约翰逊县如何通过激光扫描来重现犯罪现场

Author:Renata BarradasGutiérrez

If a picture says thousand words, imagine how 3D laser scanning augments perception to find truth in a crime scene investigation. Johnson's County Sheriff Office in Kansas, USA, has been using Leica Geosystems laser scanning technology for eight years. Reporter caught up with Andrea Reed from Johnson's County Sheriff Office criminalistics laboratory during HxGN LIVE 2018 to learn how laser scanning solutions from Leica Geosystems is bringing people back to any crime scene.

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Capturing trusting evidence is critical. Could you please explain how laser scanning is used by Johnson's County to document and reconstruct scenes for public safety?

Laser scanning allows us torecreate crime scenes, so people step back into the crime scene in a digital reality. We use theLeica ScanStationto determine the spatial relationships, because crime scene photographs don't allow us to reallyshow the spatial relationship between items and evidence。

In our agency, in Johnson County, Kansas, USA, we use laser scanning to document major crime scenes – whether it's a homicide, a suspicious death, officer-involved shootings, or any shooting scenes where we can do some reconstruction or use the ballistics rods.

Our crime scene investigators are proficient in using Leica ScanStations andLeica Cyclone 3D点云处理办公软件。我们n create different outputs, such as snapshots in Cyclone software and show different types of pictures from the scanned data. We can also createTruViewlinks, which allow people to step into the crime scene in a virtual way.

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How does Leica Geosystems 3D laser scanners and software provide a forensic tool over traditional methods of crime scene mapping?

Laser scanning takes out the human factor of any type of error。3D laser scanning goes above and beyond tape measures, protractors, and laser measuring devices and it's much more accurate andmore precise than traditional methodsof taking measurements by hand. And then when you go into what we can do with the data it far exceeds any other methods.

I always tell people, “You only have one time, one chance, to document and collect and preserve evidence at a crime scene. So why in the world would you not want to do it to the highest level of accuracy that you can?” And what better way than with a Leica Geosystems 3D laser scanner?

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Leica Geosystems软件如何支持您的需求？

Traditional methods only permit us to create 2D diagrams. With Cyclone you cancreate 3D models with different perspectives and floor plan layouts。和TruView Localpeople can actually step into a crime scene. TruView allow us toshare point cloud data with an internet link to see a virtual and photo-realistic view of the sites。There was a case where we used a fly-through that showed the defendant had the opportunity to exit through a doorway but instead continued ahead to commit a homicide. We were able to show through scan data the path this person took, passing by an exit.

During the conference I've heard about the Leica Geosystems Incident Mapping Software,Leica Map360,这I think would be extremely advantageous to us back at our laboratory and in our crime scene unit. I'm really excited to go back, and talk to my boss, and explain “this is what I think we should be using, here are the advantages to it, and this is how we can use it”, and just really step up our game.

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What were the features in Map360 that caught your attention?

Map360 seemed like an射击事件重建的更轻松的工作流程我真的很喜欢你怎么能diagram out scenes by using the point cloudsyou collected and captured. The desktop software allows users tocreate court ready documents并使犯罪现场的视觉表现更加视觉表现。

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Could you provide an example on how data captured with laser scanning helped Johnson's County Sheriff Office to solve a case?

There is one case where we used the scan data beyond a floor plan and a layout of the scene. The District Attorney for the case said that the shooting reconstruction was key to the entire case. The defendant was stating they had acted in self-defence, however, using Cyclone we were able to show the different perspectives and use the trajectory cones, providing a morein depth look at the crime scene。它使陪审团可以根据我们能够通过旋风展示的东西来了解该人的位置，最终抹黑自卫主张。

The output of该软件可以帮助我们进行法庭展览。我们经常在大型海报板上有平面图布局，以解释我们发现了哪种证据以及在哪里。我们可以在3D激光扫描仪输出布局中显示，其中一切都在犯罪现场。这确实有助于将陪审团定为我们所谈论的内容以及我们在谈论的犯罪现场的何处。

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What have you learned at HxGN LIVE that will improve your work?

我参加了一次会议Leica Cyclone REGISTER 360。We didn't realise that we had it at our disposal and now that I know that we have REGISTER 360 as part of our licensing, we can provide a more useful workflow and additional output.

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What is the major take away for you at HxGN LIVE 2018?

Knowing the technology is there and it is going to keep changing, making things better and improving our workflow.