Grant and Andrew's testimonial experiences. As usual, the Fredericks family has been quite open with what they're on about. It's good for business after all.

So why does the new overlay tool remind me of the spoon?

The Camera Match Overlay does not bring a point cloud into ACE. The Camera Match Overlay does not integrate with a scanner's software to insert CCTV frames or video. What the Camera Match Overlay does is quite novel, and entirely sidesteps the issue of a mixed-methods approach.

You see, when using the Camera Match Overlay tool in iNPUT-ACE, you're working in ACE to "toggle the opacity" of ACE (where the CCTV footage exists) whilst you reposition ACE's UI, and thus the footage, as an overlay to your preferred scanning tool (where the point cloud exists). This is a manual process that requires that you match the "zoom level" of the scene in your scanning tool to that of the CCTV frame(s), as well as manually positioning the ACE overlay. But, once "eyeballed," you can lock in this positioning in ACE's UI. As a technical aside, I would imagine that your GPU and monitor's performance will be critical, as well as your eyesight, in properly "eyeballing" the alignment.

Thus, there is no spoon. ACE serves up the CCTV footage (projects) with a faded opacity so that you can work in your 3D tool.  I know that the Fredericks' use the legacy tool, SceneVision-3D to work with point cloud data. But, I'm sure that the overlay will work with any vendors' tools once properly set-up.

Now, on the science side, it seems that ACE can help you make some calculations of error with the assistance of your scanning tool, producing a report to address margin of error. And ... as you should know, margin of error is directly related to your region of interest. The farther away from the camera your object of interest is, the larger the error will be ... as well as your nominal resolution. It seems that ACE reports the error in a few ways - with the final number being a function of "scanner accuracy," "calibration accuracy," and "resolution accuracy." The scanner accuracy comes from your scanner. The calibration accuracy seems to come from the overlay (not sure how it handles potential mis-alignment). The resolution accuracy is really just nominal resolution for the region of interest.

For close up work, it seems that error won't be much of a problem unless, for example, your subject is within the normal distribution for human heights. But at longer distances, the error can be in the ~2'-4' range; not much if you're trying to measure a skid mark but too big if you're trying to measure a person's height. Back to that manual process of aligning views, with a high nominal resolution, being off by just a few pixels will significantly affect your error - so again, pay close attention to that step in your process.

One problem you'll have to overcome is that most scanning software lack any sort of video output to save out your pretty demonstratives. You won't be able to export your demonstratives out of ACE either -  remember, it's just overlaying the UI. But, if you've got an Omnivore, or Camtasia, you've got all that you need. Remember, these are demonstratives. You're working in the world of the abductive - taking your best shot to demonstrate your theory of the case in which you are working.

Now for the disclaimers.

Don't try this without training and experience in every single piece of your puzzle. Given that these demonstratives will be used to illustrate your opinion, please get certified as an analyst. Make sure that you understand the foundation science and rules of this discipline. Get to ACE's training. Make sure that training includes an appropriate amount of time on the Camera Match Overlay tool. Make sure that the tool works with your chosen scanner software. Make sure you're trained and experienced on that tool as well. Make sure that you have training in Forensic Photographic Comparison as well as Forensic Photogrammetry. If you're using Camtasia, get trained and certified there as well (I did). If you're using an Omnivore, get trained. Why? Because in the world of demonstratives, you're demonstrating your theories, opinions, and conclusions. It's your opinion, thus it becomes all about you and the foundations of your work.

Have a good day, my friends.